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Full text of "An ecological characterization of Coastal Maine (north and east of Cape Elizabeth)"

Biological Services Program 



FWS/OBS-80/29 
October 1980 



AN ECOLOGICAL 
CHARACTERIZATION 
OF COASTAL MAINE 




Fish and Wildlife Service 



U.S. Department of the Interior 



Volume Three 



Hi 



■O 



im 



FWS/OBS-80/29 
October 1980 



AN ECOLOGICAL CHARACTERIZATION OF COASTAL MAINE 
(North and East of Cape Elizabeth) 



Stewart I. Fefer and Patricia A. Schettig 
Principal Investigators 



Volume 3 



The principal investigators wish to 
gratefully acknowledge the excellent 
guidance provided by the project's 
steering committee; the U.S. Fish and 
Wildlife Service National Coastal 
Ecosystems Team; and the contributions 
made by the many authors and 
reviewers . 

Special recognition is warranted for 
John Parsons, for his invaluable tech- 
nical editorial assistance, and for 
Beth Surgens, Cheryl Klink, and Renata 
Cirri for their tireless attention to 
production details throughout the 
study period. 



WHO/ 

DOCUMENT 

COLLECTION 



The study was conducted as part of the Federal Interagency Energy/Environment 
Research and Development Program of the Office of Research and Development, 
U.S. Environmental Protection Agency; the U.S. Army Corps of Engineers Tidal 
Power Study; and the U.S. Fish and Wildlife Service National Coastal Ecosystems 
Project. 



Department of the Interior 
U.S. Fish and Wildlife Service 

Northeast Region 
One Gateway Center, Suite 700 
Newton Corner, Massachusetts 02158 



TABLE OF CONTENTS 



Volume 1 



Page 



LIST OF FIGURES (for all volumes) x 

LIST OF TABLES (for all volumes) xlv 

ACKNOWLEDGMENTS 



xx 



CHAPTER 1 
CHAPTER 2 
CHAPTER 3 



ORGANIZATION OF THE CHARACTERIZATION 

THE COASTAL MAINE ECOSYSTEM 

HUMAN IMPACTS ON THE ECOSYSTEM . . . 



1-1 
2-1 
3-1 



Volume 2 



CHAPTER 4 
CHAPTER 5 
CHAPTER 6 
CHAPTER 7 
CHAPTER 8 
CHAPTER 9 
CHAPTER 10 



THE MARINE SYSTEM 

THE ESTUARINE SYSTEM 

THE RIVERINE SYSTEM 

THE LACUSTRINE SYSTEM 

THE PALUS TRINE SYSTEM 

THE FOREST SYSTEM 

AGRICULTURAL AND DEVELOPED LANDS 



4-1 
5-1 
6-1 
7-1 
8-1 
9-1 
10-1 



Volume 3 



LIST OF FIGURES 
LIST OF TABLES 
ACKNOWLEDGMENTS 



CHAPTER 11: FISHES 

DATA SOURCES 

THE MAJOR FISHES OF COASTAL MAINE 

DISTRIBUTION 

Seasonal Occurrence and Migration 

Anadromous and Catadromous Fish Distribution 
REPRODUCTION 

Fecundity , 

Spawning Habits , 

EARLY LIFE HISTORY , 

larval Populations 

FOOD AND FEEDING HABITS , 

FACTORS AFFECTING DISTRIBUTION AND ABUNDANCE . , 

Water Temperature , 

Salinity . 

Competition 

Predation and Harvest 

Diseases and Parasites , 

Dams and Obstructions 

Water Quality 

Turbidity 

Dissolved oxygen 

Pathogens 



-1 

-2 

-2 

-6 

-14 

-14 

-15 

-15 

-16 

-20 

-20 

-23 

-28 

-28 

-29 

-29 

-31 

-31 

-31 

-32 

-33 

-33 

-33 



li 



Chapter 11 (Continued) 

Toxicants 11-33 

Radioactivity 11-35 

Nutrients 11-35 

pH 11-35 

IMPORTANCE TO HUMANITY 11-36 

MANAGEMENT 11-44 

RESEARCH NEEDS 11-46 

CASE STUDY: SHORTNOSE STURGEON 11-48 

Range and Distribution 11-48 

Reproduction and Growth 11-48 

Food and Feeding Habits 11-49 

Predation 11-50 

Importance to Humanity 11-50 

REFERENCES 11-51 

CHAPTER 12: COMMERCIALLY IMPORTANT INVERTEBRATES 12-1 

SOFT- SHELL CLAM ( Mya arenaria ) 12-2 

Distribution and Abundance 12-2 

Life History 12-2 

Habitat Preferences 12-3 

Factors of Abundance 12-3 

Human Impacts 12-4 

Importance to Humanity 12-4 

Management 12-5 

BLUE MUSSEL ( Mytilus edulis ) 12-7 

Distribution and Abundance 12-7 

Life History 12-7 

Habitat Preferences 12-8 

Factors of Abundance 12-8 

Human Impacts 12-9 

Importance to Humanity 12-9 

Management 12-9 

SEA SCALLOP ( Placopecten magellanicus ) 12-10 

Distribution and Abundance 12-10 

Life History 12-11 

Habitat Preferences 12-11 

Factors of Abundance 12-12 

Human Impacts 12-12 

Importance to Humanity 12-14 

Management 12-14 

AMERICAN LOBSTER ( Homarus americanus ) 12-14 

Distribution and Abundance 12-14 

Life History 12-15 

Habitat Preferences 12-15 

Factors of Abundance 12-16 

Human Impacts 12-16 

Importance to Humanity 12-17 

Management 12-17 

Rock Crab (Cancer irroratus ) and JONAH CRAB (Cancer borealis ) . . 12-18 

Distribution and Abundance 12-18 

Life History 12-19 

iii 



Chapter 12 CContinued) 

Habitat Preferences 12-19 

Factors of Abundance 12-19 

Human Impacts 12-20 

Importance to Humanity 12-20 

Management 12-20 

NORTHERN SHRIMP ( Pandalus borealis ) 12-20 

Distribution and Abundance 12-20 

Life History 12-22 

Habitat Preferences 12-22 

Factors of Abundance 12-22 

Human Impacts 12-23 

Importance to Humanity 12-23 

Management 12-23 

MARINE WORMS 12-24 

Bloodworm (Glycera dibranchiata) 12-24 

Distribution and abundance 12-24 

Life history 12-25 

Habitat preferences 12-26 

Factors of abundance 12-26 

Sand worm ( Nereis virens ) 12-26 

Distribution and abundance 12-26 

Life history 12-27 

Habitat preferences 12-27 

Factors of abundance 12-28 

Human Impacts 12-28 

Importance to Humanity 12-28 

Management 12-30 

RED TIDES 12-30 

Life History 12-30 

Factors of Abundance 12-31 

Importance to Humanity 12-31 

Management 12-32 

RESEARCH NEEDS 12-32 

REFERENCES 12-34 

CHAPTER 13: MARINE MAMMALS 13-1 

DISTRIBUTION AND ABUNDANCE 13-2 

Cetaceans 13-6 

Pinnipeds 13-8 

REPRODUCTION 13-11 

FEEDING HABITS 13-11 

FACTORS AFFECTING DISTRIBUTION AND ABUNDANCE 13-14 

Food Availability 13-14 

Disease and Parasites 13-14 

Predation 13-15 

Pollutants 13-15 

Organochlorines 13-16 

Heavy metals 13-17 

Petroleum 13-21 

Habitat Disturbances 13-21 

iv 



Chapter 13 (.Continued) 

IMPORTANCE TO HUMANITY 13-23 

History of Whaling ..... 13-23 

MANAGEMENT 13-27 

RESEARCH PRIORITIES 13-29 

REFERENCES 13-30 

CHAPTER 14 : WATERBIRDS 14-1 

DATA SOURCES 14-2 

WATERBIRD GROUPS 14-2 

SEABIRDS 14-3 

Historical Trends 14-9 

Present Status of Seabirds 14-10 

Breeding species 14-10 

Nonbreeding summer residents 14-15 

Winter residents 14-15 

Migratory residents 14-16 

Reproduction 14-17 

Feeding Habits 14-18 

Natural Factors Affecting Abundance 14-21 

Predation 14-21 

Food supply 14-21 

Nesting habits 14-23 

SHOREBIRDS 14-24 

Historical Trends 14-29 

Present Status of Shorebirds 14-29 

Breeding summer residents 14-29 

Winter residents 14-30 

Migratory residents 14-30 

Role of Shorebirds in the Ecosystem 14-35 

WADING BIRDS 14-35 

Historical Perspective 14-35 

Present Status of Wading Birds 14-37 

Breeding birds 14-37 

Feeding Habits 14-38 

HUMAN IMPACTS ON WATERBIRDS 14-41 

Habitat Loss 14-41 

Tidal Power 14-41 

Environmental Contamination 14-42 

Oil 14-42 

Toxic chemicals 14-43 

Heavy metals 14-44 

Plastic and other artifacts 14-44 

Other Disturbance 14-44 

MANAGEMENT 14-45 

RESEARCH NEEDS 14-45 

REFERENCES 14-47 

CHAPTER 15: WATERFOWL 15-1 

WATERFOWL GROUPS 15-7 

Resident Waterfowl 15-8 

Breeding Species 15-9 



Chapter 15 (.Continued) 

Wintering Species 15-10 

Migrants 15-10 

WATERFOWL ASSESSMENT 15-10 

Breeding Populations 15-14 

Migration and Staging Areas 15-28 

Waterfowl Habitat 15-31 

Region 1 15-31 

Region 2 15-32 

Region 3 15-32 

Region 4 15-32 

Region 5 15-33 

Region 6 15-33 

Ecological Interactions 15-34 

FACTORS AFFECTING DISTRIBUTION AND ABUNDANCE 15-35 

Natural Factors 15-35 

Human Factors 15-37 

POTENTIAL IMPACTS OF HUMAN ACTIVITIES 15-38 

Forestry Practices 15-38 

Industrial or Urban Development 15-38 

Oil Pollution 15-38 

Tidal Power Development 15-38 

Island Development 15-38 

Non-consumptive Use 15-40 

MANAGEMENT 15-40 

DATA GAPS 15-42 

CASE STUDY: THE BLACK DUCK 15-43 

REFERENCES 15-47 

CHAPTER 16: TERRESTRIAL BIRDS 16-1 

DATA SOURCES 16-2 

SEASONAL OCCURRENCE 16-2 

HABITAT PREFERENCE 16-11 

Outer Islands and Headlands 16-11 

Shores of Lakes, Rivers, Ponds, and Streams 16-11 

Palustrine 16-11 

Open Fields and Wet Meadows 16-12 

Old Fields, Edges, and Successional Habitats 16-12 

Forests 16-12 

Coniferous forests 16-18 

Deciduous forests 16-18 

Mixed forests 16-19 

Rural and Developed Land 16-19 

ABUNDANCE OF TERRESTRIAL BIRDS 16-19 

Breeding Bird Survey 16-20 

Christmas Bird Counts 16-23 

ASPECTS OF MIGRATION 16-24 

REPRODUCTION 16-25 

Time of Nesting 16-25 

Nest Type and Location 16-25 

Nesting Cycle 16-27 

FACTORS AFFECTING DISTRIBUTION AND ABUNDANCE 16-27 

Human Related Factors Affecting Abundance 16-28 

vi 



Chapter 16 (Continued) 

Habitat alteration 16-28 

Chemical contaminants 16-29 

Accidental mortality 16-30 

Hunting mortality 16-31 

Other factors 16-31 

IMPORTANCE TO HUMANITY 16-31 

MANAGEMENT RECOMMENDATIONS 16-32 

CASE STUDY: THE BALD EAGLE 16-33 

Introduction 16-33 

Status 16-33 

Taxonomy 16-33 

Historical distribution and abundance 16-33 

Breeding population 16-35 

Wintering population 16-38 

Migration 16-41 

Habitat 16-42 

Characteristics of eagle habitat 16-42 

Food Habits 16-42 

Reproduction 16-43 

Natural Factors of Abundance 16-43 

Human-caused Factors of Abundance 16-44 

Socioeconomic Importance 16-47 

Management 16-47 

Protection 16-47 

Research Needs 16-49 

REFERENCES 16-51 

CHAPTER 17: TERRESTRIAL MAMMALS 17-1 

DATA SOURCES 17-4 

DISTRIBUTION AND ABUNDANCE 17-5 

Regional Distribution 17-5 

Habitat Preferences 17-7 

ROLE OF MAMMALS IN THE ECOSYSTEM 17-12 

FACTORS OF ABUNDANCE 17-15 

Natural Factors Affecting Abundance 17-16 

Human Factors 17-21 

Direct mortality 17-23 

Environmental contaminants 17-28 

IMPORTANCE TO HUMANITY 17-28 

MANAGEMENT 17-31 

REFERENCES 17-34 

CHAPTER 18: REPTILES AND AMPHIBIANS 18-1 

DISTRIBUTION AND ABUNDANCE 18-3 

HABITAT PREFERENCES 18-3 

BREEDING HABITS 18-4 

FOOD HABITS 18-6 

FACTORS OF ABUNDANCE 18-7 

Natural Factors 18-7 

Human Factors 18-7 

Agriculture . 18-7 

Pollution 18-7 

vii 



Chapter 18 (Continued) 

Impoundments 18-8 

Land, water, and forest disturbances 18-8 

IMPORTANCE TO HUMANITY 18-9 

MANAGEMENT 18-9 

RESEARCH NEEDS 18-9 

REFERENCES 18-10 

CHAPTER 19: COMMERCIALLY IMPORTANT FOREST TYPES 19-1 

SPRUCE-FIR TYPE 19-4 

Habitat Conditions 19-4 

Reproduction and Early Growth 19-8 

Management Methods 19-8 

Management of uneven-aged stands 19-10 

Management of even-aged stands 19-11 

Natural Enemies 19-14 

MAPLE-BEECH-BIRCH TYPE 19-14 

Habitat Conditions 19-14 

Reproduction and Growth 19-15 

Management Methods 19-15 

Management of uneven-aged stands 19-15 

Management of even-aged stands 19-16 

Natural Enemies 19-17 

WHITE PINE-HEMLOCK -HARDWOOD TYPE 19-17 

Habitat Conditions 19-17 

Reproduction and Growth 19-18 

Management Practices 19-18 

FUELWOOD 19-22 

Species Used 19-22 

Silvicultural Methods 19-22 

CHRISTMAS TREE PRODUCTION 19-25 

RESEARCH NEEDS 19-25 

REFERENCES 19-27 

CHAPTER 20: ENDANGERED, THREATENED AND RARE PLANTS 20-1 

DATA SOURCES 20-10 

ENDANGERED AND THREATENED PLANTS 20-10 

The Estuary Monkey Flower 20-10 

Ram's-Head Lady 's-Slipper 20-11 

Auricled Twayblade 20-12 

Pale Green Orchis 20-12 

Ginseng 20-13 

Orono Sedge 20-13 

Long's Bitter Cress 20-13 

RARE PLANTS 20-15 

UNIQUE OR RESTRICTED PLANT COMMUNITIES 20-15 

Coastal Plateau Bogs and Shrub Slope Peatlands 20-17 

Outer Headlands and Outer Island Communities 20-17 

Freshwater Intertidal Emergent Wetlands 20-18 

Brackish Intertidal Emergent Wetlands 20-18 

Atlantic White Cedar Forested Wetlands 20-18 

FACTORS OF ABUNDANCE 20-19 

viii 



Chapter 20 CContinued) 

PROTECTION OF ENDANGERED, THREATENED, AND RARE PLANT SPECIES . . . 20-20 

MANAGEMENT 20-21 

RESEARCH NEEDS 20-21 

REFERENCES 20-23 

Volume 4 
APPENDICES 

Volume 5 
DATA SOURCE APPENDIX 

Volume 6 
ATLAS 



IX 



LIST OF FIGURES 

11-1 Diversity of fishes in Maine systems 11-13 

11-2 Seasonal abundance of fish larvae in the upper 
estuarine, lower estuarine, and offishore areas 
of the Boothbay region (Chenoweth 1973) 11-22 

11-3 Feeding habits and food resources of fishes 11-22 

11-4 The percentage similarity between the diets of ten species 
of gadiform fishes in the Gulf of Maine (numerical 
values given in the left half of the matrix, ranges 
in the right half), Langton and Bowman (1978) 11-27 

11-5 A food partition plot indicating the major prey of each 
of 15 predacious fishes of the Gulf of Maine. Major 
prey is defined as any prey category comprising £. 10% by 
weight of the diet for any one predator (Langton 
and Bowman 1978) 11-27 

12-1 Pound (x 10 5 , solid line) and dollar values (x 10 5 , 

dotted line) of clam landings for coastal Maine from 

1968 to 1978. (December, 1978, data are estimated.) .... 12-6 

12-2 Pound (x ICh , solid line) and dollar values (x 10 , 

dotted line) of mussel landings for coastal Maine from 

1968 to 1978. (December, 1978, data are estimated.) .... 12-6 

12-3 Pounds (x 10^ , solid line) and dollar values (x 10^ , 
dotted line) of scallops landed in coastal Maine from 
1968 to 1978. (December, 1978, data are estimated.) .... 12-13 

12-4 Pounds (x 10 6 , solid line) and dollar value (x 10 6 , 

dotted line) of lobsters landed in coastal Maine from 

1968 to 1978. (December, 1978, data are estimated.) .... 12-13 

12-5 Correlation of lobster catch (thousands of metric tons) 
and number of traps fished (hundred thousands) in 
Maine for 1897 to 1976 (Maine Department 
of Marine Resources 1977) 12-18 

12-6 Pounds (x 10 5 , solid line) and dollar values (x 10 4 , 

dotted line) of rock crab landed in coastal Maine from 

1968 to 1978. (December, 1978, data are estimated.) .... 12-21 

12-7 Pounds (x 10$ , solid line) and dolalr values (x 10 5 , 
dotted line) of shrimp landed in coastal Maine from 
1968 to 1978. (December, 1978, data are estimated.) .... 12-21 



12-8 Pounds (x 1Q \ solid line) and dollar values (x 10 h , 

dotted line) of hloodworms landed in coastal Maine from 

1968 to 1978. (December, 1978, data are estimated.) .... 12-29 

12-9 Pounds (x lO 1 * , solid line) and dollar values (x 10 1 * , 

dotted line) of sandworms landed in coastal Maine from 

1968 to 1978. (December, 1978, data are estimated.) .... 12-29 

14-1 Trends in populations of nesting herring gull, eider, 
black guillemot, and puffin in Maine since 1900 
(adapted from Drury 1973 and Korschgen 1979) 14-11 

14-2 Trends in populations of nesting great black-backed gull, 
double-crested cormorant, arctic and common tern, and 
razorbill auk in Maine since 1900 (adapted from 
Drury 1973 and Korschgen 1979) 14-11 

14-3 Timing of egg laying, incubation, and breeding of 

seabirds in coastal Maine (crosshatch represents overlap) . . 14-18 

14-4 Relative abundance and migration of the migratory 

shorebirds of coastal Maine from April through November. 

Band width reflects relative abundance for individual 

species only (adapted from Morrison 1976a, McNeil 

and Burton 1973, Palmer 1949, and Gobeil 1963) 14-31 

15-1 The wildlife management units (large numbers, heavy 
lines) and the characterization regions (small 
numbers, light lines) in Maine (Maine Department 
of Inland Fisheries and Wildlife) 15-11 

15-2 Maine Department of Inland Fisheries and Wildlife 
winter waterfowl inventory units (large numbers, 
dotted lines) and characterization regions (small 
numbers, light lines) in Maine (Maine Department 
of Inland Fisheries and Wildlife) 15-12 

15-3 Boundries of coastal counties and characterization 
regions (Maine Department of Inland Fisheries 
and Wildlife) 15-13 

15-4 Estimated numbers (x 100) of wintering black ducks 
among the winter waterfowl inventory units of 
coastal Maine for each year, 1952 to 1974 15-17 

15-5 Estimated number (x 100) of wintering goldeneyes 
among the winter waterfowl inventory units of 
coastal Maine for each year, 1952 to 1974 15-18 

15-6 Estimated number of wintering buffleheads among the 
winter waterfowl inventory units of coastal 
Maine for each year, 1952 to 1974 15-19 



XI 



15-7 Estimated numbers (x 100) of wintering scaups among 
the winter waterfowl inventory units of 
coastal Maine for each year, 195.2 to 1974 15-20 

15-8 Estimated number (x 100) of wintering eiders among 
the winter waterfowl inventory units of 
coastal Maine for each year, 1952 to 1974 15-21 

15-9 Estimated number (x 100) of wintering scoters 
among the winter waterfowl inventory units of 
coastal Maine for each year, 1952 to 1974 15-22 

15-10 Estimated numbers of wintering old squaws among the 
winter waterfowl inventory units of coastal 
Maine for each year, 1958 to 1974 15-23 

15-11 Estimated numbers (x 1000) of wintering ducks for 

coastal Maine for each year, 1952 to 1974 15-24 

15-12 Phenophase Diagram of the Monthly Activities of 

the Male and Female Black Ducks in Maine 15-45 

16-1 Urban, suburban, agricultural, successional, and 
edge habitats and their associated bird species. 
Horizontal lines indicate the range of habitats preferred . . 16-13 

16-2 Generalized plant succession (from left to right) 
and associated bird species in a spruce-fir forest 
in Maine. Horizontal line indicate range of 
preferred habitat 16-15 

16-3 Generalized secondary plant succession and associated 
bird species in a white pine (left half) and scrub 
pine (right half) forest. Horizontal lines indicate 
range of preferred habitats 16-16 

16-4 Generalized secondary plant succession (from left 

to right) and associated bird species in the deciduous 

forest and mixed deciduous/coniferous forest. 

Horizontal lines indicate the range of preferred habitats . . 16-17 

16-6 Proposed bald eagle management programs of the 

Maine Department of Inland Fisheries and Wildlife 16-50 

17-1 Relationship between wildlife management units 

and the characterization regions in coastal Maine 

(Maine Department of Inland Fisheries and Wildlife 1974) . . 17-6 

17-2 Habitat preferences of terrestrial mammals found 

in the characterization area (after Godin 1977) 17-8 

17-3 Food preferences of terrestrial mammals found 

in the characterization area (Godin 1977) 17-13 



Xll 



17-4 Relationship between previous winter conditions 

(based on the winter severity index) and the harvest 

of white-tailed deer in the six regions, adjusted for 

length of hunting season and number of hunters 17-20 

19-1 Geographic sampling units in Maine 

(Ferguson and Kingsley 1972) 19-7 

19-2 Site ndex curves for eastern white pine in New 

England (curves corrected to breast-height age of 

50) (Frothingham 1914) 19-20 

20-1 Comparison of the Three Types of Bogs Found Along 

the Maine Coast (adapted from DAmman 1979) 20-1 



xin 



Table 
.1-1 

.1-2 

.1-3 
.1-4 



.1-5 



.1-6 



.1-7 



.1-9 

.1-10 

.1-11 
.3-1 

.3-2 

.3-3 

.3-4 

.3-5 



LIST OF TABLES 



The Major Fishes of Coastal Maine 

and Their Primary Realms of Importance 



The Fishes of Coastal Maine: Their Seasonality, 
Relative Abundance, Habitat and System 
Preferences, and Distribution 



Spawning Characteristics of Fishes of Coastal Maine . . . . 

The Relative Abundance (expressed as percentage composition) 
of Larval Fishes Inhabiting the Marine Offshore Gulf 
of Maine, Lower Sheepscot Estuary and Upper Sheepscot 
Estuary (Montsweag Bay) 

Feeding Habits and Major Food Items of 

the Fishes of Coastal Maine 



Human Activities That Potentially Influence 
Fish Abundance and Distribution 



Landing Statistics (pounds and dollar values) 
for Maine Fisheries, 1879 to 1976 



Landings (pounds) and Value (dollars) of 

the Major Commercial Fish Species in Maine in 1977 

Landings (Pounds X 1000) of Major 

Commercial Fishes from 1880 to 1977 



Major Sport Fishes of the Characterization Area . . . 

Major Roles of Agencies Involved in Fishery Management 

The Habitats and Estimated Abundance 

of the Cetaceans of Maine 



The Habitats and Estimated Abundance 
of Pinnipeds of Maine 



Summary of Recorded Random Sightings of Marine 

Mammals in the Six Regions of the Characterization Area 

Distribution of Seal Haulout Sites Among 

the Regions of the Characterization Area , 



Reproductive Characteristics of Marine 
Mammals of Coastal Maine 



Pa S s 
11-3 

.1-8 
1-17 



1-21 

.1-24 

.1-30 

1-37 

1-39 

1-40 
1-43 
1-47 

.3-3 

.3-5 

.3-7 

.3-10 

L3-12 



xiv 



"In nn 



13-6 Principal Food Items (expressed as percentages 

in parenthesis) of Marine Mammals in Maine Waters 13-13 

13-7 Organochlorine Residues (in ppm wet tissue) in 
Blubber Tissues of Marine Mammals from the 
Characterization Area and Some Surrounding Areas 13-18 

13-8 Mercury Residues (in ppm wet tissue) in Liver 
Tissue of Marine Mammals from the 
Characterization Area and Other Areas 13-20 

13-9 Reported Incidental Catch and Strandings of 

Cetaceans in Maine Waters Since 1975 13-22 

14-1 Common Seabirds of Coastal Maine. (Species breeding in 

Coastal Maine are indicated by an asterisk.) 14-4 

14-2 Common Shorebirds of Coastal Maine 14-5 

14-3 Common Wading Birds of Coastal Maine 14-6 

14-4 Seabirds Rare in Coastal Maine 14-7 

14-5 Seasonal Occurrence and Relative Abundance of Seabirds 
Regularly Occurring in Various Habitats in the 
Characterization Area 14-8 

14-6 Estimated Numbers (percentage contribution to the total 
in parentheses) of Nesting Pairs of Seabirds (breeding 
summer residents) in Each Region of the Characterization 
Area in 1977 14-12 

14-7 Percentage of Total Nesting Pairs of Seabirds Breeding 

on 126 Major Islands in Coastal Maine During 1977 14-14 

14-8 Feeding Habits of Seabirds Regularly Occurring 

in the Characterization Area 14-19 

14-9 Food Types of Seabirds Regularly Occurring 

in the Characterization Area 14-22 

14-10 Resident Status and Relative Abundance of the 

Shorebirds of Coastal Maine 14-25 

14-11 Major Feeding Areas of Shorebirds of Coastal Maine 14-26 

14-12 Roosting Habitat Types of the Shorebirds of Coastal Maine . 14-27 

14-13 Major Fall Migration Periods of the 

Shorebirds of Coastal Maine 14-33 

xv 



14-14 Resident Status and Relative Abundance of Wading 

Birds in Coastal Maine for Regions 1 to 3 , and 4 to 6 ... 14-36 

14-15 Estimated Number of Pairs of Wading Birds (number of 
colonies in parenthesis) Breeding in Each Region 
of the Characterization Area in 1977 14-38 

14-16 Preferred Feeding Habitats of Wading 

Birds in Coastal Maine 14-39 

14-17 Preferred Food of Wading Birds of Coastal Maine 14-40 

15-1 Resident Waterfowl Species in the Characterization Area . . 15-2 

15-2 Breeding Waterfowl Species in the Characterization Area . . 15-3 

15-3 Wintering Waterfowl Species in the Characterization Area . . 15-4 

15-4 Migrant Waterfowl Species in the Characterization Area . . . 15-5 

15-5 Estimated Number of Major Waterfowl Species in the 
Waterfowl Inventory Units of Coastal Maine in 
the Winters from 1975 to 1979 15-15 

15-6 The Percentage Composition of Breeding Waterfowl 

Species, Based on Brood Counts, in Each Wildlife 
Management Unit (6 to 8), for the Units Combined, 
and Their Percentage Contribution to State Totals 
as Compiled from Maine Department of Inland Fisheries 
and Wildlife data from 1956 to 1965 and 1966 to 1976 . . . 15-25 

15-7 Average Number of Broods of Ducks Per Acre Per Year 

in Different Wetland Types for Each Wildlife Management 

Unit (6 to 8) from 1956 to 1965 and 1966 to 1976 15-26 

15-8 Acres and Numbers (in parentheses) of Different Wetland 
Types for Wildlife Management Units 6 to 8 and 
Contribution to the State Total (adapted from Maine 
Department of Inland Fisheries and Wildilife 
Wetland Inventory Files) 15-27 

15-9 Comparison of the National Wetlands Inventory 

Classification and Circular 39 Wetland Types Used 

in the Maine State Wetland Inventory 15-29 

15-10 Average Annual Number of Pond and Diving Ducks 
Killed by Hunters in the Coastal Counties 
of Maine from 1966 to 1975 15-41 

16-1 Relative Abundance and Habitat Preferences 
of Terrestrial Birds Found in Coastal Maine 
Only During the Breeding Season 16-3 



xvi 



10-80 



16-2 Relative Abundance and Habitat Preferences 

of Terrestrial Birds Found in Coastal Maine Year Round . . . 16-7 

16-3 Relative Abundance and Habitat Preferences 
of Terrestrial Birds Found in Coastal Maine 
Only During the Winter Months 16-9 

16-4 Relative Abundance and Habitat Preferences 
of Terrestrial Birds Found in Coastal Maine 
During Spring and/or Fall Migration 16-10 

16-5 Common Edge Species of Birds in the Characterization Area . 16-14 

16-6 Average Number of Birds (in order of abundance) 

Counted per Route for Each Forest Type in the Breeding 

Survey for the Region of Coastal Maine in 1977 16-21 

16-7 Indices of Relative Abundance for Birds 

in Maine determined from the 1971-77 Breeding 

Bird Surveys, (the 197 6 Index was set at 100) 16-22 

16-8 Bird Species That Require Artificial Feeding for 

Successful Overwintering in Coastal Maine 16-24 

16-9 Index of Relative Abundance for Birds Counted 
During Annual Christmas Bird Counts in the 
Characterization Area from 1969 to 1977; 
Indexes based on 1976 Index of 100 16-26 

16-10 Historical (pre-1960) Breeding Sites of the Bald 

Eagle in the Characterization Area 16-34 

16-11 Bald Eagle Nesting and Fledging Recruitment in the 

Characterization Area in 1962 to 1970 and 1972 to 1979 . . . 16-37 

16-12 Regional Variation in Bald Eagle Nesting and Fledging 

Recruitment in Maine between 1977 and 1979 16-39 

16-13 Number of Wintering Bald Eagles Counted and Percentage 

Mature in Maine During Mid-January 1977, 1978, and 1979 . . 16-40 

16-14 Contaminant Residue Concentrations (ppm wet weight, mean 
and range) in Unhatched Bald Eagles Eggs, by Location 
and Nesting Success in Maine between 1967 and 1979 16-46 

17-1 Mammals Known to Occur Within the Characterization 

Area, Listed by Order 17-2 

17-2 Amounts (square miles, except shoreline) of Major 

Habitat Types in Wildlife Management Units 6, 7, and 8, 

Which Encompass the Characterization Area I 7 - 3 

xvii 



17-3 Regional Distribution of Species of Mammals Not 

Found in All Regions of the Characterization Area 17-4 

17-4 Available Habitat, Species Densities, and Total Population 
Estimates for Selected Species of Game and Furbearing 
Mammals in Wildlife Management Units 6, 7, and 8 17-18 

17-5 Average Annual Legal Harvest of White-tailed Deer 

Q959 to 1977) and Black Bear (1969 to 1977) for 
Each of the Six Regions in the Characterization Area .... 17-25 

17-6 Annual Harvest (Number of Pelts Tagged) and Average 

Price per Pelt (1976 to 1977 average) of 7 Species of 

Furbearers in Coastal Maine 17-26 

17-7 Number of Deer Killed by Causes Other than Legal 

Hunting in Maine, 1969 to 1977 17-27 

17-8 Number of Moose Killed by Causes Other than Legal 

Hunting in Maine, 1969 to 1977 17-27 

17-9 Average Number of Man-days of Hunting Expended on 

7 Species of Game Mammals in Wildlife Management 
Units 6, 7, and 8 During 1971 to 1972 through 1976 to 1977 . 17-29 

17-10 Average Number of Man-days (in parenthesis) of Trapping 
for 11 Species of Furbearing Mammals for Wildlife 
Management Units 6, 7, and 8 During the Period 
1973-1974 through 1976-1977 17-30 

17-11 Incidence of Rabies in Coastal Counties, Listed West 

to East, of Maine from 1971 through 1977 17-32 

17-12 Incidence of Rabies in Wild and Domestic Mammals 

in Maine from 1971 through 1978 17-33 

18-1 Habitats and Distribution of Herptiles in Coastal Maine . . 18-2 

18-2 Herptile Breeding Seasons and Habitats 18-5 

19-1 Common Commercial Tree Species 

of the Characterization Area 19-2 

19-2 Forest Types of the Characterization Area 19-5 

19-3 Area (acres x 1000) of Commercial 

Forest Types of the Characterization Area 19-6 

19-4 Selected Silvical Characteristics of Important 

Commercial Tree Species of the Characterization Area .... 19-9 



xvm 



19-5 Cubic -foot Yield/acre of Fully Stocked, Even-aged 
Stands of Second-growth Red Spruce in the 
Northeast by Stand AGe, Site, and Stand Type 19-13 

19-6 Yields, by Stand Age and Site Index, for Stands of 

New England White Pine at the Upper Level of 
Stocking, in Board Feet/acre and in Cubic Feet/acre .... 19-21 

19-7 Approximate Weight, Mositure Content, and Available 

Heat Units of Selected Woods, Green and Air -dry 19-23 

19-8 Average Stumpage Price by Species for Sawtimber 

and Pulpwood, March 197 9 19-24 

20-1 The Scientific and Common Names, Habitat, and Status 

of Endangered and Threatened Herbaceous Plant Species in 

Coastal Maine, Listed by the Smithsonian Institution .... 20-2 

20-2 Rare Plant Species of Coastal Maine 20-3 



xix 



ACKNOWLEDGMENTS 

This report Is the result of a cooperative effort on the part of many individuals. Their names and contributions 
are listed belcw. 



The Organization of the Characterizat ion 
The Coastal -laine Ecosystem 

Human Impacts on the Ecosystem 
The Marine System 



The Estuarine System 



The Riverine System 
The Lacustrine System 



The Palustriae System 

The Forest System 

Agricultural and Developed Land 

Fishes 



Commercially Important Invertebrates 

Ma r i n e Mamma 1 s 

Waterbirds 

Waterfowl 

Terrestrial 3irds 



Stewart Fefer 
Patricia Schettig 
Stewart Fefer 
Edward Shenton 
Barry Timson 
Dave Strimaitis 
Stewart Fefer 
Norman Famous 
Lawrence Thornton 
Dr. Peter Larsen 
Richard Lee 
Dr. Peter Larsen 
Lee Doggett 
Dr. Chris Garside 
Dr. Jerry Topinka 
Dr. Tim Mague 
Charles Yentsch 
Toby Garfield 
Dr. Ray Gerber 
Dr. Peter Larsen 
Lee Doggett 
Dr. Chris Garside 
Dr. Jerry Topinka 
Dr. Tim Mague 
Toby Garfield 
Dr. Ray Gerber 
Stewart Fefer 
Patricia Schettig 
Lawrence Thornton 
Russell McCullough 
Stewart Fefer 
Dr. Ronald Davis 
Stewart Fefer 
Meryl Freeman 
Stewart Fefer 
Dr. Craig Ferris 
Dr. Craig Ferris 
Patricia Schettig 
Stanley Chenoweth 
Beth Surgens 
Lee Doggett 
Susan Sykes 
Patricia Schettig 
Cheryl Klink 
Norman Famous 
Dr. Craig Ferris 
Howard Spencer, Jr. 
Dr. Kenneth Reinecke 
John Parsons 
Norman Famous 
Charles Todd 
Dr. Craig Ferris 



U.S. Fish and Wildlife Service 
U.S. Fish and Wildlife Service 

New England Coastal Oceanographic Group 

Mahoosuc Corporation 

Environmental Research and Technology 

University of Maine at Orono 
N.J. Department of Environmental Protection 
Bigelow Laboratories for the Ocean Sciences 
Bigelow Laboratories for the Ocean Sciences 

Bigelow Laboratories for the Ocean Sciences 
Bigelow Laboratories for the Ocean Sciences 
Bigelow Laboratories for the Ocean Sciences 
Bigelow Laboratories for the Ocean Sciences 
Bigelow Laboratories for the Ocean Sciences 
Bigelow Laboratories for the Ocean Sciences 
Bowdoin College 



Maine Cooperative Fishery Unit, Orono 
University of Maine at Orono 
University of Maine at Orono 
University of Maine at Orono 

Maine Department of Marine Resources 
U.S. Fish and Wildlife Service 

Bigelow Laboratories for the Ocean Sciences 

U.S. Fish and Wildlife Service 



Maine Department of Inland Fisheries and Wildlife 
U.S. Fish and Wildlife Service 
U.S. Fish and Wildlife Service 



University of Maine at Orono 



XX 



l n_pn 



< 



Terrestrial Mammals 
Reptiles and Amphibians 

Commercially Important Forest Types 
Endangered, Threatened, and Rare Plants 

Atlas Introduction 

Technical Guidance and Conceptual 

Framework 
Editor 
Technical Editing 



Artwork and Layout 

Data Collection and Analysis 



Word Processing 



Data Source Appendix 
Cartography 



Production Manager 



Dr. Craig Ferris 
Dr. Craig Ferris 
Sally Rooney 
Dr. David Canavera 
Norman Famous 
Dr. Craig Ferris 
Beth Surgen 
Dean Johnson 
Curt Laffin 
Dr. James Johnston 
Eileen Dunne 
John Parsons 
Kenneth Adams 
Norman Benson 
Carroll Cordes 
Carolyn French 
Wiley Kitchens 
Martha Young 
Eleanor Bradshaw 
Nancy Perry 
Lynn Bjorklund 
Beth Surgens 
Cheryl Klink 
Renata Cirri 
Peter Moberg 
Terry McGovern 
Porter Turnbull 
Jean Garside 
Veronica Berounsky 
Linda Cummings 
Renata Cirri 
Ruth Walsh 
Peg Colby 
Teve MacFarland 
Doris Dombrowsky 
Dot Dimetriff 
Joyce Aiello 
Linda Cummings 
Elaine McLaughlin 
Dean Johnson 
Beth Surgens 
Eleanor Bradshaw 
Lynn Bjorklund 
Nancy Perry 
Liam O'Brien 
Carl Melberg 
Mike Fantasia 
Steve Gale 
Renata Cirri 



University of Maine at Orono 
University of Maine at Orono 



U.S. Fish and Wildlife Service 
U.S. Fish and Wildlife Service 
U.S. Fish and Wildlife Service 
Consultant 



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University of Maine at Orono 

University of Maine at Orono 

University of Maine at Orono 

University of Maine at Orono 

Bigelow Laboratories for the Ocean Sciences 

Bigelow Laboratories for the Ocean Sciences 

U.S. Fish and Wildlife Service 

Consultant 

Bigelow Laboratories for the Ocean Sciences 

Bigelow Laboratories for the Ocean Sciences 

Bigelow Laboratories for the Ocean Sciences 

Bigelow Laboratories for the Ocean Sciences 
U.S. Fish and Wildlife Service 

U.S. Fish and Wildlife Service 



U.S. Fish and Wildlife Service 
U.S. Fish and Wildlife Service 
U.S. Fish and Wildlife Service 
U.S. Fish and Wildlife Service 
Consultant 



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XXI 



Chapter 1 1 
Fishes 



Authors: Patricia Shettig, Stanley Chenoweth, Beth Surgens 




Over 100 species of fishes, representing 40 families, inhabit the marine, 
estuarine, and freshwater systems of coastal Maine. The majority are resident 
species, and many have commercial and recreational value. Fishes are both 
predators and prey in aquatic food chains and play an important role in energy 
flow within aquatic systems because of their great abundance at different 
trophic levels. 

Fishes generally can be classified into two major categories: pelagic and 
demersal. Pelagic fishes (e.g., herrings, mackerel, and striped bass) are 
highly mobile and range freely throughout the water column. They feed mostly 
on plankton and other pelagic organisms. Demersal fishes (e.g., flounders, 
sculpins, and cod) are less mobile and usually stay on or near the bottom. 
These fishes feed mostly on benthic invertebrates and other bottom fishes. 
Freshwater fishes, for the most part, are semidemersal in habit. Because most 
marine and estuarine fishes are highly mobile, geographic and habitat 
preferences are difficult to identify. 

The habitat and food requirements of most fishes vary according to the life 
stage of the fish. If fish resources are to be managed effectively the 
environmental requirements of species or groups of species at each life stage 
of the fish must be understood. Unfortunately, very few of these requirements 
are known. 

This chapter discusses the status and distribution of fish species in coastal 
Maine habitats and systems and the factors that influence their distribution 
and abundance. Marine and estuarine fishes are emphasized. Natural factors 
that affect the distribution and abundance of fishes include salinity, 
temperature, food availability, streamflow and cover, competition, predation, 
and disease. Water pollution, barriers tc migration, and overharvesting 
(overfishing and selective fishing) are the most severe limiting factors to 
fish populations in coastal Maine. 



11-1 



10-80 



Fish populations are important ecologically and as a renewable commercial and 
recreational natural resource. For many species the management of fisheries 
on a single species basis has not been entirely successful. The existing 
structure and process for management of the fishery resources is discussed in 
this chapter under "Management." Research priorities and additional data are 
identified under "Research Priorities." The consumer role of fishes in 
aquatic food webs is discussed further in "The Marine System," chapter 4; "The 
Estuarine System," chapter 5; "The Riverine System," chapter 6; "The 
Lacustrine System," chapter 7; and "The Palustrine System," chapter 8. 
Relevant fish distributional data are given in atlas map 4. The corresponding 
scientific names of all common names of fishes mentioned in the text are found 
in the appendix to chapter 1. A brief life history of the shortnose sturgeon, 
a Federally listed endangered species, is given. 

DATA SOURCES 

Most of the information on the distribution of coastal marine and estuarine 
fishes in this chapter comes from Chenoweth ( unpublished ) , The Research 
Institute of the Gulf of Maine (TRIGOM; 1974), Maine Yankee Atomic Power 
Company surveys (1970 to 1976), Central Maine Power Company (1974 to 1975), 
Tyler (1971), and MacKay and coworkers (1978). Detailed data from these 
surveys covers the Boothbay region (lower Sheepscot and Damariscotta Rivers) , 
the Sheepscot River-Montsweag Bay area, Penobscot Bay (near Sears Island), 
central Passamaquoddy Bay and the Deer Isle/Campobello Island area. Complete 
lists of species found in these surveys are provided in appendix tables 1 to 
7. 

Ongoing surveys that have provided and will continue to provide data on the 
seasonal distribution of groundfish along the Maine coast are: National 
Marine Fisheries Service (NMFS) Groundfish Survey Program, and Maine 
Department of Marine Resources (MDMR) Inshore Groundfish Survey Program which 
began in spring 1979. The NMFS Fishery Research Center in Woods Hole, 
Massachusetts, also provided extensive data on the food habits of important 
Atlantic marine fishes. General distribution, life history, and behavioral 
information on Gulf of Maine fishes was acquired from Bigelow and Schroeder 
(1953), Clayton and coworkers (1976), Scott and Messieh (1976), and Leim and 
Scott (1966). Data on the distribution of inshore, freshwater fishes was 
provided by Maine Department of Inland Fisheries and Wildlife (MDIFW) . Fish 
life history information was obtained from Scott and Crossman (1973), Everhart 
(1958), and Scarola (1973). 

THE MAJOR FISHES OF COASTAL MAINE 

Many fishes of coastal Maine are of commercial and sport value and some are 
important ecologically because of their role in the food chain or their 
scientific interest. The major fishes of coastal Maine and their primary 
realms of importance are listed in table 11-1. 

The gadids are members of the cod family and are principally marine bottom 
fishes. (The burbot is a freshwater gadid.) They include Atlantic cod, 
haddock, the hakes (red, white, and silver), American pollock, and Atlantic 
tomcod. All but the tomcod are fished commercially. These species 
contributed over 28 million pounds of the total Maine landings in 1977 (Lewis 
1979). The hakes are important summer migrants to Maine waters; the other 

11-2 



Table 11-1. The Major Fishes of Coastal Maine and Their Primary "ealms of Importance. 



Species Category 



Commercial Sport Ecological 



Gad ids 

Atlantic cod X X 

Haddock X 

Hakes (red, white, and silver) X 

American pollock X 

Atlantic tomcod X 

Skates 

Little, winter, and thorny X 

Herrings 

Atlantic herring X X 

Atlantic menhaden X X 

American sand lance X 

Redfish X X 

Atlantic mackerel X X 

Sculpins X 

Rock gunnel X 

Flounders 

Winter flounder X X 

American plaice X X 

Yellowtail- and witch flounder X 

Smooth flounder and windowpane X 

Anadromous and catadromous Fishes 

Alewife XXX 

Atlantic salmon X 

American shad X 

Blueback herring X X 

American eel X X 

Rainbow smelt X X 

Atlantic sturgeon X 

Shortnose sturgeon X 

Striped bass X X 

Freshwater fishes 

Trout (brook, brown, lake, and rainbow) X 

Smallmouth- and largemouth bass X 

White perch X 

Yellow perch X X 

Chain pickerel X 

Minnows X 

White sucker X 

Brown bullhead X 



11-3 



10-80 



gadids are resident year-round. The tomcod is more common in estuaries than 
the other gadids. 

The skates, also resident marine bottom fishes, are stingray-like in 
appearance and are very abundant along coastal Maine. The winter skate, 
little skate, and thorny skate are common in the shallow, cool waters along 
the coast. The skates are of little commercial importance, although some may 
be used as bait (Thomson et al. 1971). 

The Atlantic herring is the most important commercial finfish in Maine waters. 
Juvenile herring support the sardine industry. Atlantic herring are pelagic 
fish usually found in groups of hundreds or thousands. They are common 
inshore and in bays and estuaries during summer months, and spend winter 
months offshore. These fish are important prey for other fishes, birds, and 
marine mammals. Herring are caught inshore by purse seine and in weirs. 
The Atlantic menhaden is a large schooling fish of the herring family whose 
commercial landings in Maine fluctuate widely (ranging from 3 million to 18 
million pounds between 1973 and 1977). Their northern range extends in the 
Gulf of Maine during summer months but they are not known to spawn there. 

The American sand lance is a small schooling fish found in shallow sandy 
bottoms along the coast and out to the continental shelf. Sand lances are 
extremely numerous and are important ecologically as food for larger fishes, 
marine mammals, and seabirds. 

The redfish is an important commercial resource in Maine, contributing over 20 
million pounds to Maine landings in 1977. A northern fish, the redfish 
prefers the deeper, colder waters of the Gulf of Maine. It is plentiful, 
also, in nearshore deep water areas (e.g., eastern Maine). 

The Atlantic mackerel migrates to coastal Maine in summer, moving in response 
to seasonal changes in temperature. The mackerel is an important commercial 
fish and supports a summer recreational fishery in Maine. Most mackerels 
leave the coast in late autumn and winter in offshore waters. 

The sculpins (Cottidae) are ubiquitous resident bottom fishes, found in 
shallow marine and estuarine waters along the coast. Sculpin include the sea 
raven, grubby, shorthorn sculpin, and longhorn sculpin. Because they are 
abundant and bottom-dwelling, sculpin are an important part of benthic food 
webs. The sea raven, shorthorn sculpin, and longhorn sculpin are of minor 
commercial importance as baitfish in the lobster fishery. 

The rock gunnel is one of the most abundant fishes along the coast, common in 
tide pools and rocky areas. It is eaten by cod and pollock but much of its 
role in coastal ecology is unknown (Clayton et al. 1976). 

Flounders are one of the major inshore groundf ishes . The winter flounder is 
the most common, found from inland areas of estuaries to Georges Bank (TRIGOM 
1974). This species is an important commercial and sport fish. The American 
plaice is probably the most numerically dominant flounder in nearshore coastal 
waters (personal communication from S. Chenoweth, Maine Department of Marine 
Resources, Augusta, ME; December 1979). The plaice is also a major commercial 
groundfish. The witch flounder and yellowtail flounder are important 
commercial resources. Witch flounder populations are centered north of Cape 

11-4 



Cod, while the yellowtail flounders are more abundant in southern New England 
waters. Neither are very common in estuaries. The smooth flounder and 
windowpane are common in bays and estuaries. Neither are sought commercially. 

The anadromous and catadromous fishes are an important resource in coastal 
Maine. Anadromous fishes are those that migrate up rivers from the sea to 
spawn in fresh or brackish waters. Catadromous fishes migrate down rivers to 
the sea to spawn. Many support commercial and sport fisheries; others are 
important ecologically. These fishes are of special interest because of their 
history. Maine's historically rich populations of anadromous fishes were 
nearly destroyed by harmful uses of dams and barriers but careful management 
since the 1960s has partially restored them. Based on its distribution, 
abundance, role in aquatic systems, and many commercial uses, the alewife may 
be the most important anadromous fish in Maine. Once an important staple in 
the diet of New England settlers (Clayton et al. 1976), the species is the 
primary one being restored by the Maine Department of Marine Resources 
Anadromous Fish Program. Alewives are the most numerous among the fishes that 
migrate up coastal streams and rivers. The alewife is an important forage 
fish, providing food for many game fishes (e.g., striped bass, bluefish, and 
some trouts), seals, waterfowl, and for the osprey and bald eagle. 
Commercially, alewives are used extensively for fish meal in fertilizers and 
animal foods. They have another important use as bait for lobster traps and 
trawl fisheries. The primary alewife fishery is carried out during the 
upstream spawning migration of adults. The blueback herring is very similar 
to the alewife in appearance and habit but the blueback is a summer migrant to 
coastal Maine, is less abundant than the alewife, and begins its spawning run 
later. Blueback herring are caught and processed commercially and used as 
lobster bait indiscriminantly from alewives. 

The Atlantic salmon is a highly prized sport fish of special interest in Maine 
and New England. Its population in coastal Maine is currently reduced, 
largely as a result of dams constructed along streams used by salmon for 
upstream migration. Of all the North Atlantic rivers where salmon have ranged 
historically, only a few rivers (e.g., the Dennys) in Maine support natural 
reproduction of Atlantic salmon. The plight of the salmon is well known, and 
its recovery is a focus of State and Federal agencies. 

Like the Atlantic salmon, American shad populations have suffered greatly at 
the expense of industrialization, dam construction, and pollution. The shad 
once supported a significant commercial fishery but its distribution is now 
limited to probably 4 or 5 stream systems in Maine. A shad 
restoration/stocking program is currently underway in the Royal River 
(personal communication from T. Squires, Maine Department of Marine Resources, 
Augusta, ME; December, 1979). 

The rainbow smelt is very common in streams, estuaries, and landlocked lakes 
along the coast. The smelt is important as a forage fish, constituting the 
most important single food item of Maine's landlocked Atlantic salmon 
(Everhart 1958). Smelt are an important recreational resource. They are 
taken with hook and line, or caught by hand or dipnet during the upstream 
spawning run. Smelt are often fished from ice shanties on frozen bays and 
estuaries in winter. They are also a highly valuable bait species. 



11-5 

10-80 



The only sturgeons found in Maine are the Atlantic sturgeon and the shortnose 
sturgeon. Neither are very numerous, and the shortnose sturgeon is listed by 
the Federal Government as an endangered species (see "Shortnose Sturgeon" 
section in this chapter). Both sturgeons are sluggish, slow swimming, bottom 
fishes that are hampered by dams and obstructions in streams. These sturgeons 
once supported a commercial market. Their roe is well known commercially as 
caviar. 

The American eel, the only catadromous fish in Maine, spends its early life 
upstream in fresh water and migrates down to the sea to spawn. Young eel 
(elvers) swim upstream in spring of the following year. The eel is an 
important commercial resource for food and bait. The extensive migrations of 
eels and the locations of their spawning areas are not well documented. It is 
known they spawn in the Sargasso Sea area rather than the Gulf of Maine. 

The striped bass is one of the most popular marine sport fishes in Maine and 
New England. It is a summer migrant to waters north of Cape Cod, appearing 
regularly in bays and estuaries, but evidence of its spawning in Maine has not 
been found in many years (Bigelow and Schroeder 1953) . 

The major freshwater fishes have sport or ecological importance. The brook 
trout, brown trout, lake trout, rainbow trout, landlocked Atlantic salmon, 
chain pickerel, white perch, yellow perch, smallmouth bass and largemouth bass 
are the major freshwater sport fishes. Minnows are small freshwater fish in 
the family Cyprinidae. They are usually abundant because they occupy a 
variety of habitats and utilize many food types, and a large number can occupy 
a small area (Everhart 1958). The golden shiner and fallfish are the most 
widely distributed minnows in the coastal zone. Minnows are important because 
of their position in the food chain. They serve as forage for many desirable 
food and sport fishes. One minnow (carp) has posed a problem in many states. 
The carp was introduced into the United States as a potential commercial fish. 
Through improper handling, this large fish has spread and proliferated in all 
types of fresh waters, competing with more desirable fishes for food and 
space. In addition, carp feeding behavior disturbs habitats by stirring up 
mud and sediments and uprooting aquatic plants while feeding. Carp control is 
of great concern to fishery managers. 

The white sucker is the most abundant and most common of the larger fishes in 
the lakes and tributary streams. They are bottom fish and serve as forage for 
many game fishes until they become too large for the game fishes to swallow. 
Large suckers may then compete with more commercially and recreationally 
desirable fishes. The brown bullhead, or hornpout, is the only member of the 
catfish family found in Maine and is widely distributed in the coastal zone. 

DISTRIBUTION 

Cape Cod represents a major biological and physical barrier separating 
populations of Atlantic fishes in the Gulf of Maine from those of the mid- 
Atlantic Bight (Colton et al. 1979). Coastal Maine waters are characterized 
by stable, resident populations of mostly boreal (northern) fish species, with 
some migratory populations of temperate species from the south and 
occasionally some subarctic species from the northeast. Reflective of the 
area's physiography, coastal fish populations are dominated by demersal marine 
and estuarine species. Data from nearshore and estuarine surveys indicate 

11-6 



that the most common fishes are the herrings (alewife and Atlantic herring) , 
the flounders (winter flounder, American plaice, witch flounder, windowpane, 
and smooth flounder), the codfish (Atlantic cod, haddock, Atlantic tomcod, 
silver hake, red hake, white hake, American pollock, and ocean pout), the 
sculpins (longhorn sculpin, shorthorn sculpin, and sea raven), the skates 
(little skate, winter skate, and thorny skate), rainbow smelt, wrymouth, rock 
gunnel, redfish, and the American eel. 

The distribution of fish species across the five aquatic systems in coastal 
Maine, their relative abundance, seasonality, and regional distribution are 
described in table 11-2. In the NWI classification, which was used in 
compiling the information, systems are not always mapped according to their 
degree of salinity and so a problem arises when the system is applied to fish 
distribution. The estuarine system as described and mapped by NWI includes 
much habitat "historically" classified as marine. Hence, many marine fishes 
are found in habitats classified as estuarine. Of the 116 species recorded, 
13 are strictly marine inhabitants, and 3 are found only in riverine systems. 
There are no strictly estuarine, lacustrine, or palustrine fish species in 
coastal Maine. The remaining 100 species, or 86%, inhabit two or more 
systems. The alewife, American eel, three-spine stickleback, brook trout, and 
white perch are found in all systems. 

The diversity of fishes in the major systems is illustrated in figure 11-1. 
The marine system supports the highest diversity of fishes, followed by the 
estuarine system, the riverine system, the lacustrine system, and the 
palustrine system. Data on the relative biomass or density of fishes by 
aquatic systems are not available. Because of their relative mobility and 
general opportunistic nature, most fishes will frequent many subsystems and 
classes among the different habitat systems for food, shelter, or spawning. 
For example, most of the fishes that inhabit or pass through an estuary will 
frequent an intertidal emergent wetland (salt marsh) at one time or another. 
It is still difficult to identify which fishes are closely enough associated 
with a particular habitat class so that their productivity might be altered by 
a perturbation of that class. 

In general, most fishes exhibit habitat, system, and class preferences, 
especially in their feeding and reproductive behavior (see sections on "Food 
and Feeding" and "Reproduction," this chapter). Most pelagic marine fishes 
(i.e., the herrings, striped bass, spiny dogfish, and mackerel) range 
throughout the open waters. Many typically demersal marine fishes are more 
closely associated with specific bottom and shore habitats. It is common to 
find the American eel, sea raven, sea snail, snakeblenny, rock gunnel, tautog, 
and radiated shanny along rocky shores and rock bottoms. Marine and estuarine 
aquatic beds are preferred by some sculpins, and by the red and white hake, 
cunner, and northern pipefish. Unconsolidated bottoms and flats in both 
marine and estuarine systems support chiefly sand lance, alligatorf ish, 
wrymouth, lumpfish, cod, the flounders, and skates. 



11-7 

10-80 



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MARINE ESTUARINE RIVERINE LACUSTRINE PALUSTRINE 

NWI SYSTEM 



Figure 11-1. Diversity of fishes in Maine systems, 



The major fishes of the rivers, lakes, and ponds are trout, sunfish, bass, 
sticklebacks, whitefish, catfish, shiners, dace, chubs, suckers, and perch. 
The freshwater fishes are important primarily for sport fishing. The trouts 
and bass are the most sought after species. The ecological role and/or 
contribution of some of the less conspicuous species (dace, chubs, shiners, 
and sticklebacks) generally is known. The freshwater systems (lacustrine, 
riverine, and palustrine) support a lower diversity of fishes than the marine 
and estuarine systems combined. The species composition of freshwater fish 
reflects a mix of both warmwater and coldwater fishes, although the abundance 
of coldwater species (e.g., trout and salmon) generally increases from 
southwest to northeast (see chapter 7, "The Lacustrine System"). A number of 
freshwater species are widely distributed among the characterization area's 
lakes and streams (table 11-2). Many are limited in their distribution by 
water quality and/or barriers. Historically, the Kennebec River (region 2) 
hosted the highest diversity of freshwater and anadromous fishes in the state 
of Maine (Foye et al. 1969). Excessive use of dams and pollution of the water 
by municipal and industrial wastes were responsible for the collapse of the 
Kennebec River fisheries. 

Many freshwater fishes have system and class preferences. Trout, salmon, 
burbot, and whitefish prefer deep, cool lakes and swift streams. Largemouth 
bass, chain pickerel, and sunfish are found along the quiet vegetated shores 
of most lakes and ponds. The brown bullhead prefers fairly deep, weedy lake 
bottoms and slow fresh streams. Finescale dace and northern redbelly dace 

11-13 



10-80 



principally inhabit cool, boggy waters. Good coverage of the general 
distribution and habitat preferences of freshwater fishes is found in Scarola 
(1973), Everhart (1958), and Scott and Crossman (1973). 

Seasonal Occurrence and Migration 

Water temperature is one of the major factors controlling the seasonal and 
daily movements of fish populations. Many fish species have preferred 
temperature ranges and move in response to seasonal and local changes in 
temperature. Gulf of Maine waters have a narrower annual temperature range 
than the neighboring mid-Atlantic Bight waters to the south. Colton (1972) 
discusses the effects of these temperature trends on the distribution and 
migration of certain marine fishes in the Gulf of Maine. The relatively 
stable seasonal temperatures tend to support a high proportion of resident 
marine fishes. The mid-Atlantic waters, on the other hand, support few 
permanent residents and are inhabited by continuously shifting populations of 
southern (temperate) migrants and some northern species. 

Some southern migrants to the mid-Atlantic Bight waters follow the summer 
thermoclines up into the Gulf of Maine. Many of these species are present in 
sufficient numbers to play a significant role in the ecology of coastal Maine. 
Common summer migrants inshore and along the coast are spiny dogfish, scup, 
silver hake, spotted hake, red hake, white hake, tautog, American shad, 
hickory shad, striped bass, menhaden, blueback herring, bluefish, Atlantic 
mackerel, butterfish and bluefin tuna. Many of these species (e.g., tuna, 
bluefish, mackerel, and striped bass) are important sport fishes in Maine and 
other Atlantic states. Not all of these species reach eastern Maine and 
Canada. Many are uncommon east of the Penobscot Bay area (scup, spotted hake, 
hickory shad, tautog, butterfish, and bluefish). Most of these summer 
migrants leave coastal Maine with the onset of cooling autumn water 
temperatures and disperse to the south. There is an additional winter 
dispersal of cod and pollock from the Gulf of Maine to waters south of Cape 
Cod but their numbers do not rival the summer migrants from the mid-Atlantic 
(TRIGOM 1974). 

Most of the resident fish species exhibit some form of seasonal and/or daily 
movements, either inshore to offshore or from shallow flats to deeper water, 
in response to changes in temperature. Many resident marine and estuarine 
fishes move offshore into deeper (warmer) waters to overwinter (e.g., the 
flounders, the skates, cunner, lumpfish, and alewife) . Resident populations 
of brown, brook, and rainbow trout show marked movements along river reaches, 
in and out of the lakes through connecting streams. Of special interest are 
the resident anadromous and catadromous fishes. 

Anadromous and Catadromous Fish Distribution 

Coastal Maine supports relatively healthy and diverse populations of 
anadromous species in comparison with many other Atlantic coastal areas. 
Resident anadromous fishes include the shortnose and Atlantic sturgeon (both 
are rare and the shortnose is an endangered species), alewife (common 
throughout), rainbow smelt (common throughout), sea lamprey (common in 
midcoastal and eastern Maine), and Atlantic salmon (rare in Maine but its 
populations are recovering in the Sheepscot, Ducktrap, Machias, East Machias, 
Dennys , and Pleasant Rivers, and Penobscot, Kennebec, and Narraguagus 

11-14 



drainages). The resident American eel, a catadromous fish, is perhaps the most 
ubiquitous fish in Maine. It is found in almost every major drainage and 
aquatic system (see atlas map 4) . 

Two of the summer migrants, American shad and blueback herring, are anadromous 
fishes, spending part of their life cycle in marine waters and swimming up 
estuaries and rivers to spawn in fresh water. Striped bass are anadromous in 
the southern part of their range but they do not commonly spawn in Maine. 

Maine's historically rich populations of anadromous fishes declined near the 
turn of the century through the 1960s as a result of dams that blocked 
pathways to spawning areas. Altered water flow and river pollution by 
municipal and industrial wastes also were factors. The status of recovery, 
problems remaining, and management strategy for the enhancement of anadromous 
fish resources are discussed under "Management," in this chapter. 

REPRODUCTION 

Spawning habits are known for most of Maine's resident marine and estuarine 
fishes, notably the anadromous fishes, and sport and commercial fishes. 
Detailed life history information by species is available in Bigelow and 
Schroeder (1953), Everhart (1958), Clayton and coworkers (1976), Scarola 
(1973), TRIGOM (1974), and Scott and Crossman (1973). 

Spawning adults and the eggs and larvae of fishes are particularly sensitive 
to changes in their environments. Many species require specific habitats, 
migratory pathways, and environmental conditions (e.g., temperature and 
salinity) for successful spawning. Anadromous fishes, such as salmon, 
alewife, smelt, and blueback herring, require unobstructed passage through 
estuarine and riverine systems to suitable freshwater spawning grounds; some 
of these fish negotiate obstructions better than others. 

Many species that spawn offshore, such as the Atlantic cod and Atlantic 
herring, migrate to certain open water areas to spawn. Spawning activity is 
synchronized for many species. This usually results in greater than normal 
concentrations of a species in a spawning area. As a result the whole 
population of a species is vulnerable to a single adverse event (e.g., fishing 
and oil spills). The eggs and larvae of most fishes are generally vulnerable 
to predation and environmental changes. They are relatively concentrated in 
numbers and have limited or no powers of locomotion by which to leave an 
unfavorable area. 

Fecundity 

The success of reproduction is determined largely by the survival of the year 
classes during their early life stages. Natural mortality usually is very 
high during that time. The reproductive strategy of most fishes involves the 
external fertilization of great numbers of eggs. A small percentage survive 
to adulthood. Fishes that show a higher degree of parental care usually lay 
fewer eggs. There usually is a trade-off effect between the number of eggs 
laid and the rate of survival of the young to maturity; that is, the energy 
that goes into producing large quantities of eggs is not available to provide 
care for the young. 



11-15 

10-80 



The Atlantic cod, a pelagic open-water spawner, can produce up to 9 million 
eggs per female per season. The females provide little or no care after the 
eggs are released in the vicinity of spawning males. This is true of most 
marine spawners. Other fish species that provide little or no care to eggs or 
young are the carp, chain pickerel, golden shiner, whitefish, lake trout, 
suckers, yellow perch, and the alewife. There are a number of fishes (e.g., 
sea lamprey, salmon, trout, and fallfish) which build nests for the eggs but 
desert them soon after spawning. In contrast, the sticklebacks, sunfish, 
bass, brown bullhead, slimy sculpin, and fathead minnow make elaborate nests 
and provide parental care to the developing young for several days or weeks. 
The usual number of eggs for the sticklebacks ranges from 20 to 100 (Clayton 
et al. 1976). 

Redfish and northern pipefish provide even more protection to eggs. Their 
eggs are protected in the oviduct or brood pouch. The young are born in a 
more advanced stage of development. In general, fishes that utilize the 
rivers, lakes, and estuaries for spawning are generally less fecund than 
marine spawners and give a higher degree of parental care. 

Spawning Habits 

Reproductive habits of the fishes of coastal Maine are summarized in table 11- 
3. The spawning season for marine fishes is well distributed throughout the 
year with notable peaks in mid-winter (primarily resident fish) and summer 
(primarily summer migrants). 

Of the 16 summer migrant species, 4 are known to spawn in coastal Maine or its 
waters offshore (silver, red, and white hake, and blueback herring), 2 are 
noted as historically common anadromous fishes (American shad and striped 
bass) and the others do not spawn in coastal Maine. 

Spawning activities generally commence earlier in western than in eastern 
Maine (Bigelow and Schroeder 1953). Among estuarine and freshwater fishes, 
spawning activity is heaviest from May through July. Exceptions are salmon, 
whitefish, and trout, which spawn in late fall (October and November, 
principally). Data on preferred water temperature for spawning in Maine are 
lacking for many freshwater and marine species, including some very common 
marine fishes (e.g., sculpins, skates, hakes, sticklebacks, sea snails, sand 
lance, eel, sea raven, smooth flounder, and rock gunnel). 

Eggs spawned externally by fishes are either planktonic (pelagic) or demersal 
(table 11-3). Planktonic eggs are buoyant, have a specific gravity about 
equal to that of fresh water, and usually float freely in the water column. 
Most marine fishes, such as the Atlantic cod, silver hake, yellowtail 
flounder, and American plaice produce planktonic eggs. Egg survival is 
sometimes affected by currents, oil slicks, and other surface disturbances. 
Most estuarine and freshwater spawners lay demersal eggs, which are relatively 
heavy, usually adhesive, and sink to the bottom or adhere to submerged 
substrates. These demersal eggs are particularly vulnerable to water level 
changes, local water quality conditions, and smothering by sediments or other 
solids. The large expanse of relatively shallow, protected waters (marine and 
estuarine subtidal) in coastal Maine provides suitable and abundant habitat 
for the spawning of many demersal egg-bearing fishes (i.e., sculpins, winter 
flounder, rock gunnel, tomcod, and skates). 

11-16 



Table 11-3. Spawning Characteristics of Fishes of Coastal Maine 5 



Species 



Principal 

spawning 

months 



Spawning 
habitat b 



Egg 



Spawning 



deposition temperatures 



JFMAMJJASOND 



Cusk 


AMJJ 




M10W 


P 




Fourbeard rockling 


AMJJ 




M10W 


P 


55°-66°F 


Atlantic cod 


JFMA 


D 


M10W 


P 


38°-47°F 


Haddock 


FMAM 




M10W 


P 


37°-41°F 


American pollock 


J ND 


M10W 


P 


38°-48°F 


Goosef ish 


JJAS 




M10W 


P 


41°-64°F 


Silver hake 


JJASO 




M10W 


P 


41°-55°F 


White hake 


FMAMJJ 




M10W 


P 


- 


Red hake 


JJASO 




M10W 


P 


- 


Cunner 


JJA 




M10W 


P 


55°-65°F 


American eel 


J 


D 


M10W 


P 


- 


Conger eel 


JA 




M10W 


U 


O 


Tautog 


JJ 




M10W 


P 


17 -20 C 


Northern pipefish 


MAMJJA 




M 





o o 


Redf ish 


MJJA 




M 





37 -49 F 


Wrymouth 


JF 


D 


M 


u 


- 


Ocean pout 


SO 




M1RB 


D 


10°C 


Sea snails 


J 


D 


M1,E1RB 


D 


- 


American sand lance 


JFMA 


D 


M1UB 


D 


- 


Witch flounder 


AMJJA 




M1UB 


P 


45°-55°F 


American plaice 


FMAM 




M1UB 


P 


37°-40°F 


Yellowtail flounder 


MAMJJA 




M1UB 


P 


50 °-52 °F 


Snakeblenny 


JF 


D 


M1UB 


U 


- 


Windowpane 


MJJA 




M1UB 


P 


50°-60°F 



a Bigelow and Schroeder (1953); Clayton et al , 
Everhart (1958); Scarola (1973), 



(1976); MDIFW (1976); Colton (1979); 



^Habitat Key; M=Marine, E=Estuarine. l=subtidal, 2=intertidal; P=Palustrine; 
R=Riverine, l=tidal, 2=lower perennial, 3=upper perennial; 
L=Lacustrine, l=littoral, 2=limnetic; 0W=open water, UB=unconsol- 
idated bottom. RB=rock bottom, AB=aquatic bed, EM=emergent, RS= 
rocky shore. 

c Egg Deposition Key: P=Planktonic, D=Demersal, O=0voviviparous, U=Unknown 

SD=Semi-demersal . 



(continued) 



11-17 



10-80 



Table 11-3. (Continued) 



Species 



Principal 


Spawning 


Sgg 


Spawning 


spawning 


habitat 


deposition 


temperature 


month 









JFMAMJJASOND 



Mailed sculpin 




J 




M1UB 


D 


_ 


Thorny skate 




AMJJAJ 




M1UB 


U 


- 


Moustache sculpin 


JF 




D 


M1UB 


U 


- 


Atlantic herring 




SON 


M1UB 


D 


3°-ll°C 


Lumpf ish 


FMAM 




M1UB 


D 


- 


Sea raven 






OND 


M1UB 


D 


- 


Rock gunnel 


JFM 


ND 


M1UB 


D 


- 


Little skate 


JFMAMJJASOND 


M1UB 


D 


- 


Winter skate 




JASON 


M1UE 


U 


- 


Longhorn sculpin 


JF 




ND 


M1UB 


D 


- 


Smooth flounder 


JFM 


D 


M1,E1UB 


U 


- 


Alligatorf ish 






OND 


M1UB 


u 


- 


Grubby 


JFMAMJ 


D 


M1,E1,UB,AB 


D 


- 


Shorthorn sculpin 


JF 




ND 


M1UB,AB 


D 


- 


Radiated shanny 




MJJA 




M 


U 


O 


Atlantic tomcod 


JF 




ND 


E 


D 


4 -44 F 


Mummichog 




JJA 




E 


D 


- 


Threespine stickleback 




MJ 




E2EM,RS,UB 


D 


o 


Four spine stickleback 




JJ 




E2EM 


D 


70 F 


Ninespine stickleback 




MJJ 




E2EM 


D 


- 


Blackspotted stickleback 




MJ 




E2EM 


D 


o 


Atlantic silver sides 




MJJA 




E2EM;M1,E1UB 


D 


68 F 

O O 


Winter flounder 


MAMJ 




E1UB 


D 


31 "37 F 

O O 


White perch 




AMJ 




E;L;P;R 


D 


52 -60 F 


Banded killifish 




JA 




RAE,L,PAB 


D 


- 


Carp 




AMJ 




R.PAB 


D 


o o 


Shortnose sturgeon 




AMJ 




R,P 


U 


15 -18 C 


Atlantic sturgeon 




MJJ 




R2 


D 


o o 


Blueback herring 




MJJ 




Rl 


D 


70 -75 F 

O O 


Rainbow smelt 




AM 




Rl,2 


D 


50 -57 n F 

o o 


American shad 




MJ 




R2,3 


D 


50 -63 n F 

O 


Sea lamprey 




MJJA 




R3UB 


D 


50 -68 F 


Atlantic salmon 






ON 


R3UB 


D 


£ c 


Alewif e 




AMJ 




P;R2;L 


D 


55 -£0 F 


Brook trout 






ON 


R3UB;P 


D 


40 F 


Brown trout 






ON 


R3UB 


D 


- 


Blacknose dace 




AMJ 




R3UB 


D 


- 


Creek chub 




AM 




R3UB 


D 


- 


Golden shiner 




MJJ 




RAB 


D 


o ~ o 


Yellow perch 




AM 




R,L,PAB 


SD 


44 -54 F 


Finescale dace 




JJA 




R.PAB 


D 


- 






(cont inu 


ed) 







li— ii 



table 11-3. (Concluded) 



Species 



Principal 

spawning 

months 



Spawning 
habitat 



Egg 
deposition 



Spawning 
temperature 



JFMAMJJASOND 



Pearl dace 

Longnose sucker 

White sucker 

Lake whitefish 

Brown bullhead 

Smallmouth bass 

Common shiner 

Longnose dace 

Rainbow trout 

Fallfish 

Landlocked Atlantic salmon 

Blacknose shiner 

Bridle shiner 

Slimy sculpin 

Northern redbelly dace 

Brook stickleback 

Largemouth bass 

Fathead minnow 

Lake chub 

Burbot JFM 

Lake trout 

Round whitefish 

Redbreast sunfish 

Pumpkinseed sunfish 

Chain pickerel 

Sunapee trout 



AM 




R3UB 


D 


- 


M 




R,PUB 


D 


- 


M 




R.PUB 


D 


- 




ND 


R2,3;L2RB 


D 


40°-50°F 


MJJ 




RUB 


D 


>65°F 


JJ 




R,L,PUB 


D 


59°-69°F 


AMJ 




R3UB 


D 


60°-65°F 


AMJJ 




R3UB 


D 


- 


AM 




R2.3UB 


D 


50°F 


MJ 




R.LUB 


D 


- 


< 


3 ON 


R,L 


D 


- 


AMJ 




R 


U 


- 


MJJ 




RAB,UB 


D 


58°-80°F 


AMJ 




R.LUB 


D 


- 


JJA 




R,PAB 


D 


- 


MJ 




R 


D 


- 


J 




L,P AB,UB 


D 


60°-70°F 


AMJ 




LUB 


D 


- 


JA 




R 


D 


- 


[ 


D 


RUB , LUB 


D 


- 


< 


BON 


L2UB 


D 


37°F 


J 


ND 


R2 , 3 , LUB 
L,PUB 


D 
D 


40°F 
65°-70°F 


JA 




L,PUB 


D 


- 


AM 




P,L 


D 


- 


< 


SON 


L2UB 


D 


- 



11-19 



10-80 



EARLY LIFE HISTORY 

Larval fish, often called fry, are particularly vulnerable to predation and 
environmental stress. The larvae of most fishes are planktonic for some time, 
have limited powers of locomotion and drift freely in the water column. The 
period of larval life varies for different species and may last from a few 
days to several years. The larvae of the winter flounder are planktonic for 
about 50 days. Atlantic herring remain in the larval stage for 5 to 7 months 
(Graham et al. 1972). Sea lamprey larvae require 5 or more years before 
undergoing metamorphosis (Lagler et al. 1962). The average duration of larval 
stages in the Gulf of Maine is about 3 to 5 months. Water temperature also 
influences the duration of the larval stage; that is, the higher the 
temperature, the faster the development of the eggs and larvae. 

The larval stage in fishes is terminated at metamorphosis, when the fishes 
develop adult features and habits. At this point they are considered 
juveniles. Final development and maturation of the gonads signals the onset 
of sexual maturity. The time required to attain sexual maturity varies among 
species and with water temperatures. For example, Atlantic silverside and 
sticklebacks reach maturity within one year after hatching, whereas freshwater 
eels require 6 to 12 years. The Atlantic sturgeon may take 15 or more years 
(Lagler et al. 1962). 

Larval Populations 

Planktonic eggs and larvae are seasonally important components of the plankton 
communities (TRIGOM 1974). Detailed data are available for the midcoast 
region (lower Sheepscot-Damariscotta estuaries), offshore Gulf of Maine, and 
the Bay of Fundy. The species compositon and seasonal abundance of the 
estuarine larval populations have been described for the Sheepscot/Back River 
estuaries by Maine Yankee Atomic Power Company surveys (1970 to 1976), for the 
lower Sheepscot estuary by Chenoweth (1973), and for the mid-coast region by 
Graham and Boyar (1965) and Graham and coworkers (1972). The offshore marine 
larvae in the Gulf of Maine and Georges Bank were sampled by Marak and Colton 
(1961) and Marak and coworkers (1962a and 1962b). Fish and Johnson (1937) 
surveyed the marine larvae in the Bay of Fundy and northern Gulf of Maine 
waters. Some of these data are given in table 11-4. Complete lists of all 
larval species found in the marine and estuarine surveys are given in appendix 
tables 8 and 9. 

Fish larvae in the offshore waters are dominated by the larvae of resident 
fishes (cod, haddock, sand lance, and flounder). Silver hake larvae dominate 
the larvae of summer migrant fishes. Larval populations in the Bay of Fundy 
are dominated by the larvae of Atlantic herring and redfish, which are typical 
northern resident species. In the Sheepscot estuary, larval abundance is 
greatest from late winter through spring, with greatest concentrations in the 
upper estuaries (figure 11-2). These estuarine larvae are composed of both 
marine and estuarine fishes. Species that utilize the estuaries as primary 
spawning and/or nursery areas (as indicated by the abundance of larvae) 
include the wrymouth, rock gunnel, sculpins , sea snails and snakeblenny 
(Chenoweth 1973), Atlantic herring, winter flounder, and Atlantic tomcod 
(Maine Yankee Atomic Power Co. 1976). 



11-20 



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10-80 



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1.0 F= 



0.1 = 



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^VVVVVVV-^V^o^ 



Figure 11-2. Seasonal abundance of fish larvae in the upper estuarine, lower 
estuarine, and offshore areas of the Boothbay region (Chenoweth 
1973). 



FEEDING HABITS 



FOOD RESOURCES 



PLANKTONIC 



NEKTONIC 



DEMERSAL AND 
SEMI-DEMERSAL 




PHYTOPLANKTON 

ZOOPLANKTON 

NEKTONIC CRUSTACEA 

FISH EGGS AND LARVAE 

LARGE FISHES 

DETRITUS, ALGAE 

INSECTS 

POLYCHAETES 

MOLLUSKS 

SMALL FISHES, SQUID 

CRUSTACEA 



Figure 11-3. Feeding habits and food resources of fishes. 



11-22 



FOOD AND FEEDING HABITS 

In the context of the total ecosystem, fish species may best be considered as 
a group occupying a specific feeding niche (Langton and Bowman 1978) . These 
niches are determined by the fishes' feeding habits (food items and habitats 
used) and may change with size or life stage. The majority of fishes are 
secondary or higher level consumers in their respective aquatic systems. A 
single species may utilize several different feeding habits during its various 
life stages. Different species may share the same food resources in a given 
area or at a given time. This information is necessary to develop an accurate 
understanding of energy transfer and trophic organization in aquatic systems. 

Fishes are classified as planktonic, nektonic, or demersal/semidemersal 
feeders (figure 11-3). Planktonic feeders, such as the herrings, Atlantic 
menhaden, and American sand lance feed high in the water column. Planktonic 
food organisms for these fish are largely pelagic crustaceans (amphipods, 
copepods , euphausiids, and mysids), schooling fishes, fish eggs, and larvae. 
Fishes that feed on the nekton feed throughout the water column, on pelagic 
crustaceans and fishes. The majority of the characterization area's migratory 
fishes are nektonic feeders. The demersal/semidemersal feeders utilize 
typical bottom food items, such as crustaceans, molluscs, echinoderms, fish, 
polychaete worms, insects, algae, and detritus. The majority of the area's 
resident marine, estuarine and freshwater fishes are demersal/semidemersal 
feeders. The feeding habits and major food items of the fishes of coastal 
Maine are listed in table 11-5. Data are organized by habitat, feeding habit 
and principal foods. Fishes that share a given resource and may be impacted 
by the availability or quality of food items may be perceived as a group. 

Detailed published work on food habits of Maine marine and estuarine fishes 
are Tyler (1971 and 1972), Langton and Bowman (1978), and Maurer and Bowman 
(1977). The latter two sources are the products of a comprehensive ongoing 
effort by the National Marine Fisheries Service to compile food habit data on 
80 major species of Northwest Atlantic marine fishes. 

Tyler (1972) looked at the food resources of the demersal marine fish of 
Passamaquoddy Bay and compared the diets of the residents and seasonal 
migrants for overlap and seasonal specialization. He found that the seasonal 
migrants did not feed on a unique set of prey species but shared some food 
resources with the resident species. Among the factors determining which 
species a predator took were prey size, prey habitat (whether the prey were 
nektonic, epifaunal, or infaunal), and whether or not the prey had a hard 
shell (Tyler 1972). Within the species, diet varied with the size of the 
individual . 

Langton and Bowman's (1978) investigations also indicate that when the diets 
of taxonomically related pairs of species are analyzed, important differences 
are apparent (figure 11-4). The similarity in diet is a relative measure of 
overlap in food habits, i.e., use of the same resource by more than one 
predator regardless of food abundance. Competition for food exists only if 
the demand for prey exceeds the immediate supply. The index of diet overlap 
shows where there is a potential for food resource competition given a certain 
set of circumstances, e.g., significant decreases in prey populations and/or 
increases in predator populations, or reduced feeding areas. 



11-23 



10-80 



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11-26 



PREDATORS 


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Figure 11-4. 



The percentage similarity between the diets of ten species of 
gadiform fishes in the Gulf of Maine (numerical values given 
in the left half of the matrix, ranges in the right half). 
Langton and Bowman (1978) . 



PREY 

Fish other than 
those specified below 

Clupeidae 

Other decapoda 

Cephlapoda 

Pandalidae 

Gadidae 

Euphausiaceae 

Scombridae 

Ophiuroidea 

Echinoidea 

Crangonidae 

Other Crustacea 

Polychaeta 

Animal remains 

Other phyla 




Figure 11-5. 



A food partition plot indicating the major prey of each of 
15 predacious fishes of the Gulf of Maine. Major prey is 
defined as any prey category comprising >10% by weight of 
the diet for any one predator (Langton and Bowman 1978). 

11-27 



10-80 



Community interactions are shown by means of a partition plot (figure 11-5). 
From this diagram it is clear that the Northwest Atlantic gadids show a 
reasonable degree of food partitioning, since major prey, except for broadest 
categories (e.g., other fishes and other Decapoda) is rarely shared by more 
than two or three predators. A similar situation has been described for a 
number of freshwater and other marine fish communities. Langton and Bowman 
(1978) support the contention that the cod fish evolved in a system where the 
availability of food was the controlling factor. In other words, competition 
for food, as the limiting resource, resulted in the development of different 
food habits by each species of fish. 

FACTORS AFFECTING DISTRIBUTION AND ABUNDANCE 

Environmental factors, both natural and human-originated, influence the 
abundance, distribution, and behavior of fish populations. These factors 
include water temperature, salinity, food availability, competition, 
predation, rate of harvest, disease and parasites, water quality, and dams and 
other obstructions. Their effects on fish may be direct (e.g., causing 
deaths) or indirect (e.g., decreasing food supplies). Early life stages, egg 
and larvae, are most vulnerable to stress from the environment, since they are 
less mobile, and usually occur close to shore where human activity is more 
concentrated (Clayton et al. 1976). 

Water Temperature 

Temperature is a major factor affecting the distribution of most fish 
populations. Seasonal and daily movements, gonad development, spawning 
activities, growth rates, osmoregulation, respiration, and the duration and 
success of egg and larval development vary with temperature. In general, 
marine fishes have a narrower range of temperature tolerance than estuarine 
fishes. This reflects the relative stability of the marine environment as 
compared to the fluctuating conditions of estuaries. Most estuarine and 
anadromous fishes are adapted to the warmer water temperatures typical of 
shallow estuarine or riverine environments in summer (16 to 26°C; 61 to 79°F). 
Pelagic fishes are generally more sensitive to temperature changes than 
demersal fishes. 

Targett and McCleave (1974) looked at the distribution and abundance of fishes 
in Bailey Cove (Sheepscot estuary, region 2) during the summer in relation to 
water temperature. Mummichogs, smooth flounders, Atlantic silversides, and 
Atlantic herring were the dominant fishes captured (98% of the catch). The 
mummichogs and Atlantic silversides were caught primarily in the inner cove 
(warmer, shallower water). Atlantic herring, smooth flounder, winter 
flounder, alewivcs, and Atlantic tomcod were captured near the outer margin 
(deeper, cooler, water) of the cove; American eel and blueback herring were 
found to use the cove primarily at night, when waters were cooler (McCleave 
and Fried 1975). The latter two groups of fishes tend to avoid the tidal cove 
when the waters become too warm. 

Other examples of temperature preference were shown in a study of the seasonal 
abundance of pelagic fishes in the deeper, main channels of the Sheepscot 
River estuary. Rainbow smelt were found to be the only year-round resident in 
the upper estuary (Recksiek and McCleave 1973). The relatively warm Back 
River estuary supports abundant populations of alewives, blueback herring, and 

11-28 



Atlantic menhaden in the summer months; whereas Atlantic mackerel, Atlantic 
herring and spiny dogfish are most abundant in the more marine (and therefore 
cooler) Sheepscot River estuary. Prolonged, near-freezing temperatures, 
rather than the annual temperature range, limit the habitability of temperate 
estuaries by pelagic fishes (Recksiek and McCleave 1973). The authors 
hypothesize that those pelagic species would be most affected by an altered 
temperature regime. 

Data on temperature effects on fish, other than mortality, are scarce. 
Potential thermal impacts on fish populations, therefore, must be considered 
before activities that could alter the temperature regime of a body of water 
are undertaken. Human activities that have the potential to alter water 
temperature and, therefore, the habitat of fishes, are summarized in table 11- 
6. These are primarily problems in freshwater and estuarine systems. Some 
activities raise water temperature by increasing surface water exposure to the 
sun. Examples are: the removal of stream cover vegetation (common in 
agriculture, forestry, and construction practices), and water flow 
impedimentation upstream from dams and impoundments. Another heat source is 
the direct addition of heated effluent from municipal and industrial waste 
disposal and power-producing operations. Eight power plants discharge cooling 
water within the characterization area (see chapter 3, "Human Impacts on the 
Ecosystem") . 

Salinity 

Marine waters generally are defined as those having a salinity concentration 
of >30 ppt. Estuarine salinities typically range from 0.5 to 30 ppt and fresh 
water is <0.5 ppt. Salinity is fairly constant (about 32 ppt) in the open 
ocean and is not considered a major factor in determining the distribution of 
marine fishes. In estuarine environments, however, salinity determines 
distribution of most organisms (Recksiek and McCleave 1973). Each species, 
and often each life stage, has a preference and a tolerance range. Anadromous 
fishes such as the Atlantic salmon, alewife, rainbow smelt, American shad, and 
blueback herring, spend their adult life in saline waters but return to 
freshwater rivers and streams to spawn. The eggs and larvae of these fishes 
develop properly only in fresh or slighly brackish water. Juvenile marine 
fishes are generally more tolerant of low and fluctuating salinites than adult 
fishes, therefore, estuarine and nearshore environments are usually dominated 
by juveniles (TRIGOM 1974). Salinity regimes vary constantly in coastal Maine 
(see chapter 5, "The Estuarine System"). Tidal flushing and freshwater inflow 
are the dominant regulators. People alter estuarine salinity through removal, 
impoundment, or addition of fresh water, and by altering water basin or 
channel configuration, which may change currents or alter tidal flow (table 
11-6). 

Competition 

Fishes compete for food, space, shelter, and spawning sites with members of 
their own species (intraspecif ic competition) or other species (interspecific 
competition). Competition is density-dependent; that is, it is governed by 
numbers of individuals present in a certain area and the availability of 
habitat. People sometimes increase competition in natural communities by 
limiting available habitat and food supply and by introducing competing 
species . 

11-29 

10-80 



Table 11-6. Human Activities That Potentially Influence 
Fish Abundance and Distribution 



Activities 






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Includes applications of biocides and fertilizers, erosion and runoff 

problems. 
b Impacts are dependent on design and mode of operation. 
c Includes spills, 
"Includes impacts associated with construction. 



11-30 



Predation and Harvest 

Predation is another important interaction among individuals of the same or 
different species. Predation, including harvest by people, influences the 
number of individuals in a population. Fishes are preyed upon by marine 
mammals, seabirds, wading birds, terrestrial birds, terrestrial mammals, 
waterfowl, and other fishes. Harvest by humans, specifically over-harvest, 
has had historic impacts on fish populations (see "Importance to Humanity," 
this chapter). People affect predation by stocking prey and predator species. 
Predation is essential for population regulation and must be wisely considered 
in management decisions. Human predation (harvest) limits must be maintained 
so as to allow for natural regeneration, during which only excess individuals 
should be harvested. 

Diseases and Parasites 

Fishes are subject to a wide variety of diseases and parasites, including 
viral, fungal, and bacterial infections, and parasitic protozoans, worms, 
crustaceans, and sea lampreys. Deficiency and degenerative diseases, such as 
cancer, rickets, blindness, and liver dysfunction, are common. Fish 
populations in the wild usually are not impaired seriously by disease and 
parasites and epidemics are rare. 

Hatchery fishes, however, are very susceptible to large scale infestations and 
may serve as carriers to the wild. Furunculosis ( Bacillus salmonicida ) is a 
disease that has spread from hatchery reared salmon to natural populations 
(Clayton et al. 1976). Disease can be a significant limiting factor in 
recovering populations. The market value of some species (cod, for example) 
is diminished by the presence of parasites. The problems and possible 
mechanisms of "codworm" infestation are discussed in chapter 13, "Marine 
Mammals." Diseased or parasite-carrying fishes may be more susceptible to 
other causes of mortality. People increase fish exposure to disease-causing 
agents and parasites, primarily through disposal of wastes in waters (table 
11-6). People also introduce potentially detrimental species to an area. The 
sea lamprey (a parasitic fish) was inadvertently introduced and became 
landlocked in the Great Lakes, where it has all but eliminated some of the 
commercial and recreational fisheries. Its habitats in Maine presently 
include the open ocean, coastal rivers, and their tributaries. There is as 
yet no evidence of harm to Maine's freshwater fish populations from sea 
lampreys (Everhart 1958). 

Dams and Obstructions 

Physical obstructions, such as water falls and artificial dams, dikes and 
weirs, are barriers to migrating fishes. The majority of the existing dams in 
the coastal zone are impassable for many anadromous fishes (American shad, 
Atlantic salmon, alewife, sturgeon, and blueback herring), and many resident 
migratory freshwater fishes (e.g., trout). Young of the catadromous eel 
(elvers) can surmount most of these barriers (personal communication from C. 
Walton, Maine Department of Marine Resources, Hallowell, ME; May, 1978). Dams 
with heights as low as 2 feet (0.6 m) can be effective barriers at low water 
levels . 



11-31 



10-80 



Data on the distribution, height, and condition of impoundments in the Maine 
coastal zone show that of the 176 surveyed impoundments, only 20 were equipped 
with fish passage facilities. These dams caused much of the decline of 
anadromous fish runs in Maine. Over 20 rivers in Maine originally supported 
Atlantic salmon runs; that number declined to less than 9 by I960 (Everhart 
1958). A recent report by the U.S. Army Corps of Engineers (1979) on the 
hydroelectric potential at existing dam sites in New England identifies a 
total of 276 dams (20% of the state total) in the characterization area. 
Nineteen of these dams are currently generating power, 56 are either partially 
breached or need total reconstruction, and 201 are existing structures 
currently in use for purposes other than hydropower. Of the 257 sites, 96 
have a potential generating capacity greater than 50 kw at 40% capacity. 
These are the sites most likely to be developed first for hydroelectric power 
generation (see atlas map 4) . 

The problems dams present to migrating fishes are by no means eliminated by 
the installation of fish passage facilities. Most fish passage facilities aid 
upstream migrating fishes but provide little, if any, help to downstream 
migrating fishes and juveniles. Undirected, the downstream migrants follow 
the flow of water over spillways or through conduits and turbines. Mechanical 
and thermal mortality or injury often result. Where falls or spillways are of 
sufficient height to create fall velocities approaching 40 feet/sec or 12 
m/sec (about 25 feet or 8 m of head) , potential for damage to fishes exists 
(Bell 1973). Although this is not usually a major problem of low-head 
hydroelectric dam facilities, of the 256 existing nonhydroelectric dam sites 
in the coastal zone, at least 17 have a gross head greater than 25 feet. 
Also, fishes tend to concentrate at fish passage facilities (waiting to go up 
or down) . This concentration increase their availability to anglers and they 
also may be easy prey for birds and other predators. 

Fish passage facilities do not always work well. Fishway configurations vary 
in approach, length of run, slope, number and size of resting pools, water 
levels and flows, and velocities. Many species require special design 
features and it is difficult to build a fish passage facility that acommodates 
all sizes or species of fish. The ability of a fish to negotiate a fishway or 
ladder is highly dependent on its swimming speed and sensory behavior. 
Sturgeon do not successfully pass pool type fishways (Bell 1973). They must 
be moved via elevator (lock), be carried, or trucked over. There are no such 
facilities in Maine. Striped bass and rainbow smelt are also very reluctant 
to use many fishways (personal communication from B. Rizzo, U.S. Fish and 
Wildlife Service, Newton Corner, MA; November, 1979). All of the existing 
fish passage facilities in Maine are either Denil fishways or vertical slot 
type. These facilities are suitable for passage of Atlantic salmon, American 
shad, blueback herring, alewife, sea lamprey and most trout (personal 
communication from B. Rizzo, Ibid ) . 

Water Quality 

Aquatic environments are the eventual sinks for most wastes and pollutants. A 
number of water quality and water chemistry parameters have profound effects 
on fishes, and human activities have demonstrable effects on these parameters. 
These water quality parameters include turbidity, dissolved oxygen, pathogens, 
toxicants, radioactivity, nutrients, and pH. The major water quality problems 
in coastal Maine are described in chapter 3, "Human Impacts on the Ecosystem." 

11-32 



Turbidity . This is a measure of the amount of suspended solids in the 
water column. These solids are usually fine organic or inorganic materials. 
They are essential to biological processes as sources of nutrients but in 
excess can cause serious problems. Extreme suspended sediment loads may be of 
natural origin or due to human activities (dredging or spoil disposal, 
construction, agricultural, or timberland runoff). High levels of solids, as 
they settle, are a particular hazard to demersal eggs and the integrity of a 
spawning area in general. The main effects are direct and acute for eggs, 
young, and adults. The two major effects are interference with oxygen 
exchange (smothering) or clogging of fish gills (Clayton et al. 1976). The 
extent of harm due to settling of suspended solids depends on the type of 
material, time of year, and the species involved. Clay particles are apt to 
form a hard, compact crust upon settling. Organic materials, such as wood 
pulp fibers, can form an impenetrable mat over the bottom (Bell 1973). This 
can render a spawning area unusable and suffocate invertebrates (fish food) . 
Silt may also contain toxic residues (from agricultural or industrial wastes), 
which may be lethal to local fishes or destroy fish food organisms. Excessive 
turbidity from organic wastes may seriously reduce the availability of oxygen 
through microbial action. Turbidity may also be caused by living material, 
such as plankton, usually in concentrations greater than . 1% by volume (Bell 
1973). 

Suspended sediments in excess reduce the penetration of light into the water 
column which may reduce the populations of submerged vascular plants, 
phytoplankton, and algae. This decreases primary productivity and affects 
available food supply in the system. High turbidity is most common in 
sluggish waters near shore and in partly enclosed areas. In general the less 
mobile (demersal) fishes have a higher tolerance for turbid water but are also 
more heavily exposed as the sediment settles (Clayton et al. 1976). 

Dissolved oxygen . Most fishes are adversely affected by reduced levels 
of dissolved oxygen (DO). Massive fish kills have been recorded as a result 
of severe oxygen depletion. Fish-kill data are not systematically maintained. 
Active, migratory fishes like the blueback herring, alewife, and menhaden, 
have high oxygen demands and are particularly sensitive to dissolved oxygen 
sags. For most cold water fishes (e.g., salmon and trout) it is desirable 
that DO concentrations be at or near saturation levels (Bell 1973). Certain 
human activities increase the oxygen demand in aquatic systems. Additions of 
organic wastes, nutrients, and sediments increase the levels of microbial 
decomposition, which consumes oxygen. Dissolved oxygen reductions are more 
often a problem of sluggish, impounded, or enclosed waters. Temperature also 
affects DO levels: higher temperatures decrease DO levels. 

Pathogens . A wide variety of pathogens, in the form of bacteria, 
protozoa, viruses, and fungi, may enter aquatic systems from municipal waste 
disposal activities or accidental spills. Chronic disturbances, such as 
municipal sewage, may permit the population to remain in place but cause 
morbidity, such as fin rot or other diseases (Clayton et al. 1976). 

Toxicants . Heavy metals, hydrocarbons, biocides, and industrial 
chemicals are particularly hazardous and lingering toxicants. Effluents from 
industrial plants and mines may contain heavy metals (e.g., copper, mercury, 
cadmium, selenium, silver, mercury, lead, zinc, and iron) in concentrations 
that are lethal to fishes or their food organisms. These elements can 

11-33 

10-80 



accumulate in fish tissue over time. Chronic, insidious effects occur as 
these elements enter the aquatic food chain. Some become concentrated in 
organisms, and are transferred from prey to predator (biological 
magnification). Certain combinations of metals (such as cadmium and zinc, 
copper and zinc, selenium and zinc) exhibit compounding effects. This factor 
must be considered when they are found in combination. The reactivity of 
these metals, and other toxic compounds, is affected by pH. Analysis of fish 
tissues from Maine has shown unusually high mercury content, for unexplained 
reasons (personal communication from A. Julin, U.S. Fish and Wildlife Service, 
Newton Corner, MA; January, 1980). In many cases, natural sources are 
suspected. 

Fuel oil, kerosene, and other hydrocarbons are directly toxic to plants and 
animals. They enter water bodies through spills or as industrial wastes and 
can be present throughout the water column and on the bottom. The shoreline 
(intertidal) zone is most heavily and persistently damaged by nearshore oil 
spills (Canada Department of Environment 1974; and NOAA 1978). The occurrence 
of oil spills in Maine is documented in chapter 3, "Human Impacts on the 
Ecosystem." Fishes, especially flounder, accumulate petroleum hydrocarbons in 
their tissues. Up to 97% of the cod and pollock embryos collected from the 
area of the Argo Merchant ship oil spill in 1976 were dead, dying, or 
malformed (NOAA 1978). Tainted fish flesh, caused by exposure to soluable 
petroleum components, make fish unmarketable. Bowman and Langton (1978) found 
that fishes did not avoid prey that were contaminated with oil. Sinderman 
(1978) summarizes the effects of oil on marine organisms based largely on 
laboratory toxicity studies. Sub-lethal and behavioral effects include 
inhibition of mating responses, reduced fecundity, chromosomal abnormalities 
in eggs, abnormal larval development, and decreased feeding activities. 

Biocides include both pesticides and herbicides. Chronic and acute toxicities 
of a given compound vary with environmental factors, such as water temperature 
and water chemistry, and biological factors, such as age, sex, size, 
condition, and species of fishes involved. The most hazardous biocides are 
those that are persistent in the environment (have low biodegradability) . 
This is common of the chlorinated hydrocarbon pesticides, such as DDT and 
Dieldrin, and polychlorinated biphenyls (PCBs). They can remain in sediments 
unchanged for many years. Many animals, including fishes, take up these 
chlorinated hydrocarbons that are present in water at sublethal levels and 
store them in their fatty tissues. Assimilation takes place both in feeding 
and in direct assimilation from the water. Death can occur when food supply 
is restricted and the animals use their body fat for energy. Equally 
disasterous is the mobilization of the contaminated body fat in reproduction. 
The transfer of toxicants may inhibit normal development of the young in this 
way (Bell 1973). 

Fishes may build up pesticide residues in their body tissues gradually without 
apparent ill effect, but other animals preying upon contaminated fishes may be 
killed or damaged by the concentrated toxicants. The establishment of 
controls for safe levels of applications of these biocides requires 
consideration of these food chain accumulation and storage phenomena. 
Pesticides can affect fish populations indirectly by eliminating food items. 
The other group of pesticides, the organic phosphates (e.g., Sevin, Orthene, 
Sumithion, Metacil, and Dylox) are generally less toxic than the chlorinated 
hydrocarbons and usually persist for less than one year. A number of studies 

11-34 



have looked at the impacts of those insecticides used in the spruce budworm 
control program (Rabeni 1978; U.S. Forest Service 1976; and Gibbs 1977). Many 
herbicides (e.g., toxaphene , inorganic sulfates, endothal, diquat, hyamine, 
delapon, silvex, and 2,4-D) at high concentrations have toxic effects on 
fishes (Workman and Neuhold 1963; Surber and Pickering 1962; McKee and Wolf 
1963; Jones 1964; Cope et al. 1970; and U.S. Department of Agriculture 1968). 
Toxicants in fish have not been a serious problem in Maine. 

Radioactivity . The exposure of plants and animals to radioactivity 
should be avoided. Radionuclides in aquatic environments may affect fishes 
through direct radiation from the water or accumulated sediments. 
Radioactivity may be absorbed onto skin, through cell membranes, or ingested 
with food and water. The major route of accumulation appears to be through 
consumption of food organisms (mostly filter feeders) which already have high 
concentrations of radionuclides from the waters around them. Radioactive 
elements and compounds enter aquatic systems through natural fallout, release 
of wastes from nuclear users, and accidental spills. Concentration and 
accumulation of radionuclides in mussels has been documented in the vicinity 
of a nuclear power plant in Plymouth, Massachusetts (personal communication 
from A. E. Eipper, U.S. Fish and Wildlife Service, Newton Corner, MA.; 
December, 1979). Radiation has not yet been a problem to the fishes of Maine. 

Nutrients . Raw materials essential to biological organisms are called 
nutrients. Excess nitrogen (in the form of nitrates) and phosphorus (in the 
form of phosphates) can lead to eutrophication in aquatic systems, enhancing 
the growth of primary producers (e.g., algae). Blooms of these plants create 
acute problems for fishes. As the bloom dies, deoxygenation occurs through 
microbial action and creates a lethal environment for organisms requiring high 
oxygen content. Chronic effects may include the eventual dominance of the 
area by species more tolerant of low dissolved oxygen levels. Excess 
quantities of nutrients are sometimes introduced through waste disposal, 
runoff from agricultural and timber lands, and accidental spills (see chapter 
7, "The Lacustrine System," and chapter 3, "Human Impacts on the Ecosystem"). 

pH. Freshwater systems with low buffering capacity are very sensitive to 
changes in the pH (a measure of acidity or alkalinity) . Marine waters are 
highly buffered by salts and carbonates, and pH is relatively uniform. Acid 
precipitation is lowering the pH (increasing the acidity) of lakes and streams 
in the northeastern U.S., including Maine, at an alarming rate (see chapter 3, 
"Human Impacts on the Ecosystem"). Natural rainfall should have a pH near 
5.7. Some species (e.g., most trout) are seriously impaired or killed at pH 
levels below 5.0. The pH of precipitation in the northeastern U.S. now ranges 
between 2.1 and 5.0 (Likens and Bormann 1974). Complete losses of fish 
populations due to acidification have been reported in the Adirondacks region 
of New York State (Schofield 1977) and Ontario, Canada (Beamish and Harvey 
1972), and other areas. Symptoms of the acidification included poor 
recruitment, failure of females to produce viable eggs, and high mortality or 
abnormalities of eggs and larvae. Reactivities of certain toxic elements and 
compounds in sediments are affected by pH. For example, aluminum, copper, and 
mercury, are released by sediments at lower pH levels. The major causes of 
acidification are: combustion of fossil fuels in power generation, and 
transportation and subsequent production of sulfuric and nitric acids in the 
atmosphere. The problem of acidification can only worsen as consumption of 
fossil fuels increases. 

11-35 



10-80 



IMPORTANCE TO HUMANITY 



The importance of fishes to humanity extends beyond their role in the energy 
flow of aquatic food webs. As a renewable resource, fishes are important to 
humans as food and industrial products, for recreation and sport, and as 
biological indicators of environmental problems. They also provide 
opportunities for scientific and educational studies in natural history, 
evolution, and resource management. 

Maine lands about 30% of the total catch of New England's commercial fishery 
and is second only to Massachusetts in total fish landed. Catch statistics 
for the last century are presented in table 11-7. From 1887 to 1931 the 
annual catch ranged from 123 to 242 million pounds and adveraged 144 million 
pounds. Between 1932 and 1940, annual landings ranged from about 67 million 
pounds (1938) to 116 million pounds (1938) and averaged only 96 million 
pounds. From 1942 to 1968 average annual landings increased to 245 million 
pounds and total landings ranged between 134 million pounds (1943) and 356 
million pounds (1950). Average and total landings declined again for the 
years 1969 to 1977, showing a range between 138 and 178 million pounds and a 
yearly average of 151 million pounds. 

The most important commercial species in the last decade, in order of 
abundance, were herring, redfish, whiting, menhaden, cod, pollock, red and 
white hake, mackerel, alewife, flounder, haddock, cusk, and eel (table 11-8). 
One hundred years of commercial landings statistics for major species are 
given in table 11-9. Herring and redfish landings remain at the top both in 
catch quantity and in dollar value. Similarly, alewife remain a steady 6th 
and 7th on the list. Cod landings now are again on the increase. The haddock 
catch declined after the mid-1930s, rebounded some in the 1950s, and again 
declined in the late 1960s. Data from the last 2 years suggest that the 
haddock catch is on the increase. Pollock catches picked up betwen 1940 to 
1960, showed a great drop during the 1960s, and now appear to be on the 
increase (1974 to 1977). Whiting (silver hake) made a sudden appearance in 
the commercial market, ranking third in catch quantity for the years between 
1939 and 1973. Menhaden is another species making a sudden appearance among 
the top seven (1973 to 1977). 

Landing points do not always represent areas of capture and undetermined 
amounts of Maine catches are landed at ports in Canada, Massachusetts, and New 
Hampshire, and vice versa. Trends in landings of principal species (tables 
11-8 and 11-9) reveal fluctuations and shifting emphases in response to fish 
abundance, market demand, gear efficiency, fishing effort, and foreign 
fishing. General declines in abundance are often unperceived statistically 
until well into the declining period. Intensified fishing effort and the 
utilization of more selective gear tend to counterbalance apparent catch 
shortages. 



11-36 



Table 11-7. Landing Statistics (pounds and dollar values) for Maine Fisheries, 
1879 to 1976 a . 



Year 



Pounds 


(1000 lb) 




NA b 


131 


380 


132 


930 


129 


560 


123 


405 


242 


390 


124 


724 


173 


843 


147 


956 


116 


707 


123 


326 


162 


940 


143 


824 


116 


236 


90 


602 


98 


498 


112 


,219 


101 


,179 


67 


,206 


116 


,167 


88 


,088 


168 


,392 


133 


,920 


161 


,285 


184 


,425 


195 


,955 


220 


,868 


303 


,504 


294 


,297 



Value 
($1000) 



1880 
1887 
1888 
1889 
1898 
1902 
1905 
1908 
1919 
1924 
1928 
1929 
1930 
1931 
1932 
1933 
1935 
1937 
1938 
1939 
1940 
1942 
1943 
1944 
1945 
1946 
1947 
1948 
1949 



2742 
2365 
2292 
2111 
2655 
2919 
2386 
3257 
3889 
4137 
4231 
4897 
4329 
3443 
2413 
2308 
3309 
2806 
2521 
2695 
2607 
5229 
7010 
7053 
12,499 
14,142 
12,870 
16,077 
14,988 



NMFS, Maine Landings, 
'not available. 



(Continued) 



11-37 



10-80 



Table 11-7. (Concluded) 



Year 



Pounds 


(1000 lb) 


356 


266 


223 


051 


298 


151 


243 


513 


285 


736 


257 


174 


279 


562 


292 


250 


316 


955 


265 


958 


294 


641 


197 


970 


294 


323 


285 


,636 


192 


575 


204 


,846 


200 


,392 


197 


,438 


218 


,731 


191 


,314 


158 


,806 


142 


,684 


149 


,271 


143 


,319 


147 


,822 


138 


,360 


177 


,835 



Value 


($1000) 


14, 


688 


15 


606 


17 


897 


16 


7 54 


16 


856 


16 


083 


16 


966 


16 


769 


19 


024 


19 


571 


20 


071 


19 


,029 


20 


365 


21 


,216 


21 


,958 


21 


,922 


24 


,329 


22 


,973 


25 


,614 


27 


533 


30 


,672 


31 


,129 


34 


817 


43 


,061 


41 


410 


48 


,499 


53 


,822 



1950 
1951 
1952 
1953 
1954 
1955 
1956 
1957 
1958 
1959 
1960 
1961 
1962 
1963 
1964 
1965 
1966 
1967 
1968 
1969 
1970 
1971 
1972 
1973 
1974 
1975 
1976 



11-38 



Table 11-8. Landings (pounds) and Value (dollars) of the Major 
Commercial Fish Species in Maine in 1977 a 



Species 



Rank Rank Utility Recent 
and pounds and dollars catch 

(1000s) (1000s) trends 



Herring 

Red fish 

Pollock 

Cod 

Flound er : sp ec ies 



1 73,050 

2 20,801 

3 10,685 

4 9126 

5 8272 



1 3545 Food and Increasing 

industrial 



2 3140 Food 
5 1406 Food 
4 1974 Food 

3 2869 Food 



Increasing 
Increasing 
Increasing 
Increasing 



Red & white hake 
Alewif e 

Menhaden 

Haddock 

Cusk 

Mackerel 

Whiting (silver hake) 

Eel 



6 

7 

8 

9 
10 
11 
12 

13 



6600 7 

3374 10 

3289 12 

2250 6 

1000 9 

330 11 

225 13 

176 8 



744 Industrial Increasing 

120 Industrial Fluctuating/ 
increasing 

71 Industrial Fluctuating/ 
decreasing 



960 Food 

163 Food 

77 Food 



Increasing 
Increasing 
Fluctuating 



17 Food and Decreasing 

industrial 

263 Food and Fluctuating 

industrial 



a Lewis 1979. 



11-39 



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11-41 



10-80 



A very important factor in recent catch trends is the adoption of the 200-mile 
(320 km) limit to foreign fishing. Since its implementation in March of 1977, 
substantially fewer foreign vessels are fishing the waters off the east coast 
of the United States. This has resulted in increased availability of many 
species to American fishermen. According to the National Marine Fisheries 
Services (NMFS) figures, the overall landings of all species at 8 New England 
ports between January and April of 1977 increased by 15 million metric tons 
over the 83 million tons taken in 1976 (Lyman 1977). 

Sport fishing is one of the oldest forms of human recreation and is enjoyed by 
many. The mean annual number of sport fishing licenses issued in Maine 
between 1968 and 1971 was 240,512. An average of 145,678 of these were sold 
to Maine residents annually during those years, which amounts to about 15 
licenses per 100 people (MDIFW 1976). The major sport species inhabiting the 
characterization area are listed in table 11-10. The catch for some sport 
species in Maine waters, e.g., bluefish and striped bass, rivals or exceeds 
their contribution to the commercial catch (Chenoweth 1977). The 200-mile 
(320 km) limit probably has affected marine sport fishing as well. Since its 
implementation in 1977, estimates of cod and pollock catches in New England by 
recreational anglers have nearly doubled, but the cause has not been 
established (Lyman 1977). 

Human activities (e.g., operating dams, log-holding ponds, and hydro-powered 
mills) on and along the waterways of Maine have had damaging impacts on both 
inland and anadromous fisheries. Efforts to improve and install fishways and 
the elimination of river log drives have aided the restoration of many species 
in several rivers. The Atlantic salmon is the fisher's prize and probably 
best known. In 1972 along the west branch of the Penobscot River, fishing 
opportunities greatly increased with the end of Great Northern Company's 
pulpwood drives. The halting of log drives on the Kennebec River in 1976 
should contribute to the recovery of that river's fishery. The Penobscot 
River (Bangor Salmon Pool) and the Machias River reported "record-breaking" 
rod catches of salmon in 1978. The removal or breaching of dams along these 
waterways was a major factor contributing to these increases. The Dennys 
River, one of Maine's smaller coastal river systems and well known for its 
Atlantic salmon, landlocked Atlantic salmon, and smallmouth bass, has also 
shown increased catches for the 1970s. According to Atlantic Salmon 
Commission records, more than 800 salmon were reported taken in Maine in 1978. 
As of August 1979, rod and trap catches were less than half of that. There is 
considerable debate over the cause of these poor 1979 returns. Contributing 
factors may be the extremely poor survival of young salmon (smolts) migrating 
down to the sea in the spring of 1977. In August, 1979, fishing for Atlantic 
salmon was officially halted for the season statewide. 

MDIFW (1976) provides detailed information on existing access for anglers and 
on the distribution, abundance, present and projected angler use of landlocked 
Atlantic salmon, brook trout, brown trout, lake trout, rainbow trout, rainbow 
smelt, lake whitefish, chain pickerel, white perch, and smallmouth and 
largemouth bass. Brown trout, rainbow trout, and smallmouth and largemouth 
bass are not native to Maine (their introductions date back to the late 1860s) 
but they comprise a major fishery today. MDIFW has stocked a number of lakes 
and ponds with brown trout, brook trout, largemouth and smallmouth bass, 
landlocked Atlantic salmon, lake trout, alewife, rainbow trout, sunapee trout, 
and chain pickerel (see appendix table 10, and "Management" in this chapter). 

11-42 



Table 11-10. Major Sport Fishes of the Characterization Area c 



Group and 
common name 



Taxonomic name 



Marine 

Bluef ish 

Atlantic cod 

Atlantic mackerel 

Winter flounder 

Shark 

Pollock 

Red fish 



Pomatomus saltatrix 

Gadus morhua 

Scomber scombrus 

Pseudopleuronectes amer icanus 

Squalidae sp. 

Pollachius virens 

Sebastes marinus 



Anadromous 

Atlantic salmon 
American shad 
Alewif e 
Striped bass b 
Rainbow smelt 

Freshwater 



Salmo salar 
Alosa sapidissima 
Alosa pseudoharengus 
Morone saxatilis 
Osmerus mordax 



Coldwater 

Landlocked salmon 
Brook trout 
Lake trout 
Brown trout 
Rainbow trout 
Lake whitefish 

Warm water 

Chain pickerel 
White perch 
Smallmouth bass 
Largemouth bass 



Salmo sala r sebago 
Salvelinus fontinalis 
Salvelinus namaycush 
Salmo trutta 
Salmo gairdneri 
Coregonus clupeaf ormis 



Esox niger 
Morone americana 
Micropterus dolomieui 
Micropterus salmo ides 



'Foye (1969); MDIFW (1976) ; Chenoweth (1977) ; Meister and Foye (1963) 



J Anadromous, but does not spawn in Maine. 



11-43 



10-80 



As biological indicators, fish are useful in helping to predict, solve, and 
avoid many ecological problems. Insight into the general effects of toxic 
substances can be determined through bioassay and bioaccumulation studies on 
fishes. Their utility as indicators, however, has intrinsic problems. 
Because of their mobility, the strict presence or absence of a particular fish 
species is not always a reliable indication of the quality of the local 
habitat. Too little is known about seasonal and long-term natural cycles and 
their influence on fish populations to determine definite cause and effect 
relationships. The impact of an acute perturbation, such as an oil spill or 
massive dissolved oxygen sag, may be clear but a particular fish's response to 
a chronic perturbation may not be evident for a long time, if at all. A less 
mobile, low-level consumer organism, such as a benthic invertebrate (e.g., 
mussel, clam, and oyster) is, in most cases, a better indicator of habitat 
"quality". 



MANAGEMENT 

Although it is beyond the scope of this characterization to make management 
recommendations for the fisheries of the Maine coast, this section is intended 
to introduce the reader to existing management authorities and to describe 
current management plans. A detailed account of the regulatory processes 
(Federal and State) and emerging management technologies associated with 
marine resource conservation was prepared by Chenoweth (1977). 

The following agencies contribute to the development of management policy for 
the various fisheries in the Maine coastal zone: 

1. Maine Department of Inland Fisheries and Wildlife (MDIFW) 

2. Maine Department of Marine Resources (MDMR) 

3. New England Regional Fisheries Management Council 

4. Maine State Legislature 

5. Atlantic Sea Run Salmon Commission 

6. National Marine Fisheries Service 

7. U.S. Fish and Wildlife Service 

The authority of the State of Maine over its fishery resources extends outward 
to 3 miles from the coast. Within this boundary the Maine Legislature has 
authority to initiate management policy through legislation. Policies are 
adopted through legislative action upon recommendations from resource agencies 
(MDIFW and MDMR), the fishing industry, sportsmen's groups, environmental 
groups, and others. 

The Commissioner of the Maine Department of Inland Fisheries and Wildlife 
authorizes research and establishes management regulations for the freshwater 
fisheries and wildlife resources within the State. The MDIFW sponsors 
statewide biological surveys of the lakes, rivers, and streams. They describe 
the major problems associated with the management of freshwater and anadromous 
fisheries in the major stream systems. These reports discuss the history, 
status, and potential of the major fisheries and evaluate specific management 
alternatives. MDIFW and the Atlantic Sea Run Salmon Commission are currently 
preparing updates on those original biological surveys, addressing fish 
restoration and management in major stream systems. Recently the MDIFW, 
taking the initiative in planning for Maine's fish and wildlife resources, has 

11-44 



compiled species assessments and developed strategic plans for the management 
of the following inland fisheries: landlocked Atlantic salmon, brook trout, 
lake trout, brown trout, rainbow trout, rainbow smelt, lake whitefish, chain 
pickerel, white perch, smallmouth bass, and largemouth bass (MDIFW 1976). 

The Commissioner of The Maine Department of Marine Resources has the authority 
to "investigate conditions affecting marine resources" and to establish 
regulations that "promote the conservation and propagation of marine organisms 
within Maine's coastal waters." For jurisdictional purposes, coastal waters 
are defined as "all waters of the State within the rise and fall of the tides 
and within the marine limits of the jurisdiction of the State" (Marine 
Resources Laws and Regulations, Revised to January, 1979). The Commissioner 
authorizes research and administers and enforces all laws that apply to the 
marine and estuarine resources of the State, with the exception of Atlantic 
salmon, which is under the authority of the Atlantic Sea Run Salmon 
Commission. 



Maine Department of Marine Resources conducts extensive biological research 
programs that contribute to the development of comprehensive fish, wildlife, 
and marine resource management recommendations. In particular, the MDMR has 
published management recommendations for the alewife, American eel, and 
striped bass resources, addressing the history, status, and future of these 
fisheries (Walton 1976; Flagg 1976; and Ricker 1976). 

The creation of the Atlantic Sea Run Salmon Commission by the legislature in 
1947 authorized the enhancement of an anadromous sport fishery in the State of 
Maine. This agency evaluates, manages, and restores the fishery potentials of 
individual watersheds. Studies and investigations include stocking programs 
and population assessments. 

The Federal Government assumes certain responsibilities or tasks in the 
management of many fishery resources because the migratory habits of certain 
species make them both interstate and international resources. These 
responsibilities are carried out by the U.S. Fish and Wildlife Service (FWS) 
and the National Marine Fisheries Service (NMFS) . Both FWS and NMFS have an 
advisory role in the issuance of Federal permits for activities that may 
affect fish habitat. 

Outside of waters on Federal lands, FWS has no management authority per se. 
FWS maintains programs of fishery research with the States for coastal 
anadromous fisheries and inland fisheries and reservoirs; it supports 
Cooperative Fishery Research Units; and it maintains a separate program to 
preserve, restore, and enhance endangered and threatened species. FWS also 
maintains Federal fish hatcheries, which provide fishes for State stocking 
programs . 

NMFS is concerned with many aspects of marine fisheries, ranging from resource 
assessment to ultimate use by consumers. It is the lead research agency for 
marine resources and fisheries outside the State's territorial waters and 
maintains a commercial catch data base within its statistics and market news 
division. The Resource Assessment Division of the Northeast Fisheries Center 
of NMFS has completed stock assessment documents on the following commercially 
important species: herring, white hake, cod, squid, northern shrimp, silver 

11-45 



10-80 



hake, pollock, redfish, and haddock. NMFS funds State research through the 
Commercial Fisheries and Research Act (PL 88-309) and the Anadromous Fish Act 
(PL 89-304). It is also responsible for the enforcement of domestic fisheries 
regulations under the authority of the Conservation and Management Act (PL 94- 
265). 

Prior to 1 January, 1977, marine resources in the waters outside a 12-mile (19 
km) boundary (offshore fisheries) were under international control. These 
fisheries were regulated by joint effort of the nations participating in the 
International Commission for Northwest Atlantic Fisheries (ICNAF), of which 
the United States was a member. Regulations included minimum mesh-size in 
trawls, minimum length of fish caught, restriction of fishing by large 
trawlers over certain areas, seasonal closures of some areas for certain 
species, species quotas, total fish quotas, and international inspection 
schemes (Chenoweth 1977). 

On 1 March, 1977, by act of Congress (Conservation and Management Act, PL 94- 
265), the United States declared management authority over all marine 
resources in an area between the 3-mile (5 km) limit of the States' 
territorial seas and a line 200 miles (320 km) from the territorial seas. In 
New England waters, the fisheries within the zone are to be regulated by the 
U.S. Department of Commerce, based upon policies established by the New 
England Regional Fisheries Management Council. The mechanism for establishing 
fisheries policy is the Fisheries Management Plan, which describes and 
analyzes the socioeconomic aspects of the fisheries, assesses the stocks for 
each major commercial species, determines the optimum yield from the 
fisheries, and recommends appropriate measures to obtain the optimum yield. 
The determination of optimum yield takes into account biological, socio- 
economic, and environmental factors. 

Coordination of management strategies and regulation between the State of 
Maine and the New England Council will be necessary to effectively manage the 
stocks of several commercial species. The 3-mile (5 km) limit is a legal and 
not a physical boundary; fish move freely across it. Allowable catch levels 
and other regulations established by the State of Maine inside the 3-mile 
limit or by the Council outside the 3-mile (5 km) limit affect stocks on both 
sides. Enforcement of regulations on fishery utilization is effective only if 
coordinated on both sides. Coordination between States is also important. 
The species for which cooperative effort is most needed are Atlantic herring, 
silver hake, cod, haddock, yellowtail flounder, and pollock. 

The key organizations involved in the development of fisheries management 
plans and their major inputs to the planning process are summarized in table 
11-11. 

RESEARCH NEEDS 

Data on the relative biomass of fishes by habitat (system and class) are 
lacking. This information is very important in identifying and quantifying 
energy flows and productivities of different habitats by region and season. 



11-46 



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11-47 



10-80 



Reproductive habits data and general life history information are still 
lacking for a number of common marine and freshwater fishes. This is 
especially true for fishes that presently have little commercial or sport 
value. 

Stock assessment is of paramount importance in fishery management. Stock 
assessment technology has developed rapidly over the past few years; however, 
adequate data are lacking for many species (Brown 1976). The relationship 
between stock size and recruitment remains poorly defined for many species. 
More laboratory and field research is needed to understand the mechanisms of 
fish reproduction and how environmental factors influence the survival of 
fishes from egg to adult stages. 

Data are needed on the trends and significance of environmental contaminant 
(pesticides, PCBs , and heavy metals) levels in fishes in the different 
drainages and rivers. 

CASE STUDY: SHORTNOSE STURGEON 

The shortnose sturgeon, Acipenser brevirostrum , is the smallest in the family 
of some 20 forms recognized worldwide and is a Federally listed endangered 
species. It is a moderate-sized (to 42 inches or 107 cm), slow-growing, long- 
lived (to 35 years or so) , anodromous fish. According to Bigelow and 
Schroeder (1953), the shortnose sturgeon is scarce in the Gulf of Maine and 
there is no reason to think it has ever been more plentiful there. 

Range and Distribution 

The shortnose sturgeon ranges historically from New Brunswick, Canada, to 
Florida, typically in large tidal rivers such as the Potomac, Delaware, 
Hudson, Connecticut, and St. John. In Maine, shortnose sturgeon occur in the 
Sheepscot River (Fried and McCleave 1973), the Kennebec River, and the 
Penobscot River systems (personal communication from T. Squires, Maine 
Department of Marine Resources, Hallowell, ME; December, 1979). Information 
is scarce but there is evidence that shortnose sturgeon enter the sea and 
wander some distance from their parent stream (Bigelow and Schroeder 1953). 
It is not so strongly migratory as other species. 

Reproduction and Growth 

Very little is known about the spawning and early life history of the 
shortnose sturgeon; the young rarely are seen. Male shortnose begin to spawn 
at a total length of about 51 cm (20 inches) and females at 61 cm (24 inches). 
Reproduction occurs once every 3 years for individual females (Dadswell 1975). 
Spawning apparently occurs in the middle reaches of large tidal rivers from 
April to June, depending on location; adults apparently return to a parent 
stream (Scott and Crossman 1973). In the Connecticut River, eggs have been 
collected in late May near the river bottom when water temperature ranged 
between 15° C and 17.8°C or 59°F to 64°F (Clayton et al. 1976). Bean (1903) 
reported shortnose sturgeon spawning in the Delaware River in brackish or 
nearly fresh water in depths of 2m to 9 m (7 feet to 30 feet). 

According to Scott and Crossman (1973), the eggs are dark brown, small, and 
less numerous per pound of fish than in other sturgeons. The eggs of a 

11-48 



related species, the Atlantic sturgeon, are 2.5 mm to 2.6 mm in diameter, are 
demersal, and stick to submerged weeds and rocks. They apparently are 
broadcast with no parental care and hatch in 7 days at 17.8 1 or 64°F (Clayton 
et al. 1976). The eggs of shortnose sturgeon hatch in about 13 days at 8°C to 
12°C or 44°F to 54°F (Carlander 1969). 

Shortnose sturgeon are slow growing. In the St. John River estuary, New 
Brunswick, Canada, shortnose sturgeon exhibited a growth rate of 1 to 3 cm/yr 
(0.4 to 1 inch/yr) although longevity was great (34+ years; Dadswell 1975). 
In the Hudson River, males mature at age V and females at age VI (Greeley 
1937). Growth data for shortnose sturgeon captured in the Hudson River are 
(from Greeley 1937): 



AGE NO. MEAN TL (mm) MEAN WT. (gm] 



III 3 480 766 

IV 5 536 807 

V 19 564 1,129 

VI 12 615 1,469 

VII 14 615 1,460 

VIII 8 653 1,660 

IX 4 795 3,098 

X 3 732 2,150 

XI 4 678 1,955 

XII 3 787 3,093 

XIII 4 665 1,941 

XIV 2 711 2,622 



Food and Feeding Habits 

Shortnose sturgeon are bottom feeders. Hudson River specimens (young 
sturgeon) fed upon sludgeworms, chironomid larvae, small crustaceans, and some 
plant material. In the St. John River estuary, shortnose sturgeon feed on 
molluscs primarily, while a specimen in the Connecticut River was found to 
prey upon burrowing mayfly larvae principally; ostracods, caddis flies, 
oligochaetes , seeds, wood, and sand were also found in its stomach (Clayton et 
al. 1976). 

Young and adult shortnose sturgeon alike compete for food with other bottom 
feeders such as suckers, but their random, suctorial feeding habit may have 
some advantage over the many species of fishes that browse on individual 
bottom organisms in the same turbid rivers (Scott and Crossman 1973). 



11-49 



10-80 



Predation 

Little is known of the predators of shortnose sturgeon, or the magnitude and 
effect of predation on their populations. Even the young fish may be 
protected from predation by their bony plates (Scott and Crossman 1973) . The 
major predator on shortnose sturgeon may be people. 

Importance to Humanity 

The shortnose sturgeon is considered too small, and its populations too low, 
for extensive commercial use. As a declared endangered species it cannot be 
legally harvested or molested for any purpose. In the past, however, the 
worth of its roe and flesh was even greater than that of the Atlantic sturgeon 
(Clayton et al. 1976). Industrial and domestic pollution, obstruction of 
spawning grounds (e.g., dam construction), and overfishing probably account 
for the decline in sturgeon stocks. 



11-50 



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Bean, T. H. 1903. Catalogue of fishes of New York. New York State Mus . 
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Bell, M. D. 1973. Fisheries Handbook of Engineering Requirements and 
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Bigelow, H. B., and W. C. Schroeder. 1953. Fishes of the Gulf of Maine. 
U.S. Nat. Mar. Fish. Bull, ( formerly U.S. Fish and Wildl. Fish. Bull.) 
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Bowman, K. E. , and R. W. Langton. 1978. Fish predation on oil-contaminated 
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Brown, B. E. 1976. Status of fishery resource assessment in the area off the 
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Carlander, K. D. 1969. Handbook of Freshwater Fishery Biology, Vol. 1. Iowa 
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Chenoweth, S.B. Unpublished Trawl Survey of the Sheepscot-Boothbay- 
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1973. Fish larvae of the estuaries and coast of central Maine. U.S. 
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Massachusetts Cooperative Fisheries Research Unit., University of 
Massachusetts, Amherst, MA. 



11-51 



10-80 



Colton, J. B. Jr. 1972. Temperature trends and the distribution of 
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Dadswell, M. J. 1975. The biology of the shortnose sturgeon ( Acipenser 
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Fish, C. J., and M. W. Johnson. 1937. The biology of the zooplankton 
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Flagg, L. N. 1976. Alewife Management Plan. Maine Department of Marine 
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Fried, S. M. , and J. D. McCleave. 1973. Occurrence of the shortnose 
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11-52 



Hauser, W. J. 1973. Larval Fish Ecology of the Sheepscot River- Montsweag 
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Langton, R. W. , and R. E. Bowman. 1978. Food Habits and Resource 
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Leim, A. H. , and W. B. Scott. 1966. Fishes of the Atlantic coast of Canada. 
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Lewis, R. 1979. An Analysis of Maine Landings. Research Reference Document 
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Lyman, H. 1977. The 200-mile limit I: The New England Regional Fishery 
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MacKay, A. A., R. Bosien, and B. Wells. 1978. Bay of Fundy Resource 
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. MIDAS files on Maine lakes and fisheries, Augusta, ME. 



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Marak, R. R. , and J. B. Colton, Jr. 1961. Distribution of fish eggs and 
larvae, temperature and salinity in the Georges Bank-Gulf of Maine area, 
1953. U.S. Dep. Commer. Nat. Mar. Fish. Serv. Spec. Sci. Rep. Fish, 
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, and D. B. Foster. 1962a. Distribution of fish eggs and larvae, 

temperature and salinity in the Georges Bank-Gulf of Maine area, 1955. 
U.S. Dep. Commer. Nat. Mar. Fish. Serv. Spec. Sci. Rep. Fish ( formerly 
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, and D. Miller. 1962b. Distribution of fish eggs and larvae, 

temperature and salinity in the Georges Bank-Gulf of Maine area, 1956. 

11-53 

10-80 



U.S. Dep . Commer. Nat. Mar. Fish. Serv. Spec. Sci. Rep. Fish ( formerly 
U.S. Fish and Wildlife Service Spec. Sci. Rept.) No. 412. 

Maurer, R. 0., and R. E. Bowman. 1977. Food Habits of Marine Fishes of the 
Northwest Atlantic - Data Report. National Marine Fisheries Service, 
Northwest Fishery Center, Woods Hole, MA. 

McCleave, J. D. , and S. Fried. 1975. Nighttime catches of fishes in a tidal 
cove in Montsweag Bay near Wiscasset, Maine. Trans. Amer. Fish. Soc. 
104(l):30-34. 

McKee, J. E., and H. W. Wolf. 1963. Water quality criteria. Publication 3A, 
2nd ed. California State Water Quality Control Board. Sacramento, CA. 

Meister, A. L. , and R. E. Foye . Fish management and restoration in the 
Sheepscot River drainage. Maine Department Inland Fisheries and 
Wildlife, Augusta, ME. 

National Marine Fisheries Service. Annual Summaries. Maine Landings. 
Gloucester, MA. 

National Oceanic and Atmospheric Administration (NOAA) . 1978. Position 
statement on the siting of an oil refinery by the Pittston Company at 
Eastport, Maine. Woods Hole, MA. 

Rabeni, C. F. 1978. The impact of Orthene, a spruce budworm insecticide, on 
stream fishes. A report to the U.S. Fish and Wildlife Service, 
Washington, DC. 

Recksiek, C. W. , and J. D. McCleave. 1973. Distribution of pelagic fishes in 
the Sheepscot River-Back River estuary, Wiscasset, Maine. Trans. Amer. 
Fish. Soc. 102(3):L541-551. 

Ricker, F. W. 1976. American Eel ( Anguilla rostrata ) Management Plan. Maine 
Department of Marine Resources, Hallowell, ME. 

Scarola, J. F. 1973. Freshwater Fishes of New Hampshire. New Hampshire Fish 
and Game Department, Division of Inland and Marine Fisheries, Concord, 
NH. 

Schofield, C. L. 1977. Acid precipitation's destructive effects on fish in 
the Adirondacks. New York's Food Life Sci. 10(3):12-15. 

Scott, W. B., and S. N. Messieh. 1976. Common Fishes. Print 'N Press Ltd., 
St. Stephen, New Brunswick, Canada. 

, and E. J. Crossman. 1973. Freshwater fishes of Canada. Fish. Res. 

Board Can. Bull. 184:966 pp. 

Sinderman, C. J. 1978. Effects of industrial contaminants on fish and 

shellfish, Part 2: Petroleum effects. Unpblished ms . National Marine 

Fisheries Service, New England Fisheries Center, Sandy Hook Laboratory 

Highlands, NJ. 

11-54 



Surber, E. W. , and Q. H. Pickering. 1962. Acute toxicity of Endothal, 
Diquat, Hyamine, Dalapon and Silvex to fish. The Progressive Fish- 
Culturist 24(4): 164-171. 

Targett, T. E., and J. D. McCleave. 1974. Summer abundance of fishes in a 
Maine tidal cove, with special reference to temperature. Trans. Amer. 
Fish. Soc. 103(2) :325-330. 

The Research Institute of the Gulf of Maine (TRIGOM) . 1974. A Socioeconomic 
and Environmental Inventory of the North Atlantic Region, 3 vols. South 
Portland, ME. 

Thomson, K. S., W. H. Weed III, and A. G. Taruski. Saltwater fishes of 
Connecticut. State Geological and Natural History Survey of Connecticut, 
Bull. 105. 

Tyler, A. V. 1971. Periodic and resident components in communities of 
Atlantic fishes. J. Fish. Res. Board Can. 28(7) :935-946 . 

. 1972. Food resource division among northern marine demersal fishes. 

J. Fish. Res. Board Can. 29(7) : 997-1003. 

U.S. Army Corps of Engineers, New England Division. 1979. Hydroelectric 
Potential at Existing Dams, New England Region, 6 vols. Waltham, MA. 

U.S. Department of Agriculture, Agricultural Library. 1968. The Toxicity of 
Herbicides to Mammals, Aquatic Life, Soil Microorganisms, Beneficial 
Insects and Cultivated Plants, 1950-1965; A List of Selected References. 
Library list No. 87. U. S. Government Printing Office, Washington, DC. 

U.S. Forest Service. 1976. Cooperative Pilot Control Project of Dylox, 
Metacil, and Sumithion for Spruce Budworm Control in Maine. Forest 
Insect and Disease Management, U.S. Forest Service, Upper Darby, PA. 

Walton, C. J. 1976. Striped Bass Management Plan. Maine Department of 
Marine Resources, Hallowell, ME. 

Workman, G. W. , and J. M. Neuhold. 1963. Lethal concentrations of toxaphene 
for goldfish, mosquitofish and rainbow trout, with notes on 
detoxification. The Progressive Fish-Culturist 25(l):23-30. 



11-55 

10-80 



Chapter 12 

Commercially Important 
Invertebrates 

Authors: Lee Doggett, Susan Sykes 




Over 1500 benthic (bottom dwelling) invertebrate species live in the marine 
and estuarine systems of Maine. The most important phyla, in terms of numbers 
of species and individuals represented, are Mollusca (snails and clams), 
Annelida (principally polychaetes) , and Arthropoda (primarily crustaceans). 

These three phyla are important consumers that feed on the direct 
(phytoplankton and macroalgae) or indirect (detritus and animals) products of 
primary production and convert them into animal protein. The energy generated 
is passed on to higher trophic levels through predation (by fish, birds, other 
invertebrates, and humans). Detritus is colonized by bacteria and becomes a 
major food source for some invertebrates (deposit feeders). Also, the 
burrowing and feeding activities of invertebrates, particularly annelids, 
release sediment nutrients into the water column. 

Species of molluscs, arthropods, and annelids live in the subtidal and 
intertidal zones (these zones are defined in chapter 4, page 4-59) of the 
marine and estuarine systems. Molluscs and arthropods are found on all bottom 
types whereas annelids are more common on unconsolidated bottoms. Some adult 
arthropods and annelids move into the water column during periodic migrations. 
Many of the species in these phyla have pelagic (living in the water column) 
larvae and, as such, are part of the water column habitat. 

The sensitivity of species of these phyla to environmental variation and 
perturbations varies considerably. Some crustaceans are particularly 
sensitive to environmental change, but some polychaetes are very resilient. 
Intertidal invertebrates tend to be less sensitive to environmental impacts 
than subtidal invertebrates. Although landings of commercial forms may 
fluctuate greatly, they are generally less sensitive to habitat alteration 
than other invertebrates. The choice of a species as a biological indicator 
depends on many factors, including the type of variation or perturbation, 
natural life cycle events, natural predation, and in the case of commercial 
species, potential changes in abundance due to overharvesting. 



12-1 



10-80 



Nine species from these phyla are discussed in this chapter. They were chosen 
for the following reasons: they represent a relatively large proportion of 
the overall benthic invertebrate production due to their abundance, size, and 
widespread availability (i.e., found along much of the Maine coast); in 
combination with fish, they are the basis of Maine's commercial fishery, and 
sufficient information about them is available to develop meaningful accounts. 

The species selected are: (1) molluscs--soft-shell clam, blue mussel, and sea 

scallop; (2) crustaceans — lobster , jonah crab, rock crab, and northern 

shrimp; and (3) polychaetes—bloodworm and sandworm. The distribution of 

commercially harvested shellfish and marine worm areas is shown in atlas map 
4. 

These species accounts for coastal Maine describe distribution and abundance, 
life history, habitat preference, factors of abundance, importance to humans, 
human impacts, and management. Data deficiencies and research recommendations 
for the nine species named are given at the end of this chapter. In addition, 
the red tide organism, Gonyaulux excavata , is discussed below. Common names 
of species are used except where accepted common names do not exist. 
Taxonomic names of all species mentioned are given in the appendix to chapter 
1. 

SOFT-SHELL CLAM (Mya arenaria) 

The soft-shell clam is a bivalve that lives in sediment at both intertidal and 
subtidal levels in estuaries and coastal regions of the ocean. This clam is a 
hardy species and is found in a wide range of salinities, temperatures, and 
sediment types. It tolerates long periods of ice cover as demonstrated in 
Denmark (Rasmussen 1973) and is capable of anaerobic respiration (Newell 
1970) , which means it can survive for limited periods of time in the presence 
of little or no dissolved oxygen. Clams are harvested in abundance by 
commercial clam diggers and, to a lesser extent, by the general public for 
private use. 

Distribution and Abundance 

In the Atlantic Ocean, the range of the soft-shell clam extends from Labrador 
to North Carolina and from Norway to France. It also occurs on the northern 
Pacific coast. Greatest abundance, based on commercial landings, occurs on 
the northeastern coast of the United States, particularly in New England and 
Maryland. Clams are nonmigratory and in favorable habitats occur in high 
densities. Commercially harvested clam flats are depicted in atlas map 4. 

Life History 

The soft-shell clam usually reproduces annually in Maine and semiannually 
south of Cape Cod. Sexual maturation of the individual depends on growth rate 
(i.e., the faster the growth, the earlier the maturation) but usually occurs 
in approximately one year (personal communication from L. L. Loosanoff, 17 
Ceross Drive, Green Brae, CA; November, 1973). 

In western Maine the species spawns during May to September, but along the 
eastern coastline, they spawn from early June to mid-August. The warmer water 
temperatures, which also occur earlier and for longer periods of time in 

12-2 



western Maine, apparently account for the differences. The factors that 
trigger spawning have not been clearly defined, although spawning has been 
induced in culture by cyclic fluctuation in water temperature (Stickney 
1964a). 

Approximately 3 million eggs a year can be produced by a clam that is 2.4 to 
3.2 inches (60 to 80 mm) in length. Gametes are released into the water 
through the exhalant siphon. Larvae are pelagic for 12 days in laboratory 
conditions (Stickney 1964a) and perhaps longer in natural conditions. In 
nature the larvae are subjected to the biotic and abiotic stresses of the 
pelagic environment. They are also carried by water currents, which 
ultimately determine their distribution. 

After about 2 weeks the larvae undergo metamorphosis and attach to the 
sediment surface by byssal threads. Upon attachment the animals are 
considered juveniles. Growth in the first summer ranges between 0.2 and 0.4 
inches (5 and 10 mm) in coastal Maine (Stickney 1964b). Growth in winter is 
slowed by a decrease in food supply as well as lower temperatures. In 
Massachusetts, natural mortality rates for dense populations after settlement 
are estimated to be 70 to 80% per year (TRIGOM 1974). 

The burrowed clam obtains its food and oxygen by flushing water through 
siphons, which are extended above the sediment surface. This action also rids 
the clam of body wastes. The animal may also adjust its siphon and take in 
bottom sediments for food, thereby feeding for longer than the period when it 
is covered with water. 

Habitat Preferences 

Clams of commercial size are most abundant in the lower one-third of the 
intertidal zone; however, they are less abundant at the mean low water line 
(personal communication from W. R. Welch, Maine Department of Marine 
Resources, Augusta, ME; November, 1979). Optimal growth rates of soft-shell 
clams in coastal Maine occur in salinities of 15 to 32 ppt. 

Pelagic larvae live in the water column of the estuarine and nearshore marine 
systems. Juveniles live in small patches of sediment found in almost every 
type of coastal aquatic habitat, whereas most adults are found in intertidal 
unconsolidated sediments. Adults have been found to live subtidally in upper 
reaches of estuaries, where temperature and salinity regimes may be 
unfavorable to their predators (Larsen and Doggett 1978b). Most of the 
commercial production comes from intertidal mud and sand flats. Adult clams 
are present in low abundances in dense clay which is found under the silt-clay 
surface of most mud flats, in sediment pockets on rocky shores, and among the 
roots of marsh grasses ( Spartina alterniflora ) in emergent wetlands. It is 
more difficult for predators to attack clams in these areas (TRIGOM 1974) and 
therefore, these clam populations are potentially a source of larvae that may 
replenish the flats. 

Factors of Abundance 

A number of natural factors contribute to fluctuations in soft-shell clam 
abundance. Among natural factors, predation is the most readily recognized. 
Diving ducks, bottom feeding fish, horseshoe crabs, boring gastropods, 

12-3 

10-80 



particularly the moon snail ( Polinices duplicata ) , and crabs (especially the 
green crab) are known to feed heavily on soft-shell clams. 

Another factor affecting abundance is high water temperatures that tend to 
increase the abundance of the predatory green crab. For example, populations 
of soft-shell clams were low from the late 1940s to the mid-1950s, and during 
the mid-1970s, when water temperatures were highest and green crabs most 
abundant (personal communication from W. R. Welch, Maine Department of Marine 
Resources, Augusta, ME; November, 1977). Boring gastropods are suspected to 
have increased mortality (based on bore holes in shells of dead clams) among 3 
to 5 year old clams in Washington County (personal communication from J. A. 
Commito, University of Maine, Machais, ME; April, 1979). 

Other factors that may affect soft-shell clam abundance are competition for 
space from blue mussels and possibly the gem clam. Aggregations of mussels 
that form reefs over clam populations on sand and mud flats may increase clam 
mortality (Newcome 1935). Gem clams are not often found in abundance with 
soft-shell clams (Bradley and Cooke 1959; Sanders et al. 1962; and Larsen and 
Doggett 1978a). Large numbers of gem clams may interfere with the settlement 
of clam larvae in some locations. 

Shifting sediments, salinity extremes (<15 ppt or >32 ppt) , and temperature 
extremes (<17°C or >23°C; 63°F or 73°F) also affect larvae adversely (Stickney 
1964a). 

Human Impacts 

Potential dangers to clam populations in coastal Maine are destruction of 
habitat and excessive commercial removal. Excessive exploitation apparently 
is a greater threat to the clam industry than habitat destruction. According 
to scientists at the Maine Department of Marine Resources, clam populations 
are severely depleted and they expect that the record high harvests of 1976 
and 1977 will probably not reoccur (personal communication from W. R. Welch, 
Maine Department of Marine Resources, Augusta, ME; November, 1977). 

Other factors potentially affecting clam abundance and survival are oil 
spills, channel dredging, shoreline construction, and the discharge of 
contaminants. However, little evidence of the effect of these factors on 
clams is available. The practice of digging clams with a clam hoe can 
increase mortality rates in clams through breakage of shells and burying of 
resident clams (Dow and Wallace 1961). 

Importance to Humanity 

The soft-shell clam strongly supports the commercial and sport-food fisheries 
of coastal Maine. The commercial industry began in the mid-19th century as a 
bait fishery for cod trawlers on the Grand Banks. From 1900 to the mid-1940s 
the clams usually were packed and sold in cans. Currently, fresh or frozen 
clams dominate the market (Hanks 1963). 

The commercial catch has fluctuated greatly in the last 25 years. Highest 
catches occurred in 1950, 1976, and 1977, when about 7 million pounds were 
landed (for 1968 to 1978 catch statistics and values see figure 12-1). The 
catch was under 2 million pounds in 1960. Annual and seasonal fluctuations in 

12-4 



commercial demand and clam abundance may limit the expansion of the soft-shell 
clam industry in Maine. In 1976 Maine supplied 70% of the total U.S. catch 
but that figure is expected to decrease in the future, because of the 
increased harvest in Maryland and the general increase in development of other 
shellfish products. 

Although "red tide" (paralytic shellfish poisoning) occurs in the coastal 
waters of Maine it apparently has little effect on the distribution or 
abundance of the soft-shell clam, but clams in the infected area may become 
unfit for human consumption (see "Red Tide," this chapter) and sufficient 
quantities of toxins may be lethal. In recent years clam harvesting has been 
banned temporarily in infected areas. 

Management 

The State of Maine's management of clam resources is based largely on an 
aggregate of town management plans (personal communication from P. L. Goggins, 
Maine Department of Marine Resources, Augusta, ME; April, 1978). The state 
legislature allows towns which have appropriated funds for shellfish 
management to restrict clam digging to specific flats within their municipal 
jurisdictions. Forty-seven out of the 102 coastal towns have clam ordinances, 
and this number includes a relatively high percentage of towns having 
substantial clam resources (personal communication from P. L. Goggins, Maine 
Department of Marine Resources, Augusta, ME; April, 1978). 

Clam ordinances vary considerably among towns. Conservation measures include 
the rotation of flats (i.e., digging for clams is prohibited periodically by 
year on certain flats) to maintain quantities of clams, restriction of 
nonresident (town) licenses, and regulation of the time of harvest. 

The State of Maine requires license fees from individuals landing more than 
1/2 bushel of clams at one time and it restricts methods of harvest, such as 
limiting use of hydraulic dredges to some areas. Hydraulic dredges, which are 
much more efficient than digging by hand, could, if used extensively, cause 
rapid depletion of stocks in Maine and excessively disturb bottom organisms 
and sediments. On the other hand, because dredging in Maine is restricted by 
law to specific areas along the coast, large scale commercial dredging is not 
likely (Mathieson and De Rocher 1974) . The State may also prohibit clam 
digging in areas where coliform bacteria counts are high or where red tide and 
industrial pollution are a threat. 

Attempts by the State to place a size limit on clams was found to have no 
effect on clam populations (Dow and Wallace 1961) and currently no limit is in 
effect. The market demand for clams smaller than 2 inches is low. 

To protect soft-shell clam beds from green crab predation, experimental fences 
have been used to exclude crabs from beds. Although this method appears to be 
effective, it is currently cost prohibitive. 

Some towns in Maine transplant clams from flats which have high concentrations 
of juvenile clams to flats which have low concentrations. A potential problem 
in this practice is that if the cyst form of the "red tide" organism has been 
ingested by transplanted clams, it will be spread to new areas. 



12-5 



10-80 














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In principle, the management of clams could be based upon optimum yields. 
Conceivably, the leasing of clam areas by competitive bidding, a practice 
common in Maryland, could motivate long term lessees to manage for optimum 
yields in Maine. 

BLUE MUSSEL ( Mytilus edulis ) 

The blue mussel is a bivalve that attaches by its byssal threads to hard 
substrates, and lives in the intertidal and subtidal zones of the marine and 
estuarine systems. They can endure extensive variations in salinity, 
temperature, and dissolved oxygen concentrations. 

Blue mussels have been cultured and harvested in western France and Spain for 
hundreds of years. Although they have substantial commercial potential, blue 
mussels have not been harvested as extensively in the United States. 
Recently, the demand for mussels as fresh food has increased in the U.S. For 
a detailed and comprehensive coverage of the mussel industry, see Lutz (1976). 

Distribution and Abundance 

In the western Atlantic the range of this species extends from the Arctic to 
South Carolina (Abbott 1974). Blue mussels are also abundant on the West 
Coast of the U.S. Commercial harvest occurs principally in Maine, 
Massachusetts, Rhode Island, and Long Island, NY. Greatest abundances in 
Maine (based on a survey of commercial-sized mussels between the Damariscotta 
estuary and Jonesport; MARITEC 1978) occur in Frenchman Bay (region 3), and 
the Blue Hill Bay - Deer Isle area (region 5). Mussel beds known to be 
commercially harvested in Maine are depicted in atlas map 4. 

Life History 

Completion of the life cycle requires about one year. In the characterization 
area, spawning occurs at low levels throughout the year, but the principal 
spawning period is between mid-May and mid-June, with another spawning 
possibly occurring in the fall (personal communication from L. S. Incze, 
University of Maine, Orono, ME; June, 1978). 

Between 5 and 12 million eggs may be produced by a single female mussel in a 
year (Field 1922). Sexes are separate and gametes are shed into the water 
where fertilization occurs. Depending on environmental conditions, the larvae 
are pelagic for approximately 19 days (personal communication from L. S. 
Incze, University of Maine, Orono, ME; November, 1977). In the pelagic 
environment, the larvae are subjected to biotic and abiotic stresses. 
Mortality at this stage is believed to be very high. 

The larvae first settle on flexible substrate such as algae, hydroids, or 
byssal threads but they may detach and resettle one or more times until they 
find an appropriate substratum. The larva may delay metamorphosis for some 
time if the appropriate substratum is not available; however, after about 8 
weeks or when a length of 0.06 to 0.4 inches (1.5 to 10 mm) is reached the 
larva will settle wherever it is at that time (Mason 1972). Upon 
metamorphosis the mussel is considered a juvenile. 



12-7 

10-80 



In the first year juvenile mussels have been observed to reach a length of 0.8 
to 1.6 inches (20 to 40 mm) in Massachusetts (Field 1922). In Denmark, 
Rasmussen (1973) found growth of 1 inch (25 mm) in the first 4 months. In the 
Damariscotta estuary, average growth of cultivated mussels for 1 year is 
approximately 2 inches (50 mm; Incze et al. 1978); however, MARITEC (1978) 
found natural populations of mussels in Maine to be 2.4 inches (60 mm) at 8.2 
years and 2.8 inches (70 mm) at 9.5 years. 

The diet of mussels consists of phytoplankton and detritus filtered from the 
surrounding water (TRIG0M 1974). 

Habitat Preferences 

West of Schoodic Point (regions 1 to 5) , mussels of commercial size are most 
abundant approximately 3.2 feet (1 m) above and below mean low water level, 
whereas most beds in the Jonesport area (region 6) are above mean low water 
level (MARITEC 1978). Subtidal beds are located almost exclusively in areas 
with good currents, especially around offshore islands and in the mouths of 
estuaries. These beds are far less numerous than intertidal beds. 

Pelagic larvae live in the water columns of estuarine and marine systems. 
Optimal conditions include an adequate food supply, salinities between 15 and 
40 ppt and temperatures ranging from 41 to 68 F (5 to 20° C). 

Juvenile and adult mussels are found in every type of intertidal habitat 
present in coastal Maine. Juveniles are extremely abundant on rocky shores, 
while both adults and juveniles are plentiful in low intertidal areas on 
gravel beaches, and as part of fouling communities on pilings and on flats, 
particularly mud flats. Mussels are especially abundant in areas of high 
water flow such as tidal falls. The commercially harvested beds are 
principally found on intertidal mud flats and unconsolidated sediments in 
shallow subtidal waters. 

Factors of Abundance 

Mussel abundance in coastal Maine is determined by a number of natural 
limiting factors which include predation, competition, and climatic factors. 
Common predators include sea ducks, gulls, whelks, starfish, crabs, and bottom 
feeding fish. The dog whelk ( Thais lapillus ) , by preying on juveniles, may 
limit mussel abundance on rocky shores, particularly in the more protected 
areas (Menge 1976) . Eider ducks have been reported to eat approximately 425 g 
(1 pt) of mussels in one day (Field 1922). Up to 80% of the stomach contents 
of these ducks in the summer is comprised of juvenile mussels (Graham 1975). 

The most significant competition among blue mussels is for food and space 
between individuals. As younger mussels settle and accumulate on established 
beds, older ones are buried and may be smothered. Theisen (1972) found that 
mussels regularly clean their shell surfaces with their foot, and he suggested 
that this cleaning action wards off other mussels trying to settle on them. 
Mussels may also move within the bed, out from under other mussels to a more 
exposed position. 

Waves generated during northeast storms, which occur in Maine in the fall, 
winter, and spring, cause high mortality rates in mussels. Some storms 

12-8 



! 



destroy entire mussel mats in the intertidal zone. Consequently, on exposed 
rocky shores, the majority of blue mussels are juveniles. 

Human Impacts 

Evidence indicates that mussel populations may be depleted if harvesting 
continues at present or greater levels (Dow and Wallace 1954; and MARITEC 
1978). Stocks of mussels are already depleted between the Damariscotta 
estuary (region 3) and Rockland (region 4) according to MARITEC 's survey 
(1978). Overharvesting and natural factors may have contributed to the 
decline in abundance. 

Other human impacts on mussels include habitat destruction, oil spills, 
dredging, and discharge of contaminants. Evidence of the effect of these 
factors on populations of mussels in coastal Maine is lacking. 

Importance to Humanity 

The blue mussel once supported a part-time shell fishery in Maine but during 
World War II the need for substitute sources of protein prompted an increase 
in fishing effort. The harvest increased during the war and peaked at over 
2.5 million pounds in 1944 (Maine Landings 1944). In 1947 the harvest 
declined to approximately 40,000 lb (Maine Landings 1947). Dow and Wallace 
(1954) feel that the decline was not only due to a decline in demand for 
mussels but also due to the fact that readily available natural stocks of 
mussels were no longer available. 

The landings of blue mussels have steadily risen since 1974 to almost 3.5 
million pounds in 1978 (see figure 12-2). This increase is attributed to 
growth in demand for inexpensive protein. 

Mussels infected by "red tide" are unfit for human consumption and in recent 
years harvesting of mussels in infected areas has been temporarily banned. 
Little effect of red tide on the distribution and abundance of mussels is 
apparent; however, high levels of toxin can cause mortalities. 

A factor that limits commercial harvest of mussels is the presence of pearls 
in the meat of the mussel. Mussels containing pearls are usually unacceptable 
commercially. Evidence exists that pearls are the result of infestation by a 
trematode ( Gymnophallus ; Lutz 1976), of which the life history is unknown. 
Evidence also exists that the adult host is a sea duck (a scoter or an eider), 
the blue mussel being the intermediate host (Stunkard and Uzmann 1958) . 
Whether natural mechanisms of pearl formation exist is not known (Lutz 1976) . 

Management 

Management of mussel resources in the State of Maine is similar to that of 
clam resources. Towns which have appropriated funds for shellfish management 
are allowed by the State to regulate harvesting activities within their 
jurisdictions. Most town ordinances, however, pertain to clams and do not 
regulate mussels specifically. 

License fees are required from individuals landing more than 1/2 bushel of 
mussels at one time. The Maine Department of Marine Resources regulates 

12-9 

10-80 



aquacultural operations. Regulations vary with location, but leasing of the 
area and/or attaining shore access is usually required. The state may close 
mussel harvesting in areas where coliform bacteria counts are high or where 
"red tide" and industrial pollution occur. 

The New England Fisheries Development Program, of the National Marine 
Fisheries Service, is studying methods of sustaining the mussel fishery. 
Problems include potential overharvesting (Lutz 1976) and the harvesting of 
poor quality mussels (those that are small in size or contain pearls). If 
harvests continue to be low in quality, commercial demand is likely to 
decline. NMFS conducted a survey through MARITEC (1978) of mussel beds 
between the Damariscotta estuary and Jonesport and made harvest and management 
recommendations . 

Mussel culture is being explored as a means of meeting market demand (Lutz 
1974; and Lutz and Porter 1977). Culturing experiments and a commercial 
culturing operation have been successful in Maine, but financial gains have 
been inadequate. However, mechanization of the currently labor-intensive 
culturing process combined with increased demand for mussels could change this 
situation. 

For culturing, individuals from natural populations at one location are 
sometimes needed to supplement natural juvenile populations in other 
locations. This practice potentially impinges on natural populations because 
it strips juvenile mussels and associated animals (amphipods and oligochaetes) 
from exposed rocky shores. Transplanting mussels carries the same risks as 
transplanting clams, i.e., the potential for spreading "red tide" via ingested 
cysts . 

SEA SCALLOP ( Placopecten magellanicus ) 

The sea scallop is a bivalve which lives on the sediment of subtidal areas. 
The large muscle that holds the two shells of the scallop together is 
harvested commercially for fresh food. Scallops are the most commercially 
valuable (price/lb) shellfish species harvested in Maine. 

Distribution and Abundance 

Scallops are found from Newfoundland to North Carolina. Although they can 
swim freely in the water, scallops do not migrate far. They often occur in 
dense but scattered populations or beds. 

Commercial harvest occurs in Newfoundland, Prince Edward Island, Bay of Fundy 
(Digby and Grand Manan) , embayments and mouths of estuaries on the coast of 
Maine, Stellwagen Bank in the Gulf of Maine, Cape Cod Bay, Georges Bank, and 
near Hudson, Baltimore and Norfolk Canyons at the edge of the continental 
shelf (Altobello et al. 1976). The largest fishery is on Georges Bank where 
65% of the total catch of the U.S. and Canada from 1940 to 1975 was taken 
(personal communication from J. A. Posgay, National Marine Fisheries Service, 
Woods Hole, MA; November, 1977). 

In Maine, the most important coastal scallop fishing areas are: Penobscot Bay 
to Mt. Desert Island, the Harrington and Pleasant Rivers, and the Jonesport 
area (Baird 1967). Lesser areas are Casco Bay, and the Piscataqua (Maine-New 

12-10 



Hampshire border) and Damariscotta Rivers. At one time the Sheepscot estuary 

supported scallops in abundance but they have largely disappeared. There is 

no proven explanation for the disappearance. Commercially valuable scallop 
beds are illustrated in atlas map 4. 

Life History 

Scallops in Maine waters are reported by Baird (1967) to reach sexual maturity 
in the third or fourth year of life or at the size of 2.2 to 2.9 inches (56 to 
74 mm). Spawning occurs from July to October, with peaks in late August in 
eastern Maine (region 6; Bourne 1964) and in September in Penobscot Bay 
(region 4; Baird 1953). Spawning is believed to be triggered by a slight 
change in temperature; however, some investigators believe a rise in 
temperature is necessary (Culliney 1974) whereas others claim a drop in 
temperature initiates spawning (Altobello et al. 1976). According to Culliney 
(1974) optimal temperatures for successful spawning of natural populations is 
about 46 to 52°F (8 to 11°C). 

No information is available on the number of eggs released per individual; 
however, it can be assumed that numbers would be several million, as is 
typical of large molluscs (TRIGOM 1974). Sexes are separate, and gametes are 
released into the surrounding water where fertilization occurs. The larvae 
are pelagic in laboratory conditions from 23 to 35 days (Culliney 1974). The 
length of this stage in natural conditions is unknown, since the planktonic 
larvae of this species of scallop have never been positively identified in the 
ocean. 

After approximately a month the larvae undergo metamorphosis and develop eye 
spots, a foot, and byssus (Culliney 1974). Settling response, according to 
Culliney (1974), is related to contact with a solid body and is not highly 
specific as to type. Natural populations of juvenile scallops have been found 
attached by their byssus to the branches of a bryozoan (Baird 1953), to a 
hydrozoan, to amphipod tubes, and to grains of sand (Larsen and Lee 1978). 

Natural mortality of juvenile scallops is high according to surveys in 
February and May on Georges Bank, which indicated a sharp drop in abundance of 
live scallops (Larsen and Lee 1978). 

Baird (1967) reports that scallops grow to 0.08 inch (2 mm) in their first 
winter and Larsen and Lee (1978) report a growth of 0.05 inch (1.3 mm) in the 
5 months after settlement on Georges Bank. These growth rates are slower than 
those observed on and around navigational buoys in the Nantucket Shoals area, 
0.08 to 0.5 inch (2 to 14 mm). The adult size generally ranges from 2 to 4.9 
inches (50 to 125 mm; Baird 1967). 

The scallop feeds on phytoplankton and suspended detritus, which it filters 
through its gills. 

Habitat Preferences 

In Maine, scallops of commercial size are most abundant in saline waters (>30 
ppt) at depths of approximately 20 m (66 feet; personal communication from D. 
F. Schick, Maine Department of Marine Resources, Augusta, ME; April, 1978). 
In the southern part of the range, i.e., Long Island to North Carolina, the 

12-11 

10-80 



commercial fishery is at depths >50 m (>165 ft). In colder waters of Maine 
scallops are sometimes found close to the low water mark. 

Pelagic larvae live in the water column of the marine and high salinity areas 
(>20 ppt) of the estuarine system. In laboratory experiments temperatures 
above 66°F (19°C) over an extended period of time were fatal to larvae. 

The juvenile and adult scallops live in subtidal marine waters and in areas of 
comparatively high salinity (approximately 20 to 25 ppt) in estuarine systems. 
Estuarine populations are generally found in deep channels where temperatures 
and salinity are least variable (Welch 1950) . They live on unconsolidated 
sediments, usually sand or gravel, and to a lesser degree on rocky bottoms. 

Factors of Abundance 

Temperature is the most critical natural factor limiting the distribution and 
abundance of the sea scallop. High summer water temperatures of 68 to 74 °F 
(20 to 23.5 °C) limit the distribution of adult scallops to deeper waters in 
the southern region of the species' range (Long Island and further south; 
Bourne 1964). The maximum temperature for larvae is about 19° C (66 °F; 
Culliney 1974). The water temperature must reach a minimum level of 46 °F (8 
C; Posgay and Norman 1958), 49°F (9.5°C; Dickie 1955) or 51°F (14°C; Culliney 
1974) for spawning to occur. In the northern part of their range, only the 
shallower waters of New England and the Maritime Provinces of Canada are warm 
enough to meet this minimum temperature requirement. 

Scallops have a limited ability to withstand reduced salinities; hence, they 
are not found in areas of low salinity (<20 ppt) in estuaries. 

Sporadic large-scale mortality has been observed in beds of sea scallops in 
Maine (as large fluctuations in landings corroborate; see figure 12-3) and 
elsewhere, but the cause has not been determined. Medcof and Bourne (1962) 
suggest that sudden, extreme change in temperature may contribute 
significantly to natural mortality. They estimate the rate of natural 
mortality in scallops over 3 years old is 10% of the population, based on 
numbers of living and newly-dead individuals in dredge catches. Merrill and 
Posgay (1964) derived the same rate for offshore populations on Georges Bank. 

Scallops can live at least 8 years (Baird 1967). Predators include Atlantic 
cod, American plaice, Atlantic wolffish, the northern starfish ( Asterias 
vulgaris ) , and the common sun-star ( Crossaster papposus ) . The extent to which 
predators affect populations of scallops is unknown. 

Human Impacts 

Fishing indirectly may lead to high mortality in scallop populations through 
disrupting the bottom sediment by dragging, and through exposing and damaging 
discarded small scallops. Medcof and Bourne (1962) estimate that fishing 
mortality may reach an annual rate of 10% in the inshore populations in Nova 
Scotia . 

Other factors potentially affecting scallop distribution and abundance are oil 
spills, dredging, spoil disposal, and discharge of heated effluents or 
contaminants . 

12-12 




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10-80 



Importance to Humanity 

The sea scallop has been used for food in Maine since colonial times, although 
a commercial fishery did not develop until the latter part of the 19th 
century. In 1910 a catch of over 2 million pounds of scallops was recorded 
for nearshore waters of Maine. 

Catch statistics have varied considerably over the last 10 years (see figure 
12-3). Variations may be the result of incomplete or inconsistent reporting 
as well as changes in abundance. 

The 1978 peak may be due to more extensive fishing for scallops in offshore 
waters. As of November 1978, at least 30% of the catch (Maine Landings 1978) 
came from the offshore fishery. In previous years the catch during the months 
when the inshore fishery is closed amounted to <1% of the total catch for the 
year. 

The inshore scallop fishery in Maine is seasonal by law (see below) . Most 
scallop fishermen harvest either lobsters, mussels, or fish during the other 
months of the year. 

Management 

Maine's inshore sea scallop fishery is subject to several state regulations. 
Since 1947 the scallop fishing season has been closed from 16 April to 31 
October. There are no closed seasons offshore of the headlands and principal 
islands in Penobscot Bay (see Maine Marine Resources Laws and Regulations, 
1979, for exact locations). The purpose of the closed-season regulation is to 
allow scallop beds disrupted by fishing to reaggregate. The effect of the 
closed season on inshore beds is unknown. 

A license is required for harvest of over 2 bu of shelled scallops or 4 qt of 
shucked scallops in any one day. Minimum legal size is 3 inches (76 mm) in 
the longest diameter. If more than 10% of any catch consists of undersized 
scallops, the fisherman is liable to a fine. The minimum-size limit is 
enforced to allow scallops to reproduce at least once before being harvested. 

AMERICAN LOBSTER ( Homarus americanus ) 

The American lobster is a decapod (i.e., ten-legged) crustacean that lives on 
subtidal bottoms. It is an omnivorous scavenger that feeds primarily at night 
and finds shelter in burrows or crevices during the day. Lobstering supports 
the largest commercial shellfish industry in Maine. 

Distribution and Abundance 

Lobsters are found from Labrador to North Carolina, from mean low water level 
to depths over 2300 feet (700 m) . Major commercial fishing occurs in coastal 
waters and along the edge of the continental shelf, particularly in the 
submarine canyons (e.g., Hudson Canyon). 

Commercial fishing in the characterization area is principally in coastal bays 
around nearshore islands and in high salinity waters (>20 ppt) of estuaries. 

12-14 



Life History 

The reproductive cycle of the American lobster is typical of crustaceans. The 
sexes are separate, and copulation occurs immediately after the female molts, 
usually in early summer or fall. The female stores the sperm in her body from 
2 weeks to 15 months before the fertilized eggs are extruded (Cobb 1976). 
Thomas (1973) estimates that eggs are released by the female between May and 
July in coastal Maine lobster populations. The age and size of a female 
determines the number of eggs produced. Approximately 10,000 eggs are 
produced by a 1 lb lobster, and 130,000 by an 18 lb lobster (Perkins 1971). 

The fertilized eggs are held on pleopods (appendages) on the female's 
underside until the following summer, when they hatch. Under laboratory 
conditions the mortality rate of the eggs until hatching is about 35% (Perkins 
1971). The length of the hatching period depends on temperature. In the 
laboratory at optimum temperature of 68°F (20°C) , hatching will occur in 16 
weeks; 39 weeks are required at 50°F (10°C; Hughes and Matthiesen 1962; and 
Cobb 1976). Hatching period and mortality rate of eggs under natural 
conditions are unknown. 

Immediately after hatching, larvae assume a planktonic (suspended in the water 
column) existence in Maine waters that lasts from 5 to 6 weeks. They are 
subjected to the biotic and abiotic stresses of the water column environment. 
As in all arthropods, which have hard outer shells, growth in American 
lobsters is achieved through molting. Larval lobsters molt four times before 
settling to the bottom. 

On assuming a benthic existence, lobsters are considered juveniles. In Maine, 
approximately 10 molts (4 as larvae) occur in the first year, after which 
juveniles molt two or three times per year. After the fifth year, molting is 
annual (usually mid-summer to early fall) but it may be biannual for adult 
females who are carrying eggs. In mature lobsters each molt results in 
increases in length of up to 14% (Cobb 1976). 

Warm temperatures increase the growth rate of lobsters. The fastest-growing 
individuals may reach sexual maturity in 4 years, but most do not mature until 
they are 5 to 7 years old. Krouse (1972) found that in Maine male lobsters 
mature at smaller sizes than females. Fifty percent of the males may be 
mature at 1.7 inches (44 mm) carapace length, whereas few females mature until 
they have exceeded the minimum length legal for harvest, 3.1 inches (81 mm). 
Thomas (1973) estimates that in Maine females mature at a size between 3.5 and 
3.9 inches (90 and 100 mm). Lobsters can live for over 20 years. 

The diet of lobster is flexible and includes crustaceans (e.g., crabs) 
molluscs (e.g., small clams), echinoderms, algae, and hydroids. It has been 
estimated by Miller and coworkers (1971) that the American lobster in Nova 
Scotia consumed approximately 10% of the secondary production in the community 
studied. 

Habitat Preferences 

Lobsters are found principally in the marine system and high salinity areas 
(>20 ppt) of the estuarine system. 



12-15 

10-80 



Larvae live in the water column and juvenile and adult lobsters in the 
subtidal zone on unconsolidated and rocky bottoms. Adults and juveniles are 
most abundant on bottoms that provide shelter in the form of rock crevices 
(rock bottom), plant life (aquatic beds), or the potential to dig a burrow 
(unconsolidated bottoms). These shelters partially protect the lobster from 
predation and from aggression from other lobsters. 

Factors of Abundance 

Natural factors that contribute to fluctuations in lobster populations include 
predation, disease, and environmental factors. Highest natural mortality 
rates occur among larvae and juveniles. Larvae are preyed upon by surface- 
feeding fish such as lumpfish, while juveniles are preyed upon by small 
bottom- feeding fish, such as the cunner. Larger bottom-feeding fish (such as 
cod, skates, and sharks) prey on adult lobsters. 

Salinity limits the distribution of lobsters in the characterization area. 
The lowest salinity tolerance in the laboratory was 13.8 ppt for larvae and 8 
ppt for juveniles and adults (Cobb 1976). Under natural conditions, lobsters, 
particularly larvae, probably avoid areas where the salinity is lower than 
approximately 20 ppt. 

Lobsters may limit their own numbers, also, but the extent of this is unknown. 
Lobsters are very territorial, aggressive, and cannibalistic. Mortality due 
to aggressive behavior is probably higher on bottoms that do not have shelter, 
i.e., crevices in rocks or sediments where lobsters can burrow. 

The species is susceptible to several fatal diseases at various stages in its 
life cycle. In the larval stage, Leucothrix mucor (a filamentous bacteria) 
collects in the gill membranes and suffocates the organism, and a fungus, 
Lagendinium sp., breaks down larval tissues. Another fungus, Haliphthoros 
milfordensis , infects juveniles and breaks down their shells, exposing more 
vulnerable inner layers. The most common disease in adults is gaffkemia, or 
"red tail," which is a bacterial (Aerococcus viridians homari) infection of 
the blood. The infection begins in an open wound usually inflicted by 
fishermen in the process of plugging the claws (immobilizing the claw with a 
wooden plug to stop cannibalism) or in notching berried (egg-carrying) 
females. These diseases may occur more frequently in lobsters that are kept 
in enclosed areas, such as containers (for aquaculture) or lobster pounds. 
Crowding of lobsters and unsanitary conditions increase the incidence and 
magnitude of disease. 

The highest natural mortality rate in lobsters occurs after molting, before 
the shell hardens. Besides being vulnerable to predation, lobsters are also 
subject to aggressive attacks, usually for territorial reasons, by other 
lobsters that are not in the process of molting and have hard shells. Also, 
lobsters in the molting stage have been found to be less resistant to high 
temperatures and low salt or oxygen levels (McLease 1956) . 

Human Impacts 

Commercial harvesting is the principal limiting factor in adult populations of 
lobsters. The fishing mortality rate of legal-sized lobsters in Maine may be 
as high as 90% (Thomas 1977). In fact, results of a tagging study (Krouse 

12-16 



1977) show that 65% and 75% out of 3000 tagged lobsters were captured within 4 
months and 1 year respectively. Recently molted animals actively seek food 
and may be trapped by fishermen more easily than hard-shelled lobsters which 
may confine their feeding activity to a smaller territory (Thomas 1973). 

Perturbations such as oil spills, dredging, spoil disposal, and discharge of 
contaminants could potentially affect lobster populations, but the effects of 
these factors on lobster distribution and abundance in Maine are unknown. 

Importance to Humanity 

The lobster industry is the largest commercial shellfish industry in Maine. 
The landings and dollar value of the lobster fishery are given for the last 10 
years in figure 12-4. 

The fishery began in the early 19th century when fishermen from other States 
came to Casco Bay. Local fishermen began to fish for lobster soon after and 
the fishery was established in Eastport by the middle of the century. 

In the early 1950s significant changes took place in the gear used in 
lobstering, especially the introduction of the hydraulic haul. With the new 
haul and bigger, more powerful boats each fisherman could manage a greater 
number of traps; thus the lobster catch increased (figure 12-5). Since that 
time fishing intensity (in terms of numbers of traps) has increased while 
catch has decreased (figure 12-5). 

Management 

Many types of restrictive regulations apply to the lobster fishery. They 
include: licensing; use of conventional traps with escape vents; maximum and 
minimum-size restrictions (3.1 to 5.5 inches, or 81 to 127 mm, carapace 
length); prohibition of removing berried lobsters, scrubbing eggs off, or 
removing those marked with a notch (marked by the MDMR to identify egg 
carrying females) on the second flipper from the right; trap limitations on a 
single line in some areas; and limitation of fishing hours in the summer (1 
June to 31 October). Lobster fishermen of 2 offshore islands (Monhegan and 
Criehaven) may petition the Commissioner of Marine Resources to control their 
fishing seasons. 

Thomas (1973) and Dow and coworkers (1975) submitted two lobster-management 
recommendations to the State legislative committees as a result of their 
research. The first was to raise the minimum-size limit from 3.1 to 3.5 
inches (81 to 89 mm). It is estimated that 80% of the legal-size lobsters 
harvested in Maine are between 3.1 and 3.6 inches (81 and 92 mm; Thomas 1973). 
This means that lobsters are caught as fast as they reach legal size and that 
most females do not spawn once before they are harvested. This recommendation 
has not yet been implemented. The second recommendation (which has been 
implemented) was to increase the space in the sides of traps, that allows 
small lobsters to escape before traps are hauled. The increase to 1.75 inches 
(44.5 mm) would reduce injury and loss of claws. 

Attempts have been made recently in Maine to explore the potential of the 
American lobster for aquaculture. If lobsters could be raised successfully it 
might be possible to supplement natural populations as well as support 

12-17 

10-80 



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2 3 4 5 6 7 8 9 10 11 12 

NUMBER OF TRAPS (X10 5 ) 

Correlation of lobster catch (thousands of metric tons) and number 
of traps fished (hundred thousands) in Maine for 1897 to 
1976 (Maine Department of Marine Resources 1977). 



commercial aquaculture. Although this species has been raised to adulthood in 
the laboratory, large-scale aquaculture is impractical. The aggressiveness of 
the species requires that each lobster be raised in an individual container, 
feeding is expensive, and lobsters are more susceptible to disease in culture 
than in the natural environment. 

ROCK CRAB ( Cancer irroratus ) and JONAH CRAB ( Cancer borealis) 

A small commercial crab fishery in Maine is supported by the rock crab and the 
Jonah crab. Most Maine fishermen commonly refer to C. borealis as the rock 
crab and to C. irroratus as the sand or mud crab. Both species are 
brachyurans, or true crabs, and may reach a size of 2.3 inches (60 mm) at 
maturity (Krouse 1976). Females tend to be smaller than males. Although 
neither species has been studied extensively, more information is available on 
the life cycle and habits of the rock crab than of the Jonah crab. 

Distribution and Abundance 

These 2 species of crab range from Labrador to Florida (TRIGOM 1974) . The 
rock crab is the more abundant of the two in the intertidal zone of coastal 
Maine and may be found from low water to 1980 feet (600 m) . The Jonah crab 
may be found from the shallow subtidal zone to a depth of 2640 feet (800 m) 
(Gosner 1971). The major areas of harvest of crabs in coastal Maine are in 



12-18 



Casco Bay, the Sheepscot and Damariscotta estuaries, upper Penobscot Bay, and 
Blue Hill Bay. 

Life History 

The sexes of rock and Jonah crabs are separate, and in Maine breeding occurs 
in the fall when females are molting (males molt later, in February or March). 
Copulation occurs just after the female molts and the several thousand eggs 
are extruded in late fall or early winter. Fertilized eggs are carried by the 
female from 6 to 9 months until they hatch. Krouse (1976) estimates that 
hatching occurs from June to August in the Gulf of Maine and that the larvae 
are planktonic until August or September (approximately 40 to 60 days). 

Krouse (1976) found that young crabs settle in the intertidal zone and remain 
there until the second year of life, or until they reach a size of 1.9 inches 
(50 mm). Then, when the temperature begins to drop, they migrate seaward. 
Growth slows considerably in winter. 

Both species are carnivores and feed on polychaetes, sea urchins, mussels, and 
starfish (Scarratt and Lowe 1972). 

Habitat Preferences 

For the first 1.5 to 2 months of life, crabs are pelagic and part of the 
meroplankton (floating eggs and larvae). As such they are subject to heavy 
predation. 

The two species inhabit different bottom types. The Jonah crab is found 
predominantly in rocky bottoms, where shelter is readily available. The young 
rock crab, under 1.9 inches (50 mm), settles on rocky bottom or rocky 
intertidal areas but may later shift to a more open environment, such as 
unconsolidated bottoms of sand or mud (Stasko 1975; and Scarratt and Lowe 
1972). The rock crab is more active than the Jonah crab and burrows quickly 
in unconsolidated bottoms, or runs, when approached by predators (Jeffries 
1966). The Jonah crab, when approached by predators, finds a crevice on a 
rocky bottom and defends itself with its large claws. 

Factors of Abundance 

The rock and Jonah crabs have a limited tolerance to extreme environmental 
fluctuations . Larval mortality is high in salinities under 20 ppt (Sastry 
1970). Jeffries (1966) found, using "walking ability" as an indicator of 
temperature effects on adults of both species, that optimal temperature for 
the rock crab was 57 to 64°F (14 to 18° C) and for the Jonah crab, 43 to 57° F 
(6 to 14 C). 

Predators on small crabs include various bottom-feeding fish and the American 
lobster. Mature crabs are sometimes preyed upon by large cod (TRIGOM 1974). 



12-19 

10-80 



Human Impacts 

Studies on Jonah and rock crabs indicate that commercial harvesting is highly 
selective, favoring larger crabs, generally males. It is believed that crabs 
are being harvested at close to the optimum capacity to sustain the population 
(personal communication from J. Cowger, Maine Department of Marine Resources, 
Augusta, ME; November 1977). The effects of fishing on these crabs are 
unknown. 

Other potential impacts include dredging and spoil disposal, oil spills, and 
other toxic discharges. The effect of these factors on the Jonah and rock 
crab populations is unknown. 

Importance to Humanity 

In the past, harvest of the rock crab and the Jonah crab has been incidental 
to the lobster fishery in Maine. Lobstermen commonly find crabs, particularly 
the rock crab, in their traps and usually discard them; however, as prices 
continue to rise, fishing intensity will increase and more crabs will be kept 
and sold by lobstermen. Fishermen who fish specifically for crabs use crab 
pots that lobsters cannot enter. 

Although landings of crabs in the last 10 years have been variable (see figure 
12-6) , the value of the crab fishery in the last few years has increased 
rapidly. The actual harvest may have been significantly greater than what the 
data indicate, as many crabbers process the meat at home and sell directly to 
retailers. Almost the entire crab harvest is sold as fresh, handpicked meat 
within the State (Fisheries Development Corporation 1977). 

Management 

Currently, there are no management regulations on crab resources in Maine. 
Harvest restrictions on the fishery are the same as those on the lobster 
fishery. 

NORTHERN SHRIMP ( Pandalus borealis ) 

The northern shrimp is a decapod crustacean that is circumboreal (i.e., found 
around the world in the boreal zone) in distribution and occurs in both 
inshore and offshore waters at various stages in its life cycle. The species 
may reach a size of 6 inches (150 mm) at maturity (TRIGOM 1974) and during its 
life span usually functions first as a male, for 2.5 to 3.5 years, then as a 
female. 

In the past, the shrimp fishery of Maine has been erratic. It reached a peak 
in the late 1960s but since then has been declining. 

Distribution and Abundance 

In New England, the northern shrimp occurs in the Gulf of Maine, especially 
near Jeffrey's Ledge, southwest of Cashes Ledge, and southeast of Mt. Desert 
Island, at depths from 30 to 1100 feet (9 to 329 m; Haynes and Wigley 1969). 



12-20 



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10-80 



Life History 

Between the ages of 1 and 3 years, most individuals of this species are 
sexually mature males. The transition to the female gender may begin as early 
as 20 months, although it is more common at 32 months, and by 43 months almost 
all individuals are functional females (Haynes and Wigley 1969). Some females 
spawn twice, although most spawn only once in their lifetimes. Estimated 
normal life span for individuals of this species in the Gulf of Maine is 4 to 
5 years (Wigley 1972). 

In offshore waters of the Gulf of Maine copulation occurs after females molt 
(Haynes and Wigley 1969). Eggs (330 to 500) are carried on the female's 
pleopods (appendages on the underside) through the winter, during which time 
females migrate inshore. Egg-bearing shrimp may prefer cold water and 
therefore in the winter move gradually inshore, where the waters are cooling 
(Stickney and Perkins 1977). The time of hatching depends on water 
temperatures during the winter in which the eggs are being carried on the 
female. In warm years hatching may take place as early as February and most 
hatching is usually completed by April (personal communication from A. P. 
Stickney, Maine Department of Marine Resources, Augusta, ME; November, 1977). 
After hatching, larvae are planktonic (suspended in the water column) until 
they lose their exopods (swimming appendages) after about three months 
(Stickney and Perkins 1977). Male juveniles remain inshore until their second 
winter (end of 2nd year) when they begin to migrate offshore. In the fall 
egg-bearing females (end of 4th year) begin their migration inshore. 

The diet of the adult shrimp varies with the season, consisting of a larger 
proportion of molluscs in the winter and crustaceans in the summer. The 
shrimp may also eat polychaetes, protozoans, and echinoderms. 

Habitat Preferences 

The northern shrimp is considered a benthic species, although males and 
females not carrying eggs may migrate vertically through the water column at 
night to feed. Shrimp live in the subtidal zone of the marine system, usually 
on unconsolidated bottoms composed of mud, silt, or sand that are high in 
carbon and nitrogen content (Bigelow and Schroeder 1939). Larvae live in the 
water column. 

Factors of Abundance 

The northern shrimp appears to have well-defined environmental requirements. 
Salinity tolerance as high as 30 to 35 ppt is suggested by Wigley (1972) and 
Haynes and Wigley (1969). The temperature tolerance of this species ranges 
from 28 to 53°F (2 to 11. 5° C), although larvae can live in waters as warm as 
57 F (14°C; TRIG0M 1974). 

There are 2 known parasites of the northern shrimp. One of these affects the 
eggs of the shrimp and has been tentatively identified as a parasitic 
dinof lagellate (Stickney 1978). The affected eggs are no longer viable and 
fecundity is reduced. The other organism is a dinoflagellate of the genus 
Gymnodinioides and infects the gills of adult shrimp (Apollonio and Dunton 
1969). It is not known if mortalities from these parasites alter the shrimp 
population. 

12-22 



Human Impacts 

Overharvesting as occurred in the late 1960s was the major limitation on 
shrimp populations. Initially the catch consisted almost exclusively of egg- 
bearing females, which are the largest individuals of the species and which 
inhabit shallower waters. In recent years larger vessels, improvements in 
fishing gear, and changes in fishing season have increased the proportion of 
males and transitionals in the catch. 

Discharges of oil and other contaminants have the potential to affect shrimp 
populations. The effect of these factors on shrimp stocks is unknown. 

Importance to Humanity 

The northern shrimp has supported a commercial fishery in Maine since 1938. 
In the early years the shrimp were harvested primarily from February to April, 
and the bulk of the catch was sold frozen (Scattergood 1952). 

In the early 1940s several packing plants for shrimp opened, and since then 
the demand for shrimp has steadily increased. A sharp decline in the fishery 
occurred in the early 1950s, with no landings at all from 1954 to 1957 (Maine 
Landings 1954 to 1957). High winter temperatures during 1950 to 1953 are 
believed to have adversely affected shrimp populations during that time 
(Apollonio and Dunton 1969). 

The harvest began to increase dramatically in the 1960s, and by 1968 the catch 
was over 12 million pounds (Apollonio and Dunton 1969). However, a decline in 
catch per unit of fishing effort followed, falling from a peak of over 6000 
lb/day fishing in 1969 to less than 2000 lb/day fishing in 1976 (Clark and 
Anthony 1977). The shrimp catch and dollar value for the last 10 years are 
illustrated in figure 12-7; the sharp decline since 1973 is apparent. 

In the 1960s the important shrimp ports in Maine were Portland, Boothbay 
Harbor, New Harbor, Rockland, Vinalhaven, and Southwest Harbor. Because of 
the recent decline in catch, the center of the Maine shrimp fishery has 
shifted to Portland. 

Management 

Although no management of the shrimp resource of Maine took place until 1973, 
MDMR began to study the northern shrimp in 1965. Research was focused on 
abundance, distribution, and life history studies. In 1969 emphasis was 
shifted to population dynamics and the development of a management model. 
Current research includes sampling of the commercial catch and of adult and 
larval populations. Stock size estimates for 1978 project a shrimp population 
in the Gulf of Maine of 1 to 3 million pounds (Atlantic States Marine 
Fisheries Commission 1977). 

The shrimp fishery of New England is regulated by the Atlantic States Marine 
Fisheries Commission, consisting of Maine, New Hampshire, and Massachusetts. 
The fisheries of Maine and Massachusetts are active in different seasons 
(Maine in winter and Massachusetts in summer) and tend to focus on different 
components of the total shrimp population (Maine inshore and Massachusetts 
offshore). Therefore, regional regulation of the fishery is difficult. 

12-23 

10-80 



In 1973 MDMR set regulations requiring the use of a minimum shrimp trawl mesh 
size of 1.5 inches (38 mm). The regulation was revised in 1975 to 1.75 
inches (45 mm) so that smaller and younger (under 3 years) shrimp would not be 
caught. This regulation has had little effect on the catch composition of 
Maine landings during the first few years of implementation (personal 
communication from D. F. Schick, Maine Department of Marine Resources, Augusta 
ME; April, 1978). 

The correlation between fishing effort and stock size has been found to be 
more significant than that between temperature and stock size, and it has been 
suggested that more severely regulated shrimp fisheries (i.e., closed seasons 
and/or quotas) cannot substantially increase abundance before the mid-1980s, 
and then only if temperatures are favorably low during the recovery period 
(Clark and Anthony 1977). Warm seawater temperatures are recognized as being 
detrimental to shrimp populations; however, the effect of temperature is 
obscured by the dramatic increase in fishing effort (60%) in recent years 
(Anthony and Clark 1978). The Northern Shrimp Scientific Committee (Atlantic 
States Marine Fisheries 1977) concludes in their report for 1977 that the 
increased fishing effort over the last 5 to 10 years has been a major factor 
in reducing the stock size, and that the population will not be able to 
recover without continued severe restriction of the fishery. 

MARINE WORMS 

This section describes the natural history and other aspects of the bloodworm 
and the sandworm in Maine. Because management and marketing of both these 
species are the same or similar, the subsections on "Importance to Humanity" 
and "Management" review the worm industry as a whole rather than by species. 

Bloodworm ( Glycera dibranchiata ) 

The bloodworm is a polychaete that burrows in unconsolidated sediments largely 
in the intertidal zone. From within the burrow the worm feeds on detritus and 
small invertebrates. It generally migrates only locally within the substrate 
but at certain times of the year bloodworms have been found in the water 
column (Dean 1978b; and Graham and Creaser 1978). This polychaete may reach a 
length of 16 inches (400 mm) and have up to 300 segments (Pettibone 1963). 
The bloodworm is one of the two species that form the basis of the commercial 
marine bait worm industry centered in coastal Maine. 

Distribution and abundance . The bloodworm range extends from the Gulf of 
St. Lawrence to the Gulf of Mexico and from central California to Mexico. The 
species has been found at all levels of the intertidal zone and to a depth of 
1300 feet (400 m) . 

The most abundant populations in Maine are generally found near the low water 
mark and may reach densities up to 17.2 worms/m (personal communication from 
E. P. Creaser, Maine Department of Marine Resources, Augusta, ME; April, 
1978). The worm usually inhabits the top 10 inches (25 cm) of the sediment 
(Klawe and Dickie 1957). 

Commercial quantities are found only in Maine, New Hampshire, and 
Massachusetts. Atlas map 4 depicts commercially important worm flats in 
Maine. 

12-24 



Life history . Detailed information on the reproductive cycle of the 
bloodworm generally is scarce. Like most polychaetes, this species has two 
sexes. Sexual maturity is reached probably in the 3rd year, and the rate of 
maturation appears to be dependent upon both temperature and the physiological 
condition of the organism (Simpson 1962). 

The bloodworm spawns primarily in June in Maine; however, rare occurrences of 
winter spawning have also been observed (Creaser 1973). Few spawners have 
been found in Maine east of Frenchman Bay (Skillings and Taunton Rivers; 
region 5; personal communication from E. P. Creaser, Maine Department of 
Marine Resources, Augusta, ME; November, 1977). Adult populations in eastern 
Maine may be recruited from distant populations by larval dispersal. 

The formation of eggs and sperm begins in the fall and by March the females 
are swollen with eggs (Creaser 1973) . The number of eggs per individual 
varies from about 3 million to almost 10 million depending on the size of the 
individual. The species undergoes limited epitoky prior to spawning, a 
phenomenon typical of certain polychaetes, in which the worm's body becomes 
structurally modified. The body wall becomes thin and fragile and the skin 
changes in pigmentation. Males and females may be distinguished just prior to 
spawning by color differences. Males are light cream in color and females are 
brown (Creaser 1973; and Klawe and Dickie 1957). 

Spawning bloodworms leave their burrows and swim to the surface in swarms to 
release their gametes. What controls the timing of swarming is not known, 
though temperature at the place of spawning, tidal amplitude, and hormonal 
factors may affect it. A minimum water temperature of 55 F (13 C) for 
spawning in Maine was reported by Creaser (1973). In a study conducted in the 
Montsweag Bay-Wiscasset area, populations of bloodworms near the Maine Yankee 
nuclear power plant spawned earlier than control populations (Mazurkiewicz and 
Scott 1973), presumably because of the warmer water near the plant. Both 
Simpson (1962) and Creaser (1973) observed swarming just prior to and during 
the second high tide of the day. It is not known if the presence of both 
sexes is required for the release of gametes during swarming. Gametes are 
emitted as a result of the muscular contraction in swimming. 

After gametes have been shed the adult is spent, and its body collapses and 
sinks to the bottom (Creaser 1973; and Klawe and Dickie 1957). Although 
Creaser (1973) concludes that all bloodworms die after spawning, Simpson 
(1962) believes that some spawners may survive. 

The fertilized eggs apparently settle to the bottom, develop to the larval 
stage, and become pelagic for a short time. Mazurkiewicz (1974) found that 
during intense periods of spawning activity numerous bloodworm larvae were 
present in the plankton. These and later larval stages were observed in the 
plankton for only a short period after spawning (Mazurkiewicz 1974) . The 
apparent disappearance of larvae from the plankton is unexplained, but they 
may leave the water column and live on the surface of the bottom. No 
information is available about the length of the larval stage. 

Adult bloodworms feed primarily on detritus (Klawe and Dickie 1957; and 
Pettibone 1963) and are especially abundant in areas rich in detritus (Dean 
and Ewart 1978). Other food items include polychaetes (including other 



12-25 

10-80 



bloodworms) and small crustaceans (Sanders et al. 1962; and Dean and Ewart 
1978). 

Habitat preferences . Bloodworms are found in both the estuarine and 
marine systems. In Chesapeake Bay the lower salinity limit for natural 
populations is approximately 15 ppt (Boesch 1971). 

This worm is found on unconsolidated bottoms of the subtidal zone and in the 
flat and beach habitats of the intertidal zone. It is most abundant in mud 
flats. 

The adult is present in the water column during spawning and at night during 
the late fall. The water column is the medium in which eggs are fertilized. 
During the late fall and winter individuals are carried by the movements of 
the water column (Graham and Creaser 1978; and Dean 1978b). 

Factors of abundance . Distribution and abundance of bloodworms are 

affected by several natural factors. For instance, larvae are known to 

require temperatures under 68 °F (20 °C) for extended periods immediately after 

fertilization, and optimal salinity for the larvae was found to be 22 to 26 
ppt (Schick 1974) . 

Predation is also a factor. For example, predation by gulls ( Larus ) and fish, 
such as striped bass, when the bloodworms are in the water column during 
spawning (Creaser 1973) may be significant. However, the magnitude of this 
and other types of mortality is unknown. According to Dean (1978b), however, 
because migrations of bloodworm occur in late fall and winter, predation 
probably is insignificant. 

Sediment type and/or detritus content may also have some effect on the 
populations of bloodworms. Evidence of sediment or detrital requirements is 
incomplete. 

Sandworm (Nereis virens) 

The sandworm is a burrowing polychaete that is often one of the most abundant 
animals in intertidal flat communities. It may reach a length of 35 inches 
(900 mm; Pettibone 1963) and is harvested commercially for the bait worm 
industry. It often leaves its burrow either to swim or crawl for several 
meters on the substrate surface and then forms another burrow. Sandworms have 
been observed migrating downstream in estuaries during ebb tides in winter 
(Dean 1978a). 

Distribution and abundance . The range of the sandworm in North America 
extends from Newfoundland to Virginia (MacGinitie and MacGinitie 1968) . 
Although common in the intertidal zone of coastal and estuarine waters, the 
sandworm also occurs subtidally down to depths of 475 feet (154 m; Gosner 
1971). Intertidal populations are most abundant near the low water mark of 
flats. The burrows of this species may be deep, up to 18 inches (45 cm) in 
the sediment (Pettibone 1963). 

Population densities of up to 537 worms/m were reported on flats in 
Wiscasset, Maine (personal communication from E. P. Creaser, Maine Department 
of Marine Resources, Augusta, ME; April, 1978), and up to 637 worms/m 2 in the 

12-26 



subtidal zone of the Sheepscot estuary (Larsen and Doggett 1978b). 
Commercially important worm flats are illustrated in atlas map 4. 

Life history . Despite in-depth studies of the reproductive cycle of the 
sandworm by Bass and Brafield (1972) in Great Britain, Rasmussen (1973) in 
Denmark, and Snow and Marsden (1974) in New Brunswick, Canada, knowledge of 
its development remains incomplete. Sexual maturation is reached in 2 to 3 
years. Most data (e.g., Bass and Brafield 1972) indicate that only males 
undergo epitoky (significant body tissue modification) before spawning and 
only males swarm. 

In coastal Maine spawning occurs from mid-March to late June and peaks in late 
April and May. Laboratory culture experiments indicate that temperature 
affects the rate of sexual maturation but does not appear to trigger 
successful spawning (Bass and Brafield 1972). Raising the temperature of the 
water in cultures causes worms to develop and release gametes more quickly but 
the gametes usually are not viable. Tidal fluctuation and subsequent changes 
in hydrostatic pressure are considered influential in the timing of spawning. 
Hormonal and physiological factors are probably significant also (Bass and 
Brafield 1972). 

At the time of swarming, males swim to the surface where they release sperm, 
and then die. Individual females release from 100,000 to 17 million eggs 
depending on the size of the female within the burrow (TRIGOM 1974), and may 
subsequently die. 

Most sandworms live to be about 3 years old but Dean (1978a) found a few worms 
up to 5 years old, plus one individual which may have been older. 

Fertilized eggs sink to the bottom and the larvae develop in the burrow for 5 
to 6 days after which they become pelagic for a short time. Growth of larvae 
is initially achieved by increasing the number of segments followed by 
enlargement of the segments (Bass and Brafield 1972). 

Larvae then resume a benthic existence, probably subtidally, and attach to the 
sediment surface. After 12 days the organism may form shallow burrows and 
after 4 months it either establishes a subtidal burrow or migrates to the 
intertidal zone. Migration to the intertidal zone also may occur after a year 
(Bass and Brafield 1972). 

Adult sandworms feed on various types of invertebrates, both in the water 
column and on the bottom. They also feed on algae, Ulva (Pettibone 1963) and 
detritus (personal communication from K. Fauchald, University of Southern 
California, Los Angeles, CA; April, 1979). 

Habitat preferences . Sandworms live in the intertidal and subtidal zone 
of both the marine and estuarine systems. This species is found in estuarine 
areas where the salinity of the water column is <0.5 ppt for over 8 hours of 
the tidal cycle (Larsen and Doggett 1978b). The greatest subtidal abundances 
(637 worms/m ) in the Sheepscot estuary occurred in an area where salinity 
varied from 0.5 to 19 ppt (Larsen and Doggett 1978b). 

The adult life of the sandworm is spent on subtidal unconsolidated sediments, 
flats, or beach/bar habitats (Larsen and Doggett 1978a). This species is 

12-27 

10-80 



found most frequently and in greatest abundance in intertidal mud flats 
(Larsen and Doggett 1978a). Larvae inhabit subtidal unconsolidated sediments 
and the water column. 

Factors of abundance . Various natural factors may influence the 
distribution and abundance of sandworms. This species is especially 
vulnerable to predation because it often emerges from its burrow to feed. 
Worms are an important food source for many fish (Pettibone 1963) as well as 
rock crabs and green crabs. 

During spawning males swimming at the water surface are often preyed upon by 
seagulls (Larus). The effect of the observed winter migration of worms (Dean 
1978a) on the total population is unknown. However, Dean (1978) believes that 
predation is minimal in the winter. 

Extended ice cover on mud flats sometimes causes high mortality of sandworms 
because of oxygen depletion (Rasmussen 1973) . Laboratory experiments with the 
sandworm indicate that this species is ordinarily extremely efficient in 
oxygen utilization (Newell 1970). In an area of the Sheepscot estuary, which 
is covered by ice most of the winter, relatively high abundances of sandworms 
(347/m ) were found in samples taken in early April (Larsen and Doggett 
1978b). This indicates that subtidal populations may not necessarily have 
high winter mortalities. 

Human Impacts 

Harvesting may have a significant effect on the abundance of sandworms. 
However, no data are available on fishing mortality of either sandworms or 
bloodworms . 

Shippers, diggers, and sportf ishermen have noted a decline in the size and 
abundance of worms in recent years (Schroeder 1978). Many worms that are 
missed in the process of digging may be damaged or left exposed to temperature 
extremes and predation. 

Landings (figures 12-8 and 12-9) and abundances reported by Larsen and Doggett 
(1978 a and b) from the intertidal zone along the coast of Maine and in the 
subtidal zone of the Sheepscot estuary (Larsen 1979) indicate that sandworms 
are more abundant than bloodworms. 

Other factors that may potentially reduce worm abundance are shoreline 
construction, dredging, toxic discharges or spills. Information on the 
effects of these factors is lacking. 

Importance to Humanity 

Marine worms are the favored bait of many saltwater sportf ishermen along the 
east coast of the United States, particularly from Long Island, NY, to 
Chesapeake Bay. Because of the demand for worms by these fishermen, the bait 
worm industry is the fourth most valuable fishery in Maine after lobster, 
clams, and finfish. 



12-28 



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12-29 



10-80 



Maine, currently, is the center of the bait worm industry, supplying over 90% 
of this country's production and it is the only area that provides a continued 
high-level supply of the two species. 

The marine worm industry began on Long Island, NY, in the 1920s, but the 
fishery gradually moved northward as local worm populations decreased in 
numbers and more abundant populations were located. The industry began in 
Maine in the early 1930s and is now centered in Lincoln and Washington 
Counties. Hancock County also supplies many worms (personal communication 
from E. P. Creaser, Maine Department of Marine Resources, Augusta, ME; April, 
1978). Approximately 1200 worm diggers and 19 dealers operate in Maine. 
Major distributers to local markets are located in New York, Boston, and 
Baltimore. 

Management 

A license is required for taking more than 125 worms/day. The method of 
harvest is limited to hand-powered devices, and recently a ban has been placed 
on digging on Sunday. 

No management plan has been adopted for these marine resources, although the 
industry has taken exceptional initiative in supporting research and 
exploration of management alternatives. For a history of the marine worm 
industry in Maine see Sperling (1979). 

Aquaculture of bloodworms has been suggested by Dow (1978) as the only way to 
reestablish and sustain the resource in Maine. However, this method was 
attempted in the early 1970s with little success. The potential for raising 
bloodworms in heated effluent from a nuclear power plant was studied. Feeding 
was a major obstacle in the study (Schick 1974), and worms in warmer water 
reach sexual maturity more rapidly and at smaller sizes. Once worms are 
sexually mature they become fragile and are of no commercial value. 

RED TIDES 

Red tides have been historically common in marine waters throughout the world. 
Red tide is a massive population explosion of a species of dinof lagellate that 
produces a substance that is toxic to many other marine species. The organism 
is planktonic and its red color, in abundance, gives the impression of a red 
tide. 

The "red tide organism" of Maine is Gonyaulax excavata (formerly known as G. 

tamarensis ; Loeblich and Loeblich 1975). It is a dinoflagellate, microscopic, 

photosynthetic, single-celled organism covered with cellulose plates, and has 
two flagellae for locomotion. 

Life History 

Gonyaulax appears to ingest organic particles for energy. It migrates within 
the water column daily, surfacing during the day and swimming downward at 
night. Reproduction in Gonyaulax is either asexual or sexual. 

The organism also exists in a cyst form that is nonmotile and has been found 
in sediment to depths of 90 m (297 feet; personal communication from C. M. 
Yentsch, Bigelow Laboratory, West Boothbay Harbor, ME; November, 1977). The 
cysts may form as a response of the organism to environmental stress. 

12-30 



In developing a model for a bloom of Gonyaulax , Prakash (1975) suggested that 
the process involved two distinct parts: initiation and continuation. Bloom 
initiation requires specific biological and chemical conditions that would 
allow exponential growth of a population. An example is the disruption of 
cyst beds caused by hydrographic disturbances. Continuation of the bloom 
would then involve hydrographic and meteorological factors that could act as 
mechanisms to concentrate the bloom. If cysts were carried to warmer surfaces 
or coastal waters in spring or summer, excystment could occur and may account 
for reappearance of Gonyaulax in spring each year (personal communication from 
C. M. Yentsch, Bigelow Laboratory, West Boothbay Harbor, ME; November, 1977). 

Factors of Abundance 

The ecology of Gonyaulax excavata has attracted the attention of an increasing 
number of scientists in recent years. One of the most puzzling aspects of red 
tide is that the blooms are composed almost entirely of this single species. 
Thus, conditions that favor a bloom of Gonyaulax must be highly selective. 

Prakash (1967) found that in culture conditions the optimal temperature and 
salinity for G. excavata were 59 to 66°F (15 to 19°C) and 19 to 20 ppt. He 
has suggested that in coastal and estuarine conditions salinity has a greater 
effect on the abundance of this organism than does temperature, although the 
effect of temperature may be expressed through cyst formation. The motile 
form of the organism is not found in nature at temperatures less than 4l°F (5° 
C; Yentsch et al. 1975). The low salinity in upper estuaries may slow 
filtration rates of shellfish to such an extent that the organisms do not take 
in toxins at a harmful level. 

Nutrient requirements of red tide organisms are not well defined. Several 
studies (Prakash 1967, 1975; Yentsch et al. 1975) have suggested that humic 
matter from land runoff may be important in controlling concentrations of 
dissolved trace metals for growth of the organism. Other research has focused 
on the role of iron, vitamins, and organic materials in Gonyaulax nutrition. 
The nitrogen and phosphorus requirements of Gonyaulax seem to be much lower 
than those of other phytoplankton species (Yentsch and Yentsch 1977). 

Benthic organisms may ingest the cyst form of the species, and accumulate the 
toxin in the absence of a bloom. One dense bed of these cysts has been 
located off the Maine coast near Monhegan Island (personal communication from 
C. M. Yentsch, Bigelow Laboratory, West Boothbay Harbor, ME; November, 1977). 
Prakash (1967) notes that sea scallops in the Bay of Fundy reach maximum 
levels of toxicity in winter, when cysts may be most abundant. 

Other factors that may influence the species abundance include predation, 
competition, and day length. 

Importance to Humanity 

The toxins Gonyaulax produces, which are harmful to other marine species, 
evoke a reaction in humans known as paralytic shellfish poisoning (PSP) . The 
poison is a group of endotoxins contained within the cell of the 
dinof lagellate that is released when the cell is broken during digestion by 
the consumer. The endotoxins block the transmission of nerve impulses along 
nerve fibers. 

12-31 

10-80 



Toxins are accumulated in the tissues of filter-feeding shellfish, such as 
clams and mussels. In sufficient quantities they may he fatal to host 
organisms, though certain species show high resistance to the poisons. People 
who eat contaminated shellfish may suffer varying degrees of PSP and may die 
from its effects. The toxins are not destroyed by cooking. 

Toxicity is 10 to 100 times greater in the cyst than in the motile organism 
(personal communication from C. A. Mickelson, Bigelow Laboratory, West 
Boothbay Harbor, ME; November, 1977). 

The recent history of red tides in Maine dates back to 1958. Following an 
outbreak of shellfish poisoning in New Brunswick in 1957, Maine officials 
initiated a sampling program in 1958. Since then, toxin G. excavata has been 
found in shellfish each year, and closings of shellfish harvest have occurred 
(Hurst 1975). Initially only the far eastern region of the coast, especially 
Washington County, was affected. 

It has been suggested that since cyst beds have become established (after 
severe blooms in 1972 and 1974) Gonyaulax will be a recurring problem along 
the entire Maine coast. Waters near Monhegan and Matinicus Islands on the 
Maine coast have been permanently closed to shellfish harvest because of red 
tide. 

Management 

The monitoring scheme initially involved monthly sampling of six stations from 
October to May, biweekly sampling until a rise in toxicity was noted (usually 
by 15 June), and weekly sampling until 1 October (Hurst 1975). The sampling 
program was expanded in 1975 to include 18 primary stations, and 98 secondary 
and tertiary stations. Primary stations are sampled weekly from April to 
October and when toxicity is first detected, secondary and tertiary stations 
are sampled (Gilfillan et al. 1976). 

Areas are closed to shellfish harvest when the toxicity level reaches 80 yg 
PSP/100 g shellfish. A toxicity of approximately 500 Pg PSP/100 g shellfish 
is sufficient to cause sickness in humans (Gilfillan et al. 1976). 

RESEARCH NEEDS 

Most aspects of the role of various species in the ecosystem are unknown and 
need to be examined. Commercial species of invertebrates should be examined 
in relation to their role in the ecosystem, and both biotic and abiotic 
factors should be addressed. 

Abiotic factors include temperature and salinity preferences of each species 
at its various life stages. Movements of water masses during the time larvae 
are in the water column should be investigated and sediment preferences of 
settling larvae, migrating juveniles and adults should be explored. 

Biotic factors include the following: food webs in relation to each species, 
competition between individuals of a species and between species, natural 
mortality rates, and energy transfer between trophic levels. 



12-32 



Natural life history studies are needed and human impacts on abundance should 
be explored. These include the effects of commercial removal and the 
potential effects of various perturbations such as dredging, spoil disposal, 
oil spills, and discharge of contaminants, on each species at various life 
stages . 

When all factors, both natural and artificial, are known, questions such as 
the following may be answered: 

1. Why have shrimp landings decreased so sharply? 

2. How are scallop beds formed and why are catches so erratic? 

3. Do worms prefer particular sediment types and/or detrital amounts in 
the substrate? 

4. Which cyclic events in life histories of populations relate to 
harvest levels? 

Many theories attempt to answer the above questions. In the past, correlation 
of a single abiotic or biotic factor with harvest has been attempted. It may 
be more valuable to correlate a variety of variables with species abundance 
and distribution. The ecosystem approach rather than the single species- 
single factor approach is necessary. 



12-33 

10-80 



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12-34 



10-80 



Cobb, S. J. 1976. The American Lobster: The Biology of Homarus americanus . 
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12-35 



Gilfillan, E. S. , J. W. Hurst, S. A. Hanson, and C. P. LeRoyer III. 1976. 
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12-37 



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12-38 

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. 1964b. Feeding and growth of juvenile soft-shell clam Mya arenaria . 

U.S. Nat. Mar. Fish. Serv. Fish. Bull. 63:635-642. 

. 1978. A previously unreported peridinian parasite in the eggs of the 

Northern shrimp, Pandalus borealis . J. Invertebr. Pathol. 32(2) :212- 
215. 

, and H. C. Perkins. 1977. Environmental physiology of commercial 

shrimp, Pandalus borealis . Project 3-202-R completion report. Maine 
Department of Marine Resources, Augusta, ME. 

Stunkard, H. W. , and J. R. Uzmann. 1958. Studies on digenetic trematodes of 
the genera Gymnophallus and Parvatrema . Biol. Bull., (Woods Hole) 
115:276-302. 

Theisen, B. F. 1972. Shell cleaning and deposit feeding in Mytilus edulis L. 
Ophelia (Denmark) 10:49-55. 

Thomas, J. C. 1973. An Analysis of the Commercial Lobster ( Homarus 
americanus ) Fishery along the Coast of Maine, Aug. 1966 - Dec. 1970. 

12-39 



NOAA (National Oceanic and Atmospheric Administration) Tech. Rep. NMFS 
SSRF-667. 

• 1977. Procedures and some findings from the lobster research project, 

State of Maine. Lobster Inf. Leafl. Maine Department of Marine 
Resources, Augusta, ME. 

TRIGOM. 1974. A Socio-economic and Environmental Inventory of the North 
Atlantic Region. Vol 1. TRIGOM (The Research Institute of the Gulf of 
Maine) South Portland, ME. 

Welch , W. 1950. Growth and spawning characteristics of the sea scallop, 
Placopecten magellanicus (Gemlin) , in Maine water. M.S. thesis, 
University of Maine, Orono, ME. 

Wigley, R. L. 1972. Fishery for northern shrimp, Pandalus borealis , in the 
Gulf of Maine. U.S. Nat. Mar. Fish. Serv. Mar. Fish. Rev. 35:9-14. 

Yentsch, C. M. , E. J. Cole, and M. G. Salvaggio. 1975. Some of the growth 
characteristics of Gonyaulax tamarensis isolated from the Gulf of Maine. 
Pages 163-180 in V. R. LoCicero(ed) , Proceedings of the First 
International Conference on Toxic Dinof lagellate Blooms. Mass. Sci. 
Tech. Found., Wakefield, MA. 

, and C. S. Yentsch. 1977. Red tides. Pages 691-694 in J. Clark (ed) , 

Coastal Ecosytem Management. John Wiley and Sons, New York. 



12-40 

10-80 



Chapter 13 
Marine Mammals 



Authors: Patricia Shettig, Cheryl Klink 




Two orders of marine mammals inhabit the nearshore Gulf of Maine region: 
Pinnipedia (seals) and Cetacea (whales and dolphins). Twenty-one species of 
whales and porpoises and five species of seals have been reported in the Gulf 
of Maine but only five species in all are common to coastal Maine. The others 
are either uncommon, rare, or are found mainly far out to sea. Most cetaceans 
exhibit rather clear migratory patterns, that is, they swim northerly along 
the coast in the spring and southerly in the fall and apparently are absent or 
scarce in winter. The Harbor seal, however, is a year round resident. 
Because of their mobility and observed seasonal migrations along the coast, 
most cetaceans have only a seasonal role in the ecology of coastal waters. 

Coastal Maine waters from the Bay of Fundy to New Hampshire are vitally 
important to many northwest Atlantic populations. This region is the major 
range of harbor porpoises and harbor seals and is essential for feeding and 
breeding (Katona et al. 1977). It is also part of the native range of the 
gray seal, whose populations were reduced by hunting in the past. The area 
east of Penobscot Bay, particularly the Mt. Desert Rock region and the 
approaches to the Bay of Fundy, appears to be an important summer feeding area 
for humpback and finback whales. Two endangered whales, the northern right 
whale and the humpback whale, make regular use of the approaches to the Bay of 
Fundy each year (Gaskin et al. 1979). 

Data for determining the abundance and changes in abundance of whale species 
for the northwest Atlantic, the Gulf of Maine, and coastal Maine generally are 
scattered and/or intermittent. Until recently, for example, no systematic or 
sustained counts of cetaceans have been made and most of the data available 
are from "chance" observations. 

The Bureau of Land Management's Cetacean and Turtle Assessment Program 
(CETAP) , conducted by the University of Rhode Island, is presently in its 
second year of field data collection on the size and distribution of cetacean 
populations from the Gulf of Maine to the coast of North Carolina. In 
addition, the New England Aquarium is currently coordinating detailed studies 

13-1 



10-80 



of marine mammals in the approaches to the Bay of Fundy and 
Cobscook/Passamaquoddy Bays. 

The interpretation of data on the relative abundance of whale species presents 
additional problems even if all species are correctly identified. Rare 
species tend to be reported more thoroughly than common ones, which can 
exaggerate their importance or relative abundance. The same bias appears with 
sightings of large species as opposed to smaller ones. An untrained observer 
is apt to misidentify a small species as the young of a larger species, so 
that minke whales are often mistaken for young finbacks (TRIGOM 1974) . The 
different habitat preferences of the various species present another problem. 
In the offshore regions many species that may be common are unlikely to be 
observed because these areas are inaccessible. In addition, while it may be 
true that most cetaceans are scarce or absent in the Gulf of Maine during the 
winter months, observation efforts are also less frequent during that time. 
Because whales are relatively scarce and are highly valued and protected 
species, most studies of the biology and interrelationships of the various 
species must be conducted at a distance, so as not to cause excessive 
disturbance, or on dead, beached, or captive animals. It is hard to get data 
representative of marine mammal populations in the wild. All of these 
problems frustrate efforts to realistically assess the abundance and relative 
importance of marine mammals in the Gulf of Maine. 

Harbor seals are relatively common along the Maine coast. Data on the 
distribution and abundance of harbor seals and harbor seal haulout sites come 
from the coastwide aerial photocensus conducted by Richardson (1973a) and 
subsequent boat surveys in 1974 and 1975 which updated information on 35 
haulout sites along the coast (Richardson 1976). Dr. James Gilbert at the 
University of Maine at Orono is conducting an update to the coastal harbor 
seal population assessment. 

Two general problems are discussed in this chapter in some detail because of 
their world-wide significance and their effects on the present and future 
status of marine mammals in Maine. One is a potential threat that is not yet 
considered an immediate danger in Maine: the pollution of coastal waters and 
their biota with industrial contaminants, especially organochlorines and heavy 
metals. The other is the world-wide decline in the abundance of whales, which 
has reached near catastrophic levels and which directly affects coastal Maine 
populations. In this context the history of the whaling industry is reviewed. 
Common names of species are used except where accepted common names do not 
exist. Taxonomic names of all species mentioned are given in the appendix to 
chapter 1. 

DISTRIBUTION AND ABUNDANCE 

Twenty-one species of whales and porpoises and five species of seals have been 
reported in the Gulf of Maine. These cetacean and pinniped species, 
respectively, and their known habitat uses and estimated abundance in the 
western North Atlantic region are listed in tables 13-1 and 13-2. Of these 
marine mammals, four cetaceans (harbor porpoise, finback whale, minke whale, 
and humpback whale) and one pinniped (harbor seal) are common in coastal Maine 
waters. These animals appear to be more common (i.e., more commonly sighted) 
in eastern Maine waters than western Maine waters. 



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13-5 



10-80 



Cetaceans 

Most of the cetaceans discussed here range along the Maine coast from about 
late April through October or early November. During the course of the year 
many of them show a clear north-south migration pattern. The harbor porpoise 
is an exception, exhibiting an onshore-offshore migration pattern. The major 
abiotic factors that influence cetacean distribution are temperature, 
currents, and physiography, but little detailed information is available. The 
finback whale is the most common of the large whales to frequent coastal Maine 
and presently the most abundant large whale in New England waters. The harbor 
porpoise is the numerically dominant cetacean in the Gulf of Maine. A summary 
of recorded sightings of marine mammals within the last few decades in the 
characterization area is given in table 13-3. 

During early spring or winter, sightings of cetaceans are common in the 
southern portion of the Gulf of Maine, Massachusetts Bay, and Cape Cod Bay. 
Apparently, the animals migrate up the coast in spring and early summer, 
remaining along the Maine and Fundy coasts until late autumn. This 
distribution trend correlates well with the distribution of herring and other 
schooling fishes, squid, and zooplankton (copepods and euphausiids) . During 
this period species generally aggregate in productive areas, such as fishing 
banks, river mouths, or estuaries. Large whales, such as the right whale and 
humpback whale, sometimes approach the coast; however, most of the species 
will be found in water between 20 and 50 fathoms (37 and 91 m) deep. Harbor 
porpoises tend to be found in relatively shallow water (20 to 50 fathoms or 
less). The 50-fathom contour appears to be an important demarcation of 
feeding areas, as does the 100-fathom (183-m) contour farther offshore (Katona 
1977). 

Over the past several years inshore movements of several species, including 
humpback whales, appear to be on the increase in North Atlantic waters but it 
is difficult to distinguish how much of the observed increase is due to an 
increase in interested observers. The apparent movement inshore seems to be 
in part due to the collapse of the capelin stocks on the Grand Banks as a 
result of overfishing (Lien and Merdsoy 1979). The whales are probably moving 
inshore in search of alternative food supplies. Gaskin and coworkers (l r 79) 
conclude that the presence of humpbacks in the herring-rich area of the 
approaches to Cobscook Bay and Passamaquoddy Bay is likely to be a regular and 
annual event. Unfortunately, the increasing occurrence of humpbacks close to 
shore increases the likelihood of their entanglement with fishing gear and 
collisions with boats. 

It is important to remember that the large whales, at least, can easily travel 
the entire Maine coast in a day or two if they choose to; consequently, their 
feeding ranges may be the whole of the Gulf of Maine. Despite their mobility, 
however, many individuals may remain in local areas for weeks or sometimes 
months. Data gathered during the period 1973 to 1976 show that humpback 
whales and finback whales regularly use the Mt. Desert Rock (region 5) region 
for feeding from June through September. Humpback whales (with calves) spent 
extended periods in the Campobello Island (region 6) region during July to 
September, 1979 (Gaskin et al. 1979). 



13-6 



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13-7 



10-80 



During the winter months Maine's cetaceans either migrate south to breeding 
grounds (e.g., the humpback whales, right whales, and minke whales) or move 
offshore where waters do not become as cold as along the coast (pilot whales 
and some finback whales). The winter ranges of the other cetaceans are not 
well known. 

Pinnipeds 

The gray seal and the harbor seal are currently the only pinnipeds of the 
Atlantic coastal waters of the United States (Katona 1977; and Richardson 
1978) . The harbor seal is the dominant seal of coastal Maine and can be 
sighted throughout the year on small islands and half-tide ledges coastwide. 
Censuses conducted by Richardson (1973 to 1976) reveal a harbor seal 
population of about 6000 that is well distributed in all embayments of the 
Maine coast, with somewhat greater densities from Casco Bay to Pemaquid 
(region 2), the approaches to Penobscot and Blue Hill Bays (regions 4 and 5), 
and in the Jonesport, Englishman Bay, and Machias Bay areas (region 6; table 
13-3). The mean density was 12 seals per square nautical mile surveyed (9/sq 
mi; 3.5/sq km). Richardson (1973a) also identified harbor seal pups. The 
highest numbers of pups were in regions 1 (87) and 5 (79). It is not known 
whether discrete populations or subpopulations function within these different 
embayments. The sites inventoried and number of seals observed are presented 
in appendix table 1 . 

Haulouts are areas used by seals for resting, sunning, feeding, breeding, and 
pupping. They are usually small islands lacking terrestrial vegetation but 
having some areas that are exposed at mean high tide, or half-tide ledges that 
are completely submerged at mean high tide. In either case the intertidal 
area is usually densely covered with macroalgae (fucoids, Chondrus sp.) and 
the approach to the water is a gentle slope. Haulouts invariably are 
surrounded by water deep enough for escape even at low tide. 

Although whelping and rearing of young occur at offshore as well as estuarine 
sites, those marine haulouts exposed to high energy wind and wave action 
appear to be utilized more for foraging and socialization. Less exposed, up- 
estuary haulouts appear to be favored for whelping, mating, and use during 
molting (Richardson 1973a) . Seasonal censuses of harbor seals conducted by 
Richardson reveal up-estuary migration of colonies in spring, with subsequent 
segregation of age and sex classes at whelping sites. Down-estuary movement 
occurs in the late fall, following breeding and molting. Greater numbers of 
seals are found at more protected, up-estuary haulouts during late spring and 
summer, whereas they utilize more exposed haulouts in deeper, ice-free water 
during winter months. The extent to which water temperature, food 
availability, and behavior affect the seasonal redistribution of these 
colonies has not been documented. 

The distribution of seal haulouts among regions in the characterization area, 
based on Richardson (1973a), is summarized in table 13-4. Over 50% of these 
haulout areas are in regions 4 and 5. Richardson (1975) identified 44 seal 
haulout areas in Maine (41 in the characterization area) known to be regularly 
utilized by seals and judged to be significant based on one or more of the 
following criteria: 



13-8 



1. haulout area where counts of pups have exceeded ten; significant 
whelping area; 

2. haulout area where gray seals are frequently sighted; 

3. haulout area where counts have exceeded 65 harbor seals, apparently 
an area affording protection and favorable foraging; 

4. a "traditional" seal ledge important for its geographic location, 
unspoiled wilderness value, or near publically or privately held 
islands (National park, Federal, State, or private conservation 
islands) ; 

5. haulout area coinciding with or near important nesting islands for 
waterbirds . 

These important seal areas are identified on atlas map 4 and are listed in 
appendix table 2. Over 78% of these important seal areas are located in or 
east of Penobscot Bay. 

The present status of gray seals in Maine coastal waters is not as well 
known. Most of the gray seals observed along the coast of Maine are transient 
individuals from Canada (Gilbert et al. 1978). Very little information is 
available to state whether the population was higher in historic times but 
they were at one time sufficiently abundant along the New England coast to 
support hunting by Indians for some time. The Western Atlantic stock, 
centered in the Gulf of St. Lawrence and along the coast of Nova Scotia, 
Canada, has been increasing since at least the mid-1960s (Gilbert et al. 
1978). Smith (1966) estimated this stock at 5000, while Mansfield and Beck 
(1977) estimated the present population to be 30,000. Estimates of pup 
production on Sable Island (Canada) have increased from about 350 in 1962 to 
over 2000 in 1976 (Mansfield and Beck 1977). Richardson (1976) reported only 
about 80 gray seals from various sightings in coastal Maine from 1965 to 1975. 
A total of 148 gray seals in 27 haulout areas have been sighted along the 
coast over several years (table 13-3 and 13-4; appendix table 3). The 
majority of these seals (91%) were sighted among the islands and ledges of 
regions 4 and 5. The only known breeding colony in U.S. waters is at Muskeget 
Island, near Nantucket, Massachusetts. Probably fewer than 30 seals exist 
there (J. Prescott, New England Aquarium, Boston, MA; November, 1979). Gray 
seals inhabiting the Gulf of Maine and Nantucket are most likely recruited 
from Sable Island, Basque Island, Camp Island, or Gulf of St. Lawrence stocks 
(all in Canada). Dispersal and migration for this species, especially 
immatures, can be widespread and extensive, as evidenced by tagging 
investigations (Mansfield and Beck 1977). Gray seals marked as pups on Sable 
Island, Nova Scotia, Canada, have been recovered in the Muskeget area, Mt. 
Desert Rock in Maine, and Barneget Light, New Jersey. Late winter sightings 
of immature gray seals in the vicinity of Penobscot and Blue Hill Bays suggest 
that some animals may be year-round residents. Potential breeding and pupping 
sites have yet to be identified. 



13-9 

10-80 



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13-10 



REPRODUCTION 

Like many of the higher mammals, cetacean and pinniped females usually produce 
one offspring per breeding cycle. This affords a high degree of protection 
and parental care for developing young. Multiple births occur at a frequency 
of about 1% or less for whales (Slijper 1962). The reproductive 
characteristics of Maine's cetaceans and pinnipeds are quite diverse (table 
13-5). All cetaceans and seals of coastal Maine mate in the water except gray 
seals, which mate on land or in water. Both seal species exhibit delayed 
implantation; cetaceans apparently do not. Cetaceans give birth to calves 
underwater, whereas seals bear their pups on islands and ledges. Lactation is 
comparatively prolonged in cetaceans (4 to 18 months) in contrast with Maine's 
seals (1 to 2 months). 

Only the harbor seal is known to breed on islands and ledges along the coast 
of Maine. Cetacean calves with their mothers have been sighted in coastal 
Maine waters (harbor porpoise, humpback whale, right whale, and minke whale). 
The nearest known major breeding ground for gray seals is Sable Island, Nova 
Scotia, Canada. Minor breeding colonies exist at Grand Manan, New Brunswick, 
Canada, and Muskeget Island, Massachusetts. Richardson's 1973 coastal 
inventory of seal haulout sites revealed 58 sites (29%) with pups present. 
Eleven of the 41 important haulout areas (26%) were judged to be significant 
whelping sites (Richardson 1975). Six of these whelping areas are in region 
5; three are in region 4 and one each in regions 1 and 2 (see appendix table 2 
and atlas map 4) . Studies of the harbor seal populations of the west coast 
and Sable Island, Canada, reveal a recruitment rate (pup production) of about 
20% of the total post-whelping population (Richardson 1973b). Similar studies 
have not been conducted on Maine harbor seal populations but a similar 
recruitment is projected. 

FEEDING HABITS 

The majority of marine mammals in Maine are fish eaters (table 13-6). Those 
fish most commonly eaten by cetaceans are schooling fishes, such as herring 
and sand lance. Squid are an important food item for pilot whales and white- 
sided dolphins and may determine local distributions of these whales. Only 
the right whale is strictly a plankton feeder (copepods and euphausiids) . 
Observations by Canadian investigators suggest that right whales exploit 
euphausiids rather than copepods in the Bay of Fundy region (Gaskin et al. 
1979). Most cetaceans are probably opportunistic and adaptable in their 
feeding, taking any food items that are present in sufficient amounts (Katona 
1977). Their mobility provides for even greater flexibility in food habits. 

Important feeding areas along the Maine coast are the upper portion of 
Jeffreys Ledge, Columbia Ledge (Mt. Desert Rock region), Passamaquoddy Bay 
(the approaches to the Bay of Fundy), and probably the mouths of most bays, 
rivers, and estuaries. 

Gray seals and harbor seals largely feed on herring and flatfish. Work by 
Mansfield and Beck (1977) in eastern Canada shows the percent occurrence of 
different food items in gray seal and harbor seal stomachs (table 13-6). 
Nonmigratory bottom fishes form the basic diet for most of the year; skates 
and flounder for the gray seal and flounder and hake for the harbor seal. In 
summer, however, large schools of fish and squid that migrate inshore form the 

13-11 

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13-12 



Table 13-6. Principal Food Items (expressed as percentages in parenthesis) of 
Marine Mammals in Maine Waters 3 



Species 



Food items 



Finback whale 

Humpback whale 

Right whale 
Minke whale 

Harbor porpoise 

Long-finned pilot whale 
Atlantic white-sided dolphin 

Killer whale 

Harbor seal 

Gray seal 



Herring (75%), sand lance (10%), krill 
(10%), miscellaneous (5%) 

Herring (75%), sand lance (10%), krill 
(10%), miscellaneous (5%) 

Copepods (80%), euphausiids (20%) 

Herring (35%), sand lance (25%), cod (25%), 
squid (10%), salmon (5%) 

Herring (50%), cod (15%), mackerel (15%), 
hake (5%), smelts (5%), miscellaneous (10%) 

Squid (80%), cod (10%), herring (10%) 

Squid (25%), herring (25%), silver hake 
(25%), smelt (25%) 

Cod (25%), herring (25%), salmon (25%), 
squid (12.5%), mammals (12.5%) 

Herring (24%), squid (20%), flounder (14%), 
alewife (7%), hake (6%), smelt (4%), 
mackerel (4%) 

Herring (16%), cod (12%), flounder (10%), 
Skate (10%), squid (6%), mackerel (5%) 



Katona 1977; Katona et al. 1977; and Mansfield and Beck 1977. 



13-13 



10-80 



principal diet; herring, cod, squid, and mackerel for the gray seal and 
herring, squid, alewife, smelt, and mackerel for the harbor seal. Field 
studies conducted by Richardson (1973b) in Maine suggest that seals forage for 
food, often diving and surfacing in local areas for periods of time. Maine 
seals probably feed on all flatfish species, sculpins, and schooling fishes. 
Crustaceans comprise an insignificant fraction of the seal's diet (Richardson 
1973b). Alewives are a major food item of seals utilizing the upper estuaries 
in late spring. Herring also appears to be a preferred prey species and may 
determine local movements and distribution of seals. Richardson (1973b) 
calculated the hypothetical predation by seals on finfish stocks. Using 
estimates of seal populations from his surveys (6000 sighted, assumed 7500 
maximum) , daily food intake of 6% of body weight for 300 days (Sergeant 1973 
and Spaulding 1964) and a mean weight by year class and life table from Bigg 
(1969), Richardson (1973b) calculated that Maine seals consume about 18 
million pounds of finfish annually. In comparison to Maine's commercial 
fishery, seals would appear to consume the equivalent of 14% of the average 
number of pounds of fish landed annually in Maine from 1967 to 1976. Since 
the total abundance of fish stocks remains unknown, it is not possible to 
determine whether seals are in serious competition with people for some fish 
species . 

FACTORS AFFECTING DISTRIBUTION AND ABUNDANCE 

The major abiotic factors that influence the distribution and abundance of 
marine mammals are water temperature, currents, and physiography but 
supporting data are scarce. The following factors are better known and will 
be discussed in terms of their influence on populations of these mammals: 
food availability, disease and parasites, predation, hunting, pollutants, and 
habitat disturbance or alteration. 

Food Availability 

One of the major biotic factors controlling the distribution and abundance of 
marine mammals is food availability. Seasonal distribution of squid, 
schooling fishes, and zooplankton may determine local populations of marine 
mammals. Aggregations of marine mammals at offshore banks have been observed. 
Evidence exists of a drastic change taking place in the summer distribution of 
humpback whales on feeding grounds in Canadian waters (Gaskin et al. 1979). 
Inshore movements of humpbacks from Grand Banks and associated offshore 
shallows may be in part due to overfishing of capelin stocks there. The 
humpbacks may be moving inshore in search of alternative food supplies (e.g., 
herring) . Considering the species composition of the major food items of 
Maine's whales, porpoises, and seals (table 13-6), there is the potential that 
overfishing of certain commercial fish species could impose limits on many 
marine mammal populations. 

Disease and Parasites 

Marine mammals fall victim to a full complement of afflictions, knowledge of 
which is quite limited because most observations are based on captive animals 
and must be extrapolated to animals in the wild. There is no evidence that 
disease and parasites severely impair individuals in the wild. Documented 
viral infections are rare (e.g., seal pox and viral hepatitis) but bacterial 
disease is common and is reported to be the single leading cause of death in 

13-14 



cetaceans (in captivity). For the most part, deaths of marine mammals go 
unobserved. In both cetaceans and pinnipeds the most debilitating bacterial 
disorders seem to be lung infections, like pneumonia. These are common but 
usually occur as a secondary infection in the wake of some other disability, 
mechanical injury, or parasitism, which lowers the animal's resistance (Katona 
et al. 1977). 

Marine mammals are also afflicted by a variety of degenerative and deficiency 
diseases, including eye failure, cardiovascular disease, ulcers, hepatic and 
renal dysfunction, vitamin deficiencies, stress, metabolic disorders, and a 
broad range of developmental abnormalities. 

Internal and external parasites are common in marine mammals. Cetaceans, in 
particular, are known to host certain parasitic barnacles, lice, and lampreys. 
Internal parasites are dominated by nematodes, which invade the respiratory, 
cardiovascular, gastrointestinal, and cranial systems. Examples include 
lungworm, tapeworm, heartworm (specific to harbor seals), and flukes. 
Parasitism is not usually a clinical problem. Most strong, healthy animals 
tolerate the parasites. Young, old, or otherwise debilitated animals may be 
sensitive to excessive infestations and may die from them. 

A seal parasite of particular concern is the nematode Porrocaecum decipiens 
(codworm). The adult codworm is found in the gastrointestinal tract of harbor 
seals, gray seals, and harp seals. Its life cycle is not known completely. 
Its eggs may hatch in the sea and the larvae invade an intermediate 
(invertebrate) host, which may be eaten by a fish. The larval codworm burrow 
into the flesh of many groundf ishes , including cod. Large infestations do not 
necessarily affect the health or nutrition of fish but may render it 
undesirable and unmarketable. Improperly frozen or cooked fish can be a 
health hazard to people; the codworm can invade the human gastrointestinal 
system. Areas of codworm infestation in groundfish have been correlated with 
high abundance of gray seals in European waters (Piatt 1975 and Young 1972) 
and with the distribution of harbor seals and gray seals in eastern Canada 
(Scott and Martin 1957). Mansfield (1968) estimated that harbor, gray, and 
harp seals accounted for 2%, 45%, and 53°/ respectively of the codworm 
infestation in the Gulf of St. Lawrence. Presently, codworm is not a problem 
in most New England fisheries but appears to be more common in eastern Maine. 
It is unknown what effect on fisheries would result from increased numbers of 
gray and harbor seals in coastal Maine. 

Predation 

In addition to people, sharks and killer whales are natural predators on 
marine mammals in the wild. Predation on orphaned harbor seal pups (which are 
unlikely to survive anyway) by black-backed gulls and ospreys has been 
observed (Richardson 1978) . Data on the magnitude of predation exclusive of 
hunting and its effect on the natural populations of marine mammals are 
lacking. Hunting is discussed below under "Importance to Humanity." 

Pollutants 

Since aquatic media are the eventual sinks for most types of pollutants, 
contaminants in the oceans and estuaries have posed serious problems to many 
forms of aquatic life. Marine mammals have been exposed to these pollutants 

13-15 

10-80 



and studies show that both cetaceans and pinnipeds may absorb them in their 
tissues in significant amounts. Organochlorines , heavy metals, and petroleum 
will be discussed in light of their known impacts on the ecology of marine 
mammals. Some of these pollutants have been discovered in marine mammals at 
higher levels than those found in any other animal. The major avenue for 
intake of these types of pollutants is through consumption of contaminated 
prey. There appear to be two related mechanisms for the observed accumulation 
and concentration of organochlorine and heavy metal pollutants. Lower trophic 
level organisms (fish and invertebrates) filter these pollutants from the 
water or sediments and thereby concentrate them. Marine mammals feeding on 
these fish and invertebrates incorporate the accumulated pollutants, store 
them, and may concentrate them further. It is expected that those marine 
mammals (toothed whales, porpoises, and seals) that feed on contaminated 
organisms of a higher trophic level would exhibit the highest concentrations 
of pollutants. Marine mammals, being long-lived, also would accumulate large 
amounts of pollutants over time. 

Organochlorines. These include the pesticide compounds DDT and dieldrin 
and other halogenated hydrocarbons, such as PCBs (polychlorinated biphenyls). 
These manufactured compounds degrade very slowly and are extremely persistent 
in the environment. Residues of these compounds have been found in certain 
seals and cetaceans, probably because of their relatively high-level position 
in the aquatic food chain and long life span. The vulnerable site of 
organochlorine deposition and retention in marine mammals is the fatty tissue 
of the blubber layers. Death or injury can occur when the animal's food 
supply is cut short or it ceases feeding (e.g., during breeding and calving or 
pupping) and the body's fat reserves are used for energy. The stored 
toxicants are then released into the bloodstream in usually harmful 
quantities. Equally disasterous is the conversion of the contaminated fat 
reserves in reproduction. Katona and coworkers (1977) present a summary of 
numerous studies reporting analyses of organochlorine residues in marine 
mammals known to inhabit the Gulf of Maine (table 13-7). Because of the 
migratory behavior of most of the cetaceans it is difficult to determine where 
these animals picked up the contaminants. It is safe to assume that among the 
harbor seals and harbor porpoises the sources are quite local. Several 
species listed by Katona and coworkers, particularly the harbor porpoise, 
pilot whale, harbor seal, and striped dolphin, showed very high levels of DDT 
and PCB which may adversely affect those populations. Helle and coworkers 
(1976) have attributed uterine occlusions in female gray seals to high PCB 
levels. In a review of current research, Katona and coworkers (1977) 
attributed low reproductive rates in Baltic Sea seals to heavy organochlorine 
pollution. 

The organochlorine residue levels found in marine mammals may vary 
considerably with local conditions, even within relatively short distances. 
Residue amounts appear to be influenced by the level of contaminant usage in 
the area of the hydrologic regime of the area, the diet of the animal, the 
reproductive state, age and, in some cases, sex of the individual. Gaskin and 
coworkers (1976) noted that harbor porpoises from the Bay of Fundy region had 
significantly higher DDT levels than those sampled from St. Mary's Bay (Nova 
Scotia, Canada) and Rhode Island. Possible reasons for this include: (1) DDT 
is concentrated in the Bay of Fundy because of runoff from New Brunswick 
streams, which drain areas of heavy DDT use; (2) the mixing and upwelling in 
the mouth of the Bay of Fundy stimulates remixing and resuspension of sediment 

13-16 



pollutants in the water column; (3) current systems in the Bay prevent loss of 
pollutants to main Atlantic waters; (4) colder waters there slow bacterial 
degradation of the contaminants. 

In some cases pollutant level analyses show trends related to age and sex of 
the animals. Harbor porpoises from the Bay of Fundy exhibit a marked increase 
in DDT level with age in males but a definite decrease with age in females 
(Gaskin et al. 1976). Presumably, the female transfers residual 
organochlorines to her fetus via the placenta. No documentation exists on 
effects of these pollutants on developing fetuses and young animals. A 
similar study of harbor seals from the Gulf of Maine and the Bay of Fundy 
reveals that lactating females had significantly lower pollutant levels than 
all other seals tested (Gaskin et al. 1973). 

A review of current trends and research results shows evidence of a definite 
decrease in organochlorine levels in Bay of Fundy harbor porpoises since 1969. 
The decrease is exhibited by both males and females regardless of age, 
although males still retain higher levels overall (Gaskin et al. 1976). It is 
hoped that continued restriction on the production and use of organochlorines 
will further reduce their presence in marine organisms in the Bay of Fundy and 
coastal Maine. 

Heavy metals . These metals, particularly mercury, are increasingly 
conspicuous in marine systems (see chapter 3, "Human Impacts on the 
Ecosystem"). Analyses of marine mammal tissue taken from the wild (by capture 
or stranding) indicate exceedingly high mercury concentrations may be present 
in certain populations. Katona and coworkers (1977) summarizes study results 
on heavy metal contamination in marine mammals known to inhabit the Gulf of 
Maine (table 13-8). 

Both mercury and cadmium concentrations in marine mammals appear to be 
positively correlated with age. Again, the relatively high trophic position 
in the aquatic food chain and long life span of most of these animals 
contribute to the high level of accumulation of heavy metals. Some 
researchers propose that harp seals have lower mercury contamination than gray 
seals or harbor seals because harp seals feed on a lower trophic level, that 
is, capelin and crustaceans vs. the cod and flatfish on which the harbor and 
gray seals feed (Katona et al. 1977). Related research indicates that 
contaminant levels of cadmium, zinc and copper in harbor seals from the German 
North sea are much higher than prey fish values. Mercury concentrations in 
seals were more than 1000 times greater than corresponding prey fish values. 

The major storage depositories for heavy metals in marine mammals are the 
liver and the brain. This pattern of mercury distribution is unique, unlike 
that of other animals tested. In people, for example, most mercury is present 
as methlymercury , which is rapidly transported throughout the body. In fish, 
the staple food of most marine mammals, almost all mercury is in the 
methylmercury form (Katona et al. 1977). However, in seals, harbor porpoises, 
and pilot whales, it has been confirmed that mercury is concentrated in the 
liver in a de-methylated form. This storage of the de-methylated mercury in 
the liver, with minimal transport to other body tissues, may be the factor 
that enables seals to maintain high contaminant levels without exhibiting 
normal mercuric poisoning effects. Current research suggests that there is a 
saturation limit and older seals may surpass that level and begin to pass 

13-17 

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13-20 



methylmercury to other tissues, for example, the brain. Katona and coworkers 
(1977) discuss research supporting the identification of the biochemical 
mechanism for mercury de-methylation and storage, perhaps a highly efficient 
selenium "trap." A one-to-one molar ratio of mercury to selenium has been 
observed in marine mammal liver tissue and the selenium may aid in binding the 
mercury to protein molecules (via sulphur bonds), thus preventing the 
transport of methylmercury. 

Documentation of the physiological effects of metal poisoning in marine 
mammals is scarce. Ingestion of large quantities of methlymercury has caused 
severe lesions and damage in harp seals (Tessaro and Ronald 1976). Freeman 
and coworkers (1975) reported that methylmercury, arsenic, cadmium, and 
selenium altered the "in vitro" biosynthesis of steroid hormones in gray 
seals. Methylmercury altered the biosynthesis of steroid hormones in an "in 
vivo" study of harp seals. This could have serious effects on mineral and 
water regulation, carbohydrate metabolism, and reproduction in contaminated 
seals . 

Petroleum . According to Katona and coworkers (1977) data on the effects 
of oil contaminants on marine mammals are scarce. Nothing of certainty is 
known about oil effects on cetaceans. Since all whales surface frequently 
they are potentially in danger of being exposed to surface oil slicks. Whales 
that are primarily surface feeders, such as the right whale, sei whale, and 
(on occasion) the humpback and finback whales could be particularly 
susceptible to surface oil slicks. It is not known whether these animals 
would actively avoid oil slicks. The available evidence indicates that 
petroleum hydrocarbons are not biologically magnified through the food chain. 
Limited studies of oil effects on seal populations reveal either no 
significant deleterious effects or inconclusive results (Katona et al. 1977). 
It is safe to presume that the impact of oil pollution will be most severe in 
populations that are already suffering from poor health or environmental 
stress, for example, climatic extremes, high density habitat, strong 
competition for food and space, and demands of reproduction (Geraci and Smith 
1976). 

Habitat Disturbance 

Habitat disturbance and changes that could influence the abundance and 
distribution of marine mammals are not well documented. Katona (1977) 
provides some possible causes and effects. Urbanization and its associated 
activities (boat traffic and pollution) are detrimental to the occurrence and 
number of cetaceans in coastal waters. It is difficult, though, to separate 
the effects of increased shipping from those associated with deteriorating 
water quality. Areas near port cities tend to have fewer cetaceans than do 
nearby undeveloped waters, probably due to human activity. Seals are 
apparently intolerant of human activities at least during the pupping and 
breeding season. Harbor seals in Maine compete for use of ledges and islands 
in areas that are valuable to commercial fishing. Fishing efforts and 
development of coastal shoreline and island property may render certain 
whelping sites unsuitable. Of the small gray seal breeding colony at Grand 
Manan, New Brunswick, Canada, Mansfield and Beck (1977) doubt that pup 
production there will ever build up from a present level of about 15 pups per 
year to its former level of 200 pups per year, because lobster fishing 
activity is high during the breeding season. Increased use of islands in 

13-21 

10-80 



Maine during the summer months may limit the use of these areas by both harbor 
and gray seals. Entrapment of seals and cetaceans in fishing gear is a 
present danger and increasing threat. 

A summary of data on the reported incidental catch and strandings of cetaceans 
in Maine waters since 1975 is compiled from Prescott and coworkers (1979) and 
shown in table 13-9. The major causes of disturbance to cetaceans have been 
entanglement in fishing gear and collision with boats. Of the 47 reported 
incidences in the U.S. Atlantic waters, 13 (36%) occured in Maine waters. 



Table 13-9. Reported incidental Catch and Strandings of Cetaceans in Maine Waters 
Since 1975 a . 



Species 



Location 



Date 



Fate and Cause 



Minke whale 1 

Unidentified 1 

Minke whale 2 

Harbor porpoise 1 

Minke whale 1 

Habor porpoise 1 

Minke whale 1 

Finback whale 1 

Harbor porpoise 1 

Humpback whale 1 

Unidentified 1 

Right whale 1 



Eastport 


7/06/76 


Dead ; 


Beals Is. 


9/15/79 


Dead; 


Mt. Desert Is. 


7/78 


Dead; 


Mt. Desert Is. 


6/78 


Dead; 


Boothbay 


7/07/75 


Dead ; 


Cranberry Is . 


6/04/79 


Dead; 


Bailey's Is. 


5/23/78 


Alive 


Isle Au Haut 


11/26/75 


Alive 


Penobscot Bay 


4/15/75 


Dead ; 


Lubec 


9/02/79 


Alive 


Offshore 


6/27/78 


Dead; 


Offshore 


11/05/76 


Dead; 



possible ship collision 

found entangled in lobster 

trap gang 

reported by fisherman 

full-term fetus found in gill 

net 

possible ship collision 

caught in gill net 

damaged gill net 

caught in lobstering gear 
caught in gill net 
: trapped in stop seine, 

released 
caught in gill net 
cuts and slashes observed 
on back, reported as right 
whale 



Total 



13 



36% 



Total US Atlantic 47 



Source: Prescott et al. 1979. 



13-22 



Noise pollution (due to boating, construction, and aircraft passage) could 
upset the food-finding mechanisms and navigational ability of many cetaceans. 
Aircraft noise has a documented detrimental effect on seals, causing fright 
and temporary site desertion (Katona 1977). Offshore oil and gas exploration 
or pipeline construction could affect cetacean distribution in local areas. 
These activities generate noise, air and water pollution and physical 
obstructions. If they are present in areas that are particularly important 
for feeding, significant disruptions of whale movement or habits could result. 
Several banks in the Gulf of Maine (Stellwagon Bank, Jeffreys and Columbia 
Ledges, and Georges Bank) are major feeding grounds for finback whales, 
humpback whales, right whales and numerous dolphin species. Anticipated OCS 
oil and gas development activities in the Georges Bank area could affect 
whales migrating through to Maine waters. It is not known whether these 
animals or the fish they feed on would simply move to another area or whether 
population damage would occur. 

IMPORTANCE TO HUMANITY 

Nearly all the historical sources, especially the older ones, mention the 
great abundance of whales and seals in the Gulf of Maine, so we know that the 
abundance and role of marine mammals in New England waters must have been much 
larger in times past than it is today. Whale and seal harvests once provided 
an important commercial industry and were a focal point in a way of life for 
coastal New England residents. Excessive harvest of these animals was the 
major cause of their decline world wide (see "History of Whaling" below). New 
England and European hunting activities seriously depleted stocks of whales 
that might have inhabited coastal Maine. With the cessation of whaling 
activities in the United States and Canada in 1972, marine mammal populations 
are no longer locally exploited for commercial yield. However, some European 
countries still hunt populations that may frequent the Gulf of Maine and 
Canada allows culling of local populations of gray seals (molted pups). 

Marine mammals are also valuable for monitoring levels of pollutants in the 
marine environment (see "Pollutants" above) . Seals in Maine may compete with 
people for food and habitat use and are definite hosts for parasitic worms, 
which infect commercially important fish (see "Habitat Disturbance" and 
"Disease and Parasites" above). The aesthetic value or wilderness experience 
of viewing marine mammals in the wild is important to residents and tourists 
alike. Whale sighting excursions out of a number of coastal towns to the 
nearshore banks are extremely popular and increasing. 

Marine mammals also provide extensive opportunities for scientific and 
educational study in natural history, evolution, and population and community 
ecology. Nearshore coastal Maine and the approaches to the Bay of Fundy are 
unique in providing access to several species of marine mammals on a regular 
basis . 



History of Whaling 



"During the 1912 voyage of the 
whaleship Daisy, Dr. Robert 
Cashman Murphy, an American 
Ornithologist, was quoted as 
saying '...the sounding of this 



13-23 

10-80 



sperm whale filled me with 
astonishment that has increased 
through the years'. He noted 
that 'killing a harpooned sperm 
whale... if you do kill 
him. . .may take anywhere from 
ten minutes to a day or 
longer'" (Mathews 1968). 

Whaling can be dated back as early as 890 A.D. along the coast of Norway. 
Most noted for whaling during the 12th through 15th centuries were the 
Basques, who pursued these mammals on a commercial basis for oil and food 
products ( Whale Fishery of New England 1968). In pursuit of the right whale, 
the Basques ventured farther and farther from their home ports, eventually 
covering a large portion of the North Atlantic. The "right" whale was so 
called because it was considered the right whale to catch, due to its slow 
swimming speed, long baleen, thick blubber, and because it floated when dead 
(Hill 1975). The French and the Icelanders were also known to have hunted 
whales during the 12th century, while English whaling was first reported 
during the 14th century. At that time the whale was declared "a royal fish," 
and the head and the tail of all whales caught along the English coast were 
given to the king and queen respectively. 

During the early 1600s, large herds of bowhead whales were recorded by 
explorers in the Arctic Ocean who were seeking a northwest passage to the 
Orient. These stocks along the groups of islands known as Spitsbergen, north 
of Norway, were quite valuable because of the bowhead' s long baleen and thick 
blubber, which is almost 2 feet (.6 m) thick. So plentiful were these stocks 
that when baleen prices were high, it was not uncommon for only the prized 
baleen to be saved, while the remainder of the whale was discarded. The 
British sent their first Arctic expedition in 1611 and the Dutch in 1612. By 
1636 there were indications of a decline in bowhead stocks around eastern 
Greenland and by 1720 the Spitsbergen fishery was ended. While the Europeans 
whaled along Canada's eastern Arctic, American whalers hunted the bowhead in 
the Bering and Chukchi Seas. 

Early explorers of the New England coast found large numbers of whales. The 
native Indians, using canoes, hunted the whales with stone-headed arrows and 
spears that were attached to short lines with wooden floats. The Eskimos were 
also whale hunters in the Arctic waters during this time period. They 
invented the "toggle" harpoon, which was widely used and later improved upon 
in 1848 by a New Bedford resident. 

During settlement of the New England colonies, whaling in nearby waters began 
to grow. By 1650, suits over the ownership of dead whales, claims of rival 
whalers, and laws governing drift whales were known to exist (Katona et al. 
1977). Regulations stipulated that the government, the town, and the owner 
all received one third of every whale taken. By 1662 the church also was 
given a portion of the take. 

The success of the Plymouth colony spurred on other colonies to engage in 
whaling, among them Salem and Hartford, Connecticut. Hartford had a 
recognized whaling industry as early as 1647 but did not prosper ( Whale 
Fishery of New England 1968 ) . By 1748 it was believed that whalers may have 

13-24 



killed off most of the whales that regularly inhabited the waters around Cape 
Cod. With decreased numbers of right whales, some of the whalers turned to 
the humpback, pursuing them on short expeditions from Nantucket and Cape Cod 
(Katona et al. 1977). 

A major portion of Nantucket's heritage centers around whaling, as it fast 
became the center of whaling in the U.S. It is uncertain exactly when shore 
whaling first began on Nantucket, though it is known to have taken place 
before 1672 (Craig 1977) and possibly as early as 1608 (Katona et al. 1977). 
At first Nantucket's waters were so plentiful with whales that there was no 
need for offshore whaling. The highest yield of shore whaling seems to have 
been around 1726, when 86 whales were taken by boats along the shore. The 
species most likely to have been taken were the right and the humpback whales. 
However, in 1712 during a strong northerly wind, Christopher Hussey's whale 
ship was blown out to sea, where it encountered a large herd of sperm whales. 
It was then that the first sperm whale known to have been taken by an American 
whaler was brought back into Nantucket. 

The sperm whale soon became the most sought after by the people of Nantucket. 
Hunters were lured by its prized sperm oil, which was considered superior to 
the oil of baleen whales for such uses as lubricants for watchmaking, fine 
leather manufacturing, and chronometer operation. The sperm oil also was used 
as a luminant for domestic lamps and street lights, while byproducts of the 
sperm oil were used for making soap and ointments as well as for various 
industrial uses. Also valued was the "whale ivory" (teeth and panbone of the 
thin lower jaw), which was used for scrimshaw. In addition there was the 
possible added inducement of ambergris (an infected mass sometimes found in 
the intestines of the sperm whale), which brought a high price from the 
perfume industry. 

To catch this valuable sperm whale it was necessary for the whalers to venture 
into the deep sea. A whole new fishery began, which reached its peak by 1847 
with New England ships operating all over the world (Hill 1975). Vast 
improvements were made to the whaling vessels, which would be at sea from 2 to 
4 years at a time or until their holds were full to capacity. Around 1730 
"try-works" were built on the vessels (instead of on the shore), thus allowing 
the oil to be boiled and stowed away while the ship was still at sea ( Whale 
Fishery of New England 1968) . By 1760 Nantucket was producing more oil than 
all other American whaling ports combined (Nelson 1971). 

With the coming of the American Revolution, Nantucket was the only port to 
continue whaling. Whaling was a necessity for Nantucket, for it and whaling 
industries were the basis of Nantucket's economy. Although many whaling ships 
and men were lost during the Revolution the industry was soon rebuilt and 
again flourished until the War of 1812. Nantucket was the only American 
whaling port during this war, also. Still, the two wars and the Great Fire of 
1845 took their toll on Nantucket's whalers and with the increased size of the 
newer ships they were no longer able to clear the sandbar located in 
Nantucket's port. In 1869 Nantucket sent her last whaling ship, the Oak , out 
to sea. New Bedford replaced Nantucket as the whaling center of the U.S. It 
was said that "...the population (there) was divided into three parts, those 
away on a voyage, those returning, and those getting ready for the next trip" 
( Whale Fishery of New England 1968). Its first ships were sent out in 1765 
and, though greatly affected by the wars, in 1857 the New Bedford fleet 

13-25 

10-80 



numbered 329 and was valued at over $12 million ( Whale Fishery of New England 
1968). 

The so-called "Golden Age" of whaling spanned the years 1825 to 1860. In 1875 
the fleet in New Bedford's port had declined to 116, in 1886 to 77, and in 
1906 to 24 ( Whale Fishery of New England 1968). Rhode Island's two major 
whaling ports were Newport and Providence. In 1731 an act was passed giving 
"a bounty of 5 shillings for every barrel of whale oil and one penny a pound 
for bone" caught by Rhode Island vessels (Katona et al. 1977). A total of 50 
ships was owned by Conecticut and Rhode Island in 1775, and Massachusetts 
owned in excess of 300. New London, Connecticut, became a great whaling port 
in 1846 and was considered third in importance in New England. Boston, 
Massachusetts, was known to have 20 whaleships in 1775 and Portsmouth, New 
Hampshire, had 2 whaling vessels at one time. 

About 1810, shore whaling began in Prospect, Maine, with an average catch of 6 
or 7 whales per year, primarily humpback (Katona et al. 1977). Between the 
years of 1835 to 1845 Bath, Bucksport, Portland, and Wiscasset, Maine, each 
had one whaling vessel operating ( Whale Fishery of New England 1968). 

After 1895 only Boston, New Bedford, Provincetown, and San Francisco whalers 
were regularly registerd. In 1903 Boston recorded her last whaleship (Mathews 
1968). In 1925 the whaling schooners John R. Manta and Margarett returned to 
the port of New Bedford, marking the end of the sailing whaleships (Whale 
Fishery of New England 1968). 

The decline in whaling was due to a number of factors, including the 
development of kerosene and other substitutes for whale products, the opening 
of the first oil well in Pennsylvania, the rise of the cotton industry in New 
Bedford around 1850 to 1875, the increased costs of outfitting the ships for 
longer voyages and the coming of the Civil War, and probably the growing 
scarcity of whales. 

During whaling's "Golden Age" men ventured out in 30-foot boats where "there 
was always the chance of a fatal accident to someone in the boat, and 
occasionally the chase took the whole crew so far from the ship that contact 
was not reestablished. After these battles with the whales, which might have 
lasted 12 hours or more, came the hard towing of the whale carcass back to the 
ship and then, in succession, with no intermission, two dangerous and 
fatiguing jobs," which involved the stripping of blubber and gathering of the 
oil-bearing parts, along with the crude refining of the oil (Craig 1977). 
Today's modern whale ships, better known as factory ships, are "capable of 
reducing a 90-foot blue whale to unrecognizable 'products' in a half-hour" 
(Hill 1975). 

During the 19th century a porpoise (harbor porpoise) fishery existed in the 
Bay of Fundy and Grand Manan Island. It was believed that the Passamaquoddy 
and Micmac Indian tribes captured several thousand porpoises yearly. Two to 
three gallons of oil could be rendered from one porpoise. This oil was 
marketed for lamps and lubricants. The porpoise fishery also was carried out 
on an irregular basis throughout New England (Sergeant and Fisher 1957) . New 
fisheries were common during the late 18th century for bottlenose dolphin 
along Long Island and from Cape May, New Jersey, during the latter part of the 
19th century. 

13-26 



The bowhead and right whales have not recovered from the "Golden Age" of 
whaling and are considered rare in the Western North Atlantic (Katona et al. 
1977). Though whaling no longer exists in U.S. waters, Canadians continued to 
take finback, sei, and minke whales until 1972, when all Canadian stations 
were closed. Hunting of humpback, blue, fin, and pilot whales has had a 
profound effect on cetacean populations in Maine. Several of the European 
countries, such as Iceland, Greenland, and Norway, still hunt whales in the 
North Atlantic on a non-commercial basis. Japan and Russia account for 80% of 
the present day catch of both commercial and noncommercial whaling (Craig 
1977). 

Today whales are used for such products as margarine, lipstick, pet food, 
tennis racket strings, and automobile wax. Russia diligently pursues the 
sperm whale for its oil. Japan claims whales are an important source of 
protein for it's island population, although over 50% of their take is sperm 
whales, which are considered inedible (Hill 1975). Japan also imports whale 
meat from other International Whaling Commission (IWC) countries. 

Some hunting of harbor porpoises or other small dolphins may still occur 
sporadically along the eastern Maine coast or adjoining Canadian waters, 
although this was expressly forbidden by the Marine Mammals Protection Act 
passed in 1972. Harbor porpoises are still hunted for subsistence in the 
North Atlantic by Iceland, Greenland, and Norway. 

Gray and harbor seals are known to have been hunted by the Indians in New 
England but the extent of this is not fully known. Both Maine and 
Massachusetts had bounties on seals (Maine from 1891 to 1905 and from 1937 to 
1947, while Massachusetts' bounties were in effect from 1888 to 1908 and from 
1919 to 1962; Gilbert et al. 1978) and Canada has had a bounty on gray seals 
since 1976 and a bounty on harbor seals in all but a few years since 1938. It 
is believed that although seals were sometimes utilized for their meat and 
hides most seals were killed to reduce competition for fish. Today there is 
no direct harvesting of seals in the characterization area but Canadian stocks 
of gray seals are culled to control local populations (Mansfield and Beck 
1977). In addition, seals are sometimes shot by fishermen, who maintain that 
the seals pirate their fish and foul their nets. 

Fossil records and fragmentary bone remains indicate that the walrus was known 
to have been an occasional visitor to Maine's coastal waters. It is believed 
that the walrus was once hunted by the Indians in Maine. Figures on its 
historic population and distribution are uncertain and difficult to establish. 

MANAGEMENT 

Jurisdiction over the conservation, management, and importation of all marine 
mammals rests with the Federal Government under the Marine Mammal Protection 
Act of 1972. This Act sets forth regulations for the taking of marine mammals 
subject to U.S. jurisdiction and provides enforcement procedures. All New 
England species are managed by the National Marine Fisheries Service 
(Department of Commerce). States are free to promulgate regulations regarding 
management of local stocks providing they satisfy the intent of the Act. In 
addition, the Act calls for initiation of a cooperative international program. 
Concurrently, the Act established the Marine Mammal Commission as a major 
authority responsible for the development of research activities and resource 

13-27 

10-80 



management recommendations. A moratorium exists at present on the taking, 
killing, or harassment of all marine mammals in U.S. waters except by permit 
issued by the Secretary of Commerce. 

The findings and declaration of policy of the Act are excerpted below: 

1. certain species and population stocks of 
marine mammals are, or may be, in danger of 
extinction or depletion as a result of man's 
activities ; 

2. such species and population stocks should not 
be permitted to diminish beyond the point at 
which they cease to be a significant 
functioning element in the ecosystem of which 
they are a part, and, consistent with this 
major objective, they should not be permitted 
to diminish below their optimum sustainable 
population. Further measures should be 
immediately taken to replenish any species or 
population stock which has already diminished 
below that population. In particular, efforts 
would be made to protect the rookeries, mating 
grounds, and areas of similar significance for 
each species of marine mammal from the adverse 
effect of man's actions; 

3. there is inadequate knowledge of the ecology 
and population dynamics of such marine mammals 
and of the factors which bear upon their 
ability to reproduce themselves successfully; 

4. negotiations would be undertaken immediately 
to encourage the development of international 
arrangements for research on, and conservation 
of, all marine mammals; 

5. marine mammals and marine mammal products 
either 

A. move in interstate commerce, or 

B. affect the balance of marine ecosystems in 
a manner which is important to other 
animals and animal products which move in 
interstate commerce, and that the 
protection and conservation of marine 
mammals is therefore necessary to insure 
the continuing availability of those 
products which move in interstate 
commerce; and 



13-28 



6. marine mammals have proven themselves to be 
resources of great international significance, 
esthetic and recreational as well as economic, 
and it is the sense of the Congress that they 
should be protected and encouraged to develop 
to the greatest extent feasible commensurate 
with sound policies of resource management and 
that the primary objective of their management 
should be to maintain the health and stability 
of the marine ecosystem. Whenever consistent 
with this primary objective, it should be the 
goal to obtain an optimum sustainable 
population keeping in mind that optimum 
carrying capacity of the habitat. 

RESEARCH PRIORITIES 

In September, 1979, the Marine Mammal Commission sponsored a workshop to 
identify and summarize information and research needs for East and Gulf Coast 
cetaceans and pinnipeds. The participants agreed that insufficient evidence 
was available to define the status and trends of cetacean and pinniped 
populations and identified those human activities that may threaten marine 
mammal species and populations as: incidental take, fishery conflicts 
(including competition), disturbance/harassment, and habitat degradation/ 
destruction. The final report on the proceedings and findings of the workshop 
has recently been released (Prescott et al. 1979). 



13-29 

10-80 



REFERENCES 

Anderson, H. T. , ed . 1969. The Biology of Marine Mammals. Academic Press, 
New York. 

Bigg, M. A. 1969. The harbour seal in British Columbia. Fish. Res. Board 
Can. Bull. 172. 

Craig, A. W. 1977. Whales and the Nantucket Whaling Museum. Nantucket 
Historical Association, Nantucket, MA. 

Freeman, H. C, G. Sangalang, and J. F. Uthe . 1975. A study of the effects 
of contaminants on steroidogenesis in Canadian gray and harp seals. 
I.C.E.S. Doc. CM. No. 7. 

Gaskin, D. E., R. Frank, M. Holdrinet, K. Ishida, C. J. Walton, and M. Smith. 
1973. Mercury, DDT, and PCB in harbor seals ( Phoca vitulina ) from the 
Bay of Fundy and Gulf of Maine. J. Fish. Res. Board. Can. 30:471-475. 

, M. Holdrinet, and R. Frank. 1976. DDT residues in blubber of harbor 

porpoise, Phocoena phocoena , from eastern Canadian waters during the five 
year period 1969-1973. ACMR/MM/SC Rep. 96. International Conference on 
Marine Mammals, Food and Agriculture Organization of the United 
Nations. Bergen, Norway. 

, G. J. D. Smith, and D. B. Yurick. 1979. Status of Endangered Species 

of Cetacea in the Western Bay of Fundy and Unique Features of This Region 
Which Command Its Protection. National Marine Fisheries Service, 
Gloucester, MA. 

Geraci, J. R. and T. G. Smith. 1976. Direct and indriect effects of oil on 
ringed seals ( Phoca hispida ) in the Canadian Arctic. J. Fish. Res. Board 
Can. 33:1976-1984. 

Gilbert, J. R. , V. R. Shurman, and D. T. Richardson. 1978. Gray Seals in New 
England: Present Status and Management Alternatives. Marine Mammal 
Commission, Washington, DC. 

Helle, E., M. Ollson, and S. Jensen. 1976. PCB levels correlated with 
pathological changes in seal uteri. Ambio 5:261-263. 

Hill, D. 0. 1975. Vanishing Giants. Rare Animal Relief, Inc. New York. 

Katona, S. K. 1977. Unpublished memorandum. Energy Resources Co., Inc, 
Cambridge, MA. 

, H. E. Winn, and W. W. Steiner. 1977. Marine mammals. Pages XIV-1 to 

169 In Center for Natural Areas,. A Summary of Environmental 
Information on the Continental Shelf from the Bay of Fundy to Cape 
Hatteras. Bureau of Land Management, New York. 

Lien, J. and N. Merdsoy. 1979. The humpback is not over the hump. Nat. 
Hist. 88:46-49. 



13-30 

10-80 



Mansfield, A. W. 1968. Seals as vectors of codworm Porrocaecum decipiens in 
the Maritime Provinces. Fish. Res. Board Can. Ann. Rep. Arctic Biol. 
Stn. , 1967-1968. 

, and B. Beck. 1977. The grey seal in eastern Canada. Technical Report 
704. Canada Fisheries and Marine Services, Ste. Anne de Bellevue, 
Quebec, Canada. 

Mathews, L. H. 1968. The Whale. Cresent Books, New York. 

Nelson, R. W. 197]. The Nantucket Whaling Museum and a Summary of Nantucket 
Whaling History. Nantucket Historical Association., Nantucket, MA. 

Piatt, N. E. 1975. Infestation of cod (Gadus morhua L.) with larvae of 

codworm (Terranova decipiens Krabbe) and herringworm, Anisakis sp. 

(Nematoda Ascaridata) in North Atlantic and Artie waters. J. Appl. Ecol. 
12:437-450. 

Prescott, J. H., S. D. Kraus , and J. R. Gilbert. 1979. East Coast/Gulf Coast 
Cetacean and Pinniped Research Workshop. New England Aquarium, October, 
1979, sponsored by the Marine Mammal Commission, Washington, DC. 

Richardson, D. T. 1973a. Distribution and Abundance of Harbor and Gray 
Seals, Acadia National Park Area. Final Report, Period July 1, 1971 to 
July 1, 1973. Maine Department of Marine Resources, Augusta, ME. 

. 1973b. Feeding Habits and Population Studies of Maine's Harbor and 

Gray Seals. Final Report, Period April, 1973, to November, 1973. Maine 
Department of Marine Resources, Augusta, ME. 

. 1975. Letter to Dr. George Waring, 2/14/75. Marine Mammal 

Commission, Washington, DC. 

. 1976. Assessment of Harbor and Gray Seals in Maine. Report to Marine 

Mammal Commission, Washington, DC. 

. 1978. Unpublished memorandum. Energy Resources Co., Inc., Cambridge, 

MA. 

Scott, D. M. and W. R. Martin. 1957. Variation in incidence of larval 
nematodes in Atlantic cod fillets along the southern Canadian mainland. 
J. Fish. Res. Board Can. 14:975-996. 

Sergeant, D. E. 1973. Feeding, growth, and productivity of Northwest Atlantic 
harp seals ( Pagophilus groenlandicus ) . J. Fish. Res. Board Can. 30:17- 
29. 

, and H. D. Fisher. 1957. The smaller Cetacea of eastern Canadian 

"waters. J. Fish. Res. Bd . Can. 14:83-115. 

Slijper, E. J. 1962. Whales. Hutchinson and Co., London. 

Smith, E. A. 1966. A review of the world's gray seal populations. J. Zool. 
(London) 150:463-489. 

13-31 



Spaulding, D. J. 1964. Comparative feeding habits of the fur seal, sea lion 
and harbor seal on the British Columbia coast. Bull. Fish. Res. Board 
Can. No. 146. 

Tessaro, S. V. and K. Ronald. 1976. The lesions of chronic methylmercury 
poisoning in the harp seal ( Peagophilus groenlandicus ) . I.C.E.S. Doc. 
CM. No. 7. 

TRIGOM. 1974. A Socioeconomic and Environmental Inventory of the North 
Atlantic Region, vol. 1. Bk. IV, Chap. 14, Marine Mammals, pages 14-1 to 
109. 

Whale Fishery of New England. 1968. Anonymous. Reynolds DeWalt Printing 
Company, New Bedford, MA. 

Young, P. C. 1972. The relationship between the presence of larval Anaskine 
nematodes in cod and marine mammals of British home waters. J. Appl. 
Ecol. 9:459-488. 



13-32 

10-80 



Chapter 14 
Waterbirds 



Authors: Norman Famous, Craig Ferris 




Waterbirds include seabirds, shorebirds, wading birds, and waterfowl and with 
the exception of waterfowl, which are discussed in chapter 15, waterbirds 
found along the Maine coast are described in this chapter. Approximately 100 
species of waterbirds breed, migrate, or winter along the Maine coast. The 
diversity of waterbirds is related to the variety of waterbird habitats found 
along the coast, including breeding habitats (coastal islands, lakes, and 
wetlands), migrating habitats (intertidal mudflats and salt marshes, deepwater 
tidal rips, protected bays, and highly productive offshore waters), and 
wintering habitats (ice free estuarine and marine waters and rocky shores). 

Waterbirds are an important and conspicuous component of the coastal 
ecosystem. They are valued mostly for recreation, including waterfowl hunting 
(common eider), bird watching, and nature study. They are high level 
consumers in the food webs, and are prone to accumulate toxic substances from 
their prey that may interfere with reproduction or cause death. People 
indirectly harm waterbirds by altering the amount and quality of their 
habitats (i.e., by dredging and filling land, impounding waters, channelizing 
streams, and developing islands). Directly, waterbirds are killed by hunters, 
poisoning, or by accident. 

The purpose of this chapter is to describe the ecological relationships of 
waterbirds within the ecosystem of the Maine coast, to summarize the 
population status of each waterbird group, and to discuss the effects of 
people on waterbirds and provide information to help mitigate these effects. 

Where information is available, the discussion of each group will contain the 
present status of breeding, wintering, and migrating populations, historical 
summaries, food and feeding habits, major feeding, roosting, or breeding 
locations in each region, and factors affecting distribution and abundance. 
Reviews of human impacts on waterbirds, the importance of waterbirds to 
society, and management considerations follow the discussion of the waterbird 
groups, and data gaps and research needs are described. Common names of 

14-1 



10-80 



species are used except where accepted common names do not exist. Taxonomic 
names of all species mentioned are given in the appendix to chapter 1. 

DATA SOURCES 

The primary data source for breeding seabirds is Maine Coastal Waterbird 
Colonies 1976-197 7 (Korschgen 1979). This source will be referred to 
hereafter as the coastal waterbird inventory. The list of important seabird 
nesting islands was obtained from Maine Department of Inland Fisheries and 
Wildlife (MDIFW) files. These files also contain more recent (1978) 
information on certain seabird colonies, especially those in Penobscot Bay 
(region 4), and common eider moulting areas. Data on least terns and piping 
plovers were acquired from the Maine State Planning Office (Dorr 1976a and 
1976b) and unpublished reports on least terns (Lee 1977). Data for coastal 
heron colonies were taken from the coastal waterbird inventory (Korschgen 
1979) and Herons and Their Allies : Atlas of Atlantic Coast Colonies , 1975 and 
1976 (Osborn and Custer 1978) , while data for inland heron colonies were 
provided by the Maine State Planning Office (Tyler 1977). 

Important feeding, roosting, and staging areas for shorebirds were obtained 
from published field reports in the Bulletin of the Maine Audubon Society 
(1946 to 1956), Maine Field Naturalist (1957 to 1967), Maine Field Observer 
(1956 to 1961), Maine Nature (1969 to 1973), and New Brunswick Naturalist 
(1970 to 1979). A card file of bird observations organized by the Portland 
Museum of Natural History and Maine Audubon Society (currently in special 
collections at the Fogler Library, University of Maine, Orono, ME) was 
examined for specific details on locations of published and unpublished 
shorebird sightings. Newsletters from local Audubon chapters also were 
reviewed for information on sightings of shorebirds. International 
Shorebird Surveys of Maine (ISS) and unpublished field notes were examined and 
numerous interviews with coastal residents familiar with shorebirds were 
conducted. Historical information was extracted from Bent (1921, 1926 ,1927, 
and 1929), Norton (1923a, 1923b, 1924a, 1924b, 1924c, 1925a, and 1925b), 
Palmer (1949 and 1962), Stout (1967), and Drury (1973 and 1974). Data for the 
regional overviews came from Drury (1973 and 1974), Brown et al. (1975), ISS 
reports (Harrington and Haber 1977; and Harrington 1979), and Maritime 
Shorebird Survey Reports (Morrison 1976a, 1976b, 1977, and 1978; and Hicklin 
1978). 

WATERBIRD GROUPS 

In this chapter, waterbirds are grouped into four categories based on 
taxonomic affinity and, to a lesser extent, by feeding habits, as follows: 

1. Seabirds. Birds that spend most of their lives at sea or along the 
adjacent coast and obtain most of their food while flying, swimming, or 
diving. Representatives of this group include shearwaters, storm petrels, 
cormorants, gulls, terns, and alcids (table 14-1). 

2. Shorebirds. Birds that obtain their food by either probing, pecking, or 
stalking prey in intertidal habitats, shallow fresh water, marshes, and 
wet meadows. Representatives of this group include sandpipers, plovers, 
turnstones, and curlews (table 14-2). 



14-2 



3. Wading birds. Birds that obtain their food by wading and stalking their 
prey in shallow water. They are relatively long legged, long necked, and 
light bodied and include herons, egrets, and ibises (table 14-3). 

4. Waterfowl. Birds that obtain their food either by diving or dabbling, 
breed in fresh water, and winter at sea, in estuaries, or open fresh 
water. This group, which includes ducks, geese, and swans, is discussed 
in chapter 15. The three waterfowl species discussed with the seabirds in 
this chapter are grebes, loons, and eider ducks. 

Within these groups, birds are further divided according to their seasonal 
occurrence in Maine as follows: 

1. Permanent residents. Species present during all seasons. The term 
"permanent resident" refers to the species rather than to individual 
birds. Birds that breed in Maine may not necessarily be the same 
individuals that winter in Maine (e.g., great black-backed gull, herring 
gull, common loon, and common eider). 

2. Breeding summer residents. Species breeding in Maine that are present only 

during the breeding season and during migration. 

3. Nonbreeding summer residents. Species that breed in the southern 
hemisphere and spend the winter season in northern waters (Wilson's storm 
petrel and the shearwaters), and non-breeding individuals of species 
breeding farther north (subadult and nonbreeding adult gannets , 
kittiwakes, fulmars, murres , and great cormorants) or to the south 
(certain herons). Most species in this category are seabirds. 

4. Migratory residents. Species present only during the fall or spring 
migration. 

5. Winter residents. Migratory species that winter locally but breed 
elsewhere (several seabirds and purple sandpipers). 

SEABIRDS 

Seabirds spend most of their lives far at sea or in the waters along the 
immediate coast. In Maine, seabirds are represented by loons, grebes, 
shearwaters, storm petrels, gannets, cormorants, eiders, gulls, terns, 
jaegers, and alcids. In the characterization area 39 species of seabirds 
occur regularly (table 14-1) and 18 species are rare visitants (table 14-4). 
Fourteen species breed in coastal Maine (table 14-1). 

Seabirds feed primarly in open water habitats and, to a much lesser extent, in 
intertidal areas. They are high level consumers, taking a variety of animal 
prey ranging from zooplankton and shrimp to finfish, and may influence the 
structure of their prey communities. Seabirds may form feeding groups with 
members of their own species and with other species of seabirds, and sometimes 
with marine mammals, finfish, bald eagles, and ospreys. Occasionally seabirds 
are prey for large falcons, bald eagles (mostly in winter), large finfish, 
marine mammals, and, of course, hunters. 



14-3 

10-80 



Table 14-1. Common Seabirds of Coastal Maine. (Species breeding in Coastal 
Maine are indicated by an asterisk) . 



Common name 



Taxonomic name 



Gaviiformes 

* Common loon 
Red-throated loon 

Pod iciped if ormes 

Pied-billed grebe 

Red-necked grebe 

Horned grebe 
Proc el lariif ormes 

Northern fulmar 

Greater shearwater 

Sooty shearwater 

Manx shearwater 

* Leach's storm petrel 
Wilson's storm petrel 

Pel ecan if ormes 
Gannet 
Great cormorant 

* Double-crested cormorant 
Anseriformes 

* Common eider 
Char ad ri if ormes 

Pomarine jaeger 
Parasitic jaeger 
Skua 

Glaucous gull 
Iceland gull 

* Great black-backed gull 

* Herring gull 
Ring-billed gull 
Black-headed gull 

* Laughing gull 
Bonaparte's gull 
Little gull 
Black-legged kittiwake 

* Common tern 

* Arctic tern 

* Roseate tern 

* Least tern 
Black tern 

* Razorbill 
Common murre 
Thick-billed murre 
Dovekie 

* Black guillemot 

* Common puffin 



Gavia immer 
Gavia stellata 

Podilymbus podiceps 
Podiceps grisegena 
Podiceps auritus 

Fulmarus glacialis 
Pu f f inu s gravis 
Puf f inus griseus 
Puf f inus puf f inus 
Oceanodroma leucorhoa 
Ocean it es ocean icus 



Morus bassanus 
Phalacrocorax carbo 
Phalacrocorax auritus 



Somateria mollissima 

Stercorarius pomarinus 
Stercorarius parasiticus 
Catharacta skua 
Larus hyperboreus 
Larus glaucoides 
Larus mar inus 
Larus argentatus 
Larus delawarensis 
Larus r idibundus 
Larus atricilla 
Larus Philadelphia 
Larus minutus 
Rissa tridactyla 
Sterna hirunda 
Sterna paradisaea 
Sterna dougallii 
Sterna albifrons 
Chlidonias niger 
Alca torda 
Uria aalge 
Uria lomvia 
Palutus alle 
Cepphus grylle 
Fratercula artica 



14-4 



Table 14-2. Common Shorebirds of Coastal Maine 



Common name 



Taxonomic name 



Semipalmated plover 

Piping plover 

Killdeer 

American golden plover 

Black-bellied plover 

Ruddy turnstone 

American woodcock 

Common snipe 

Long-billed curlew 

Whimbrel 

Upland sandpiper 

Spotted sandpiper 

Solitary sandpiper 

Willet 

Greater yellowlegs 

Lesser yellowlegs 

Red knot 

Purple sandpiper 

Pectoral sandpiper 

White-rumped sandpiper 

Baird's sandpiper 

Least sandpiper 

Dunlin 

Short-billed dowitcher 

Long-billed dowitcher 

Stilt sandpiper 

Semipalmated sandpiper 

Western sandpiper 

Buff-breasted sandpiper 

Marbled godwit 

Hudsonian godwit 

Ruff 

Sanderling 

Red phalarope 

Wilson's phalarope 

Northern phalarope 



Charadrius semipalmatus 
Charadrius melodus 
Charadrius vociferus 
Pluvialis dominica 
Pluvialis squatarola 
Arena ria interpres 
Philohela minor 
C apella gallinag o 
Numenius americanus 
Numenius phaeopus 
Bartramia longicauda 
Act it is maculariaa 
Tringa solitaria 
Catoptrophorus semipalmatus 
Tringa melanoleucus 
Tringa flavipes 
Calidris canutus 
Calidris maritima 
Calidris melanotos 
Calidris fuscicollis 
Calidris bairdii 
Calidris minutilla 
Calidris alpina 
Limnodromus griseus 
Limnodromus scolopaceus 
Micropalama himantopus 
Calidris p usillus 
Calidris mauri 
Tryngites subruf icollis 
Limosa f edoa 
Limosa haemastica 



Philomachus pugnax 
Calidris alba 
Phalaropus fulicarius 
Steganopus tricolor 
Lobipes lobatus 



14-5 



10-80 



Table 14-3. Common Wading Birds of Coastal Maine, 



Common name 



Taxonomic name 



Great blue heron 
Green heron 
Little blue heron 
Cattle egret 
Great egret 
Snowy egret 
Louisiana heron 
Black-crowned night heron 
Yellow-crowned night heron 
Least bittern 
American bittern 
Glossy ibis 



Ardea herodias 



Butorides striatus 


Florida caerulea 


Bubulcus ibis 


Casmerodius albus 


Egretta 


thula 


Hydranassa 


tricolor 


Nyct icorax 


nyct icorax 



N. violacea 



Ixobrychus exilis 



Botaurus lentiginosus 
Plegadis falcinellus 



14-6 



Table 14-4 . Seabirds Rare in Coastal Maine. 



Common name 



Taxonomic name 



Arctic loon 

Western grebe 

Eared grebe 

Yellow-nosed albatross 

Cory's shearwater 

British storm petrel 

Magnificient frigatebird 

Long-tailed jaeger 

Ivory gull 

Lesser black-backed gull 

Mew gull 

Franklin's gull 

Sabine's gull 

Forster's tern 

Royal tern 

Caspian tern 

Sooty tern 

Black skimmer 



Gavia arc tic a 

Aechmophorous occidentalis 
Podiceps caspicus 
Diomedea chlororhyncho s 
Puf f inus diomedea 
Hydrobates pelagicus 
Fregata magnif icens 
Stercorarius longicaudus 
Pagophila eburnea 
Larus fuscus 
Larus canus 



Larus pipixcan 
Xema sabini 
Sterna forsteri 
Thalasseus max imu s 
Hydroprogne caspia 
Sterna fuscata 
Rynchops niger 



The coastal waters have been divided into the following four general physical 
zones to describe the distribution and abundance of seabirds: 



1. 



Estuarine. Deepwater tidal habitats and adjacent wetlands which are 
usually semienclosed by land but have access to open ocean (Cowardin 
et al. 1979). 
Inshore Marine. Marine waters within 6 miles (10 km) of land. 

Offshore Marine. Marine waters beyond 6 miles extending out to the 
300-foot (91-m) depth contour. 
Pelagic. Deep marine waters beyond the 300-foot depth contour. 



The distribution and abundance of seabirds in each of these 4 zones and in 
inland lakes are presented in table 14-5. Most species show a preference for 
one or two zones but may feed in all of them. 

These zones are not always distinct. For example, inshore waters overlap 
offshore and pelagic waters if the 300-foot depth contour occurs within 6 
miles of shore. This situation is common in region 6 and as a result many 
pelagic and offshore species can be seen in inshore and estuarine waters such 
as Machias, Passamaquoddy, and Cobscook Bays. 



14-7 



10-80 



Table 14-5. Seasonal Occurrence and Relative Abundance of Seabirds 
Regularly Occurring in Various Habitats in the 
Characterization Area 



Seasonal occurrence 


Inland 


Estu- 


In- 


Off- 


Pelagic 


and common 


name 


lakes 


arine 


shore 


shore 




Breeding residents 














Common loon 




2 


2 


2 


1 





Common eider 







2 


2 


2 





Greater black-backed 


gull 


2 


2 


2 


2 


2 


Herring gull 




2 


2 


2 


2 


2 


Razorbill 










2 


2 


2 


Black guillemot 







1 


2 


2 





Leach's storm petrel 













1 


2 


Double-crested cormorant 


2 


2 


2 


1 





Laughing gull 







2 


2 


1 





Common tern 




1 


2 


2 


2 





Roseate tern 







1 


1 


1 





Arctic tern 







1 


2 


2 


1 


Least tern 







2 


2 


1 





Common puffin 










1 


1 


1 


Nonbreeding summer res: 


Ldents 












Wilson's storm petrel 











2 


2 


Greater shearwater 










1 


2 


2 


Sooty Shearwater 













1 


2 


Manx Shearwater 

Fulmar „ 
w-CommonMurre 
Migratory ^effidents 



















1 


1 

1 
1 


1 

1 



Gannet 










1 


2 


2 


Pomarine jaeger 













1 


2 


Parasitic jaeger 













1 


2 


Skua 
















1 


Ring-billed gull 




1 


2 


2 


1 





Black-headed gull 



















Bonaparte's gull 




1 


2 


2 


2 





Little gull 



















Black tern 




1 


2 


2 








Winter residents 














Common loon 




2 


2 


2 


1 





Common eider 







2 


2 


2 





Greater black-backed 


gull 


2 


2 


2 


2 


2 


Herring gull 




2 


2 


2 


2 


2 


Razorbill 










2 


2 


2 


Black guillemot 







2 


2 


2 





Red-throated loon 










1 








Red-necked grebe 










1 


1 









(Continued) 









14-8 



Table 14-5. (Concluded) 



Seasonal occurrence 


Inland 


Estu- 


In- 


Off- 


Pelagic 


and common name 


lakes 


arine 


shore 


shore 




Winter residents (cont.) 












Horned grebe 





2 


2 


2 





Northern fulmar 








1 


2 


2 


Great cormorant 





1 


2 


2 





Glaucous gull 





1 




1 


1 


Iceland gull 





1 




1 


1 


Black-legged kittiwake 





1 




2 


2 


Common murre 










1 


2 


Thick-billed murre 










1 


2 


Dovekie 










2 


2 



0~rare or absent; l=uncommon; 2=abundant or common. 



Historical Trends 

During the 19th century, populations of most species of seabirds declined 
because of human exploitation and disturbance of nesting colonies. Hunting, 
egg-collecting, and disturbance of nesting islands by grazing sheep, 
introduced pets, lumbering, and construction led to the elimination of 
breeding populations of double-crested cormorants, great black-backed gulls, 
eiders, puffins, and black guillemots along the Maine coast by the 1870s 
(Norton 1923b; Drury 1973). Between 1870 and 1900, terns, laughing gulls, and 
herring gulls were slaughtered to provide feathers for the millinery industry. 
Many of the herring gull colonies on inshore islands were abandoned during the 
1890s and the only known large colony remaining was on No Mans Land Island 
(region 4; Norton 1923b). Leach's storm petrels and some species of terns 
survived in moderate numbers during this period (Drury 1973 and 1974). 



State laws 
was financi 
National As 
a result 
guillemots , 
have begun 
11,000 pai 
populations 
Cormorants 



protecting seabirds were enacted as early as 1901 and enforcement 

ally supported by the American Ornithologist's Union and the 

sociation of Audubon Societies. Most species increased markedly as 

of protection. After 1900, numbers of common eiders, black 

and puffins increased steadily until recently, when their numbers 

leveling off (figure 14-1). Herring gulls increased from about 

rs in 1900 to over 40,000 pairs in the 1920s. Since then 

have fluctuated between 20,000 and 36,000 pairs (figure 14-1). 

and great black-backed gulls recovered more slowly than other 

14-9 



10-80 



species. They were presumably scarce prior to 1930, after which they have 
increased markedly (figure 14-2). 

Common terns increased from a low of around 1000 pairs in 1900 to nearly 9000 
pairs in 1930. Arctic terns, on the other hand, remained fairly stable 
throughout the period (figure 14-2). Since the 1950s numbers of both common 
and arctic terns have decreased, presumably as a result of increases in 
numbers of herring and black-backed gulls which prey on eggs and chicks and 
also steal food from adult birds that are on their way to feed nestlings. 
Roseate terns, laughing gulls, puffins, and razorbills are also frequent 
victims of gull predation (Nettleship 1972) . Gulls also may take over 
preferred nesting sites. Puffin and razorbill populations are currently 
stable, but all three species of terns and the laughing gulls are declining in 
Maine . 

Although numbers of Leach's petrels seemed to be unaffected by exploitation in 
the last century, their numbers have declined since 1900 because of habitat 
disturbance on their nesting islands (e.g., construction, logging, and 
grazing) . 

Present Status of Seabirds 

Breeding species. Fourteen species of seabirds breed along the Maine 
coast (table 14-5) . The common loon breeds on inland lakes and least terns 
nest on sand beaches on the mainland. All other species nest in colonies on 
offshore islands. The characterization area has a total of 321 nesting 
colonies of seabirds and supports the largest breeding populations of arctic 
terns, double-crested cormorants, Leach's storm petrels, common eiders, 
razorbills, common puffins, and black guillemots in eastern U.S. waters. 

Region 4 has the most seabird colonies (117), followed in decreasing order by 
regions 3 (60); 1 (50); 5 (39); 6 (34); and 2 (21). A complete list of 
nesting colonies and their locations are presented in the appendix table 1. 
The most important nesting islands are shown on atlas map 4. 

The common eider is the most abundant nesting seabird along the Maine coast 
(table 14-6). Over 22,000 pairs nest on 240 islands. Eiders nest in all 6 
regions of the characterization area but 41% are found in region 4. Leach's 
storm petrels are nearly as abundant as the common eider but are much more 
localized in distribution. Petrels nest in 17 colonies in regions 3 to 6 but 
nearly 95% of the population breeds in only 4 colonies in region 5 (table 14- 
6). 

The herring gull ranks third in abundance (16,695 pairs). It breeds in all 6 
regions but is most abundant (36%) in region 4. The double-crested cormorant 
(14,549 pairs), great black-backed gull (6575 pairs), and black guillemot 
( 2665 pairs) are also found in all six regions, and like the herring gull and 
common eider are most abundant in region 4 (table 14-6) . 

Of the large-bodied terns, the common and arctic terns are about equally 
abundant (1393 and 1640 pairs respectively), whereas the roseate tern is much 
less abundant (55 pairs). These terns nest on 29 coastal islands in either 
mixed species (3 islands) or single-species colonies (26 islands). More than 
one-half of the breeding population of arctic terns south of Labrador nests on 

14-10 



1 0000 -i 



u 

-i 
< 
o 
CO 

o 

I 
I 

a. 

< 

O 

J 

(0 

cc 

< 

a. 

u. 
O 

DC 
LU 
CO 

5 
3 



1000 - 



100 - 




1900 



1980 



Figure 14-1. Trends in populations of nesting herring gull, eider, black 
guillemot, and puffin in Maine since 1900 (adapted from Drury 
1973 and Korschgen 1979). 



10000 -a 



...• li""-*"*:.— — ^ ARCTIC TERN 



-J 
< 

o 
CO 

o 

s 

X 

£ 

< 
u 
o 



CO 

oc 
< 

Q. 
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O 
CC 
LU 
00 

S 
3 



1000- 



100 - 



COMMON TERN 



DOUBLE-CRESTED CORMORANT 



GREAT BLACK-BACKED GULL 



RAZORBILL 



1900 



1910 



-~i r 1 1 — ~\ 1 1 

1920 1930 1940 1950 1960 1970 1980 



Figure 14-2. 



YEAR 

Trends in populations of nesting great black-backed gull, 

double-crested cormorant, arctic and common tern, and 

razorbill auk in Maine since 1900 (adapted from Drury 1973 

and Korschgen 1979). 

14-11 



10-80 



Table 14-6. Estimated Numbers (percentage contribution to the total in 
parentheses) of Nesting Pairs of Seabirds (breeding summer 
residents) in Each Region of the Characterization Area in 
1977. a 



Species 






Reg 


;ion 






Total 




1 


2 


3 


4 


5 


6 


character- 
ization 
area 


Common eider 


1836 


425 


4420 


9047 


2855 


3683 


22,266 




(8) 


(2) 


(20) 


(41) 


(13) 


(17) 




Leach's storm petrel 


- 


- 


77 


966 


18,053 


35 


19,131 








(<D 


(5) 


(94) 


(<D 




Herring gull 


3182 


689 


1025 


6044 


2373 


3382 


16,695 




(19) 


(4) 


(6) 


(36) 


(14) 


(20) 




Double-crested cormorant 


1638 


891 


2065 


5162 


3714 


1079 


14,549 


Great black-backed gull 


(11) 
864 


(6) 

644 


(14) 
642 


(35) 
1601 


(26) 
1717 


(7) 
1107 


6575 




(13) 


(10) 


(10) 


(24) 


(26) 


(17) 




Black guillemot 


20 


33 


260 


1158 


830 


364 


2665 




(1) 


(1) 


(10) 


(43) 


(31) 


(14) 




Common tern 


213 


350 


225 


390 


700 


20 


1898 




(ID 


(18) 


(12) 


(21) 


(37) 


(1) 




Arctic tern 


- 


350 


10 


505 


700 


75 


1640 






(21) 


(1) 


(31) 


(43) 


(5) 




Laughing gull 


" 


" 


32 
(14) 


49 
(21) 


150 
(65) 




231 


Common puffin 




" 


" 


125 
(100) 


~" 




125 


Roseate tern 


- 


35 


- 


- 


20 


- 


55 


Razorbill 


- 


(64) 


- 


15 
(60) 


(36) 


10 
(40) 


25 


Least tern 




(100) 










7 



^orschgen 1979. 



14-12 



Petit Manan (region 5), Matinicus Island (region 4), and Machias Seal Island 
(region 6, ownership disputed by U.S.; Drury 1973). 

Laughing gull populations have never been high in Maine, comprising less than 
250 pairs in 1977. This scarcity is perhaps due to the abundance of herring 
gulls, which displace laughing gulls from preferred nesting locations (Nisbet 
1973). More importantly, laughing gulls are at the northern end of their 
range in Maine. Laughing gulls are always found nesting in association with 
either common or arctic terns. 

The common puffin breeds in one colony at Matinicus Rock in region 4 (125 
pairs). It also nests in proximity to the Maine coast at Machias Seal Island 
in New Brunswick (1100 pairs estimated; personal communication from R. Newell, 
Acadia University, Department of Biology, Wolfville, Nova Scotia, Canada; 
February, 1979). The National Audubon Society, in cooperation with Cornell 
University, is attempting to reestablish the puffin on Eastern Egg Rock 
(region 3), formerly the southernmost breeding colony. They are using 
transplanted, hand-reared young from Newfoundland and decoys to attract 
potential breeders. 

The razorbill (25 pairs) and the least tern (20 pairs) are the least abundant 
breeding seabirds along the Maine coast. The razorbill nests on two islands 
(one each in regions 4 and 6) and the least tern nests on two sand beaches on 
the mainland (Popham Beach and Sprague River Beach in region 2). 

Common loons breed on inland lakes and ponds in all six regions, although they 
are more abundant in regions 5 and 6 than in regions 1 to 3. A higher level 
of human activity in regions 1 to 3 is presumed responsible for the lower 
populations there (personal communicatione from B. Christenson, University of 
Maine, School of Forest Resources, Orono, ME; March, 1979). 

Although seabirds nest on 321 islands in the characterization area the 
majority of nesting birds of most species are found on far fewer islands. 
Based on criteria jointly developed by the U.S. Fish and Wildlife Service 
(FWS), the University of Maine, and the Maine Department of Inland Fisheries 
and Wildlife, 127 islands have been designated "significant" breeding islands. 
These islands contain single species colonies that comprise 1% or more of the 
total breeding population of that species, or mixed species colonies whose 
aggregate percentage is 1% or more of the total breeding population of all 
species combined. These 127 islands contain over 90% of the total coastal 
Maine breeding populations of Leach's storm petrels, laughing gulls, common 
terns, arctic terns, razorbills, and puffins, and over 80% of cormorants, 
eiders, and black guillemots (table 14-7). Approximately half of the breeding 
populations of herring and black-backed gulls also nest on these islands. 
Region 4 has the largest number of significant breeding islands (46) , followed 
in decreasing order by regions 3 (20), 5(19), 6 (17), 1(17), and 2(8). These 
islands are indicated by an asterisk in appendix table 1, and all 127 islands 
are plotted on atlas map 4. A region by region account of the most important 
islands follows. 

Region 1 has 17 major nesting islands. The five most important islands are 
Outer Green, Stockman, Grass Ledge, White Bull Island, and Ram Island (Casco 
Bay). 

14-13 



10-80 



Table 14-7. Percentage of Total Nesting Pairs of Seabirds Breeding on 
126 Major Islands in Coastal Maine During 1977 



Common name Regions Total 



Leach's storm petrel 

Double-crested cormorant 

Common eider 

Great black-backed gull 

Herring gull 

Laughing gull 

Common tern 

Arctic tern 

Roseate tern 

Razorbill 

Black guillemot 

Common puffin 

TOTAL ISLANDS 



11 5 

7 1 
5 6 

8 2 

10 17 
21 
44 



<1 


5 


12 


30 


16 


36 


6 


14 


2 


21 


14 


21 


10 


16 


1 


31 


- 


60 


5 


40 


- 


100 



5 


6 


for all 
regions 


94 


<1 


99 


23 


6 


87 


12 


15 


87 


17 


10 


58 


8 


12 


53 


65 


- 


100 


33 


10 


96 


43 


5 


100 


25 


- 


69 


- 


40 


100 


30 


13 


89 


- 


- 


100 



17 8 20 46 19 17 127 



a Korschgen 1979. 

Region 2 has 8 major nesting islands. The 5 most important are North 
Sugarloaf Island, White Island, Heron Island, Pumpkin Island, and Pond Island. 
North Sugarloaf supports a large mixed colony of arctic, roseate, and common 
terns, and once supported laughing gulls. It is particularly vulnerable to 
human disturbance because it is located near the mainland in a high-use 
recreation area (Popham Beach State Park). The only least terns nesting in 
the characterization area nest in this region at Popham Beach and along 
Sprague River Beach. Further details on these two locations can be found in 
Dorr (1976a) and Lee (1977). The Maine Audubon Society monitors populations 
in these two colonies. 

Region 3 has 20 major nesting islands. The five most important include 
Killick Stone Island, The Brothers Island, Western Egg Rock, Metinic Green 
Island, and Metinic Island. Currently region 3 supports fewer seabirds than 
in the past. For example, this region formerly supported the southernmost 
breeding colony of common puffins (Eastern Egg Rock) and several additional 
colonies of Leach's storm petrels. It is now the southernmost breeding area 
in Maine for Leach's storm petrels. 

Region 4 has 46 major seabird islands. Among the regions it has the greatest 
number of nesting islands for all species except common, roseate, and least 
terns, and the greatest number of nesting pairs for all species except terns, 
great black-backed and laughing gulls, and Leach's storm petrels. The most 
important nesting island in Maine, Matinicus Rock, is in region 4. It has 

14-14 



the only common puffin colony in Maine owned by the Federal Government and has 
one of the only two razorbill colonies in the coastal zone, as well as large 
numbers of arctic terns, laughing gulls, guillemots, and some Leach's storm 
petrels . 

The largest numbers of cormorants, eiders, herring gulls, and black guillemots 
nest in region 4 (35%, 41%, 36%, and 43% of total State populations 
respectively). The 5 most important colonies are on Matinicus Rock, Wooden 
Ball Island, Thrumcap Island, Seal Island, and No Mans Land Island. 

Region 5 has 19 major seabird breeding islands. This region is most important 
for Leach's storm petrels, great black-backed gulls, laughing gulls, common 
terns, and arctic terns. The 5 most important breeding islands include Petit 
Manan Island, Great Duck Island, Little Duck Island, Schoodic Island, and Ship 
Island. Great Duck Island has the largest petrel colony south of 
Newfoundland, and Petit Manan Island and Machias Seal Island (in region 6) are 
the most important areas south of Newfoundland for breeding arctic terns. 

Region 6 has 17 major seabird islands. The 5 most important islands are Old 
Man Island (east), Libby Island, Browney Island, The Brothers, and Ballast 
Island. Old Man Island has one of the only two U.S. razorbill colonies in the 
coastal zone. The region is very important for arctic terns, common puffins, 
and razorbills (Machias Seal Island) and contains Maine's largest eider colony 
(Libby Island) . 

Most of the important colonies are located west of Cutler (few islands are 
located along the coast east of Cutler). To the east, Cobscook Bay supports 
small numbers of eiders, cormorants, herring gulls, and great black-backed 
gulls. Two important seabird nesting islands in Cobscook Bay are Goose Island 
and Spectacle Island. 

Nonbreeding summer residents . Nonbreeding summer resident birds breed in 
the southern hemisphere during our winters and spend their winter in the North 
Atlantic. The most common species are the sooty, manx, and greater 
shearwaters, Wilson's storm petrel, and some southern skuas (table 14-5). The 
northern fulmar has been observed more frequently in recent years. These 
species are generally found in offshore and pelagic waters but wander inshore 
during periods of extended fog or east-southeast winds. They are more common 
in regions 5 and 6 and their abundance increases with distance from land. 
Their seasonal occurrence in the Gulf of Maine (based primarily on Bluenose 
Ferry sightings) was recently reviewed by Finch et al. (1978). 

Winter residents . Seventeen species of seabirds are found along the Maine 
coast in winter (table 14-5). Eleven species are found primarily in inshore 
and estuarine waters and six species inhabit offshore and pelagic waters. 

The herring gull, common eider, and great black-backed gulls are the most 
abundant winter residents. They are found in inshore and estuarine waters 
throughout the coastal area. Horned grebes and great cormorants are somewhat 
less abundant than the above species. Horned grebes are found throughout the 
coastal zone, usually as single birds or in small groups of less than 10. 
Occasionally they will be found in flocks as large as 300 during the fall and 
spring migration. 

14-15 



10-80 



Great cormorants are found throughout inshore areas and around inner and outer 
islands. They occupy habitat similar to that used by double-crested 
cormorants during the summer but they do not extend as far into estuaries. 
They arrive in mid-September and depart in April and early May. A few (mostly 
subadults) may spend the summer on outer islands or ledges. 

The red-throated loon and red-necked grebe are uncommon winter residents along 
the Maine coast. Red-throated loons are usually found in harbors, coves, and 
outer estuaries, whereas red-necked grebes frequent outer headlands and 
islands . 

Glaucous and iceland gulls are found in association with herring gulls and 
great black-backed gulls in coastal bays and estuaries, and around garbage 
dumps, fish processing plants, and raw sewage outlets. Individuals are 
scattered throughout the coastal zone but the greatest numbers (as many as 
100) are found near Lubec and Eastport (region 6) . 

Among the offshore and pelagic species the kittiwake and fulmar are the most 
abundant and occur in flocks numbering in the thousands. They are most 
abundant in the waters of regions 5 and 6. In Passamaquoddy Bay kittiwakes 
have occured in flocks of over 10,000, and more than 48,000 have been seen in 
the eastern approaches to the Bay of Fundy. The dovekie may occur in rafts 
(groups of birds in the water) numbering in the thousands, especially in the 
Quoddy region (off the southern end of Grand Manan Island and the Cutler 
headlands). Inshore they are generally found in small groups numbering less 
than 20. 

Common and thick-billed murres are uncommon in the coastal zone. They are 
usually found offshore and around outer islands of regions 5 and 6 but small 
numbers are occasionally found inshore near harbors, inner islands, and 
coastal headlands. 

Migratory residents. Six species of seabirds are found along the Maine 
coast only during migration (table 14-5). Most of these are more common in 
fall than in spring and may remain in coastal waters for several months. They 
are locally common near upwellings and tidal rips. Bonaparte's gull is the 
most abundant migrant. Typically, concentrations of a few hundred are found 
in the outer and middle portions of estuaries, such as Back Bay in Portland 
(region 1), Raccoon Cove in Lamoine (region 5), and Mason's Bay near Jonesboro 
(region 6). Several thousand can be found in Cobscook Bay (region 6) and tens 
of thousands in Passamaquoddy Bay near Eastport. Concentrations of several 
hundred are often found roosting on inland ponds and lakes along the coast. 

The ring-billed gull is a common migrant, with flocks of a few hundred 
occurring in the upper portions of coastal estuaries, such as the Pleasant 
(region 6), Jordan (region 5), Union (region 4), Damariscotta (region 3), and 
Kennebec Rivers (region 2) and Back Bay in Portland (region 1). It is also 
very abundant (a few thousand) in Passamaquoddy Bay (region 6) in August and 
September. Ring-billed gulls have increased in recent years, both as 
nonbreeding summer residents and as winter residents. 

The gannet is a common migrant in both spring and fall. It is most abundant 
offshore but is commonly observed from coastal headlands during periods of 
easterly and southeasterly winds. 

14-16 



Other less common migrants include the skua, parasitic jaeger, and pomarine 
jaeger. They are offshore and pelagic species that only enter the 
characterization area occasionally. 

Reproduction 

With the exception of the common loon all species of seabirds that breed along 
the coast nest in colonies. Colonial nesting in birds is thought to evolve 
when the following conditions prevail: (1) relative freedom from predation, 
particularly ground predators, such as mammals and reptiles; (2) food sources 
are concentrated and patchy in distribution, so that many individuals must 
feed together and territorial defense of food supplies is not possible; and 
(3) a shortage of preferred nesting sites exists, so that many individuals 
must nest together. Colonial nesting in turn benefits individual pairs in 
defending against predators. The major predators in seabird colonies are 
other birds, primarily gulls, crows, and ravens. Colony members can sometimes 
drive these predators away by attacking together. 

Nesting in colonies also helps birds locate food. Since food sources are 
often widely distributed in marine systems, birds that are successful in 
locating food are followed from the colony to the source by other birds. 

As a group, seabirds have small clutches (1 to 5 eggs), relatively protracted 
development periods for nestlings, and delayed breeding in adults (up to 5 
years for petrels). Low predation rates and patchy, often distant food 
supplies, make it adaptive to invest more time and energy in a few eggs and 
young rather than trying to raise a large brood (which might die of exposure 
or starve). Even among the seabirds these reproductive characteristics vary. 
Petrels lay one egg, nest in protected burrows, and delay breeding until the 
adults are 5 years old. Petrels feed far offshore and spend much time 
searching for food. They may remain away from the nest for up to 2 days. The 
young develop very slowly to accommodate the scarce food supplies. They may 
remain in the nest for over 60 days. 

In contrast, gulls, terns, eiders, cormorants, and guillemots lay two or more 
eggs, usually in exposed nests, and breed at an earlier age (2 to 4 years). 
The nesting islands are closer to inshore and estuarine waters, which are more 
productive than offshore waters. Consequently the young develop more rapidly 
than do petrels. 

Along the Maine coast, seabirds nest from mid-April (great black-backed gulls) 
through late October (Leach's storm petrel). Each species has a peak laying 
period that may vary up to three weeks, depending on weather conditions and 
disturbances (figure 14-3). Also, birds in the southwestern regions (1 and 2) 
begin nesting earlier than birds in the northeastern regions (5 and 6). The 
laying peaks for several species overlap. Great black-backed gulls, herring 
gulls, cormorants, and eiders start nesting in late April and early May, while 
terns, alcids, Leach's storm petrel, and laughing gulls initiate nesting in 
late May and early June. 

In late summer large rafts of moulting eiders form at several locations along 
the coast. At the same time large concentrations of herring gulls and great 
black-backed gulls occur in nearshore estuarine feeding and roosting areas. 
These concentrations occur in August after the young birds have fledged. 

14-17 

10-80 



The largest postbreeding concentrations occur in the eastern portion of region 
6 (Passamaquoddy Bay, south Lubec, and Machias Bay), as this area is adjacent 
to large gull colonies in the vicinity of Grand Manan Island (i.e., 16,000 
pairs on Kent Island, New Brunswick). 

Feeding Habits 

Among seabirds each group of species uses a characteristic feeding method 
(table 14-8). Birds that feed at or near the surface do so by dipping (bird 
in flight drops to the surface to snatch prey), pattering (bird in flight uses 
its feet to disturb the surface, which attracts prey), surface seizing (bird 
grabs prey while sitting on the surface), scavenging (bird feeds on offal, 
cannery waste, or at sewage outflows), pursuit diving (bird dives from the 
surface to chase prey in the upper depths), and shallow plunging (bird plunges 
from the air into the water to a shallow depth to seize prey) . Birds that 
feed in deeper waters practice pursuit plunging (bird plunges into the water 
while flying and then swims or 'flies' underwater pursuing its prey), deep 
plunging (bird dives deeper than shallow plunging), pursuit diving, and bottom 
feeding (bird usually dives from surface to gather benthic invertebrates and 
bottom dwellers). Jaegers, gulls, and terns often steal food from other 
seabirds (Hatch 1970 and 1975). 



APRIL MAY JUNE JULY AUG. 



SEPT. 



OCT. 



NOV. 




Leach's storm petrel 

Double-crested cormorant 

Common eider 

Great black-backed gull 

Herring gull 

Laughing gull 

Large terns 

Least tern 

Common puffin 

Black guillemot 

Razorbi 



Figure 14-3. Timing of egg laying, incubation, and breeding of seabirds 
in coastal Maine (crosshatch represents overlap). 



14-18 



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14-20 



Knowledge of feeding methods is important in evaluating potential 
environmental impacts. For example, in the event of an oil spill birds that 
spend most of their time on the water and dive for their food are more 
susceptible to feather oiling than are birds that feed on the wing. Creation 
of impoundments for tidal power may reduce the amount of intertidal mudflats 
and adversely affect species that feed there. 

As a group seabirds feed primarily on fish and crustaceans but also consume 
cephalopods, other invertebrates, offal and garbage (table 14-9). Birds that 
feed by dipping, pattering, and surface seizing eat crustaceans, other 
invertebrates, small fish, and cephalopods. Birds that feed by pursuit 
diving, shallow plunging, and deep plunging eat fish and, to a lesser extent, 
large invertebrates. Birds that feed on the bottom take benthic invertebrates 
and some fish. 

Along the Maine coast food may be abundant overall but is usually concentrated 
in specific habitats and may be dispersed in patches. Some species of 
seabirds (e.g., terns) are better adapted for finding these patches of food 
and their activity in turn attracts other species. As a result, feeding 
associations between seabird species are common. They usually avoid competing 
with each other by using different feeding methods and by selecting different 
prey. 

Seabirds may also feed with pods of marine mammals (whales, dolphins, and 
seals) and sometimes with large fish (such as tuna and mackerel) according to 
Baltz and Morejohn (1976). Fishermen may use groups of feeding terns, gulls, 
and shearwaters (as well as marine mammals) to locate schools of fish. 

Natural Factors Affecting Abundance 

The factors that control the abundance of seabirds along the Maine coast are 
not entirely known. The following paragraphs summarize the ways in which 
predation, food supply, and nesting habits might affect abundance. 

Predation. Except during the breeding season, seabirds are relatively 
free from natural predators. Small islands afford the safest breeding 
locations because they are relatively free of mammalian predators. Gulls 
(herring and great black-backed), ravens, crows, and great horned owls may 
prey heavily on the eggs and flightless young. Islands with introduced 
mammalian predators or islands that occasionally are attached to the mainland 
by ice make poor seabird nesting areas. 

Food supply . The effects of limited food supply are difficult to quantify 
in offshore areas, where food supplies usually are widely scattered. In 
Massachusetts a positive correlation exists between the annual herring harvest 
and tern nesting success (Nisbet 1973). An increase in garbage dumps resulted 
in higher survival of herring and great black-backed gulls and largely 
accounted for their population explosion in Maine and elsewhere in New England 
(Drury and Kadlec 1974). The large flocks of Bonaparte's, herring, and great 
black-backed gulls, and northern phalaropes (see "Shorebirds" below) found in 
Passamaquoddy Bay in late summer occur where marine upwelling areas and tidal 
rips concentrate foods such as euphausiid shrimp. 



14-21 



10-80 



Table 14-9. Food Types of Seabirds Regularly Occurring in the 
Characterization Area 



Major 


Fish 


Cepha- 


Crusta- 


Other 


Garbage 


feeding habitats 




lopods 


ceans 


inverte- 


and 


and common names 








brates 


offal 


Estuaries-Inshore 












Common loon 


2 














Red-throated loon 


2 














Red-necked grebe 








2 








Horned grebe 








2 


2 





Pied-billed grebe 











2 





Double-crested cormorant 


2 







1 





Common eider 










2 





Glaucous gull 













2 


Iceland gull 













2 


Great black-backed gull 













2 


Herring gull 













2 


Ring-billed gull 













1 


Black-headed gull 







1 








Laughing gull 


2 




1 





1 


Bonaparte's gull 







1 





1 


Little gull 


2 




1 








Common tern 


2 







1 

1 


1 


Roseate tern 


2 







1 


1 


Least tern 


2 














Black tern 


2 








1 





Onshore-Offshore 












Great comorant 


2 


1 





1 





Arctic tern 


2 


1 





1 


1 


Dovekie 


1 





2 


1 





Black guillemot 


2 


1 


2 








Offshore-Pelagic 












Northern fulmar 








2 





2 


Greater shearwater 


2 


2 


2 








Sooty shearwater 


2 


2 


2 








Manx shearwater 


2 














Leach's storm petrel 





1 


2 


2 





Wilson's storm petrel 


1 


2 


2 


2 





Gannet 


2 


2 











Pomarine jaeger 


2 




1 


1 


1 


Parasitic jaeger 


2 




1 


1 


1 


Skua 













1 


Black-legged kittiwake 


2 




2 


1 





Razorbill 


2 


(Cont 



inued) 


1 






14-22 



Table 14-9. (Concluded) 



Major 
feeding habitats 

and common names 



sh 


Cepha- 


Crusta- 


Other 


Garbage 




lopods 


ceans 


inverte- 
brat es 


and 

offal 


2 


1 





1 





2 


1 





1 





2 


■ 












Common murre 
Thick-billed murre 
Common puffin 



0=negligible or infrequently used; l=frequently used; 2=pref erred food 



Birds that feed on the wing, such as terns and petrels, have difficulty 
feeding during periods of bad weather (Dunn 1973). Rough seas may also 
prevent diving species from feeding. Many common murres have perished after 
prolonged periods of bad weather in Alaska (Sealy 1973). 

Nesting habits . Along the Maine coast nesting habitat may be limiting for 
Leach's storm petrel, least terns, and common loons. Petrels nest on islands 
in underground burrows that they themselves excavate. Excavation is easier in 
the duff under spruce-fir forests than in the sod on treeless islands. 
Several islands formerly used by nesting petrels have been cleared of timber 
and burned, or grazed by sheep, resulting in the development of thick, 
impenetrable sod. These islands are now uninhabitated or have very small 
breeding colonies [i.e., Wooden Ball, Little Green and Large Green Islands 
(region 4), Libby Island and the Brothers Island (region 6), and 14 others 
summarized by Drury (1973)] . 

Least terns prefer to nest on sand beaches. The few that are present in Maine 
are found primarily on the mainland (region 4) , where predation and human 
disturbance are high. They have never been abundant in Maine. 

Because of the large number of islands along coastal Maine, the availability 
of nesting habitat should be adequate for most of the other species of 
seabirds. Apparently arctic, common, and roseate terns, laughing gulls, and 
possibly puffins and razorbills, require islands free of nesting herring and 

14-23 



10-80 



great black-backed gulls for successful nesting. For example, most of the 
larger tern and laughing gull colonies in New England have been taken over by 
herring and black-backed gulls (Nisbet 1973). In Maine many of the successful 
tern and alcid colonies are found on islands where lighthouse keepers 
controlled herring gull numbers (Drury 1973). Young puffins and razorbills 
are also frequent victims of gull predation. If gull-free islands are 
required by these species of seabirds, then adequate nesting habitat may be 
lacking. 

SHOREBIRDS 

Shorebirds are a closely related group of species (order Charadriiformes , 
suborder Charadrii) that are represented in Maine by sandpipers, plovers, 
turnstones, godwits, curlews, dowitchers, and phalaropes. Thirty-three 
species of shorebirds commonly occur along the Maine coast (table 14-2) . 
Seven additional species visit occasionally in very low numbers. The Maine 
coast is most important as a feeding and resting area for migrating 
shorebirds, but six species (piping plover, spotted sandpiper and four upland 
species) breed along the coast and one species (purple sandpiper) is a winter 
resident (table 14-10). Of the six breeding species the killdeer, snipe, 
woodcock, and upland sandpiper are primarily found in upland habitats and are 
discussed in chapter 16, "Terrestrial Birds." 

Shorebirds are found in most marine, estuarine, and palustrine habitats 
ranging from deepwater marine to estuarine intertidal emergent wetland 
(saltmarsh) . Most species have specialized feeding and roosting habitats 
(tables 14-11 and 14-12 respectively). The most important feeding habitats 
are estuarine and marine intertidal mudflats, and the most important roosting 
habitats are sand and gravel beaches or spits, and nearshore ledges. 
Shorebirds may also roost on salt pannes in estuarine intertidal emergent 
wetlands, in fields, golf courses, on tops of buildings, or on rocky ledges. 

Shorebirds feed largely on marine and estuarine invertebrates in the 
intertidal zone and may help supress the abundance of many prey species. They 
consume a substantial amount of the secondary production of the intertidal 
system and, because of their transient nature, represent an important energy 
loss from these systems. Shorebirds, in turn, serve as prey for certain 
falcons (including the endangered peregrine), accipiters, and marsh hawks. 

Shorebirds are now of little direct economic importance, although in the past 
they were hunted and sold as food in many urban centers and used in the 
millinery trade. They have high aesthetic and recreational values (bird 
watching) . 

Shorebirds should be given special consideration by management authorities 
because large numbers of these birds depend on coastal habitats for feeding 
and resting during their long migration from the Arctic breeding grounds to 
South American wintering areas (Morrison 1977). In addition, they often 
concentrate in relatively small areas, a practice which can make them 
susceptible to habitat disturbance and certain environmental contaminants. To 
date, migratory shorebirds generally have been neglected by decisionmakers who 
plan coastal developments. They are given only modest consideration in 
environmental impact statements and in oil-spill cleanup plans. 

14-24 



Table 14-10. 



Resident Status and Relative Abundance of the 
Shorebirds of Coastal Maine. 



Resident status 
and species 



Relative abundance 



Spring Summer Fall Winter 



Breeding residents 
Piping plover 
Spotted sandpiper 

Wintering residents 
Purple sandpiper 

Migratory residents 
Semipalmated plover 
American golden plover 
Black-bellied plover 
Ruddy turnstone 
Whimbrel 

Solitary sandpiper 
Willet 

Greater yellowlegs 
Lesser yellowlegs 
Red knot 
Least sandpiper 
White-rumped sandpiper 
Dunlin 

Pectoral sandpiper 
Short-billed dowitcher 
Stilt sandpiper 
Semipalmated sandpiper 
Marbled godwit 
Hudsonian godwit 
Sanderling 

Rare visitors 

Baird's sandpiper 

Long-billed dowitcher 

Western sandpiper 

Buff-breasted sandpiper 

Ruff 

Wilson's phalarope 




2 








2 


2 


2 











1 





2 


2 


2 





2 


2 


2 








1 


1 





2 


2 


2 





1 


1 


1 





2 


2 


2 





1 


2 


2 








1 


1 





2 


2 


2 








1 


1 





1 





2 





1 


1 


2 





2 


2 


2 








1 


1 





2 


2 


2 




















1 


1 





1 


2 


2 














































































= rare or absent; 1 = occasional or uncommon; 2 = common 



14-25 



10-80 



Table 14-11. Major Feeding Areas of Shorebirds of Coastal Maine. 



Species 


Mud 


Sand and 


Estuarine 


Riverine 


Marine 


Ter- 




flats 


gravel 


intertidal 


system 


and 


rest- 






beaches 


emergent 
marsh 




estuarine 
rocky 
shore 


rial 


Semipalmated plover 


2 


2 


1 


1 


1 





Piping plover 





2 














American golden plover 


1 








1 





2 


Black-bellied plover 


2 


2 


1 





1 





Ruddy turnstone 


1 


2 








2 





Long-billed curlew 


2 


2 


2 











Whimbrel 


2 


2 


2 








2 


Spotted sandpiper 


1 


2 


2 


2 


2 


2 


Solitary sandpiper 


1 


1 


2 


2 





1 


Willet 


2 


2 


2 








1 


Greater yellowlegs 


2 


2 


2 


2 





1 


Lesser yellowlegs 


2 


2 


2 


2 








Red knot 


2 


2 














Purple sandpiper 


1 


2 








2 





Least sandpiper 


2 


2 


2 


2 


2 





White-rumped sandpiper 


1 


2 











1 


Dunlin 


2 


2 


1 





1 





Pectoral sandpiper 


2 


1 


2 


2 





2 


Short-billed dowitcher 


2 





2 


1 





1 


Stilt sandpiper 


2 





2 











Semipalmated sandpiper 


2 


1 


2 


1 








Western sandpiper 


2 


2 


2 











Buff-breasted sandpiper 


' 














2 


Marbled godwit 





1 


2 











Hudsonian godwit 








2 








2 


Ruff 








1 








1 


Sander ling 


1 


1 








1 





Wilson's phalarope 


1 





2 











Baird's sandpiper 


1 


1 











1 


Killdeer 


1 





2 


2 





2 



0=rarely or never used; l=frequently used; 2=pref erred. 



14-26 







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14-28 



Historical Trends 

Although accurate historical records of shorebird numbers are scarce, several 
accounts indicate they were very abundant from colonial times until the 1870s. 
About that time market hunters were faced with declining waterfowl populations 
and turned to shorebirds. At the same time some species (red knot and white- 
rumped sandpiper) were being hunted on their wintering grounds in Argentina. 
By the 1890s and early 1900s many species of shorebirds became scarce (Norton, 
quoted in Palmer 1949 and Cooke 1915). The eskimo curlew, golden plover, 
whimbrel, and long-billed curlew suffered the greatest losses. The eskimo 
curlew was particularly susceptible to hunting and remains on the verge of 
extinction. 

Laws protecting shorebirds were enacted during the late 1800s and early 1900s. 
In 1900 the Lacey Act outlawed interstate transportation of hunted birds. In 
1918 most of the small sandpipers and certain of the larger plovers, curlews, 
and godwits, came under full protection of the Migratory Bird Treaty Act. 
Hunting seasons on plovers and yellowlegs were allowed until 1927. Since 
that time most species have made remarkable recoveries although they have 
probably not recovered their pre-1870 population levels. Loss or 
deterioration of habitat may prevent a full recovery. 

Present Status of Shorebirds 

Breeding summer residents. The piping plover and spotted sandpiper are 
the two species of shorebirds breeding along the Maine coast that are 
discussed in this chapter. The willet breeds in the Scarboro Marshes just 
outside the characterization area southwest of region 1. Four upland species 
are discussed in chapter 16, "Terrestrial Birds." 

The piping plover nests in loose colonies on the upper portions of sand 
beaches. There are six known nesting areas in Maine, two of which (Popham 
Beach and Sprague River Beach in region 2) are in the characterization area 
(atlas map 4) . In 1976 these two colonies contained four and eight nesting 
pairs respectively (Dorr 1976b). In addition, piping plovers are reported 
each year in appropriate breeding habitat in Reid State Park (region 2), but 
no nests have been reported. 

Piping plovers return to Maine from southern wintering areas in early April. 
Eggs are usually laid in early May but nesting and renesting occurs throughout 
the month. The eggs (3 or 4) are incubated for 27 days. Although the young 
are capable of leaving the nest and feeding themselves almost immediately 
after hatching, they remain under parental attention for at least 6 weeks. 
They depart from Maine in mid- to late August. 

Populations of piping plovers have been declining along the east coast over 
the last few decades and the species has been placed on the National Audubon 
Society's Blue List for New England (Arbib 1978). Increased recreational use 
of beaches by bathers, off road vehicles, fishermen, and pets disturb breeding 
colonies and reduce nesting success. Opening private beaches to the general 
public will certainly result in additional disturbances to piping plover 
breeding areas. 



14-29 

10-80 



In contrast to the specialized breeding habitat required by the piping plover, 
the spotted sandpiper nests in a wide variety of coastal and inland habitats, 
usually as solitary pairs. They nest along rocky shores, in estuarine 
emergent wetlands, on small islands, and along the shores of inland lakes and 
streams. Spotted sandpipers are very common in Maine and are not currently 
threatened by human activities. 

Spotted sandpipers usually migrate singly or in small groups and arrive on the 
Maine coast in late April and early May. Eggs (3 to 4) are laid in mid- to 
late May and hatch in mid-June. The young leave the nest the same day they 
hatch and are capable of feeding themselves but are under parental care for 
about 6 weeks. Spotted sandpipers leave the Maine coast by mid-September for 
southern wintering grounds. 

Winter residents . The purple sandpiper is the only species of shorebird 
that regularly winters along the coast of Maine. A few individuals or small 
groups of dunlins, sanderlings, or ruddy turnstones may winter along the 
coast, especially in southwestern Maine (regions 1 and 2). 

Eastern Maine (regions 4 through 6) and adjacent New Brunswick support one of 
the largest known wintering populations of purple sandpipers in North America. 
Small numbers begin to arrive along the outer islands and rocky coastline in 
late July and August but most arrive in October and November. They remain 
along the Maine coast until April or early May. 

Purple sandpipers are generally found in rocky intertidal areas along exposed 
coastlines. Most of the wintering areas known to be important for purple 
sandpipers are along the mainland (atlas map 4). Offshore islands also are 
used but their overall importance is unknown. Purple sandpipers also may be 
found on sand and gravel bars where they feed on amphipods , mussels, and 
barnacles. Flocks of less than 100 are most common, although occasionally as 
many as 500 to 1000 may be seen. 

Migratory residents . The greatest numbers of shorebirds and shorebird 
species are found along the Maine coast during migration. Some 20 species 
occur regularly in Maine during either the spring or fall migration and 
another six species are occasional or rare visitors (table 14-10; figure 14- 
4). 

The northern phalarope is the most abundant species of migrant shorebird, 
although it is not widely distributed in inshore waters along the coast. The 
waters in the mouth of Passamaquoddy Bay near Eastport (region 6) support an 
estimated one-half to 2 million phalaropes annually, which may constitute the 
largest concentration in the North Atlantic (Morrison 1977). Over 1 million 
birds also have been observed near Mount Desert Rock (region 4; Finch et al. 
1978) and in the waters southwest of Grand Manan, New Brunswick. Phalaropes 
congregate in areas where tidal upwellings concentrate foods such as 
euphausiid shrimp. 



14-30 



a. < 
< 5 



z 

3 



O 
< 



< 



O 

o 



o 
o 



> 
o 
z 



o 

iu 
Q 



Semipalmated plover 
Piping plover 
Golden plover 
Black-bellied plover 
Ruddy turnstone 
Whimbrel 
Spotted sandpiper 
Solitary sandpiper 
Willet 

Greater yellowlegs 
Lesser yellowlegs 
Red knot 
Purple sandpiper 
White-rumped sandpiper 
Least sandpiper 
Dunlin 

Dowitcher sp 
Stilt sanapiper 
Semipalmated sandpiper 
Western sandpiper 
Butt-breasted sandpiper 
Baird s sandpiper 
Marbled godwit 
Hudsonian godwit 
Rutt 

Sanderling 
Pectoral sandpiper 




Abundant to 
common 



common to 
uncommon 



uncommon, 
occasional or rare 



Figure 14-4. Relative abundance and migration of the migratory 
shorebirds of coastal Maine from April through 
November. Band width reflects relative abundance 
for individual species only, (adapted from Morrison 
1976a, McNeil and Burton 1973, Palmer 1949, and - 
Gobeil 1963). 

14-31 



10-80 



The semipalmated sandpiper is also abundant along the Maine coast. Between 
300,000 and 500,000 birds pass through the characterization area each year, 
which constitutes 6% to 10% of the total population migrating along the 
eastern U.S. (Spaans 1979). Tens of thousands of semipalmated plovers, short- 
billed dowitchers, black-bellied plovers, and ruddy turnstones also use the 
Maine coast during migration. 

The Maine coast is more important to migrating shorebirds during the fall than 
during the spring. This is because most species follow an elliptical 
migration route, moving south along the east coast of the U.S. in the fall and 
returning through the central plains States in the spring. 

The "fall" migration is actually a summer and fall migration, beginning in 
July and extending through November. The earliest migrants are the short- 
billed dowitcher, lesser yellowlegs, and least sandpiper, which begin arriving 
the first week of July. Semipalmated sandpipers, semipalmated plovers, 
whimbrels, sanderlings, red knots, and greater yellowlegs follow in mid-July. 
The ruddy turnstone and hudsonian and marbled godwits arrive in late July or 
early August, and the black-bellied plover and white-rumped sandpiper arrive 
in early to mid-August. The greatest numbers of birds are usually present 
between 25 July and 25 August, although the timing may vary up to a week or 
ten days, depending on weather conditions. 

For most species of shorebirds, the adults and juveniles migrate at different 
times in the summer-fall migration. The adults leave the breeding grounds 
before the young are capable of sustained flight, and the juveniles follow 3 
to 4 weeks later. This produces two "peaks" in the numbers of migrants (table 
14-13). Exceptions to this are the short-billed dowitcher, which has three 
peaks (comprised of adult males, adult females, and juveniles), and the dunlin 
and purple sandpipers, which have a single peak in October or November. 

The spring migration period is much shorter than the fall, beginning in mid- 
April and extending through early June. The greatest numbers of birds are 
present between mid-May and the first week of June and all species have only 
one peak. 

The importance of the Maine coast to migrating shorebirds stems from the 
abundance of feeding and roosting habitats. Commonly used feeding areas 
include mudflats, salt marshes, sand and gravel beaches, mussel bars, and 
blueberry fields and bogs, while major roosting habitats are gravel and sand 
beaches, salt marshes, rocky shores, fields, and pastures. Each species has 
preferred feeding and roosting habitats (tables 14-11 and 14-12), and the 
importance of a region to a particular species depends on the abundance of its 
preferred habitats in that region. In general, intertidal mudflats, 
sandflats, bogs, and blueberry barrens are more common in regions 5 and 6, 
while sand and gravel beaches and salt marshes are more common in regions 1, 
2, and 3. 

Specific areas known to be used consistently by large numbers of migrating 
shorebirds are listed by regions in the appendix table 2 and are plotted on 
atlas map 4. This list is not complete since information is not available on 
much of the coast. 



14-32 



Table 14-13. Maj or f a n Migration Periods of the Shorebirds of 



Coastal Maine c 



Species 



Adults 
mo/dav 


Juveniles 

mo/dav 


7/25 - 


8/22 


8/25 - 9/15 


8/10 - 


9/10 


9/15 -10/06 


7/25 - 


8/25 


8/25 - 9/15 


8/15 - 


9/10 


9/25 -10/20 


7/20 - 


8/15 


9/01 - 9/15 


7/20 - 


8/20 


8/25 - 9/15 


8/10 - 


9/10 


10/10 -11/10 


7/15 - 


8/20 


8/25 - 9/15 


7/10 - 


8/15 


8/10 - 8/25 


7/20 - 


8/20 


8/20 - 9/15 



Semipalmated plover 
Black-bellied plover 
Ruddy turnstone 
Greater yellowlegs 
Lesser yellowlegs 
Red knot 

White-rumped sandpiper 
Least sandpiper 
Short-billed dowitcher 
Semipalmated sandpiper 



a Modified from Morrison 197 6a, 



14-33 



10-80 



Region 1 contains 12 feeding areas and 6 roosting sites. Greatest 
concentrations of birds and bird species are usually found at Back Cove 
(Portland) , Presumpscot River flats (Portland) , Fore River (South Portland) , 
Middle Bay (Brunswick), and Maquoit Bay (Brunswick). Although shorebird 
concentration areas are poorly documented in region 1, especially west of 
Mackworth Point, MDIFW is conducting systematic waterbird surveys (including 
shorebirds) of the Casco Bay region every two weeks from September, 1979, to 
October, 1980. 

Region 2 has 10 major feeding areas and 5 roosting areas. Major feeding areas 
include the tidal flats along the Kennebec River, Spirit Pond (Phippsburg) , 
Popham Beach, Sprague River Beach, Reid State Park, Hermit Island Flats 
(Phippsburg) , New Meadows River (West Bath) , and Winnagance Creek (South 
Bath). Roosting areas are generally poorly known for this region. The 
largest roosting area (5000+ birds) known is on Morse River Beach at Small 
Point. 

The two piping plover breeding colonies of the characterization area are 
located in region 2 at Popham Beach and Sprague River Beach. 

Region 3 is characterized by rocky headlands and rock bound islands with 
relatively few intertidal mudflats and salt marshes. There are 14 feeding 
areas and 3 roosting areas. The mudflats along the St. George River in 
Thomaston, the intertidal flats at Spruce Head (St. George) and the intertidal 
flats and saltmarshes along the Weskeag River (South Thomaston), are the major 
shorebird areas. Up to 12,000 semipalmated sandpipers and 1000 semipalmated 
plovers have been observed along the St. George River. The region is also 
important for ruddy turnstones and purple sandpipers. 

Region 4 is a large region with 13 important feeding areas and 3 major 
roosting areas. Shorebird areas in this region are poorly documented. The 
most important areas (based on historic accounts) are Rockland Harbor, 
Brookline, and the Bagaduce River estuary. Because of its large number of 
islands this region supports large flocks of wintering purple sandpipers, 
migrating ruddy turnstones and least sandpipers, and breeding spotted 
sandpipers. The Penobscot River valley is an important inland migration 
corridor for spotted sandpipers and killdeer. In addition, many least 
sandpipers migrate along the shores of the Penobscot. 

Region 5 has 33 major feeding areas and 14 important roosting sites (areas of 
more than 1000 birds). The number of roosting areas is probably 
underestimated. The coastal zone east of Mt. Desert Island (Trenton Bay to 
Perry; region 6) is probably the most important fall migratory stopover area 
in eastern U.S. for semipalmated sandpipers, semipalmated plovers, white- 
rumped sandpipers, and whimbrels. It is also very important for short-billed 
dowitchers, black-bellied plovers, and ruddy turnstones. 

The largest known semipalmated sandpiper and semipalmated plover roost in the 
eastern U.S. is located in Wards Cove (east Carrying Place Cove on Ripley 
Neck), Harrington (region 5). More than 40,000 semipalmatd sandpipers and 
2400 semipalmated plovers have been reported from this location. The 
extensive flats along the Pleasant and Harrington Rivers, Mill Creek, Flat 
Bay, Back Bay, and Narraguagus Bay (Harrington-Milbridge area) are also 
important feeding areas for the above species , as well as for short-billed 

14-34 



dowitchers, greater and lesser yellowlegs, and black-bellied plovers. The 
intertidal flats in Steuben, Dyer Bay, Sullivan, and Sorrento are important 
feeding areas for semipalmated plovers, black-bellied plovers, red knots, and 
yellowlegs. Petit Manan Point is a regular stopover area for whimbrels, red 
knots, and godwits. The large mussel and barnacle populations on the Bar 
Harbor gravel bar attract an abundance of turnstones (up to 600). Many small 
sandpipers and plovers roost on offshore ledges and small islands (i.e., Dry 
Ledges in Harrington). 

Region 6 has 36 major feeding areas and 40 roosting sites. Large 
concentrations of semipalmated sandpipers (more than 50,000 birds) have been 
observed at Half-Moon and Carrying Place Coves in Eastport, the Lubec Narrows 
in south Lubec, and Machias Bay. The most important known roosting areas in 
this region are Sprague Neck and the mouth of Holmes Stream (both in Holmes 
Bay, Cutler), four locations on the Lubec flats (South Lubec and Campobello 
Island), Johnson's Cove Beach (Eastport), and Pleasant Point (Perry). 

Role of Shorebirds in the Ecosystem 

Shorebirds feed primarily on amphipods and oligochaete worms, which in turn 
feed on detritus. Mudflats that are heavily used by shorebirds have high 
numbers of these detritovores and low amounts of detritus (personal 
communication from M. J. Risk, McMaster University, Hamilton, Ontario, Canada. 
May 1979; and Yeo 1978). Migratory shorebirds convert much of their food into 
fat, which provides energy for the long flights to South American wintering 
grounds. As a result this energy is lost from the local estuarine 
environment. The magnitude of this loss and the effect on the estuarine 
environment have not been determined. Studies in nearby Nova Scotia have 
shown that populations of preferred prey ( Corophium volutator, a small 
amphipod) can be measurably reduced where shorebirds concentrate in large 
numbers. The greatest concentrations of shorebirds are on the last mudflats 
to be covered by the rising tide, and the first flats open after high tide. 

WADING BIRDS 

Wading birds include the herons, egrets, ibises, and bitterns, (order 
Ciconiiformes) . They have relatively long legs and necks and small bodies. 
Six species of wading birds breed in coastal Maine, and six others are 
nonbreeding summer residents or visitants (table 14-14). None are regular 
winter residents. They feed in shallow water in marine and estuarine 
intertidal areas and palustrine, riverine, and lacustrine systems. Wading 
birds feed on a variety of prey including reptiles, fish, insects, other 
invertebrates, birds, small mammals, and some plant material. Because wading 
birds are top level consumers, biocides tend to accumulate in their tissues. 
For this reason, wading birds could serve as indicators of levels of 
environmental contamination. 

Historical Perspective 

Like seabirds and shorebirds, wading birds were hunted for food, for bait, for 
sport, and for their feathers (the millinery industry) during the 1800s. In 
addition, many nesting colonies were disturbed or destroyed by vandals. Early 
reports (summarized by Palmer 1949) suggest that wading birds declined in Knox 
County (region 4) between 1820 and 1851, in western Maine between 1885 and 

14-35 

10-80 



Table 14-14. 



Resident Status and Relative Abundance of Wading Birds 
in Coastal Maine for Regions 1 to 3, and 4 to 6 . 



Resident status 
and species 



Relative abundance 



Breeding 
1 to 3 4 to 6 



Nonbreeding 
1 to 3 4 to 6 



Breeding residents 

Great blue heron 

( Ardea herodias ) 
Green heron 

( Butorides striatus) 
Least bittern 

( Ixobrychus exilis ) 
American bittern 

( Botaurus lentiginosus ) 
Black-crowned night heron 

( Nycticorax nycticorax ) 

Snowy egret 

(Egretta thula) 

Nonbreeding residents 



2 


2 


2 


2 


1 





1 


2 


1 


1 


1 






Little blue heron 

( Florida caerulea ) 
Cattle egret 

( Bubulcus ibis ) 
Great egret 

( Casmerodeus albus) 
Louisiana heron 

( Hydranassa tricolor) 
Yellow-crowned night heron 

(N. violocea ) 
Glossy ibis 

( PI egad is falcinellus) 



1 





1 


1 


1 





1 





1 





1 






0=rare or absent; l=uncommon; 2=common. 



14-36 



1908 (Brewster 1924), and in Casco Bay (region 1) between 1880 and 1900 
(Kendall 1902). Norton reported that wading birds showed a marked increase 
for three decades after protection, which was followed by another decline for 
which he gave no explanation (Palmer 1949). During this period the only 
colonially nesting species were the great blue heron and black-crowned night 
heron. 

Wading birds in general are probably more abundant in Maine today than in any 
previous period. Evidence for this is indirect, however, as no systematic 
inventories were conducted until the mid-1970s. Currently, all species of 
wading birds, except the black-crowned night heron, are increasing in Maine. 
The number of species breeding along coastal Maine is also increasing. The 
snowy egret first nested in Maine in the early 1960s. The glossy ibis, little 
blue heron, and Louisiana heron now breed in Maine south of region 1, and 
nonbreeding individuals of these species have been observed in all six regions 
of the characterization area. 

Present Status of Wading Birds 

Breeding birds . Of the six species of wading birds breeding in the 

characterization area, the great blue heron, black-crowned night heron, and 

snowy egret nest in single or mixed-species colonies, and the green heron and 
least and American bitterns nest solitarily. 

There are 22 nesting colonies of wading birds in the characterization area, 
most of which (90%) are on islands. The location of each colony is plotted on 
atlas map 4. The great blue heron is the most abundant colonial nesting 
wading bird (table 14-15). Over 900 pairs nested in 19 different colonies 
during 1977 (Korschgen 1979; and Tyler 1977), which constituted the largest 
breeding population of any state north of New Jersey (Osborn and Custer 1978) . 
Seventy-nine pairs of black-crowned night herons nested in four colonies along 
coastal Maine in 1977, and seven pairs of snowy egrets nested in two colonies. 
The snowy egret is at the northern limit of its breeding range in Maine. 
However, it is extending northward and can be expected to nest in other 
locations in the characterization area in the future. Three other species of 
colonial nesting wading birds, the little blue heron, Louisiana heron, and 
glossy ibis, are also extending their breeding ranges northward. These 
species currently nest along the Maine coast south of the characterization 
area . 

Breeding populations of green herons, and least and American bitterns are more 
difficult to determine than those of colonial nesters and are currently 
unknown. The green heron is common around estuarine intertidal emergent 
wetlands, where it nests in trees. It also may be found in palustrine 
wetlands. The least and American bitterns nest on the ground in emergent 
vegetation such as cattails, bulrushes, and sedges. The American bittern is 
fairly common in palustrine habitats and, to a lesser extent, in estuarine 
intertidal emergent wetlands. The least bittern is known to nest at only two 
locations in Maine; a brackish marsh in Newcastle (region 2) and Bear Brook 
Pond in Acadia National Park (region 5). 

Wading birds arrive on their nesting grounds in early to mid-April. Eggs are 
laid in late April and early May and hatch between late May and June. Young 
fledge from mid-July through early August. Most herons leave Maine in October 

14-37 



10-80 



and November to winter in southern States. A few (mostly great blue herons) 
attempt to overwinter. 

Feeding Habits 

Wading birds usually feed by 'standing and waiting' and 'walking or stalking.' 
Other methods include 'disturbing and chasing,' 'aerial feeding,' 
'plunge/diving,' and 'swimming.' Most feed in the daytime but the black- 
crowned night heron feeds in the evening and at night (Kushlan 1976). 

Wading birds may feed with others of their own or different species and 
sometimes with terns (Bertin 1977), pied-billed grebes (Mueller et al. 1972), 
mergansers (Emlin and Ambrose 1970), or shorebirds. In these associations 
different species may feed directly on the same prey or feed on prey disturbed 
by other waterbirds. 

In Maine estuaries, wading birds feed mostly on killifish, minnows, eels, 
crustaceans, insects, and occasionally birds, small mammals, and plant 
material (tables 14-16 and 14-17) . In palustrine, riverine, and lacustrine 
habitats they feed on a variety of fish, frogs, tadpoles, small mammals, 
birds, crustaceans, and insects. On land they take a variety of amphibians, 
small mammals, and insects. 



Table 14-15. . Estimated Number of Pairs of Wading Birds (number of colonies 

in parenethesis) Breeding in Each Region of the Characterization 
Area in 1977 5 . ] , 

Species Region Total 



Great blue heron 95 75 150 188 340 57 905 

(2) 1 (1) (7) (4) (3) (19) 

Black-crowned 41 30 8 79 

night heron (2) (1) (D W 

Snowy egret 6 1 ' 

(1) (1) (2) 



'Tyler 1977; Korschgen 1979, 



14-38 



Table 14-16. Preferred Feeding Habitats of Wading Birds of Coastal Maine 



Species 



Intertidal Marshes Pools Streams Fields 
mudflats 



Great blue heron 

Green heron 

Little blue heron 

Cattle egret 

Great egret 

Snowy egret 

Louisiana heron 

Black-crowned night heron 

Yellow-crowned night heron 

Least bittern 

American bittern 

Glossy ibis 



+ 
+ 
+ 

+ 
+ 
+ 
+ 
+ 



+ 


+ 


+ 


+ 


+ 


+ 


+ 


+ 


+ 


+ 






+ 


+ 




+ 


+ 




+ 


+ 




+ 






+ 






+ 






+ 


+ 


+ 



+ 



+ 



+ 



14-39 



10-80 



Table 14-17. Preferred Food of Wading Birds of Coastal Maine 



Species 



Inverte- Fish Reptiles 

brates and 

amphibians 



Birds Mammals 



Great blue heron 


+ 


+ 


+ 


Green heron 


+ 


+ 




Little blue heron 


+ 


+ 




Cattle egret 


+ 






Great egret 


+ 


+ 


+ 


Snowy egret 


+ 


+ 


+ 


Louisiana heron 


+ 


+ 


+ 



Black-crowned 
night heron 

Yellow-crowned 
night heron 

Least bittern 

American bittern 

Glossy ibis 



+ 



+ 



+ + 

+ + 

+ + 

+ + 



+ 



+ 
+ 
+ 



+ 



14-40 



HUMAN IMPACTS ON WATERBIRDS 

Since the late 1800s many human activities have had both positive and negative 
effects on waterbird populations. Disturbance during the breeding season, 
loss of valuable feeding and nesting habitat, and environmental contamination 
by oil, heavy metals, and organochlorine compounds are currently the major 
threat to waterbirds in Maine. Some of the positive effects of people in 
coastal Maine include the protection of waterbirds by law, the preservation of 
certain key waterbird colonies, and the inadvertent creation of upland feeding 
areas for shorebirds partial to cleared land. 

This section will discuss how habitat loss, environmental contamination, and 
disturbances by people affect waterbirds. 

Habitat Loss 

Excessive loss of important breeding, feeding, and nesting habitat is 
detrimental to most waterbirds. Losses include the complete elimination of a 
specific habitat such as the filling of a wetland or construction on most 
small islands. Sheep grazing or timber harvesting on bird islands may 
seriously reduce nesting cover. Terns, laughing gulls, and Leach's storm 
petrels have been affected the most by these activities (Drury 1973) . 

Tidal Power 

Tidal power, which is yet to be developed in Maine, is given special 
consideration here because the feasibility of developing several large scale 
tidal power projects has been under investigation (Cobscook Bay in region 6 
and Taunton Bay in region 5). 

Impoundments created by tidal barrages are likely to adversely affect birds 
that feed on intertidal mudflats and in the vicinity of deepwater tidal rips. 
The degree to which an estuary or the adjacent marine deepwater ecosystems 
will be affected depends on characteristics of the estuary and the type of 
generation facility used (e.g., turbine type, one or two pool impoundments, 
and position of the sluice). Several generalizations based on existing and 
planned tidal obstructions may be made. 

The area of intertidal mudflats that is presently exposed is likely to be 
reduced because tidal amplitude is reduced (especially along the lower tide 
range), water is temporarily impounded and will cover mudflats (feeding areas 
will be available for shorter periods of time) , and water may be inadvertently 
obstructed by the barrage (i.e., the area below lower turbine level) or 
deliberately retained for peak power generation beyond the normal period of 
low tide. 

Increased sedimentation behind the impoundment may alter the species 
composition and abundance of mudflat invertebrates (Yeo 1978; Risk et al. 
1977). Such changes occurred in a barrage-like impoundment in the northern 
Bay of Fundy (Yeo 1978). Lower densities and biomass of important shorebird 
foods, such as the small amphipod Corophium volutator , were found in the 
substrates behind the obstruction. Lower shorebird numbers also have been 
reported in that area (personal communicatione from S. Boates , Acadia 
University, Wolfville, Nova Scotia, Canada; June, 1979). Species most likely 

14-41 

10-80 



to be adversely affected by loss of habitat and changes in food availability 
due to tidal barrages include shorebirds (particularly semipalmated 
sandpipers, semipalmated plovers, and black-bellied plovers), Bonaparte's 
gulls, herring and black-backed gulls, and great blue herons. Altered tidal 
flow and regimes that cause changes in such factors as salinity, turbidity, 
temperature, and nutrient content interact to affect invertebrate communities. 
This, in turn, affects their avian predators. 

Species feeding in or among tidal rips, tidal convergences, and tidally- 
related upwellings might be adversely affected if these oceanographic features 
are altered. One of the largest inshore tidal rips and upwelling areas in the 
eastern U.S. occurs in waters off Eastport, Maine (region 6). Tides ebbing 
from Cobscook Bay converge with waters draining Passamaquoddy Bay to form rips 
and convergence lines. High tidal ranges and local bottom topography 
contribute to the dynamics of this system. This area is a major feeding area 
for northern phalaropes, Bonaparte's gulls, herring and black-backed gulls 
(10,000 to 50,000), kittiwakes, and dovekies. Altering the timing of water 
draining either bay may affect the position, extent, and duration of the tidal 
rips, which may sharply reduce the abundance of food on which these birds 
feed. 

Tidal amplitude outside the enclosed area also is likely to increase, which 

may affect the amount and quality of intertidal feeding areas. Estuarine 

emergent wetlands (salt marshes) are likely to be adversely affected by 

altered tidal amplitude, but intertidal mud flats might increase offsetting 
losses inside the barrage. 

Environmental Contamination 

Several types of environmental pollutants may adversely affect survival and 
reproduction of waterbirds. These include oil, pesticides and other toxic 
chemicals, heavy metals, and industrial and domestic wastes. Several 
excellent reviews of the effects of environmental contamination on waterbirds 
(including waterfowl) have been published in technical journals. Much of this 
section was summarized from the review papers of Ohlendorf and coworkers 
(1978a), Howe and coworkers (1978), Farrington (1977), Lincer (1977), and 
Albers (1977 and 1978). 

Oil . Contamination of marine and estuarine systems by oil poses a serious 
threat to waterbirds along the Maine coast. Oil enters coastal waters by 
spillage during transfer operations, discharges from refineries, regular 
discharges from inhabited areas (street runoff, sewage discharge, and 
boating), and by catastrophic spills. The extent of oil contamination in 
Maine is discussed in chapter 3, "Human Impacts on the Ecosystem." Casco Bay 
(region 1) and Penobscot Bay (region 4) have the largest numbers of oil spills 
in Maine. 

The most serious effect of oil spills on waterbirds is feather oiling. Oil 

disrupts the structure of feathers, destroying their insulating properties and 

buoyancy. Moderately or heavily oiled birds drown or die of exposure. The 
latter is potentially serious in the cold waters along the Maine coast. 

A number of oil or petroleum products are toxic to birds. Birds ingest oil 
while preening oil-coated feathers, drinking, or eating oil-covered food, and 

14-42 



may die or suffer physiological or behavioral changes, including reproductive 
failure (Crocker et al. 1974 and 1975; Grau et al. 1977; Miller et al. 1977; 
Szaro et al. 1978a; and Wooton et al. 1979). Birds may also ingest petroleum 
products contained in tissues of fish or marine invertebrates. 

Nesting birds can transfer oil from their feathers or feet to eggs while 
incubating. Small amounts of oil (equal to a few drops) can kill embryos 
inside the eggs (Albers 1977; Szaro and Albers 1977; Albers and Szaro 1978; 
Szaro et al. 1978b; and others). Bird embroys are most sensitive during the 
first 10 days of incubation. 

Oil spills also damage marine and intertidal environments where waterbirds 
feed, nest, and roost. Birds often abandon areas after an oil spill because 
habitat quality is poor and prey populations are reduced (Buck and Harrison 
1967; Abraham 1975; and Hope Jones et al. 1978). Recovery can take as long 
as 10 years. 

Among the waterbird groups, seabirds are probably most vulnerable to oil 
spills because they have a greater chance of coming in contact with oil. 
Seabirds that spend most of the time on the water, such as eiders, cormorants, 
alcids, loons, and grebes, are more susceptible to feather-oiling than species 
that feed on the wing (such as petrels, terns, and, to a lesser extent, 
gulls). All species of seabirds that breed along the coast of Maine could 
suffer reduced reproductive success from egg-oiling if a spill occurred during 
the nesting season (April to June) . 

Shorebirds would be most vulnerable to spills during migration, particularly 
if spills occurred or washed ashore at night when large numbers of birds are 
concentrated on roosts near the waters edge. Wading birds are less 
susceptible to feather oiling than other waterbirds because they have long 
legs and their feathers do not always come in contact with the water, but oil 
could be transferred from their feet to eggs. 

Toxic chemicals . The most important toxic chemicals in marine and 
estuarine systems are the chlorinated hydrocarbons, DDT and its metabolites 
DDD and DDE, and polychlorinated biphenyls (PCBs). Use of DDT has been banned 
in the U.S., so little or no DDT, DDD, or DDE currently enter Maine waters. 
Migratory birds may be exposed to these chemicals in wintering areas outside 
the U.S. PCBs are used primarily for industrial products, such as heat 
exchangers and condensors (Ohlendorf et al. 1978a). Large quantities of PCBs 
enter the marine system primarily in industrial waste, sewage sludge, and when 
plastics are burned and transported in the atmosphere. These chemicals occur 
in concentrations around industralized areas (Howe et al. 1978). 

Chlorinated hydrocarbons are chemically stable, relatively insoluble in water, 
and may remain in the ecosystem for long periods of time. They can accumulate 
in the fat of organisms and concentrations can magnify as they pass from prey 
to predator along the food chain. Very little is lost by way of excretion. 
Concentrations are highest in species of birds such as eagles, ospreys, 
herons, and terns, that feed on fish. For this reason fish-eating species 
make good indicators of the abundance of hydrocarbons. 

Chlorinated hydrocarbons may affect birds directly by killing them or by 
interfering with their reproductive processes (i.e., eggshell thickness) and 

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indirectly by killing their food supply. Direct mortality may occur when 
birds are under unusual physiological stress and fats are being mobilized 
(Ohlendorf et al. 1978b). Stress occurs during migration, periods of food 
shortage (especially in winter when intertidal flats are ice-covered) , during 
reproduction, disease or injury, and after exposure to oil or other 
environmental hazards. Female eiders may be particularly vulnerable because 
they do not feed during incubation. Dead eiders with high concentrations of 
DDT were found on nests in the Netherlands (Howe et al. 1978). Females of 
most species may be vulnerable during the egg-laying period because fat 
reserves are used for egg synthesis. 

Heavy metals . Heavy metals in the environment, particularly mercury and 
lead, have caused biologists to be concerned about effects on birds. Mercury 
enters the environment through a variety of sources, including fungicides, 
germicides, industrial uses, heating or burning of fuels and ores, and from 
oil discharges from ships and refining industries (Merlini 1971; and Howe et 
al. 1978). The most toxic form is methyl mercury (Westoo 1967; and Fimreite 
1974). Mercury may accumulate in birds as it passes through the food web. In 
Maine it is found in eels, mergansers, and eagles (see chapter 15, 
"Waterfowl"). It probably occurs in other waterbirds that feed extensively on 
eels, or those (such as herons) that feed on the same prey as eels. 

Lead enters the environment mostly from industrial, automotive, and municipal 
sources and from lead shot (Howe et al. 1978). Waterfowl mortality from lead 
poisoning may reach between 1.5 and 2 million birds each year in the United 
States (Banks 1979). Lead is not known to accumulate in food chains. Eagles 
may injest lead shot from the flesh of their prey, usually ducks. 

Plastic and other artifacts . Small particulate pollution composed mostly 
of plastic beads and irregular shaped particulates up to 0.2 inches (0.5 cm) 
in diameter is commonly found in plankton samples and is found in the stomachs 
of birds and fish that feed on plankton (e.g., plastic has been found in 
Leach's storm petrels in New Brunswick) and birds that feed on plankton- 
feeding fish. The effects on birds are relatively unknown but intestinal 
blockage may be one possible consequence (Ohlendorf et al. 1978a). Small 
rubber thread cuttings are often ingested by common puffins who mistake them 
for fish (Ohlendorf et al. 1978a). These may accumulate into entangled balls 
of rubber in the gizzard. 

Larger waste materials are problems along beaches where birds may become 
entangled in kite strings, fishing lines, plastic containers, and "six-pack" 
containers. The wrack line is often the source of many potential hazards. 
Birds foraging in dumps may also encounter these hazards. In one common tern 
colony in New York 14 young and 7 adults were found trapped by kite strings 
(Howe et al. 1978). The magnitude of these problems in Maine has not been 
investigated but several instances of entangled birds have been observed. 

Other Disturbance 

Disturbance by people has the greatest adverse impact on a nesting colony. 
Picnicking, bird watching, nature tours, and other activities disturb nesting 
waterbirds. Deliberate vandalism, of course, has the most injurious effect of 
all. Eggs and young are vulnerable to predation (Drury 1973; Hunt 1972; 
Nisbet 1973; Mendall 1976; and Robert and Ralph 1975), chilling and 

14-44 



overheating, and the young may starve if the adults are kept from feeding 
them. The presence of sheep, pets, and pests associated with human habitation 
results in disturbance to, and even destruction of, colonies. Cats and dogs 
have had particularly harmful effects on several former storm-petrel colonies 
(Gross 1935). Least terns, common loons, and piping plovers are especially 
vulnerable because they nest on the mainland, where human disturbance is 
greater. Nesting success of least terns is lower on Popham Beach than on 
nearby Sprague River Beach, perhaps because the former is much used while the 
latter is less so, being privately owned. Breeding success of common loons is 
low in southwestern Maine compared to other parts of the State, primarily 
because of unnatural fluctuations in water levels, harrassment by motor boats, 
numerous shoreline cottages and predation by raccoons attracted by cottages 
and camps. 

Birds are more sensitive to disturbance by people early in the nesting cycle 
(prelaying and laying stages) and will abandon their nests more readily then 
than after the young have hatched. However, many species can renest if nests 
are lost or abandoned early, whereas renesting is seldom attempted if young 
are lost. 

MANAGEMENT 

The U.S. Fish and Wildlife Service and the Maine Department of Inland 
Fisheries and Wildlife are jointly responsible for managing waterbirds along 
the Maine coast. This primarily involves protection. Problems concerning 
management should be directed to those agencies. 

The continued existence of healthy populations of waterbirds along the Maine 
coast depends on maintaining adequate amounts of breeding, feeding, and 
roosting habitats. Development of shorelines and coastal islands, or high 
levels of human activity could cause birds to abandon important habitats. 
Owners of these areas, or those who control access, developers, planners, and 
the general public, need to be made aware of the necessity of protecting 
nesting, feeding, and roosting habitats. 

RESEARCH NEEDS 

More information is available on waterbirds than on most other groups of 
vertebrates found along the Maine coast. Nonetheless, there are areas in 
which further information is needed. 

Basic inventories of nonbreeding, migrating, and wintering seabirds, migrating 
and wintering shorebirds, and nonbreeding wading birds need to be made on a 
regional basis to determine the abundance of various groups throughout the 
coastal zone and the periods during which they are present. The locations and 
seasonal uses of various types of habitats, such as feeding and roosting 
habitats for shorebirds, tidal upwellings, mudflats, brood-rearing areas for 
terns, and post-breeding molting areas for eiders, need to be documented. 

Breeding populations of solitary nesting waterbirds, such as spotted 
sandpipers, common loons, and American bitterns, need to be assessed in 
coastal Maine, and breeding colonies of colonial nesting species need to be 
monitored. 



14-45 

10-80 



The effects of human visitation, pets, livestock grazing, buildings, and other 
human activities on breeding seabirds need to be determined, and the extent to 
which these activities affect current colonies needs to be assessed. 

The influence of human disturbance (dogs, bird watchers, boats, and clam- 
diggers) on concentrations of feeding and roosting shorebirds, and the degree 
of the problem along the coast of Maine needs to be determined. If human 
disturbance is found to be adversely affecting waterbirds, methods need to be 
devised to mitigate or eliminate these disturbances. 



14-46 



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Ontario, Canada. 



14-54 



"VL 



Chapter 15 
Waterfowl 



Authors: Howard Spencer, Jr., John Parsons, Kenneth J. Reinecke 




The waterfowl of coastal Maine (ducks, geese, and swans of the family 
Anatidae) are a higly visible and valuable natural resource. Because most 
waterfowl are migratory, they are managed by regulatory controls and habitat 
protection or improvement by Federal and State agencies and by international 
agreement . 

Waterfowl inhabit a wide range of aquatic habitats and some terrestrial 
habitats, consequently their seasonal distribution and daily movements in 
coastal Maine are controlled largely by the abundance and diversity of 
available habitat, and by habitat change and alterations. The general 
abundance of most species of waterfowl of coastal Maine are largely determined 
by conditions that prevail in their breeding and wintering grounds outside of 
Maine. The diversity of the waterfowl habitat of coastal Maine (feeding, 
breeding, nesting, and wintering grounds in freshwater, estuarine, and marine 
habitats) is demonstrated by the diversity of waterfowl found there. 

This chapter attempts to identify major waterfowl resources and their seasonal 
distribution and abundance along the coast of Maine, their interactions among 
ecosystem components, and their response to human-induced factors and 
management . 

The common and scientific names (American Ornithologists' Union 1957, 1973a, 
1973b, and 1976) and the relative abundance of the waterfowl species among 
resident, breeding, wintering, and migratory populations of coastal Maine, 
based on most recent estimates, are given in tables 15-1 to 15-4. Of the 140 
species of waterfowl now recognized in the world, about 45 breed in North 
America (Johnsgard 1975). Thirty-six of the North American species breed in, 
migrate through, or winter in coastal Maine in sufficient numbers to be 
considered in this report. One of these, the eider duck, is also discussed in 
chapter 14, "Waterbirds" , because of its breeding distribution. 



15-1 



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15-6 



Waterfowl in Maine annually support about 140,000 person-days of hunting and a 
kill of 100,000 retrieved birds. The hunting pressure and kill for coastal 
Maine, which is about two-thirds of the state total, has generated an 
important recreational and hunting industry for a number of coastal 
communities, and emphasizes coastal habitats and estuarine systems as critical 
waterfowl habitat. 

Although waterfowl are a widely recognized resource, needs for their 
protection and management sometimes are controversial. For example, the eider 
duck feeds heavily on cultured mussels, which has raised an unresolved 
conflict of interest. The magnitude of human destruction of the natural 
habitat of waterfowl in some areas of the coast of Maine is disturbing. Oil 
spills, toxic wastes (e.g., pesticides and heavy metals), and increased 
recreational boating are examples of environmental problems. Waterfowl are an 
intergral component of coastal Maine and coastal zone planning and management. 

Much of the data for this chapter were drawn from the Maine Department of 
Inland Fisheries and Wildlife (MDIFW) division files at the Orono Research 
Section. Waterfowl often are associated with seabirds (e.g., gulls, terns, 
and cormorants), shorebirds (e.g., phalaropes, plover, and yellowlegs), and 
raptors (e.g., eagles and hawks), and the interactions of some of these groups 
are described in chapter 14, "Waterbirds" , and chapter 16, "Terrestrial 
Birds." 

Because much of the literature on the waterfowl of Maine has been prepared for 
counties and research units, or for the state as a whole, it is sometimes 
difficult to identify the data with particular regions of the characterization 
study area, but its general application to coastal Maine is reasonably clear. 

Common names of species are used except where accepted common names do not 
exist. Taxonomic names of all species mentioned are given in the appendix to 
chapter 1 . 

WATERFOWL GROUPS 

To better understand waterfowl populations and their interactions with 
ecosystem components, waterfowl populations or species may first be identified 
as "groups" based on migratory habits or residential status. Using these 
criteria, waterfowl are grouped as resident, breeding, wintering, and migrant 
species (Palmer 1949; and Spencer 1975). These groups, as used in this 
chapter, are overly simplified because some or all species or populations are 
migratory at one time or another. 

A brief description of the groups are as follows: 

1. Resident species. Those present throughout the year (table 15-1). 

2. Breeding species. Those that breed in Maine but usually winter 
elsewhere (table 15-2) . 

3. Wintering species. Overwintering migrants (table 15-3). 

4. Migrants. Those species that are usually present only during spring 
and fall migration (table 15-4) . 

15-7 

10-80 



More detailed descriptions of these groups (based upon Palmer 1949; Spencer 
1975; and unpublished data of Maine Department of Inland Fisheries and 
Wildlife) are given below. 

Resident Waterfowl 

Although the term resident, as defined here, is useful, it should not be 
interpreted literally to mean the same individuals of a species remain in 
Maine throughout the year. For example, black ducks and goldeneyes that breed 
in Maine may winter elsewhere, and most black ducks and goldeneyes that winter 
on the Maine coast may breed elsewhere. Only a few waterfowl are permanent 
breeding residents. Black ducks probably come the closest; some breed in 
inland waters but winter along the coast. 

Among the resident species listed in table 15-1, the black duck is by far the 
most important because it is highly sought as a game bird, rates high as a 
table bird, and comprises over 30% of the annual statewide waterfowl kill. A 
ground nester, the black duck is abundant throughout the year in coastal Maine 
and comprises at least 35% of the breeding population. From 10,000 to 30,000 
black ducks winter on the Maine coast. 

The mallard has always been present in Maine but in small numbers. Mixed 
pairs of male mallards and female black ducks commonly occur. The mallard is 
as popular and widely sought as the black duck, but the mallard comprises less 
than 5% of the annual hunting kill. In winter most mallards are scattered 
among the black duck flocks, some of which are domestic mallards turned wild. 

The goldeneye, an inland breeder, is the only resident diving duck in Maine. 
It breeds mostly in northeast Maine but is thought to also breed occasionally 
in eastern and central Maine. Banding data indicate very few goldeneyes 
reared in Maine are brought down by hunters, or winter in Maine. The origin 
of migrating or wintering goldeneyes is not known. This duck contributes only 
about 3% of the annual hunter's kill. The goldeneye, and the smaller 
bufflehead, comprise much of the coastal duck hunting when black ducks are 
scarce . 

The hooded and American mergansers appear to qualify as residents. The hooded 
merganser breeds throughout the state. The American merganser, much less 
abundant than the hooded merganser, also thrives throughout the state but 
tends to avoid the more southerly coastal areas. Although the mergansers are 
not usually considered a desirable table bird because of their fish eating 
habits, they comprise about 2% of the annual hunting take. From 2000 to 3000 
mergansers winter along the coast. 

The American merganser breeds in small numbers along the coast. Among the 
ducks, the size and survival of the broods of individual mergansers are 
unusually high. Factors limiting their general abundance in coastal Maine are 
not known. In winter this duck is common offshore, usually near islands or in 
tidal estuaries. Pilot studies suggest this species may serve as an indicator 
of biocides and heavy metals in coastal waters (personal communication from R. 
B. Owen, Jr., School of Forest Resources, University of Maine, Orono, ME.; 
February, 1979) . 



15-8 



The American eider is Maine's only resident sea duck (ducks that usually 
inhabit nearshore coastal waters). It is abundant as a breeder from Machias 
Bay southwesterly to Cape Elizabeth (see atlas map 4) . It winters in 
abundance from Narraguagus Bay, Washington County, to Cape Neddick, York 
County. Although eiders also are abundant in the winter off Cape Cod, 
Massachusetts, few have been observed in southern Maine. Small numbers are 
observed in Machias Bay but none in Cobscook Bay. 

The Canada goose has been a resident of Maine primarily because of propagation 
and release programs at the FWS Moosehorn National Wildlife Refuge, and a 
transplant program by MDIFW. At least 40 broods comprised of 170 goslings 
were hatched in Maine in 1977 (Spencer and Corr 1977). A few of these birds 
were planted in the characterization area. Most of the Canada geese 
apparently remain in Maine during the year. 

Breeding Species 

The wood duck is by far the most abundant and universally distributed breeding 
duck in Maine, but few inhabit the estuarine or coastal waters (table 15-2). 
They are most abundant as breeders in the central and southwest regions 
(regions 1, 2, and 3) and less numerous in the northeast (regions 4, 5, and 
6). This species heavily utilizes managed beaver impoundment areas and well 
conceived and managed nest box programs. The wood duck is the most numerous 
of the three cavity-nesting waterfowl (the others are the goldeneye and hooded 
merganser). It is one of the most beautiful of waterfowl, a dabbling species 
(feeds on or near the bottom by tipping), and a highly desirable game and 
table bird. Although it is an early fall migrant (it is implied in this 
chapter that fall migrants may fly south as early as July) , and near the 
northern limits of its range, the statewide hunting kill in 1976 was 10,000 
ducks (only black duck and green-winged teal exceeded that number) . In early 
fall, during migration, wood ducks tend to congregate along the coast where 
most of the wood ducks are taken by hunters. Hunting mortality would be 
higher if the wood ducks did not migrate south so early in the hunting season. 

The blue-winged and green-winged teal make up a small but regular component of 
the waterfowl breeding population of coastal Maine. The blue-winged teal is a 
predominantly freshwater bird that prefers shallow, grass/sedge, emergent, 
palustrine wetland as breeding habitat. It is a very early fall migrant and 
is abundant in the coastal areas only in late August and early September. Due 
to their early migration, they are not a reliable part of the hunter's 
harvest. For example, the annual estimated Statewide blue-winged teal killed 
from 1975 to 1977 was 2483, 2814, and 663 respectively. 

The green-winged teal, as a breeder, is less numerous than the blue-wing in 
coastal Maine. The green-winged teal prefers smaller palustrine wetlands for 
breeding purposes and is often found in the shrub/scrub class of palustrine 
habitat. Apparently the migrant contingent of the species is fairly abundant 
in coastal waters from late August until mid-November. Although they seem to 
prefer inland freshwater habitats, they occasionally inhabit estuarine areas. 
The green-winged teal traditionally is the second most important duck for 
hunting in Maine. Although it probably is the smallest of game ducks, it is 
highly sought in Maine and is an excellent table bird. Hunters killed 8000 to 
12,000 green-winged teal annually from 1975 to 1977, contributing 11% to 14% 
of the state total. 

15-9 



10-80 



The ring-necked duck, a diving species, breeds throughout coastal Maine, but 
prefers the deeper palustrine and riverine marshes. Most local birds migrate 
south in September and all are usually gone by the end of November. This 
species, rarely observed on saltwater in Maine, makes up from 1% to 4% of the 
hunter's bag. Region 6 supports the major coastal breeding population. 

Wintering Species 

Among the wintering species, only the bufflehead, old squaw, and white-winged 
scoter are widely distributed and relatively abundant in the coastal area. 
Although greater scaup occur mostly in flocks of over 100 birds, they are 
traditionally observed in only a few specific areas, which may reflect rather 
specific habitat requirements in the winter. 

Although not classified as wintering species, as given in table 15-3, large 
numbers of other species winter in the estuaries and bays of the Maine coast. 
Major overwintering birds, in order of abundance from 1975 to 1977, are eiders 
and black ducks, which make up the majority, goldeneyes, scaups, and 
buf f leheads . 

Migrants 

Among the migrant species of coastal Maine, brant, greater snow geese, and 
lesser scaup are observed regularly in flocks up to several hundred but 
generally only in specific areas at specific times (table 15-4). Pintails, 
and other migrant waterfowl not mentioned above, occur incidentally as singles 
or small flocks (<10) in estuaries and coastal waters. 

WATERFOWL ASSESSMENT 

The problems associated with monitoring and managing waterfowl populations 
were reviewed by the U.S. Fish and Wildlife Service in a recent environmental 
impact statement (U.S. Fish and Wildlife Service 1975), part of which says: 

"The situation with migratory birds is similar to that for 
most other wild animal populations in which the condition 
of the resource is monitored by a variety of techniques 
that yield information used in evaluating the status of 
each population. ...Habitat surveys, indices of 
population size, band recovery rates, production 
estimates, survival estimates, and harvest information are 
used to evaluate population status." 

All of the above methods have been used to some extent by the Maine Department 
of Inland Fisheries and Wildlife (MDIFW) to assess Maine waterfowl 
populations. Since the early 1970s, as a result of comprehensive waterfowl 
planning by FWS, most surveys and investigation data have been recorded and 
analyzed on a "wildlife management unit" basis. These units are shown in 
figure 15-1 for comparison with the regional boundaries of the 
characterization area. Figure 15-2 gives a simlar comparison of the 
characterization area with winter waterfowl inventory units established by the 
MDIFW in 1952. Figure 15-3 shows how the coastal county boundaries are 
positioned in relation to the characterization area. Selected data from MDIFW 
investigations are summarized and discussed below. 

15-10 




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10-80 



The winter inventory is an aerial survey conducted annually by much the same 
personnel over the same area during the first two weeks in January. It 
provides the only direct visual estimates of Maine's waterfowl populations. 
Waterfowl counts are made at elevations between 100 and 300 feet. The entire 
shoreline, including islands and ledges, are surveyed in each wildlife 
management unit. A number of factors may influence the accuracy of the 
counts . 

Light and tide conditions vary constantly during the course of the survey, and 
several species form into common flocks. Color patterns and flight 
characteristics of goldeneyes, bufflehead, and mergansers are most easily 
differentiated. Other common waterfowl of Maine are readily identifiable 
because they occur in small flocks, usually less than 100. In Chesapeake Bay 
and Bear River marshes, flocks number in the tens of thousands, whereas in 
Maine, flocks rarely reach 500 individuals, and most are much smaller. 
Because of probable error and limitations just described, statistical 
appraisal is not applicable. The annual wintering population estimates for 
major species from 1952 to 1979 are shown in table 15-5. The annual 
population estimates of 8 species of wintering waterfowl are given for each 
waterfowl inventory unit (figures 15-4 to 15-11). 

Among the species in the winter inventory, the black duck is perhaps the 
easiest to identify, consequently, winter estimates of its abundance are 
likely to be most accurate. The increase in black duck counts Statewide from 
1960 to 1975, and the sharp decline in Casco Bay, Muscongus Bay, and Penobscot 
Bay units since 1975 are unexplainable . The winter population estimates for 
most duck species were much higher in 1975 than in 1979 (table 15-5). It is 
not known whether the wintering population changes reflected by the data were 
caused by weather or other factors in the wintering grounds, or by habitat 
alteration or breeding failures in other areas of its overall range. 

Breeding Populations 

The status of waterfowl breeding populations in coastal Maine and the wildlife 
management units is best assessed by using the results of a recent compilation 
of 21 years of production data (MDIFW) . The numbers of broods of each species 
were counted periodically and listed by wetland type or by wildlife management 
unit. The data in tables 15-6 to 15-8 are used in this analysis. The species 
composition of breeding waterfowl populations in the coastal wildlife 
management units in 1956 to 1965 and 1966 to 1976, and the State as a whole, 
are given in table 15-6. Breeding ducks were largely black ducks, wood ducks, 
ring-necked ducks, and goldeneyes. The data also show a sizeable reduction in 
the percentage of black ducks and wood ducks from 1956 to 1965 and 1966 to 
1976, and an increase in ring-necked and goldeneye ducks. Although changes 
were shown for other waterfowl, the numbers were too small for analysis. 

The duck brood estimates (eider excluded) for the waterfowl of Maine are based 
on the average number of duck broods per acre for seven inland wetland types 
from 1956 to 1965 and from 1966 to 1976 (table 15-7). These estimates 
probably are conservative because there are no data from several tidal wetland 
types which are known to produce young, and because the estimates are based on 
actual counts (many could have been missed) . 



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15-24 



Table 15-6. The Percentage Composition of Breeding Waterfowl Species, Based 
on Brood Counts, in Each Wildlife Management Unit (6 to 8), for 
the Units Combined, and Their Percentage Contribution to State 
Totals as Compiled from Maine Department of Inland Fisheries 
and Wildlife data from 1956 to 1965 and 1966 to 1976. 



Species 



1956 to 1965 



WMU 



Combined 
units 

6 to 8 



Statewide 



Black duck 
Ring-necked duck 
Wood duck 
Goldeneye 
Hooded merganser 
Blue-winged teal 
Common meganser 
Mallard 



38 


53 


62 


48 


36 


15 


2 


21 


21 


17 


32 


21 


- 


tr 


- 


tr 


4 


3 


- 


3 


1 


12 


4 


6 


tr 


- 


- 


tr 



44 

17 

20 

8 

8 

3 

tr 

tr 



Percentage of State 

Total 13 17 



39 



100 



1966 to 1976 



Black duck 
Ring-necked duck 
Wood duck 
Goldeneye 
Hooded merganser 
Blue-winged teal 
Common merganser 
Mallard 



25 


24 


57 


26 


64 


36 


4 


44 


4 


15 


3 


12 


- 


5 


4 


3 


6 


2 


11 


4 


1 


19 


- 


11 



29 

25 

12 

18 

8 

4 

3 

tr 



Percentage of State 
Total 12 



32 



100 



15-25 



10-80 



Table 15-7. Average Number of Broods of Ducks Per Acre Per Year in Different 
Wetland Types for Each Wildlife Management Unit (6 to 8) from 
1956 to 1965 and 1966 to 1976. 



Wetland Type' 



Wildlife Mgt. Unit 



Units 
6-8 
Combined 



All units 

d-8) 
Statewide 



1956 to 1965 



2 


Fresh meadows 




- 


0.61 


1.91 


0.85 


0.27 


3 


Shallow fresh 


meadow 


- 


0.45 


1.53 


0.54 


0.15 


4 


Deep fresh marsh 


1.08 


0.74 


0.46 


0.66 


0.30 


5 


Open water 




0.33 


0.52 


0.58 


0.38 


0.31 


6 


Shrub swamp 




0.73 


0.60 


1.07 


0.67 


0.18 


7 


Wooded swamp 




- 


0.54 


- 


0.53 


0.75 


8 


Bog 




- 


- 


0.17 


0.17 


0.10 



Average 



0.37 



0.50 



0.58 



0.46 



0.21 



1966 to 1976 



2 Fresh meadows 

3 Shallow fresh marsh 

4 Deep fresh marsh 

5 Open water 

6 Shrub swamp 

7 Wooded swamp 

8 Bog 



- 


0.53 


3.34 


2.24 


0.23 


- 



0.42 



0.90 



0.20 



0.57 


0.12 


2.63 


0.14 


0.23 


0.14 


0.41 


0.13 


0.20 


0.48 


- 


4.29 



Average 



0.28 



0.59 



0.81 



0.43 



0.13 



Wetland types after Shaw and Fredine (1956) and McC'all (1972); see 
table 15-9 for National Wetland Inventory equivalents. 



15-26 



Table 15-8. Acres and Numbers (in parentheses) of Different Wetland Types 
for Wildlife Management Units 6 to 8 and Contribution to the 
State Total (adapted from Maine Department of Inland Fisheries 
and Wildlife Wetland Inventory Files). 







Wildl 


ife Mgt. 


Units 




Percent- 






Wetland type 








Units 
6-8 


age of 
State 


State 










total 






6 


7 


8 




Total 




2 


Fresh meadow 


5757 


5539 


6467 


17,763 


31 


57,683 






(90) 


(77) 


(97) 


(264) 


(20) 


(1273) 


3 


Shallow fresh 


3775 


4738 


2379 


10,892 


47 


22,956 




marsh 


(52) 


(63) 


(74) 


(189) 


(50) 


(381) 


4 


Deep fresh 


1819 


3581 


4008 


9408 


36 


25,901 




marsh 


(32) 


(51) 


(128) 


(211) 


(52) 


(404) 


5 


Open water 


81,651 


63,493 


96,869 


240,013 


23 


1,047,578 






(256) 


(209) 


(312) 


(777) 


(25) 


(3123) 


6 


Shrub swamp 


11,493 


12,658 


12,386 


36,537 


17 


210,513 






(205) 


(174) 


(301) 


(680) 


(12) 


(5779) 


7 


Wooded swamp 


4080 


8660 


5322 


18,062 


6 


293,727 






(79) 


(129) 


(98) 


(306) 


(6) 


(4611) 


8 


Bog 


9257 


3408 


5921 


18,586 


11 


166,324 






(138) 


(33) 


(79) 


(250) 


(11) 


(2257) 




TOTAL 


117,832 


102,077 


133,352 


353,261 


19 


1,824,682 






(852) 


(736) 


(1089) 


(2677) 


(15) 


(17,828) 



Wetland types from Shaw and Fredine (1956) and McCall (1972); see table 15-9 
for National Wetland Inventory equivalents. 



15-27 



10-80 



On the basis of table 15-7, duck broods from 1956 to 1965 were most abundant 
in fresh meadows (1.91 in Wildlife Managment Unit 8, and an average of 0.85 in 
the three Wildlife Management Units combined). Duck broods were most abundant 
in deep fresh marshes from 1966 to 1976 (3.34 in unit 6, 2.24 in unit 7, 0.81 
in unit 8, and 2.63 for the three units combined), but no breed counts were 
made in fresh meadows during that period. Abundance declined slightly from 
0.46 to 0.43 for the three regions in the two time periods, and Statewide 
averages declined from 0.21 to 0.13. Causes for these differences are 
unknown. An average of 5 ducklings fledged per brood was estimated for 
waterfowl. This estimate is considered to be conservative, generally constant 
from year to year, and somewhat higher than for the eider. 

The waterfowl breeding habitat by wetland type for the coastal units, and the 
Statewide acreage and number of areas are summarized in table 15-8. Table 15- 
9 compares the National Wetlands Inventory Classification scheme with the 
wetland types identified by the MDIFW. Brood abundance from 1966 to 1976 is 
used to calculate estimated annual brood production (table 15-7) . The data 
indicate that 64% of the annual brood production of Maine (exclusive of 
eiders) is in the coastal units. The coastal Wildlife Management Units 
produced an average of 67,500 ducklings (exclusive of eiders) annually from 
1966 to 1976. No known major changes have occurred since. Further 
extrapolation of these data would probably be subject to considerable error. 

The fledging survival for eiders is difficult to determine due to their 
creching behavior (broods combine and are reared by a female) and because 
brood rearing takes place in open coastal waters, usually adjacent to islands. 
The smaller clutch size of the eider (4 to 6 eggs) plus the exposure of newly 
hatched ducklings to gull predation and other hazards of the coastal 
environment suggest fewer than 4 ducklings per brood live to the flight stage. 
Assuming 3 fledglings for the 11,500 broods, an estimate of 34,500 young 
eiders survived. 

Migration and Staging Areas 

Migratory waterfowl tend to concentrate at certain locations and exhibit 
relatively strong habitat preferences. Most of the southerly migration takes 
place in August through November. Some stay a few days, others remain for a 
month or two. It is characteristic of the dabblers (black ducks, mallards, 
wood ducks, green-winged teals, and blue-winged teals) to concentrate in 
relatively protected areas near an abundance of food. These are called 
staging areas. Migratory waterfowl in the fall are frequently composed of a 
high percentage of young birds (only a few months old) . 

Merrymeeting Bay in region 2 is one of the largest staging areas in the 
northeast Atlantic. Each autumn and spring this bay supports up to 40,000 
waterfowl at one time. Concentrations begin to build in mid-August and last 
until the hunters or weather sends them southward. Black ducks and green- 
winged and blue-winged teal are most common but a number of other waterfowl 
species have been recorded, including the fulvous whistling duck. The 
attractiveness of Merrymeeting Bay to waterfowl is due to the remarkable 
abundance of high quality aquatic vegetation. Among the latter, wild rice 
( Zizania aquatica ) is of prime importance. 



15-28 



Table 15-9. Comparison of the National Wetlands Inventory Classification 
and Circular 39 Wetland Types Used in the Maine State Wetland 
Inventory 



Circular 39 types 



NWI wetland and deepwater habitats 



Classes 



Water regimes 



Water 
chemistrv 



Type 1 —Seasonally flooded basins or flats 
Wet meadow (Dix and Smeins 1967; Stewart and 

Kantrud 1972) 
Bottomland hardwoods (Braun 1950) 
Shallow-freshwater swamps (Penfound 1952) 



Emergent Wetland 
Forested Wetland 



Temporarily Flooded Fresh 
Intermittently Mixosaline 

Flooded 



Type 2— Inland fresh meadows 
Fen (Heinselman 1963) 
Fen, northern sedge meadow (Curtis 1959) 

Type 3— Inland shallow fresh marshes 
Shallow marsh (Stewart and Kantrud 1972; Golet and 
Larson 1974) 

Type 4 — Inland deep fresh marshes 

Deep marsh (Stewart and Kantrud 1972; Golet and 
Larson 1974) 



Type 5— Inland open fresh water 
Open water (Golet and Larson 1974) 
Submerged aquatic (Curtis 1959) 

Type 6— Shrub swamps 
Shrub swamp (Golet and Larson 1974) 
Shrub-carr, alder thicket (Curtis 1959) 

Type 7 — Wooded swamps 

Wooded swamp (Golet and Larson 1974) 
Swamps (Penfound 1952; Heinselman 1963) 

Type 8— Bogs 

Bog (Uansereau and Segadas-vianna 1952; Heinselman 1963) 
Pocosin (Penfound 1952; Kologiski 1977) 



Type 9— Inland saline flats 

Intermittent alkali zone (Stewart and Kantrud 1972) 



Emergent Wetland Saturated 



Fresh 
Mixosaline 



Type 10— Inland saline marshes 
Inland salt marshes (Ungar 1974) 



Type 1 1 — Inland open saline water 

Inland saline lake community (Ungar 1974) 



Type 12— Coastal shallow fresh marshes 
Marsh (Anderson et al. 196H) 
Estuarine bay marshes, estuarine river marshes 

(Stewart 1962) 
Fresh and intermediate marshes (Chabreck 19721 



Emergent Wetland 



Emergent Wetland 
Aquatic Bed 



Aquatic Bed 
Unconsolidated 
Bottom 

Scrub-Shrub 
Wetland 



Forested Wetland 



Semipermanently Fresh 

Flooded Mixosaline 

Seasonally Flooded 

Permanently Flooded Fresh 
Intermittently Mixosaline 

Exposed 
Semipermanently 

Flooded 

Permanently Flooded Fresh 
Intermittently Mixosaline 

Exposed 

All nonlidal regimes Fresh 
except Permanently 
Flooded 

All nontidal regimes Fresh 
except Permanently 
Flooded 



Scrub- Shrub 


Saturated 


Fresh 


Wetland 




(acid onlvl 


Forested Wetland 






Moss- Lichen 






Wetland 






Unconsolidated 


Seasonally Flooded 


Eusaline 


Shore 


Intermittently 

Flooded 
Temporarily Flooded 


Ilypersaline 


Emergent Wetland 


Seasonally Flooded 
Semipermanently 
Flooded 


Eusaline 


Unconsolidated 


Permanently Flooded 


Eusaline 


Bottom 


Intermittently 
Flooded 




Emergent Wetland 


Regularly Flooded 


Mixohaline 




Irregularly Flooded 


Fresh 




Semipermanently 






Flooded-Tidal 





(Continued) 
15-29 



10-80 



Fable 15-9. (Concluded) 



Circular 39 types 



NWI wetland and deepwater habitats 



Classes 



Water regimes 



Water 
chemistry 



Type 13— Coastal deep fresh marshes 
Marsh (Anderson et al. 1968) 
Estuarine bay marshes, estuarine river marshes 

(Stewart 1962) 
Fresh and intermediate marshes (Chabreck 1972) 

Type 14— Coastal open fresh water 
Estuarine bavs (Stewart 1962) 



Type 15— Coastal salt flats 
Panne, slough marsh (Redfield 1972) 
Marsh pans (Pestrong 1965) 

Type 16— Coastal salt meadows 
Salt marsh (Redfield 1972; Chapman 1974) 

Type 17 — Irregularly flooded salt marshes 
Salt marsh (Chapman 1974) 
Saline, brackish, and intermediate marsh (Eleuterius 1972) 

Type 18— Regularly flooded salt marshes 
Salt marsh (Chapman 1974) 

Type 19— Sounds and bays 

Kelp beds, temperate grass flats (Phillips 1974) 

Tropical marine meadows (Odum 1974) 

Eelgrass beds (Akins and Jefferson 1973; Eleuterius 1973) 

Type 20— Mangrove swamps 
Mangrove swamps (Walsh 1 974) 
Mangrove swamp systems (Kuenzler 1974) 
Mangrove (Chapman 1976) 



Emergent Wetland Regularly Flooded Mixohaline 

Semipermanently Fresh 

Flooded-Tidal 



Aquatic Bed 
Unconsolidated 
Bottom 


Subtidal 
Permanently 
Flooded-Tidal 


Mixohaline 
Fresh 


Unconsolidated 
Shore 


Regularly Flooded 
Irregularly Flooded 


Hyperhaline 
Euhaline 


Emergent Wetland 


Irregularly Flooded 


Euhaline 
Mixohaline 


Emergent Wetland 


Irregularly Flooded 


Euhaline 
Mixohaline 


Emergent Wetland 


Regularly Flooded 


Euhaline 
Mixohaline 


Unconsolidated 

Bottom 
Aquatic Bed 
Flat 


Subtidal 

Irregularly Exposed 
Regularly Flooded 
Irregularly Flooded 


Euhaline 
Mixohaline 


Scrub- Shrub 

Wetland 
Forested Wetland 


Irregularly Exposed 
Regularly Flooded 
Irregularly Flooded 


Hyperhaline 
Euhaline 
Mixohaline 
Fresh 



15-30 



In the spring, Merrymeeting Bay is a stopping place for thousands of northward 
moving Canada geese and ducks. They begin to arrive in mid-March and some 
remain through mid-May. Apparently these birds feed on plants carried over 
from the previous growing season as well as new growth. Merrymeeting Bay is a 
highly important area that should be preserved and intensively managed for 
waterfowl and other natural resources. It has been studied and investigated 
by various individuals and agencies and for an in-depth review and discussion 
refer to Reed and D'Andrea (1973). 

In addition to Merrymeeting Bay, various other estuaries, bays, and inlets 
along the coast are valuable as nesting and feeding areas for migrating and 
wintering waterfowl. Inland palustrine, lacustrine, and riverine systems are 
used by migrating ducks and geese. The distribution and nature of these 
habitats are reviewed in the following section. 

Waterfowl Habitat 

Depending on the species, season, weather, or purpose of use, the waterfowl of 
coastal Maine utilize all of the wetland types. Breeding ducks usually avoid 
areas affected by strong tides and favor the freshwater wetlands. Migrants 
seem to prefer coastal marshes and open waters, and wintering birds favor 
sounds, bays, and tidal flats. Wetlands designated as important to waterfowl 
are presented in atlas map 4. 

Waterfowl largely use habitats that provide their preferred foods. The 
exception is in winter when ice cover strongly effects their distribution. 
Various studies indicate food habits vary among species, age groups, and 
season (Mendall 1949; Martin et al. 1951; and Reinecke 1977). Breeding game 
ducks and their newly hatched ducklings depend largely on invertebrates for 
food. After 6 weeks of age the young tend to feed more on vegetative foods. 
In the fall, vegetation is heavily used by inland waterfowl populations, 
whereas invertebrates dominate in the estuarine and marine systems. Eelgrass 
(Zostera marina) is the only true marine vegetable food of sufficient quality 
and abundance along the Maine coast to be a major food for ducks. In general, 
waterfowl in marine waters feed largely on eelgrass and invertebrates (bottom 
organisms) in the fall, winter, and early spring. 

Region 1 . This region has less inland waterfowl nesting habitat than any 
of the other regions but supports more wintering waterfowl because of its high 
quality marine littoral zone. Most areas are feeding grounds for migrating 
and wintering birds (table 15-5). There is an abundance of waterfowl food 
nearshore along the coast and nearby coastal islands, and in some estuarine 
areas where there are extensive tidal flats, mussel bars, and eelgrass beds. 
Eiders nest on certain islands in this and all other regions (see chapter 14, 
"Waterbirds"). 

In average winters marine habitats adjacent to islands provide ice-free 
feeding grounds for waterfowl when inshore bays and tidal marshes are frozen 
(this applies to all regions). The many ledges and bars associated with the 
outer islands of Casco Bay are also important wintering areas for scoters, 
eiders, and old squaw ducks. These same areas are used by migratory brant in 
spring. 



15-31 

10-80 



Region 2. This region has a greater proportion of palustrine, riverine 
tidal, and estuarine emergent wetlands than any of the other regions. It 
includes the estuaries of three major rivers; the Kennebec, Androscoggin, and 
Sheepscot. This region also includes Merrymeeting Bay, where the largest 
concentrations of waterfowl are found. 

Region 2 is similar to region 1 because the ice cover in estuaries forces 
wintering or migrating waterfowl to use the areas adjacent to the many islands 
for feeding and protection. Major species are sea ducks, i.e., eiders, 
scoters, and old squaw ducks, which tend to winter as near shoreward as ice 
permits . 

The Maine Yankee Atomic Power Plant is located within this region adjacent to 
the Sheepscot estuary at Wiscasset. To date this plant, or its construction 
and wastes, have had no measurable effect on habitat utilization by waterfowl 
(Spencer 1974) . The non-tidal wetlands of this region are numerous and highly 
productive for breeding waterfowl (table 15-6) as well as for spring and fall 
migrants . 

Region 3. This region encompasses the coast from Boothbay to Port Clyde 
and includes the Damariscotta, Medomak, and St. George River estuaries, and 
Muscongus Bay. The nearshore marine waters are important to wintering and 
migrating sea ducks (scoters, eiders, and old squaw ducks), and to breeding 
eiders. The estuaries are heavily utilized in fall, winter, and spring by 
black ducks, goldeneyes, and buf f leheads . The Medomak estuary, particularly 
from 1960 to 1975, supported a large population of black ducks. Although 
there has been a drastic unexplained decline since 1975, similar but less 
drastic declines occurred in other areas of Maine. There also was a slight 
decline in wintering goldeneyes and buf f leheads . Available evidence suggests 
a combination of factors were responsible for these declines. The possibility 
of habitat change in the estuarine system cannot be discounted entirely. 
Here, as in other parts of the coast, casual observations by several observers 
indicated a reduction of the density and abundance of eelgrass may have taken 
place. The last survey of the eelgrass beds was made around 1969. The 
interaction of eelgrass and black ducks, and other Maine wintering waterfowl, 
needs to be better understood and represents an obvious data gap. 

Population changes in the St. George River estuary have not been as great as 
in the Medomak estuary (Maine Department of Inland Fisheries and Wildlife 
survey data). Comparable data for the Damariscotta estuary are lacking, but 
in the case of the St. George estuary eelgrass has not been abundant at any 
time in the past two decades. A future concern in this region is the 
preservation and management of island nesting habitat for eiders. 

Region 4 . This region largely is represented by the Penobscot Bay 
estuary. It has a large variety of wetland and marine habitat and is the 
center of breeding eider colonies. As in region 3, management of these 
nesting islands is of prime concern. Of particular importance to breeding 
eiders, and all wintering sea ducks, are the islands of the Muscle Ridge 
group; Isleboro, Deer Isle, North Haven-Vinalhaven, and Isle au Haut 
complexes. The southeastern end of Isle au Haut is a wintering area for 
harlequin ducks. 



15-32 



Among the lesser estuaries, two (Weskeag River and Marsh Stream) are 
characterized by sizeable (for Maine) tidal marshes. Major portions of these 
two wetlands are owned and managed by the MDIFW to benefit watefowl and other 
wildlife. Principle waterfowl species utilizing these marshes are black 
ducks, goldeneyes, buffleheads, and Canada geese. Most intensive use occurs 
during spring and fall migration periods. The estuaries of the Penobscot, 
Orland, and Bagaduce Rivers traditionally have been prime wintering and 
migration areas for black ducks, goldeneyes, buffleheads, and limited numbers 
of greater scaup. During winter, all of these estuaries freeze progressively 
further seaward, and from shore to center channel. The Orland and Bagaduce 
Rivers may freeze almost completely, and the main stem of the Penobscot River 
frequently requires ice-breakers to clear the way for passage above Bucksport 
(see chapter 2, "The Maine Coast Ecosystem"). During intense cold, tidal 
flats usually freeze during the ebb tide and the flood tide tempertures are 
insufficiently high to thaw them between tides. When the flats are frozen, 
the black duck and other dabblers are forced into a narrow band between the 
low water mark and the maximum feeding depth (24 inches; 61 km). Although 
food may be abundant and readily available in the vicinity of an island 5 to 
10 miles (8 to 16 km) seaward, black ducks remain in their traditional 
wintering habitats even if starvation threatens. 

The Bagaduce estuary, noted for its lush and extensive eelgrass beds, has not 
shown a winter decline in duck abundance. This estuary, and the Penobscot and 
Orland estuaries in region 4, have not experienced major declines in wintering 
birds since 1976 (MDIFW file data). These eelgrass beds in region 4 also 
provide food for a flock of wintering Canada geese. 

Region 5 . The Narraguagus River is the largest in this region but is 
long, narrow, and little used by waterfowl. Narraguagus Bay, with its highly 
irregular shoreline, extensive intertidal flats, and many islands, is 
excellent marine wintering and migration habitat for black ducks, goldeneyes, 
buffleheads, scoters, eiders, and old squaws. Region 5 is about the eastern 
limit of significant eider wintering and molting areas. The marine waterfowl 
environment of this region is characterized by many small, shallow, and well 
protected bays with large acreages of intertidal flat feeding areas. 
Excellent beds of eelgrass are known in some areas west of Schoodic Point, in 
the Mt. Desert Island Narrows, Goose Cove, and Taunton Bay. Smaller, more 
sparse, stands occur in other nearby areas. 

The Frenchman's Bay area is the most important wintering area for greater 
scaup on the entire coast. Several small tidal rivers empty into Frenchman's 
Bay and are important to other wintering and/or migrating waterfowl. From 
west to east these include: the Jordan River, Trenton; Skillings River, 
Lamoine; and the Taunton River, Sullivan. 

East of Schoodic Point, Gouldsboro Bay, Dyer Bay, Pigeon Hill Bay, Back Bay, 
Flat Bay, Harrington River Estuary, and the Pleasant River Estuary are all 
important for wintering and migratory waterfowl. 

Region 6 . This northeastern most region stretches from the western 
boundary at Addison, to Calais, to the head of tide on the St. Croix River 
estuary. From the Addison boundary to Cutler Harbor the coastline is highly 
irregular with many bays, coves, islands, and tidal stream estuaries. It is 
excellent habitat for all migrating and wintering waterfowl species of Maine 

15-33 

10-80 



although scaup seldom occur in significant numbers. The increased tidal range 
in this region results in very extensive flats that provide thousands of acres 
of feeding grounds for black ducks. Presumably, invertebrate foods are 
abundant and black duck populations utilizing the Machias and Cobscook Bay 
units have not declined recently as have populations farther southwest. No 
extensive eelgrass beds have been observed during low altitude flights over 
the area at low tide. Generally the intertidal flat habitat is heavily 
utilized by black ducks irrespective of ice conditions. 

Wintering eiders are not commonly observed east of Beals Island. The most 
recent 5-year average count for eiders in the Machias Bay unit (table 15-5) 
was only 32, and none for Cobscook Bay. 

The coast from Cutler Harbor to Lubec is bold, rock-bound, and, for Maine, 
fairly regular. Waterfowl are not numerous along this stretch. In contrast, 
the vast tidal flat between West Quoddy Head and Lubec, in additon to being a 
general feeding area for many species of waterfowl and shorebirds, is one of 
the few important stopovers for migrating brant. More than 5000 have been 
estimated at times during the spring migration (personal communication from M. 
A. Redmond, Lubec, Maine; February, 1979). From West Quoddy Head upriver, 
throughout Cobscook Bay and northward to Calais, tides may reach or exceed 20 
feet (6 m; 22.8 ft., or 7 m, at Calais). Within this area, the Cobscook Bay 
complex of inlets, tidal creeks, and rivers, plus strong tidal flows and rich 
invertebrate fauna, create many acres of excellent wintering and migration 
habitat for waterfowl. Scoters and old squaws frequent the deeper areas and 
mussel bars, and goldeneyes, buffleheads, and black ducks utilize the 
shallower areas and intertidal flats. Cobscook Bay has not experienced the 
recent decline in wintering black duck numbers. Because of the strong tidal 
flow, winter ice conditions are seldom as severe in region 6 as in regions 1 
to 5. 

Although waterfowl density in inland waters is not as high in region 6 as it 
is farther southwest, it is still high particulary for ring-necked ducks. The 
low density human populations and lack of human development compared to the 
rest of the coast, contribute further to the region's value as a natural area. 

Ecological Interactions 

Many ecological interactions take place among waterfowl, especially those 
related to food and feeding habits. Breeding waterfowl, especially pre- and 
post-nesting females and young up to about 6 weeks of age, tend to feed 
heavily on invertebrate foods. The tendency towards eating plant food is 
strongest in late summer and fall. This is notably true for the black duck, 
wood duck, and blue-winged teal (Drobney 1977; and Swanson et al. 1977). What 
effect feeding waterfowl may have on the abundance and distribution of 
invertebrates (bottom dwelling forms) or on aquatic vegetation in Maine is not 
known, but any changes are likely to be highly localized. An example is the 
eider duck which sometimes depletes cultured oyster beds in the central 
coastal area (personal communication from G. G. Donovan, Maine Department of 
Inland Fisheries and Wildlife, Augusta, ME.; August, 1977). Blue mussels 
sometimes are eaten in abundance by eiders and scoters. 

A high abundance of toxin-producing dinof lagellates ( Gonyaulus excavata ) , red 
tide organism, and their assimilation and accumulation in the fleshy tissues 

15-34 



of mussels and clams, has caused considerable public concern in Maine. A very 
limited collection of eiders (<20 birds) feeding in an area where mussels were 
highly toxic, revealed the birds had been feeding largely on nontoxic crabs 
and eider tissues contained very low concentrations of the toxin (personal 
communication from G. G. Donovan, Maine Department of Inland Fisheries and 
Wildlife, Augusta, ME.; August, 1977). The relation of the red tide organisms 
to waterfowl needs further investigation. 

The mergansers, with the possible exception of the hooded merganser, are 
primarily fish eaters. Although not abundant breeders in coastal Maine, the 
common merganser may be a troublesome predator on juvenile salmonids in rivers 
and ponds (Munro and Clemens 1937; and Elson 1962). 

A winter food relationship among eels, common mergansers, and bald eagles has 
been established in the rivers and estuaries of coastal Maine. According to 
studies by R. B. Owens, Jr. (personal communication, School of Forest 
Resource, University of Maine, Orono , ME.; February, 1979), the mergansers 
feed heavily on small eels, some of which might be heavily contaminated with 
heavy metals or pesticides. The contaminated mergansers are fed on by bald 
eagles which assimilate the contaminants in their body tissues. It is not 
known how serious this problem is in Maine (although heavy metal and pesticide 
residues are high in nonproductive eagle eggs), or how the contaminants affect 
mortality rates of wildlife or threaten human health. 

Another interaction that has management implications is the competition for 
nest boxes. Erected for nesting wood ducks, goldeneys, and hooded mergansers, 
MDIFW studies (Spencer and Corr 1977) indicate as many as 10% of these 
occupied boxes may contain mixed clutches with two of the three species. In 
addition, American kestrels, tree swallows, starlings, bees, and hornets 
frequently use nest boxes, reducing the value of the boxes for tree-nesting 
ducks. Carefully selected sites, proven installation techniques, and regular 
maintenance greatly enhance their use by nesting ducks. 

FACTORS AFFECTING DISTRIBUTION AND ABUNDANCE 

The many factors affecting the distribution and abundance of a species or 
group of species at various times and places are difficult to measure. 
Natural and human-made factors known to influence coastal waterfowl are 
described below. 

Natural Factors 

Natural factors influencing population size and distribution are disease, 
parasites, predation, quantity and quality of habitat, food supplies, and 
weather. The only disease troublesome to coastal Maine, primarily in the 
Penobscot Bay area, is fowl cholera ( Pasteurella multocida ) which afflicts 
nesting eider ducks (Gershman et al. 1964). Since its discovery in 1963 near 
Camden, it has reoccurred in several years but has not been widespread. Fowl 
cholera can cause the loss of nearly all adult females in a specific island 
nesting colony, but islands only a few miles away may escape the disease 
entirely. The disease does not appear to measurably reduce the breeding 
population coastwide. Annual monitoring of the disease's occurrence and 
sanitation operations, when necessary, is a continuing need. 

15-35 

10-80 



Parasites may, at times, cause some waterfowl losses, but their overall effect 
is difficult to assess. The acanthocephalan, Polymorphus botulis, is common 
in the intestines of many Maine eiders and has caused local mortality 
(Grenquist 1970). Blood parasites in freshwater breeding areas are commonly 
transmitted to ducks by biting flies (Diptera). These include protozoan 
malaria-like parasites of the genera Leucocytozoon , Haemoproteus , and 
Plasmodium. O'Meara (1954) found an abundance of blood parasites in samples 
of central Maine waterfowl. Infections of Haemoproteus nettionis and 
Leucocytozoon simondi were found in more than 80% of a sample of Maine wood 
ducks collected on the Penobscot River between Old Town and Lincoln (Thul 
1977); <1% were infected with Plasmodium circumf lexum . Although these 
parasites are common among waterfowl, no evidence has been found that it 
leads to mortality. The debilitating effects of parasites probably reduce the 
resilience of waterfowl to disease or predation. 

Predation is another natural mortality factor whose effects are difficult to 
measure. Predation alone is not known to materially reduce waterfowl 
populations in coastal Maine. The most serious predation affects nests, 
nesting adults, and/or young. Mammals that prey on eggs and ducks are 
raccoon, skunk, red fox, mink, weasels, bobcat, and perhaps coyotes. 
Significant avian predators are gulls, crows, and great-horned owls. Owls 
usually take adult and young ducks, whereas crows and gulls are essentially 
nest predators. Both the herring gull and the great black-backed gull 
regularly take ducklings. In some instances gull predation on a nesting 
colony of eider ducks may reduce breeding success and potential. The raccoon 
is the most serious predator on nest boxes. The snapping turtle is sometimes 
a significant predator on young ducks in freshwater habitats. 

The distribution, size, and quality of aquatic habitats have a great influence 
on the abundance of coastal waterfowl. Waterfowl habitat was discussed 
earlier and is mentioned here only to recall some of the factors that may 
influence breeding or wintering populations. 

Cavity-nesting waterfowl have the most specific nesting habitat requirements. 
Accordiing to Spencer and Corr (1977), wood ducks, hooded mergansers, and 
goldeneyes utilize a high proportion of artificial nest boxes in the central 
coastal area (regions 2 and 4, particularly). Populations of these species 
appear to have increased by well designed nest box programs. Whether this 
reflects a lack of adequate natural sites, a preference for boxes, or greater 
success in boxes, is unknown. It is probably safe to assume the artificial 
boxes are less subject to predation than natural sites. 

The status of beaver populations also has a direct effect on the amount and 
quality of waterfowl breeding habitat. In fact, beaver impoundments may be 
the optimum habitat for black ducks, wood ducks, and hooded mergansers. 
Depending upon the nature of the individual flowage, blue-winged teal, green- 
winged teal, and ring-necked ducks also often utilize beaver ponds for nesting 
and brood rearing. Optimum beaver management is also good waterfowl 
management in Maine. 

Tidal habitat for wintering and migrating birds is highly diverse and variable 
throughout coastal Maine. Winter-inventory data (MDIFW files) indicate 
drastic declines in the number of waterfowl (particularly black ducks) 
utilizing major tidal areas. Winter populations in the Kennebec River and the 

15-36 



Medomak River estuary (region 2) have declined sharply. This reduction may 
have been caused by changes in the availability of eelgrass either as a 
vegetable food or for the associated invertebrate fauna. 

In the last decade there has been a significant reduction in pollution in the 
Penobscot and Kennebec estuaries. Whether the effect of cleaner water has 
been favorable or unfavorable to waterfowl populations using these areas is 
unknown . 

Although food supplies are usually adequate in high quality waterfowl 
habitats, food supplies can change rapidly. Most inland Maine waters support 
only small quantities of vegetative duck foods. In riverine and/or lacustrine 
systems, sharp changes in water levels may alter food availability. 

In some rivers, dams help reduce flooding and increase minimum flows which may 
help maintain an abundance of aquatic foods, especially for dabbling ducks. 

Weather sometimes causes high duck mortality during the breeding season. 
Unusually low temperatures or heavy precipitation in late April, May, and June 
may cause heavy losses of nests or young ducklings, depending upon the nesting 
habits of the species. For example, black ducks (early nesters) are apt to be 
affected by floods in late April and May, whereas ring-necked ducks (late 
nesters) are more susceptible in June. 

Cold, wet weather during nesting sometimes causes high brood mortality at a 
time in the breeding season when it is too late for renesting. Extreme 
weather during migration might either prolong or hasten movement in spring or 
fall. Early winter weather seems to affect black ducks and geese most by 
icing their feeding grounds (usually mud flats). Low temperatures can 
severely restrict black duck food availability. Black duck losses due to 
starvation are known to occur, but it is difficult to assess because of their 
habit of hiding and starving in a particular area even if food is available 
nearby. 

Human Factors 

Human-made changes in habitat sometimes adversely, and severely, affect 
waterfowl. Hunting and natural mortality have recently been shown to be in 
balance with recruitment up to a threshold level in mallards (Anderson and 
Burnham 1976), but what that level is for various waterfowl in Maine has not 
been defined. Annual variation in breeding success is the major factor 
causing variations in abundance. 

Human activities may be beneficial or harmful. The intentional management of 
beaver and well conceived and executed nesting box programs favor some species 
of ducks, but intensive urban and suburban development of wetland shorelines, 
and recreation and boating activity may reduce waterfowl production locally. 
Because of human causes it is clear that in recent decades there has been a 
reduction in waterfowl habitat in many inland water areas of coastal Maine. 

Although hunting mortality has been shown to be largely compensatory in 
relation to natural mortality, banding data reveal local breeding populations 
may be subjected to excessive kill in the fall before they disperse. 



15-37 



10-80 



POTENTIAL IMPACTS OF HUMAN ACTIVITIES 

Human developments described elsewhere in this report, and their potential 
impacts upon the environment, are listed in chapter 3. Some of the more 
important potential impacts on waterfowl are reviewed below. 

Forestry Practices 

Logging and cutting in coastal Maine forests affect waterfowl primarily by 
destroying breeding habitat. The abandonment of old logging dams in recent 
decades, and their subsequent deterioration, resulted in lower water levels in 
ponds and the drainage of others. 

The use of pesticides for forest management in summer may destroy a major food 
source (largely adult or larval insects) for nesting females and young 
ducklings. Herbicides are currently being used as a means of improving forest 
stands by killing certain hardwoods. Clearcutting of hardwood forests, 
especially near streams and ponds, reduces the availability of nesting sites 
for cavity-nesting ducks. 

Industrial or Urban Development 

Land use changes occurring on or near wetlands causes degradation or loss of 
waterfowl habitat. Highway construction, housing, commerical construction, 
and summer recreation activities all take a toll. The development of 
recreation facilities and housing is one of the biggest threats to waterfowl 
in lacustrine systems . 

Oil Pollution 

Oil spills occurring in harbors, bays, and rivers could cause locally sever 
losses of waterfowl. Spills originating from shipping historically have been 
the most damaging in or near the port of Portland. Continued spills and 
waterfowl losses are expected, and if additional oil ports or refineries are 
developed, spills and waterfowl losses are likely to increase. 

Tidal Power Development 

The potential effect of the proposed tidal power facilities in the Cobscook 
Bay area (region 6) upon waterfowl is difficult to evaluate. Changes in the 
water regime could adversely affect the availability and quality of marine 
invertebrate foods for waterfowl. The potential effect of power development 
on mud flats, water levels, and ice formation has not been assessed. This 
developement could be of considerable importance to the abundance and 
distribution of wintering birds and should be emphasized in any environmental 
impact statement concerning tidal power development. 

Island Development 

Several State, Federal, and private agencies support programs that acquire or 
protect the nesting islands of coastal Maine. Eider breeding colonies on 
privately owned islands usually are least protected. The future of the eider 
in coastal Maine depends largely on how the islands are developed for use, and 
whether the protection of eiders is considered in planning. 

15-38 



Small Hydro-electric Dams 

This type of installation is currently being considered as a possible 
alterantive or supplement to other types of power supply in Maine. The effect 
of their operations on waterfowl depends largely on the number, location, and 
seasonal water level requirements of the impounded areas insofar as it effects 
depth, aquatic plant growth, exposure of mud flats, and ice formation. 
Construction and operation of a small power dam on the Kennebago River in 
Stetsontown, Franklin County, created sizeable, high quality palustrine 
emergent wetland adjacent to the river channel (Kennebago Logans). Waterfowl 
abundance was high in the area for a number of years but in the last 15 years, 
heavy recreation (fishing and summer homes) resulted in a sharp decrease of 
waterfowl. 

Overhead Power Transmission Lines 

Although the edge effect or openness of transmission line corridors benefits 
some terrestrial species, waterfowl often are killed when flying into the 
lines. The frequency and magnitude of such losses are directly related to 
their proximity to large waterfowl concentrations. Although not documented, 
several observers reported frequent waterfowl collisions with powerlines at 
Merrymeeting Bay (region 2) where a complex of lines crosses the Bay and 
adjacent tributaries (e.g., Chops, Abagadasset Point, and Cathance River). If 
more power lines are needed in the future, careful consideration should be 
given to their location, including the desirability of underground 
installation. 

Game Farm Mallard Releases 

Thousands of game farm mallards have been released to the wild for many years 
in Maine. "Easter ducks" often are released on town mill ponds, and for 
several years the Bowdoinham Rod and Gun 'Club released 1000 to 3000 
"environmentally conditioned" domesticated mallards in the vicinity of 
Merrymeeting Bay and other areas throughout the State. There is little 
evidence these releases increased waterfowl abundance or hunting, and the 
Maine Chapter of The Wildlife Society opposes further releases. It is 
speculated that releases contributed to increased hybridization between 
mallards and Maine's native black ducks. Recent evidence suggests the 
frequency of black duck and mallard hybridism is increasing (personal 
communication from R. E. Kirby, Migratory Bird and Habitat Research 
Laboratory, U.S. Fish and Wildlife Service, Laurel, MD.; May, 1977). 

SOCIOECONOMIC IMPORTANCE 

Waterfowl resources are often categorized into either "consumptive" or "non- 
consumptive" uses. "Consumptive" infers the killing of waterfowl (hunting) as 
opposed to "non-consumptive", such as bird watching, art forms, and 
photography. 

Consumptive Uses 

The magnitude and economic importance of the waterfowl of coastal Maine are 
best appraised by analyzing duck stamp sales and waterfowl surveys. (Duck 
stamps are required for all hunters over 16 years of age.) Duck stamp sales 

15-39 

10-80 



in Maine average near 18,000 annually. Another 2000 hunters under 16 years 
old also hunt, which brings the total to approximately 20,000. About 83% of 
these hunt ducks (17 / are stamp collectors, etc.) and hunt an average of 5.5 
days per season, killing an average of 4.5 birds. The total waterfowl person- 
days of hunting in Maine is about 100,000 annually. The average hunter kills 
about one bird per day. 

From 1966 to 1975 more than 75% of the waterfowl harvest of Maine was in the 
coastal counties. According to a 1972 to 1976 survey there were about 27,000 
Statewide duck hunters. The average annual number of each species of duck 
killed, and the totals for each county, are given in table 15-10. They 
averaged about 8 ducks a season. The 8343 hunters of geese averaged 0.6 geese 
per season. About 73% (19,667) of the duck hunters and 67% (5573) of the 
goose hunters hunted in Wildlife Management Units 6, 7, and 8. 

Economic surveys of hunting and fishing show waterfowl hunters in Maine spend 
an average of $83 per year on their sport (National Analysts 1978). If the 
number of waterfowl hunters in coastal Maine approximates 34,000 (which is 
higher than other estimates) as suggested by National Analysts (1978), the 
sport generates about $2.75 million annually. 

Non- consumptiv e Use 

Non-consumptive waterfowl use in coastal Maine has not been determined, but 
judging from the number of bird clubs and the interest in them, non- 
consumptive use is a common practice. Both consumptive and non-consumptive 
users contribute to the management and preservation of waterfowl by purchasing 
hunting licenses and duck stamps, and supporting habitat acquisition and 
protection. 

MANAGEMENT 

The term "management" in this section includes research or fact finding 
programs needed to provide a sound basis for overall management. This 
includes both population management through regulation, and habitat management 
through protection, acquisition, and development. 

The U.S. Fish and Wildlife Service and the Maine Department of Inland 
Fisheries and Wildife have the responsibility for managing (including 
regulation) waterfowl in Maine. Overall, hunting regulations of waterfowl are 
a function of USFWS. Within its regulatory framework, hunting regulations 
imposed by the MDIFW may be more restrictive but never less so. In addition 
to providing enforcement personnel, both agencies carry out individual and 
cooperative research and management programs. The Moosehorn, Petit Manan, and 
Rachel Carson National Wildlife Refuges are managed by the USFWS. The Maine 
Cooperative Wildlife Research Unit, Maine Field Station, Migratory Bird and 
Habitat Research Laboratory, Biological Servies Program, and Wildlife 
Services, are Fish and Wildlife Service supported activities. Within the 
MDIFW, regional wildlife biologists are responsible for managing waterfowl 
areas and carrying out survey and inventory tasks within their regions. The 
migratory bird research leader (Orono, ME.) and assistants are responsible for 
planning, designing, coordinating, and executing the overall MDIFW 
scientific/technical migratory bird program. The latter is described in a 
comprehensive long range "Wild Duck Management Plan" (Spencer 1975). This 

15-40 



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plan sets long range goals for assuring the continued well being of the 
waterfowl resources while providing recreational and aesthetic values. It 
also sets out to maintain waterfowl populations that will assure an annual 
harvest of approximately 100,000 birds. The plan covers the period 1975 to 
1979 and provides management guidelines based on an analysis of past waterfowl 
populations, assessment of present conditions, and an evaluation of probable 
future conditions and needs. In addition to management and research programs, 
MDIFW also has an active and ongoing habitat acquisition program which places 
considerable emphasis on waterfowl. As an example, the Department either owns 
or manages approximately 200 State owned coastal islands that support 
waterfowl and/or seabird nesting colonies (see atlas map 3) . 

DATA GAPS 

Current deficiences or gaps in the knowledge of waterfowl biology or ecology 
weaken efforts to manage and protect coastal waterfowl resources. Description 
of the data gaps here should provide some guidelines for future research. 

The black duck traditionally was the most numerous and sought after duck of 
the Atlantic Flyway. Current information (primarily winter inventory data) 
suggests a long term gradual decline in abundance, but the reason for this 
decline is unknown largely because methods of waterfowl population appraisal 
generally are inadequate. Black duck population research is currently 
emphasized by the USFWS , the Canadian Wildlife Service, the Atlantic Flyway 
Council, and the MDIFW. In Maine, as well as throughout the range of black 
ducks in the United States, improved winter inventories and habiat surveys are 
needed. Other studies that concern black ducks are the effects of various 
pesticides (e.g., spruce budworm sprays) and environmental contaminants 
(particularly heavy metals) on waterfowl and other living resources. The 
effect of such agents on food abundance or availability could be limiting. 
The impact of hunting on black duck populations also needs study. 

The value of eelgrass as food for wintering black ducks, as well as for other 
wintering waterfowl, has yet to be determined. Little quantitative 
information is available regarding coastal ice formation in winter and 
mortality of winter populations. 

The effect of the "red tide" organism on waterfowl is a managment concern. 
Red tide has been common in much of coastal Maine in recent years and, 
although no waterfowl mortality has been observed in Maine, black duck 
mortality caused by red tide organisms occurred on Massachusetts' north shore. 
Whether contaminated waterfowl (those that have fed on toxic burdened 
invertebrates) are safe for human consumption is uncertain. 

Little is known of the factors affecting the abundance of the common 
goldeneye. No comprehensive, definitive study has been made of this species 
in North America and very little banding has been carried out. The goldeneye 
is an important component of the coastal Maine harvest but the location of its 
breeding grounds is unknown. Most Maine hatched and reared goldeneyes are 
usually harvested in northwest Maine, adjacent areas in Canada, and northern 
Vermont. Little is known of the population dynamics or status of the species. 

The ecological role of mergansers among coastal waterfowl merits further 
investigation. Their significance as predators on salmonids has not been 

15-42 



evaluated in Maine and their relationship as food for wintering bald eagles 
particularly needs study. They often are prey for eagles and may well be 
carrying heavy loads of pesticides and/or heavy metals accumulated from the 
consumption of contaminated fish. The estuarine systems of the Penobscot and 
Kennebec Rivers are areas of particular concern. 

CASE STUDY: THE BLACK DUCK 

This description of the biology and habits of the black duck, a species 
nesting in freshwater wetlands of coastal Maine, is representative of the type 
of information that should be developed for all major ducks of coastal Maine. 
This species was selected because its breeding and wintering ecology have been 
studied in Maine in considerable detail (Coulter and Miller 1968; Hartman 
1963; Mendall 1949; and Reinecke 1977). This case study essentially describes 
the arrival of the breeding pairs at the nesting area and their life through 
the following spring. Excellent resumes of the life history of black ducks 
(and other Maine waterfowl) are contained in Bellrose (1976b) and Palmer 
(1976). 

After the breakup of winter ice, black ducks migrate from wintering areas 
along the coast of Maine to northern breeding marshes in Maine and Canada. 
Although the migrants travel in flocks, most birds pair before reaching the 
breeding grounds. Although older adult females frequently return to marshes 
they formerly used in previous breeding attempts (Coulter and Miller 1968), 
yearling females are much less precise. Black ducks breed and nest mostly in 
freshwater marshes, shrub swamps, beaver f lowages , woodland brooks, and 
streams. The monthly activities (phenophases) of male and female black ducks 
are shown in figure 15-12. 

Spring arrival dates vary according to the latitude of the breeding site and 
weather conditions. In coastal Maine most birds arrive in late March through 
mid-April. Within a week to 10 days after arrival the female examines 
terrestrial nesting cover either from the water or afoot. Most nests are 
constructed during the second week of April through the first week in May 
(Coulter and Miller 1968). Soon after arrival at the breeding marsh, mated 
pairs isolate themselves from others of their species and establish a 
prenesting territory. At this time males become protective and aggressive. 
They attempt to drive away other black duck males or pairs. Daily breeding 
and nesting activities consist of feeding, resting, plumage maintenance, 
courtship, copulation, and exploration of the breeding marsh. 

The development of the female ovary in preparation for egglaying begins about 
7 days before the first egg is laid. At this time the female experiences a 
change in nutritional requirements (Krapu 1977). Nesting ducks feed 
extensively on aquatic invertebrates at this time (Swanson et al. 1977). 
Although a vegetable feeder during much of the year, from 60% to 70% of the 
female black duck diet consists of clams, snails, mayflies, caddisfly larvae, 
sowbugs, and other invertebrates (Reinecke 1977). 

The nest site selected by the female normally provides overhead cover and has 
sufficent ground litter available for her to dig a shallow cup in the ground 
with her feet. Other characteristics of the nest site are highly variable. 
The nest may be located on a floating bog mat, in the woods, or in a blueberry 
field a thousand or more feet from the nearest water. In sedge-meadows, 

15-43 

10-80 



leatherleaf ( Chamaedaphne calyculata ) , sweetgale ( Myrica gale), and sedges 
(Carex spp.) are common nest site habitats. Upland nests studied by Coulter 
and Miller (1968) were found in nettles (Urtica dioica ) , raspberries (Rubus 
spp.), and American yew ( Taxus canadensis ) . The variability of black duck 
nest sites may prevent nest predators from forming an efficient search image 
for locating nests (Reed 1974). Coulter and Miller (1968) reported that at 
least a third of the female black ducks under observation produced a second 
clutch of eggs when the first was destroyed. Some produced third clutches. 

A black duck clutch in Maine averages about 10 eggs (Coulter and Miller 1968). 
They are generally laid at the rate of one per day. The weight of a clutch is 
60% of the weight of the female bird, and the physiological stress of egg 
production is associated with a weight loss of about 100 g during nesting, 
including 50 g of fat (Reinecke 1977). The lipid energy reserves carried by 
the female are a significant input into the energy requirement of the bird 
during reproduction (Owen and Reinecke 1977). 

During egg-laying, the female usually visits the nest in the morning and 
spends an increasing amount of time (2 to 10 hours) at the nest as the clutch 
nears completion (Caldwell and Cornwell 1975). The female is rarely at the 
nest at night until the clutch is complete. During egg-laying, the male rests 
and preens when the female is in the nest, and joins her for feeding, bathing, 
and preening when she is away from the nest. 

As the female increases her time at the nest, the bond between the pair 
weakens. Soon after the female begins incubating the clutch, the male 
abandons her, becomes less aggressive, and joins other groups of feeding and 
resting males. The female assumes sole responsibility for hatching the eggs 
and rearing the young. 

After abandoning the females, the males form flocks and move to larger marshes 
and estuaries to molt their wing feathers and begin a period of 
f lightlessness . The flightless period lasts about 4 weeks in May and June. 
By early fall most adult males concentrate on intertidal flats along the 
coast. 

During incubation the females remain on the nest except for one to four 
(average of 2.3) rest periods of from 1 to 3 hours (average of 80 minutes) per 
day (personal communication from J. K. Ringelman, School of Forest Resources, 
University of Maine, Orono, ME.; June, 1978). Incubation of the clutch 
requires 25 to 27 days. The egg-bound ducklings establish vocal contact with 
the female and open (pip) the eggshells during the final 2 days of incubation. 
The downy young remain in the nest until they are dry and the sheaths have 
been rubbed from their down feathers. When they are dry and the weather 
favorable, the female leads them to water. The average life span of females 
is probably less than 2 years; Anderson (1975) reported mallards averaged only 
1.7 years. This suggest most females produce only 1 or 2 broods per lifetime. 

The mortality rate of juvenile black ducks is high. Despite the 10 egg mean 
clutch size (Coulter and Miller 1968), Spencer (1967) reported in an 18-year 
study the average class III (6 weeks to fledging) brood size was only 5 for 
the 560 broods observed. The range was 4.3 to 6.0 young per class III brood 
(figure 15-12). 



15-44 




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The downy young feed at or above the water surface for 1 to 2 weeks; some of 
the food items described by Reinecke (1977) were chironomid (midge) pupae and 
adults, spiders, caddisflies, and mayflies. Aquatic invertebrates constitute 
about 90% (dry weight) of the diet of the young through the first 6 weeks of 
life. Snails, clams, mayflies, caddisflies, sowbugs , and fly (Diptera) larvae 
are an excellent source of highly digestible energy and protein for the young 
during rapid growth (2-10 weeks). By the age of 8 weeks the juveniles are 
consuming a diet higher in plant seeds and tubers and are making their first 
flights. In late summer the juveniles wander about, primarily on inland 
waterways (personal commuication from J. K. Ringelman, School of Forest 
Resources, University of Maine, Orono, ME.; June, 1978). The females that 
raised broods often remain at the breeding areas after the fledglings have 
gone. The adults undergo postnuptial molt of flight feathers at this time and 
may remain flightless until late September. 

Black duck migration begins in August just after they regain their flight 
feathers. Many move down the major river systems toward the coast in fall. 
Some winter on the Maine coast and others winter south as far as North 
Carolina (Geis et al. 1971). Migration occurs principally during October and 
November and most reach their wintering grounds by early December. 

Coastal Maine, which contains extensive black duck winter habitat, supported 
about 92% of Maine's wintering black duck population during January, 1979. 
The homing of black ducks to specific wintering areas or to breeding marshes 
in spring is equally strong (Spencer and Corr 1977). During winter the birds 
spend most of their time feeding and resting. Winter feeding is regulated 
somewhat by the tidal rhythms and weather conditions. Winter foods (Hartman 
1963) include intertidal invertebrates such as the edible mussel ( Mytilus ) , 
soft-shell clam ( Mya ) , sandworms ( Nereis ) , amphipods ( Gammarus , Orchestia ) , 
and isopods ( Idothea ) . 

During severe weather, feeding birds remain in open water areas kept free of 
ice by the strong tidal currents. Winter is a period of high stress for black 
ducks on the Maine coast. Both adult and immature birds lose weight at this 
time. Reinecke (1977) estimated black ducks may starve in only 3 to 7 days if 
severe ice conditions prevent feeding. 

Courtship activity and pair formation for the black duck begin in the fall and 
occur through the winter on warm sunny days. With increasing temperatues in 
February, courtship increases sharply and most birds are paired by the time 
spring migration brings the birds back to the nesting marshes. 



15-46 



REFERENCES 

Addy, C. E. 1945. A Preliminary Report on the Food Habits of the Black Duck 
in Massachusetts. Res. Bull. No. 6. Massachusetts Department of 
Conservation, Boston, MA. 

American Ornithologists' Union. 1957. Check-list of North American birds, 
5th ed. Washington, DC. 

1973a. Thirty-second supplement to the "American Ornithologists' 
' Union Check-list of North American Birds." Auk 90(2) -.411-419 . 

. 1973b. Corrections and additions to the thirty-second supplement to 

the "American Ornithologists' Union Check-list of North American Birds." 
Auk 90(4):887. 

1976. Thirty- third supplement to the "American Ornithologists' Union 



Check-list of North American Birds." Auk 93(4) :875-879 . 

Anderson, D. R. 1975. Population Ecology of the Mallard part V. U.S. Fish 
and Wildl. Serv. Resour. Publ. No. 125. 

, and K. P. Burnham. 1976. Population Ecology of the Mallard part VI. 



U.S. Fish and Wildl. Serv. Resour. Publ. No. 128. 

Attwood, Stanley B. 1973. The Length and Breadth of Maine. Maine Studies 
No. 96. University of Maine at Orono, Orono, ME. 

Bellrose, F. C. 1976. Ducks, Geese, and Swans of North America. Stackpole 
Books, Harrisburg, PA. 

Caldwell, P. J., and G. W. Cornwell. 1975. Incubation behavior and 
temperatures of the mallard duck. Auk 92:706-731. 

Carney, S. M. , M. F. Sorensen, and E. M. Martin. 1978. Average Harvest of 
Each Duck Species in States and Counties During 1966-75 Hunting Seasons. 
Admin. Rep. Office of Migratory Bird Management, U. S. Fish and Wildlife 
Service, Laurel, MD. 

Coulter, M. W. , and W. R. Miller. 1968. Nesting Biology of Black Ducks and 
Mallards in Northern New England. Bull. 68-2. Vermont Fish and Game 
Department, Montpolier, VT. 

Crocker, A. D. , J. Cronshaw, and W. N. Holmes. 1974. The effect of crude oil 
on intestinal absorption in ducklings ( Anas platyrhynchos ) . Environ. 
Pollut. 7(3) : 165-177 . 

Drobney, R. D. 1977. The Feeding Ecology, Nutrition, and Reproduction 
Bioenergetics of Wood Ducks. Ph.D. Thesis. University of Missouri, 
Columbia, MO. 

Elson, P. F. 1962. Predator-prey relationships between fish-eating birds and 
Atlantic salmon. Bull. Fish. Res. Board Can. No. 133. 

15-47 

10-80 



Geis, A. D., R. I. Smith, and J. P. Rodgers. 1971. Black duck distribution, 
harvest characteristics, and survival. U.S. Fish and Wildl. Serv. Spec. 
Sci. Rep. -Wildl. No. 139. 

Gershman, M. , J. F. Witter, and H. E. Spencer, Jr. 1964. Case report: 
Epizootic of fowl cholera in the common eider duck. J. Wildl. Manage. 
28:587. 

Grenquist, P. 1970. On mortality of the eider duck ( Somateria mollissima ) 
caused by acanthocephalan parasites. Suomen Riista (Finland) 22(l):24-34. 

Hartman, F. E. 1963. Estuarine wintering habitat for black ducks. J. Wildl. 
Manage. 27 (3) : 339-347 . 

Korschgen, C. E. 1979. Coastal Waterbird Colonies: Maine. U.S. Fish and 
Wildlife Service, Biological Services Program, FWS/OBS-79/09 . 83pp. 

Krapu, G. L. 1977. Nutrient Factors Affecting Reproductive Potential in 
Dabbling Ducks. Presented at Waterfowl and Wetlands: An Integrated 
Review. A Special Symposium of the Midwest Fish and Wildlife Conference, 
Madison, Wisconsin: December 1977. 

Martin, A. C, H. S. Zim, and A. L. Nelson. 1951. American Wildlife and 
Plants. McGraw Hill, INc, New York. 

McCall, Cheryl A. 1972. Manual for Maine Wetlands Inventory. Game Division, 
Maine Department of Inland Fisheries and Wildlife, Augusta, ME. 

Mendall, H. L. 1949. Food habits in relation to black duck management in 
Maine. J. Wildl. Manage. 13(1) :64-101 . 

Munro, J. A., and W. A. Clemens. 1937. The american merganser in British 
Columbia and its relation to the fish population. Bull. Fish. Res. Board 
Can. No. 55. 

National Analysts, Division, Booz, Allen, and Hamilton Inc. 1978. National 
Survey of Hunting, Fishing, and Wildlife Associated Recreation, Addendum- 
Maine. Fish and Wildlife Service, U. S. Department of the Interior, 
Washigton, DC. 

O'Meara, D. C. 1954. Brood parasites in Maine Waterfowl Especially 
Leucocytozoon spp. MS Thesis. University of Maine at Orono, Orono , ME. 

Owen, R. B., Jr., and K. J. Reinecke. 1977. Bioenergetics of Breeding 
Dabbling Ducks. Presented at Waterfowl and Wetlands: An Integrated 
Review. A Special Symposium of the Midwest Fish and Wildlife Conference. 
Madison, Wisoncsin; December. 1977. 

Palmer, R. S. 1949. Maine birds. Bull. Museum Comp. Zool. 102. 

, ed. 1976. Handbook of North American Birds. Vols. 2 and 3. Yale 



University Press, New Haven and London. 



15-48 



Reed, A. 1974. Requirements of breeding black ducks in tidal marshes of the 
St. Lawrence estuary. Pages 120-135 in The Waterfowl Habitat Management 
Symposium at Moncton, New Brunswick, Canada; 30 July to 1 August, 1973. 

, and D' Andrea. 1973. Conservation Priorities Plan 34, Merrymeeting 



Bay. The Smithsonian Institution Reed and D' Andrea, Land and Space 
Planning. South Gardiner, ME. 

Reinecke, K. J. 1977. The Importance of Aquatic Invertebrates and Female 
Energy Reserves to Black Ducks Breeding in Maine. Ph.D. Thesis. 
University of Maine at Orono, Orono, ME. 

Shaw, P. S. and C. G. Fredine. 1956. Wetlands of the United States; Their 
Extent and Value to Waterfowl and Other Wildlife. U. S. Fish and Wildl. 
Serv. Circ. 39. 

Spencer, H. E., Jr. 1967. Waterfowl Production Studies. Mimeo. JCR A-2 
Proj . W-37-R-16. Statewide Wildlife Investigations, Maine Department of 
Inland Fisheries and Wildife, Augusta, ME. 

. 1974. Waterfowl Population Investigations 1973. Fifth Annual Report. 

Vol. 1. Maine Yankee Atomic Power Co. Augusta, ME. 

. 1975. Wild Duck Management Plan for Maine, 1975-90. Maine Department 

of Inland Fisheries and Wildlife, Augusta, ME. 

, and P. 0. Corr. 1977. 1976-77 Migratory Bird Project Report. Wildl. 

Div. Leafl. Ser. 9(1). Maine Department of Inland Fisheries and Wildlife, 
Augusta, ME. 

, , and A. Hutchingson. 1978. 1977-78 Migratory Bird Project 



Report. Wildl. Div. Leafl. Ser. 10(1). Maine Department of Inland 
Fisheries and Wildlife, Augusta, ME. 

_, and G. G. Donovan. 1973. 1972 Migratory Bird Project Report. Game 
Div. Leafl. Ser. 5(1). Maine Department of Inland Fisheries and Wildlife, 
Augusta, ME. 

_, and A. Hutchinson. 1974a. An Appraisal of the Fishery and Wildlife 
Resources of Eastern Penobscot Bay Planning Unit. Unpub. mimeo to Coastal 
Planning Group, State Planning Office, Maine Department of Inland 
Fisheries and Wildlife, Augusta, ME. 

_, and _. 1974b. An Appraisal of the Fishery and Wildlife Resources 

of Eastern Hancock County Planning Unit. Unpub. mimeo to Coastal Planning 
Group, State Planning Office, Maine Department of Inland Fisheries and 
Wildlife, Augusta, ME. 

_, and . 1974c. An Appraisal of the Fishery and Wildlife Resources 



of Lincoln County Planning Unit. Unpub. mimeo to Coastal Planning Group, 
State Planning Office, Maine Department of Inland Fisheries and Wildlife, 
Augusta, ME. 



15-49 

10-80 



, and . 1974d. An Appraisal of the Fishery and Wildlife Resources 
of Bath-Brunswick Regional Planning Unit. Unpub . mimeo to Coastal 
Planning Group, State Planning Office, Maine Department of Inland 
Fisheries and Wildlife, Augusta, ME. 

Swanson, G. A., G. L. Krapu, and J. R. Serie. 1977. Foods Consumed by 
Dabbling Ducks on the Breeding Ground with Emphasis on Laying Females. 
Presented at Waterfowl and Wetlands: An Intergrated Review. A Special 
Symposium of the Midwest Fish and Wildlife Conf . , Madison, Wisconsin; 
December 1977. 

Thul, J. 1977. A parasitological and morphological study of migratory and 
non-migratory wood ducks (Aix sponsa ) of the Atlantic Flyway. Wildlife 
Disease Research Progress Report Dec. 7, 1977. College of Veterinary 
Medicine, University of Florida, Gainsville, FL. 

U. S. Fish and Wildlife Service. 1975. Final Environmental Statement for the 
Issuance of Annual Regulations Permitting the Sport Hunting of Migratory 
Birds. U. S. Government Printing Office, Washington, DC. 



15-50 



Chapter 16 
Terrestrial Birds 



Authors: Norman Famous, Charles Todd, Craig Ferris 




The birds discussed in this chapter are those that breed, migrate, or winter 
in terrestrial and vegetated palustrine habitats found along the Maine coast. 
Approximately 70% of the terrestrial birds found in Maine belong to the order 
Passeriformes , which includes warblers, vireos, flycatchers, thrushes, 
finches, and blackbirds. The remaining 30% include hawks (Falconiformes) ; 
grouse (Galliformes) ; woodcock, snipe, and killdeer (Charadriiformes) ; rails 
(Gruiformes) ; doves (Columbiformes) ; owls (Strigiformes) ; nighthawks and 
whipoorwills (Caprimulgiformes) ; swifts and hummingbirds (Apodiformes) ; and 
woodpeckers (Piciformes) . This chapter does not discuss waterfowl (see 
chapter 15, "Waterfowl") or seabirds, shorebirds, and wading birds (see 
chapter 14, "Waterbirds") . 

Nearly 230 species of terrestrial birds have been observed in Maine. Fifty- 
seven of these only occur accidentally and are so rare they do not warrant 
further discussion (appendix table 5). Of the remaining 171 species, 95 are 
present only during the breeding season (late spring and summer) , 51 are 
permanent residents, 15 are winter residents, and 10 are found only during the 
spring and fall migrations (tables 16-1 through 16-4). 

Terrestrial birds are found in all types of terrestrial and vegetated 
palustrine habitats. They are generally abundant in Maine, as elsewhere, 
except during winter when terrestrial birds are scarce in Maine. 

Terrestrial birds are important to people because of their recreational, 
sporting, and ecological values. People affect birds through habitat 
alteration, toxic chemicals, and accidental mortality. 

This chapter summarizes the seasonal occurrence of terrestrial birds in Maine, 
their habitat preferences, relative abundance, important aspects of migration 
and reproduction, factors affecting abundance, effects of people on birds, and 
management recommendations and data gaps. Additional information on life 
history characteristics for individual species is given in appendix tables 1 
to 4. A special case study on the status of bald eagles in Maine is also 

16-1 



10-80 



presented. Common names of species are used except where accepted common 
names do not exist. Taxonomic names of all species mentioned are given in the 
appendix to chapter 1. 

DATA SOURCES 

Information for this chapter was obtained from books and other published and 
unpublished souces. Breeding population trends were determined from data 
provided by the U.S. Fish and Wildlife Service's (USFWS) Cooperative Breeding 
Bird Survey (Robbins and Van Velzen 1974) . Wintering population trends were 
obtained from Audubon Christmas Bird Counts published in American Birds 
(formerly Audubon Field Notes ) . Miscellaneous records for accidental 
visitants and rare breeders were accumulated from Maine Field Naturalist , 
American Birds , Maine Birds (Palmer 1949), and an Annotated Checklist of Maine 
Birds (Vickery 1978). Data on regional distribution were derived from 
Cruickshank (1950), Bond (1971), Knight (1908), Maine Field Naturalist , (1946- 
1969), and personal field experience. The Woodcock Management Plan (Corr et 
al. 1977a) and statistics from the Maine Department of Inland Fisheries and 
Wildlife (MDIFW) were examined for woodcock information. The distribution of 
each breeding bird species is currently (1979) being mapped by the Maine 
Breeding Bird Atlas program in cooperation with Bowdoin College. 

SEASONAL OCCURRENCE 

Most species (approximately 90%) of terrestrial birds found in Maine are 
migratory and are only present part of the year. Because of this, birds can 
be grouped according to their seasonal occurrence. The largest group consists 
of the 95 species that only are present during the breeding season (late 
spring and summer), and then migrate south of Maine for winter (table 16-1). 
The second largest group (51 species) consists of permanent residents; birds 
present in Maine throughout the year (table 16-2) . Since the permanent 
residents also breed in Maine, the total number of terrestrial bird species 
breeding in Maine is approximately 145. It should be noted that many 
permanent resident species are also migratory, and while the species may be 
present year round, the same individuals may not be. Some individuals that 
breed in Maine migrate south for winter and are replaced by individuals that 
breed further north. A third group of birds is the winter residents (15 
species; table 16-3). For the most part these are birds that breed further 
north (i.e., snowy owls and northern finches) and are present in Maine only 
during winter. The last group consists of 10 species that occur in Maine only 
during spring and/or fall migration (table 16-4). An important species in 
this group is the peregrine falcon, an endangered species. Small numbers of 
peregrines are observed each year along the coast of Maine as they migrate 
from breeding areas in northern Canada to wintering areas in the southern 
United States. Peregrines are usually seen along the marine shorline; over 
salt marshes, tidal mudflats, beaches, and on offshore islands. They are also 
observed from mountains along migration routes used by raptors. Peregrines 
occur in Maine from mid-March through mid-May during spring migration, and 
from mid-August through mid-November on the fall migration. They feed on 
large songbirds, shorebirds, and waterfowl that are abundant along the coast 
during migration. 



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16-10 



HABITAT PREFERENCE 

An important characteristic of terrestrial birds is that each species has 
strong preferences for particular habitats, especially during the breeding 
season. While this is true of most wildlife, birds seem to be more selective 
than other vertebrates and their habitat preferences are better known. 
Factors important in habitat selection include the type of vegetation 
(grasses, herbaceous plants, shrubs, and trees), vegetation structure 
(density, height), plant species composition (deciduous, coniferous), 
presence of particular nesting sites or cavities and preferred nesting 
materials, song perches, and food abundance. 

The habitat preferences of terrestrial birds are indicated in tables 16-1 
through 16-4. For simplicity, nine classes of habitats are identified: (1) 
coastal shoreline, islands and outer headlands; (2) shores of lakes, ponds, 
streams, and rivers; (3) palustrine; (4) open fields and wet meadows; (5) old 
fields, edges, and other early successional habitats; (6) coniferous forests; 
(7) deciduous forests; (8) mixed forests; and (9) rural and developed land. 
Brief descriptions of these habitats, and the birds commonly occurring in 
each, follow. 

Outer Islands and Headlands 

Coastal islands and upland habitats along the shores of marine and estuarine 
waters are the primary nesting habitat for two very important terrestrial bird 
species; the bald eagle and the osprey. Both species nest in large trees near 
water, usually in areas with little human disturbance. Both species also nest 
inland along shores of lakes, ponds, and rivers, and in palustrine habitats, 
but the majority of their breeding populations are located along the coast. 

The coast is also an important migration area for peregrine falcons and 
merlins. Many other species migrate along the coast but use habitats not 
unique to the coast. Snow buntings and lapland longspurs may winter along the 
coast as well. 

Shores of Lakes, Rivers, Ponds, and Streams 

Only five species of terrestrial birds are found primarily along streams, 
lakes, and ponds, all of which are breeding species: belted kingfisher, tree 
swallow, rough-winged swallow, bald eagle, and osprey. The belted kingfisher 
nests in holes dug into banks and feeds on small fishes. The two swallows 
nest in cavities and feed on flying insects over the water. Bald eagles and 
ospreys also nest in these habitats, although they are most abundant along the 
coast and outer islands. 

Palustrine 

Approximately 28 species of birds utilize wetland habitats along the coast; 22 
are breeding residents, one is a permanent resident (bald eagle), one is a 
winter resident (short-eared owl), and four are migratory residents. Breeding 
birds typically found in wetlands include rails (Virginia and sora rails, 
common gallinule, and American coot), Wilson's snipe, marsh hawks, marsh 
wrens, red-winged blackbirds, common grackles, common yellowthroats , Wilson's 
warblers, swamp sparrows, and Lincoln's sparrows. Others that may be found 

16-11 

10-80 



in wooded swamps include several warblers (Tennessee, Nashville, and parula 
warblers, and northern water thrush), the yellow-bellied flycatcher, and the 
rusty blackbird. During migration and/or winter, palustrine habitats are 
important for several raptors, including peregrine falcon, snowy owl, short- 
eared owl, gyrfalcon, and merlin. 

Open Fields and Wet Meadows 

Open fields and wet meadows are used by approximately 32 species of birds. 
They are used as feeding areas by species such as hawks and swallows that nest 
in adjacent habitats, and as nesting and feeding areas for blackbirds (red- 
winged, meadowlark, bobolink) and sparrows (song, savannah, vesper, field, and 
sharp-tailed; figure 16-1). If suitable nesting cavities are available, 
American kestrels will nest and feed in these habitats. Many species of 
hawks, blackbirds, and sparrows feed in open fields and wet meadows during 
non-breeding seasons, also. 

Old Fields, Edges, and Successional Habitats 

Nearly 60 species of birds are found in successional or edge habitats, 
including 34 breeding residents, 14 permanent residents, 7 winter residents, 
and 4 migratory residents. Successional habitats form a continuum from 
relatively open, young serai stages, such as those found on recently abandoned 
farmland or clearcut forests, to older stages dominated by tall shrubs and low 
trees. Edge habitats occur where two structurally different habitats come 
into contact. Edges are found where forests are adjacent to fields or 
clearcuts, around clearings within forests, along the margins of ponds, lakes 
and streams, along highway and transmission line rights-of-way, and in rural 
and urban areas. Because of the range of vegetation types found in 
successional and edge habitats, it is difficult to generalize about the bird 
species found there. Often many different successional stages are found in 
the same general area and birds preferring each stage are found together. 
There are a few bird species considered true "edge" species (table 16-5). 
Edge species require both of the component habitats for successful nesting, 
using one habitat type for nesting or as song advertisement areas, and the 
other for feeding. Bird species utilizing edge habitats, and successional 
habitats in spruce-fir, pine, and deciduous forests are listed in figures 16-1 
through 16-4 respectively. 

Forests 

Bird populations in Maine's forests are usually the richest of any terrestrial 
habitats in both density and species. One reason is that forests have a 
variety of vegetative types (herbs, shrubs, and trees), and bird species 
adapted to utilize the different "layers" of forest vegetation occur together. 
In addition, there is usually a range of successional stages within forest 
stands caused by cutting, wind throw, or natural mortality that allows bird 
species adapted to early successional stages to exist. 

Forest birds can be grouped into those found in coniferous forests and those 
found in deciduous forests. Mixed coniferous-deciduous forests are inhabited 
by both groups of birds. 



16-12 




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10-80 



Table 16-5. Common Edge Species of Birds in the Characterization Area 



Mourning dove 

Black-billed cuckoo 

Common flicker 

Eastern kingbird 

Alder flycatcher 

Blue jay 

Grey catbird 

Brown thrasher 

American robin 

Starling 
Nashville warbler 

Yellow Warbler 

Magnolia warbler 

Chestnut-sided warbler 



Common yellowthroat 
Common grackle 
Brown-headed cowbird 
Cardinal 
Indigo bunting 
American goldfinch 
Rufous-sided towhee 
Savannah sparrow 
Vesper sparrow 
Dark- eyed junco 
Chipping sparrow 
Field sparrow 
White-throated sparrow 
Song sparrow 



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Coniferous forests . Two major types of coniferous forests are found 
along the Maine coast: spruce-fir and white pine-hemlock-hardwood (see 
chapter 9, "The Forest System"). A third type, scrub pine, is locally common 
in the characterization area. Fifty-nine species of terrestrial birds 
regularly occur in coniferous forests. Thirty-four are breeding residents, 14 
are permanent residents, 7 are only present during winter, and 4 only during 
migration (tables 16-1 thorugh 16-4) . 

Spruce-fir forests are composed of balsam-fir (Abies balsamea ) , and red, 
white, and black spruce (Picea rubens , P. glauca , and P. mariana ) . The bird 
associations occupying these forests have been studied extensively in Maine, 
and habitat requirements of most species are fairly well known (Davis I960; 
Morse 1968, 1971a, 1976, 1977; Rabenold 1978; Crawford and Titterington 1979; 
and Titterington et al. 1979). 

Characteristic bird species found in mature spruce-fir forests are 
blackburnian, black-throated green, and yellow-rumped warblers, golden-crowned 
kinglets, and hermit and Swainson's thrushes. Cape May, Tennessee, and bay- 
breasted warblers are frequently found in spruce-fir stands infested with 
spruce budworm. The parula and magnolia warblers, slate-colored junco, and 
white-throated sparrow are found in young forests, and in disturbed or open 
stands with well-developed understories . The common bird species associated 
with all successional stages of spruce-fir forests are depicted in figure 16- 
2. 

The other type of coniferous forest common along the Maine coast is dominated 
by white pine ( Pinus strobus ) , eastern hemlock ( Tsuga canadensis ) , and several 
hardwood species. The understory and shrub layers are generally more 
developed in pine-hemlock-hardwood stands than in spruce-fir. Characteristic 
bird species found in these forests include pine, black-throated green, 
yellow-rumped, Canada, and black-and-white warblers, common flickers, and 
white-throated sparrows (figure 16-3). 

A third type of coniferous forest found along the coast is a scrub pine 
community. These stands are dominated by either jack, pitch, or red pine 
( Pinus banksiana , P. rigida , and P. rubra , respectively). These forests are 
characteristically low and open with a dense ericaceous shrub layer and, 
because of this, many species of birds assocaited with these habitats are 
early successional or edge species. Common birds include rufous-sided 
towhees , white-throated sparrows, Nashville warblers, common yellowthroats , 
and yellow-rumped warblers (figure 16-3). 

Deciduous forests . Deciduous forests in coastal Maine are usually 
intermixed with coniferous forests. Large continuous areas of deciduous 
forest are uncommon along the immediate coast. Mature deciduous forests are 
multilayered (ground, shrub, low and high canopy trees), while successional 
forests, dominated by birches ( Betula spp.) and aspens ( Populus spp.), have 
only overstory and shrub layers. Approximately 35 species of terrestrial 
birds utilize deciduous forests. Twenty-five are breeding residents, 8 are 
permanent residents, 1 is a wintering species, and 1 is a migratory resident 
(tables 16-1 through 16-4). The most common birds found in deciduous forests 
are the red-eyed vireo, ovenbird, least flycatcher, American redstart, veery, 
wood thrush, ruffed grouse, and yellow-bellied sapsucker (figure 16-4). The 
black-throated blue warbler, scarlet tanager, rose-breasted grosbeak, and 

16-18 



pileated woodpecker are found in mature hardwood stands dominated by sugar 
maple ( Acer saccharum ) , American beech ( Fagus grandifolia ) , and yellow birch 
( Betula allegheniensis ) ; the northern hardwoods. 

Mixed forests . Bird species associations in mixed forests are difficult 
to characterize because of the intermixing of spruce-fir, pine, and deciduous 
forest bird communities. Species composition and relative abundance vary in 
proportion to preferred vegetation types. Mixed stands often have a greater 
diversity of bird species because of the combination of species adapted to 
each type. Approximately 53 species are found in mixed forests: 29 breeding 
residents, 20 permanent residents, 3 winter residents, and 1 migratory 
resident (tables 16-1 through 16-4). 

Rural and Developed Land 

Over 70 species of birds are found in habitats described as rural, suburban, 
or urban. Many of these species are successional and edge species. Thirty- 
five are breeding residents, 27 are permanent residents, 8 are winter 
residents, and 3 are migratory residents. Highly urbanized areas are 
dominated by 3 introduced species: starling, house sparrow, and rock dove or 
pigeon. The density of urban birds is often as high as in forested habitats 
because of the abundance of these 3 species (Erskine 1977). Bird species 
commonly found in rural or suburban areas include song sparrows, northern 
orioles, warbling vireos, house wrens, chipping sparrows, mockingbirds, 
mourning doves, swallows, chimney swifts, crows, blue jays, robins, yellow and 
chestnut-sided warblers, American redstarts, red-eyed vireos, and gray 
catbirds, among others (figure 16-1). 

ABUNDANCE OF TERRESTRIAL BIRDS 

The abundance of terrestrial birds is affected by several factors, including 
abundance of preferred habitats, food supply, weather, and predation (see 
"Factors Affecting Distribution and Abundance" below) . On a local scale bird 
populations have been determined on small areas (<100 acres; <40 ha) by spot- 
mapping, which estimates the number of breeding pairs on a unit of land 
(Robbins 1970) . The effects of various land use practices on breeding bird 
populations can be assessed using this method. 

On a regional scale long term trends in the relative abundance of birds are 
determined with index counts of breeding (Breeding Bird Survey) and wintering 
(Christmas Bird Counts) birds. While these index counts cannot be used to 
predict the bird populations on any particular area, they can point out 
significant increases or decreases in the abundance of bird species which can 
then be examined more closely. Additional surveys have been made to determine 
the abundance of bald eagles and ospreys in coastal Maine. Information on the 
bald eagle is contained in a special case study at the end of this chapter. 
The relative abundance of each species of terrestrial bird found along the 
Maine coast is given in tables 16-1 through 16-4. 



16-19 

10-80 



Breeding Bird Survey 

This nationwide survey samples bird populations along randomly selected 
driving routes, each 25 miles (45 km) long. Birds are counted during 3-minute 
stops every half mile along a route. By comparing only routes run in 
consecutive years by the same person(s) (to reduce observer bias) trends in 
species abundance can be determined. The survey is biased in favor of those 
bird species found along secondary roads so comparisons of abundance between 
species are not valid unless habitat availability along routes is determined. 

There are 17 breeding bird survey routes in the characterization area. Based 
on general vegetation zones suggested by Kuchler (1964) and Peterson (1975), 
these routes can be grouped into southern New England (4 routes in region 1), 
northern hardwood (9 routes in regions 2 to 5), and spruce-hardwood (4 routes 
in region 16) . 

The abundance of birds along survey routes is represented as either overall 
abundance (birds per route) or frequency of occurrence (percent of the 50 
stops on which a species occurs). The 20 most common species in each of the 
three zones are summarized in table 16-6. Regions 1 to 5 show similar trends 
in species abundance, but region 6 has some important differences. Hermit 
thrushes, red-eyed vireos, Nashville warblers, and solitary vireos are more 
common in region 6 than elsewhere, whereas wood thrushes, yellow warblers, 
song sparrows, red-winged blackbirds, grackles , catbirds, and robins are less 
abundant. These differences result from differences in habitat availability 
due to changes in land-use patterns. Some of these changes are described in 
chapter 9, "The Forest System" and chapter 10, "Agricultural and Developed 
Land." 

Breeding bird surveys have also been used to detemine trends in the abundance 
of individual species (table 16-7) . Significant long-term increases in wood 
thrushes and rufous-sided towhees have occurred in the characterization area, 
probably because of natural range expansion. Hermit thrushes have declined 
perhaps because of interspecific competition with wood thrushes (Morse 1971b). 

The breeding bird survey documented severe reductions in songbird numbers 
after spraying Phosphamidon and Fenitrothion for control of spruce budworm in 
New Brunswick (Pearce et al. 1976). Reduced numbers of small insectivorous 
songbirds were documented following severe cold springs in New Brunswick 
(Erskine 1978). In Maine, declines of swallows following a cold spell in May, 
1974, and the effect of the cold winter of 1976 on species such a winter wren, 
yellow-bellied sapsucker, hermit thrush, ruby-crowned kinglet, and eastern 
phoebe, that winter in the southeastern U.S., have also been demonstrated 
using results from the Breeding Bird Survey. 

The osprey is a breeding resident which is relatively abundant in coastal 
Maine. It nests on coastal islands and on the mainland along the shores of 
marine and estuarine waters. Available information on the locations of nesting 
ospreys is included in atlas map 4. No complete inventories of the breeding 
osprey population in coastal Maine have been conducted, but a majority of the 
island nests have been located. 



16-20 



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16-21 



10-80 



Table 16-7. Indices of Relative Abundance for Birds in Maine determined from 

the 1971-77 Breeding Bird Surveys, (the 1976 Index was set at lH0) a 



Species 




Indi 


=x of 


Relative Abundance 






1971 


1972 


1973 


1974 


1975 


1976 


1977 


American kestrel 


51 


432 


259 


136 


167 


100 


110 


Rock dove 


158 


63 


34 


23 


55 


100 


108 


Mourning dove 


100 


126 


7" 


116 


113 


100 


107 


Chimney swift 


106 


133 


146 


126 


90 


100 


115 


Common flicker 


132 


147 


127 


93 


112 


100 


116 


Yellow-bellied sapsucker 


245 


202 


175 


147 


118 


100 


56 


Hairy woodpecker 


29 


35 


26 


24 


122 


100 


140 


Downy woodpecker 


33 


75 


71 


71 


150 


100 


260 


Eastern kingbird 


120 


120 


106 


84 


106 


100 


118 


Eastern phoebe 


64 


71 


68 


74 


70 


100 


75 


Alder flycatcher 


43 


69 


30 


71 


121 


100 


101 


Least flycatcher 


47 


63 


47 


55 


46 


100 


132 


Eastern wood pewee 


82 


89 


96 


96 


78 


100 


109 


Tree swallow 


96 


109 


124 


92 


99 


100 


114 


Bank swallow 


311 


210 


348 


214 


96 


100 


136 


Barn swallow 


113 


115 


103 


89 


91 


100 


120 


Cliff swallow 


125 


241 


183 


78 


139 


100 


165 


Blue jay 


137 


145 


176 


139 


104 


100 


115 


Common crow 


104 


73 


79 


87 


94 


100 


88 


Black-capped chickadee 


137 


133 


151 


131 


106 


100 


176 


White-breasted nuthatch 


184 


102 


327 


187 


350 


100 


550 


Winter wren 


46 


92 


108 


168 


80 


100 


62 


Grey catbird 


59 


68 


74 


73 


88 


100 


94 


Brown thrasher 


129 


105 


6A 


70 


95 


100 


102 


American robin 


128 


119 


114 


100 


106 


100 


101 


Wood thrush 


92 


103 


96 


85 


116 


100 


120 


Hermit thrush 


122 


116 


122 


123 


112 


100 


56 


Veery 


109 


100 


104 


119 


111 


100 


112 


Ruby-crowned kinglet 


71 


64 


57 


71 


96 


100 


20 


Golden-crowned kinglet 





.25 


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5 


37 


100 


22 


Cedar waxwing 


112 


116 


66 


72 


100 


100 


111 


Starling 


126 


142 


107 


97 


114 


100 


109 


Solitary vireo 


111 


74 


74 


114 


80 


100 


75 


Red-eyed vireo 


104 


98 


77 


88 


107 


100 


222 


Black-and-white warbler 


26 


38 


41 


60 


86 


100 


108 


Nashville warbler 


14 


45 


51 


67 


99 


100 


110 


Parula warbler 


25 


56 


41 


46 


64 


100 


104 


Yellow warbler 


70 


63 


59 


60 


56 


100 


99 


Black-throated green warbler 


32 


46 


61 


63 


74 


100 


117 


Chestnut-sided warbler 


44 


68 


69 


60 


95 


100 


147 


Ovenbird 


75 


90 


92 


112 


97 


100 


92 



Index was calculated after Bailey (1967) 



(Continued) 
16-22 



Table 16-7. (Concluded) 



Species 



1971 



Index of Relative Abundance 



1972 1973 1974 1975 1976 1977 



Common yellowthroat 
American redstart 
Bobolink 

Eastern meadowlark 
Red-winged blackbird 
Northern oriole 
Common grackle 
Brown-headed cowbird 
Rose-breasted grosbeak 
Purple finch 
American goldfinch 
Rufous-sided towhee 
Savanna sparrow 
Chipping sparrow 
White-throated sparrow 
Song sparrow 



71 


75 


92 


92 


111 


100 


103 


86 


81 


84 


99 


77 


100 


116 


54 


43 


36 


66 


76 


100 


77 


49 


98 


61 


45 


72 


100 


131 


110 


109 


96 


99 


99 


100 


116 


138 


79 


100 


139 


71 


100 


102 


150 


139 


148 


138 


110 


100 


98 


118 


129 


139 


76 


75 


100 


89 


83 


77 


57 


81 


97 


100 


113 


107 


88 


91 


85 


81 


100 


77 


106 


120 


87 


69 


95 


100 


94 


148 


109 


93 


117 


125 


100 


128 


87 


110 


89 


113 


125 


100 


148 


140 


177 


95 


66 


115 


100 


121 


119 


146 


144 


141 


155 


100 


105 


93 


103 


98 


93 


104 


100 


112 



Christmas Bird Counts 

Wintering population trends of terrestrial birds are more variable than 
breeding populations. Weather severity, seed crops, small mammal populations, 
snow cover, breeding success, and fall migration patterns contribute to this 
variability. Many seed-eating and raptorial species occur on a cyclical or 
irregular basis corresponding to availability of food supplies on their 
breeding grounds. Invasions of northern seed-eating finches are synchronous 
throughout the U.S. in years of seed failures in the arctic and sub-arctic 
(Bock 1976). 

People influence the local abundance of wintering birds by planting fruit- and 
seed-bearing plants, and by providing bird feeders. About 16 species of semi- 
hardy bird species are able to winter in Maine because of food provided at 
bird feeders (table 16-8). 

The Audubon Christmas Bird Counts assess the relative abundance of birds 
during late December. These counts are inherently variable in both count 
effort and observer expertise, however, much of this variability can be 
removed by standardizing the counts and only comparing counts conducted during 
consecutive years. Evidence from an independent census method suggests that 
results from Christmas Bird Counts reflect real population trends, but they 
overemphasize roadside and urban birds and underestimate dispersed woodland 
species . 

16-23 



10-80 



Table 16-8. Bird Species That Require Artificial Feeding for Successful 
Overwintering in Coastal Maine. 



Ring-necked pheasant (stocked) 

Mourning dove 

Rock dove 

Mockingbird 

American robin 

Starling 

House sparrow 

Red-winged blackbird 

Rusty blackbird 

Common grackle 

Brown-headed cowbird 

Cardinal 

House finch 

Dark-eyed junco 

White-throated sparrow 

Song sparrow 



Relative abundance of terrestrial birds wintering in Maine from 1969 to 1977 
is presented in table 16-9. The index shows differences in relative abundance 
for each species compared to a base year (1976) which was given a value of 
100. The northern finches (pine siskin, common redpoll, pine grosbeak, and 
purple finch) show the greatest variability in abundance. With the exception 
of the tree sparrow, the sparrows generally have synchronous increases and 
decreases, particularly the song sparrow and white-throated sparrow. The 
hairy and downy woodpeckers, crow, starling, and goldfinch show little 
variation from one year to the next. The golden-crowned kinglet, yellow- 
rumped warbler, cowbird, purple finch, and junco have been generally 
decreasing, whereas the sharp-shinned hawk, mourning dove, northern shrike, 
and pine grosbeak have been increasing. 

ASPECTS OF MIGRATION 

Migratory birds arrive on their breeding grounds in Maine during April and May 
and depart for their wintering areas in late July, August, or September. 
During the spring period many other birds pass through Maine enroute to 
breeding areas farther north. 

Weather has a major effect on arrival and departure dates of migrants. 
Inclement weather, particularly cold weather in early spring, adversely 
affects insectivorous species by reducing food availability. For example, in 
the spring of 1974 many scarlet tanagers died from starvation during a cold 

16-24 



spell in late May that affected northern New England and New Brunswick (Zumeta 
and Holmes 1978). In spring, birds follow warm fronts north, and in fall they 
move south with the prevailing winds of cold fronts. 

Terrestrial birds migrate along the coast, along major inland waterways, and 
along prominent geological features such as mountain ridges (especially hawks 
which utilize deflected winds for soaring) . In spring many insectivorous 
birds follow river valleys north feeding on emerging insects. In fall they 
return to Maine and concentrate along the coast, after which they either fly 
directly to wintering areas in the West Indies or move in a southerly 
direction along the coast. Raptors, particularly peregrine falcons, merlins, 
kestrels, sharp-shinned hawks, and cooper's hawks, follow the coastline. 
Their primary prey are other smaller migrant birds. Peak movements of sharp- 
shinned hawks correspond with large movements of flickers, a frequent prey 
item of these hawks. Marsh hawks in Maine are more common along the coast 
than inland. They prey on shorebirds, other small birds, and small mammals in 
estuarine emergent marshes and coastal barrens. Areas along the coast at 
which hawks are known to concentrate are Harpswell Neck (region 1), Baileys 
Island (region 1), the Camden Hills (region 4), Mt. Waldo (region 4), the 
hills bordering Somes Sound (region 5), and Cadillac Mountain (region 5). 
Coastal peninsulas in region 6 are also used by migrating hawks but 
quantitative data are lacking. 

REPRODUCTION 

Time of Nesting 

The nesting period for most terrestrial bird species breeding in coastal Maine 
extends from May through July. Some species initiate nesting activities 
earlier (hawks, owls, and ravens) or later than this (goldfinches and cedar 
waxwings). Most migratory species begin nesting between mid-May and the first 
week of June. Individuals from the southwesternmost portions of the 
characterization area (regions 1 to 3) may begin nesting up to 10 days earlier 
than individuals of the same species nesting in the northeastern portion 
(region 6). Because the nesting season in Maine is relatively short compared 
to other areas of the U.S., most species raise only a single brood. 

Nest Type and Location 

Terrestrial birds nest in many locations either in open nests or cavity nests. 
Open nests are more exposed to predators and weather than cavity nests. They 
are placed in shallow depressions on open ground (nighthawks and killdeers), 
in dense vegetation on or near the ground (many warblers, blackbirds, 
thrushes, and marsh hawks), in shrubs (thrushes, brown thrashers, and 
catbirds), in tree canopies (many warblers, vireos , grosbeaks, tanagers, 
accipiters, and broad-winged hawks), in large open trees (hawks and ospreys), 
and in or on buildings (swallows and phoebes). Cavity nesters use a wide 
range of nest sites, including tree trunks (woodpeckers, owls, kestrels, 
great-crested flycatchers, nuthatches, chickadees, and bluebirds), sand, 
gravel, and peat banks (bank swallows and kingfishers), and buildings, 
bridges, and bird houses (purple martins, rough-winged swallows, and tree 
swallows) . 



16-25 



10-80 



Table 16-9. Index of Relative Abundance for Birds Counted During Annual Christinas 
Bird Counts in the Characterization Area trom 1969 to 1977; Indexes 
based on 1D7G Index of 100. 



Species 








YEARS 












1969 


1970 


1971 


1972 


1973 


1974 


1975 


1976 


1977 


Goshawk 


321 


57 


302 


94 


132 


20 


173 


100 


82 


Sharp-shinned hawk 


21 


184 


164 


123 


27 


11 


52 


100 


70 


Rough-legged hawk 





32 


36 


40 


11 


83 


40 


100 


21 


Bald eagle 


199 


96 


134 


159 


80 


86 


142 


100 


157 


Ruffed grouse 


569 


155 


636 


900 


160 


397 


269 


100 


566 


Rock dove 














6 


57 


111 


100 


57 


Mourning dove 


4 


5 


23 


27 


48 


32 


77 


100 


79 


Pileated woodpecker 


9 


3 








167 


77 


336 


100 


57 


Hairy woodpecker 


88 


137 


132 


135 


87 


145 


112 


100 


110 


Downy woodpecker 


117 


127 


136 


150 


93 


206 


109 


100 


94 


Blue jay 


65 


95 


82 


123 


84 


45 


69 


100 


68 


Common raven 


238 


183 


194 


227 


56 


59 


133 


100 


102 


Common crow 


159 


174 


141 


145 


91 


73 


91 


100 


74 


Black-capped chickadee 


98 


74 


102 


137 


105 


135 


139 


100 


120 


Boreal chickadee 


723 


230 


504 


203 


130 


206 


331 


100 


183 


White-breasted nuthatch 


172 


215 


115 


187 


152 


267 


115 


100 


140 


Red-breasted nuthatch 


183 


93 


139 


512 


50 


119 


123 


100 


51 


Brown creeper 


215 


42 


108 


88 


72 


155 


78 


100 


57 


Robin 


44 


4 


147 


18 


56 


18 


28 


100 


14 


Golden-crowned kinglet 


310 


61 


406 


364 


244 


470 


89 


100 


86 


Northern shrike 


21 


52 


31 


55 


25 


78 


106 


100 


181 


Starling 


171 


164 


206 


200 


176 


180 


161 


100 


198 


House sparrow 


217 


83 


67 


149 


68 


79 


94 


100 


51 


Red-winged blackbird 


117 


23 


144 


109 


79 


122 


53 


100 


56 


Common grackle 


34 


11 


52 


20 


41 


77 


80 


100 


57 


Brown-headed cowbird 


1084 


99 


516 


244 


527 


162 


151 


100 


108 


Evening grosbeak 


49 


58 


79 


53 


15 


48 


33 


100 


33 


Purple finch 


6 


87 


172 


25 


16 


6 


9 


100 


14 


Pine grosbeak 








1008 


1003 


8 


76 


562 


10 1 


779 


Common redpoll 


6271 


22 


4168 


21 


3 


9 


593 


100 


1988 


Pine siskin 


610 


76 


542 


290 


33 


23 


59 


100 


139 


American goldfinch 


5 


18 


40 


61 


27 


39 


34 


100 


30 


Dark-eyed junco 


539 


234 


257 


321 


133 


105 


101 


100 


31 


Tree sparrow 


65 


155 


120 


86 


51 


78 


84 


100 


62 


White-throated sparrow 


29 


1 


8 


11 


39 


9 


15 


100 


4 


Fox sparrow 


32 


1 


15 


5 


5 


6 


5 


100 


4 


Song sparrow 


40 


9 


26 


36 


32 


24 


26 


100 


7 


Snow bunting 


229 


381 


149 


123 








77 


100 


68 



16-26 



Nesting Cycle 

The nesting cycle of most terrestrial species may be divided into six phases 
(Black 1976): 

1 . Prenesting 

2. Nest building 

3. Egg laying 

4. Incubation (brooding) 

5. Nestling 

6. Fledgling 

Prenesting is the period between arrival on the breeding grounds and the 
beginning of nest construction. Pair formation, pair bond maintenance, and 
nest site selection take place during prenesting. 

Nest building may take up to a week for most passerines. Eggs are usually 
laid at a rate of one per day, with incubation beginning after the last egg is 
laid. High energy demands are placed on the female during the egg laying 
period. 

Brooding (incubation) keeps eggs at their optimal temperature and, to a lesser 
extent, provides a suitable humidity. Incubation for most small passerines 
lasts 12 to 14 days. Hole nesters incubate about 2 days longer than other 
small passerines (Welty 1975). 

The nestling stage lasts 12 to 13 days. Energy demands again increase for 
both male and female as they feed the nestlings. Disturbance of nests after 
the 7th or 8th day of the nestling stage often results in premature fledging 
and subsequent loss of all or part of the brood. 

Fledglings are under parental care for the next 10 to 12 days. These figures 
are average figures for small (warbler size) passerines and vary for 
individual species. Generally larger birds take longer for each phase. 

FACTORS AFFECTING DISTRIBUTION AND ABUNDANCE 

Natural factors affecting the distribution and abundance of terrestrial bird 
populations include habitat availability, competition, predation, disease, and 
weather. The abundance of suitable habitat is the most important factor 
affecting bird distribution. Unless disturbed, terrestrial habitats in 
coastal Maine eventually become forested (see chapter 9, "The Forest System"). 
Palustrine sites also fill with sediment and organic matter and become 
forests, but this is a much longer process than on upland sites (see chapter 
8, "The Palustrine System"). Natural factors returning forests to early 
successional stages include wind storms and fire, but people are the most 
influential force affecting land use patterns in coastal Maine. 

Competition for nest sites, food supply, roosting sites, and song perches 
limit the population size of some species. Territoriality is an intrinsic 
spacing mechanism for most species of terrestrial birds, and tends to reduce 
intraspecific competition for food and nesting sites. Competition between 
species is avoided by slight differences in habitat preference, food habits, 
feeding behavior, or preferred feeding heights. 

16-27 

10-80 



In general, predation and disease do not seem to be important factors limiting 
bird populations in coastal Maine. Ground nesters are more subject to 
predation than species nesting above ground or in cavities. Common predators 
on birds in coastal Maine include hawks, crows, ravens, blue jays, red 
squirrels, chipmunks, raccoons, foxes, coyotes, weasels, and domestic pets. 

Human Related Factors Affecting Abundance 

Human activities in coastal Maine affecting the distribution and abundance of 
terrestrial birds include habitat alteration, use of pesticides and 
herbicides, accidental mortality caused by collisions with automobiles or 
buildings, and hunting. Although the extent to which these factors effect 
bird populations in coastal Maine is not known, the general ways birds are 
affected are summarized below. 

Habitat alteration . Any activity that alters the composition and 
structure of a plant community also affects the relative abundance and species 
composition of the bird populations. Humans induce changes through logging 
(clearcutting or partial cutting), fire, herbicidal application, highway 
construction, transmission line construction, brush clearing, cull removal, 
and urban or suburban development. 

Extensive studies on the effects of clearcut logging on bird populations were 
conducted recently in northern Maine (Burgason 1977; Titterington 1977; and 
Titterington et al. 1979). Total densities of breeding birds decreased by 
half immediately after clearcutting, but increased to precut levels within 7 
years. Species composition also was affected, since species preferring forest 
habitats were replaced by edge species and species preferring early 
successional stages. 

Clearing for highway and transmission line corridors effects bird populations 
in a manner similar to that of clearcutting. Densities of breeding birds in a 
highway right-of-way decreased from 7 birds/acre (17 birds/ha) to 3 birds/acre 
(8.5 birds/ha; Ferris 1977). The association of birds replacing forest 
inhabiting species was mostly edge species and ground feeding birds. Unlike 
succession following clearcutting, the right-of-way association persists 
indefinitely because natural vegetation succession is arrested by mowing, 
herbicides, and brush clearing. An indirect effect of highways on bird 
populations results from increases in cowbird and starling populations along 
highways. Cowbirds are brood parasites and reduce the nesting success of 
other birds nesting in the right-of-way and adjacent forest habitat. 
Starlings use natural cavities as nesting sites and successfully outcompete 
native bird species for the limited number of natural cavities. 

Herbicides are used to control hardwood tree species in spruce-fir areas. 
This affects bird populations by altering habitat structure and species 
composition (Best 1972; Dwernychuk and Boag 1973; and Beaver 1976). The birds 
most affected include those utilizing immature deciduous forests (birch-aspen- 
red maple forest type) and early successional habitats (many edge species). 
Ruffed grouse are adversely affected as their preferred food sources include 
aspens, which are target species for herbicide treatments. 

Small alterations of habitats cause subtle changes in bird populations. The 
clearing of brush or the removal of blowdown trees in forests may lower the 

16-28 



densities of birds utilizing the ground and shrub layers. Removing dead and 
diseased trees may reduce the number of hole-nesting species (McClelland 
1977). Removal of hedgerows from agricultural and developed areas eliminates 
nesting cover and song perches for many edge nesting species that feed in 
fields or in hedgerow habitats (sparrows, certain warblers, blackbirds, 
flycatchers, and American kestrels). Hedgerow removal in England, for 
example, has been a major factor in the decline of species utilizing shrub 
habitats (Murton and Westwood 1974). Sand and gravel removal in bank swallow 
colonies during the breeding season results in swallow mortality. 

Habitat modifications can be beneficial to birds. Populations of edge species 
and species breeding and foraging in open habitats increase as blocks of 
forest are removed. Bird species benefiting from forest clearing include 
bobolinks, meadowlarks, savannah sparrows, horned larks, blackbirds, mourning 
doves, kestrels, and killdeer. Birds benefiting from herbicide treatments 
include species utilizing young and old conifers because plant succession is 
directed toward the rapid return of coniferous forests. Deciduous forest and 
mixed deciduous forest serai stages are eliminated. In contrast to ruffed 
grouse, spruce grouse benefit from this type of silvicultural treatment. 
Chimney swifts, barn swallows, cliff swallows, purple martins, phoebes, 
nighthawks, and rough-winged swallows benefit from nesting directly in or on 
buildings, bridges, or other structures. Bank swallow colonies and kingfisher 
burrows increased with the commercial excavation of gravel and sand deposits. 
Three introduced species, starling, rock dove (pigeon), and house sparrow, are 
so well adapted to developed environments they are considered pests in many 
areas because of their habit of nesting in or on human dwellings. 

Chemical contaminants . The primary sources of environmental contaminants 
that affect terrestrial birds in the characterization area are the chemicals 
used in spraying programs for the control of forest and agricultural insect 
pests. Secondary sources include heavy metal contamination , terrestrial oil 
spills, and air pollution. These have minor regional effects but may be 
significant locally. 

Prior to 1972, DDT and its derivatives (organochlorine compounds) were major 
causes for the decline of certain terrestrial birds that eat fish or other 
birds, especially osprey, eagles, and accipitrine hawks (Cooper's and sharp- 
shinned) . These chemicals degrade slowly and concentrate in tissues of birds 
high on the food chain. 

Since 1972 organophosphate and carbamate compounds have been used for the 
control of insect pests in Maine. These compounds break down rapidly and do 
not accumulate to toxic levels within food chains. Chemicals now used for the 
control of spruce budworm are Sevin, Dylox, and Orthene . Sevin is used most 
extensively on Maine's forest lands. Dylox is used primarily along the coast 
(near blueberry barrens) because of its low toxicity to bumblebees which 
pollinate blueberries, and Orthene is used near lakes, ponds, and rivers. 
Other chemicals used in Maine (currently registered by the Maine Department of 
Agriculture, Pesticide Control Board) include Fenitrothion, Phosphamidon, 
Mexacarbate, Guthion, Lannate, and Matacil (currently in experimental use 
only, but expected to be registered in 1980). Sevin, Dylox, Orthene, Lannate, 
and Matacil do not cause acute damage to birds but may affect their behavior 
and reproductive success (Moulding 1976). Acute damage to birds from the 
spraying of Phosphamidon and Fenitrothion insecticides for spruce budworm 

16-29 

10-80 



control was reported in New Brunswick (Pearce et al. 1976; and Erskine 1978). 
Declines in the population of small, high canopy feeding passerines in sprayed 
areas were reported in 1975. 

The major agricultural spraying program in coastal Maine is for control of the 
blueberry maggot (see atlas map 2 for the distribution of blueberry barrens). 
Guthion has been used since 1969 for the control of this pest. Prior to that, 
DDT and sodium arsenate compounds were used. Guthion is considered more 
toxic than chemicals used on spruce budworm. Three bird species (marsh hawks, 
vesper sparrows, and upland sandpipers) currently considered declining on a 
regional basis by the National Audubon Society (Arbib 1979), nest or feed in 
blueberry barrens sprayed with Guthion. The vesper sparrow began declining in 
eastern Maine during the 1940s (Bond 1947). The relationship between the 
declining populations of these species, blueberry field management techniques, 
and Guthion needs evaluation. 

In addition to direct toxicity, insect control programs deprive birds of food 
during the breeding season, a time when nearly all terrestrial birds in 
coniferous forests are insectivorous. Most of these feed in the canopy where 
food loss from insect control programs is greatest. Outer canopy feeders 
(middle and upper canopy species) are most affected, while bark drillers, bark 
gleaners, ground feeders, and shrub feeders are less affected. 

Although the subject has not been studied extensively, evidence suggests 
changes in behavior and reproductive success may be related to changes in food 
supply. For example, a recent study evaluating the effects of Sevin on birds 
reported a steady decrease in canopy feeders for 8 weeks following spraying 
(Moulding 1976). The decrease was the result of birds moving into nearby 
unsprayed areas where food was more accessible. These trends are similar to 
those reported for the insecticides Dylox (Chambers 1972; and Caslick and 
Cutright 1973), Orthene, and Matacil (Pearce 1970; and Moulding 1976). In the 
above studies a 12% to 16% decline in numbers was reported 2 to 3 weeks 
following field applications of the pesticides. Moulding' s study extended to 
8 weeks after spraying, at which time a 45% decline in bird numbers was 
reported. He concluded, "...nesting failure with concurrent food stress might 
lead to a breakdown in further nesting behavior or a shift toward unsprayed 
habitats for renesting later in the season, with a resulting site loyalty 
shift expressed the following year." The nestlings of birds flying longer 
distances to gather food in unsprayed areas could have reduced growth rates or 
reduced fledging success. 

Accidental mortality . An estimated 62 million birds die annually in the 
U. S. as a result of collisions with automobiles and human-made structures 
(Banks 1979). An estimated 297 of human-induced mortality results from road 
kills. The most common victims are song sparrows, robins, house sparrows, 
small owls, and pine grosbeaks. Birds also collide with lighthouses, radio 
towers, transmission lines, large plate-glass windows, airport ceilometers, 
and bridges. 

Little quantitative data on collision fatalities are available for coastal 
Maine. Kills have been reported for lighthouses and airport ceilometers 
(Ferren 1959; Fobes 1956; Packard 1958; and Reitz 1954) but mortality at large 
towers has not been reported in the coastal zone. Plate glass windows on 
large buildings and houses result in the death of many migrating birds. 

16-30 



Transmission lines also kill or injure large numbers of birds (Willard 1978). 
The magnitude of this problem is difficult to assess because victims usually 
do not fall directly below the lines or supporting structures and are usually 
removed by scavengers. However, researchers working along transmission lines 
agree power lines kill large numbers of birds. A recent symposium was 
conducted to evaluate the effect of transmission lines on birds (Avery 1978), 
and an environmental impact statement on the effects of transmission lines on 
wildlife was recently prepared for an area in northern Maine (Center for 
Natural Areas 1978). Both are important sources of data on actual and 
potential impacts and offer valuable management suggestions. Efforts to place 
lines away from migration routes or areas where birds must pass on a regular 
basis, such as between breeding and feeding areas, would be valuable. The 
placement of transmission lines leading from coastal power-generating centers 
needs to be considered in selecting future power generating sites. 

Hunting mortality . Four species of terrestrial birds are hunted for 
sport in coastal Maine: ruffed grouse, American woodcock, Wilson's snipe, and 
ring-necked pheasant (raised and released for hunting). Hunting can account 
for a substantial portion of the annual mortality of these species, but the 
harvest levels are regulated so as not to be detrimental to their populations. 
Most woodcock and snipe harvested are migrants from other areas, but early 
season hunting takes many local birds. Breeding populations of woodcock 
appear to be stable (Corr et al. 1977a). Population levels of grouse are 
variable as is their harvest. 

Other factors . Terrestrial birds are sensitive to disturbance during the 
breeding season. Disturbances early in the breeding cycle may cause birds to 
abandon their nests, while disturbances later in the cycle may cause young 
birds to fledge prematurely or cause increased predation on young birds. 
Cutting hay before young birds have fledged (i.e., late June and early July) 
may result in the loss of many field nesting species (bobolink, meadowlark, 
savannah sparrow, killdeer, and upland sandpiper). Disturbances early in the 
nesting cycle usually have less effect than disturbances later in the season 
since renesting may be possible. 

IMPORTANCE TO HUMANITY 

Terrestrial birds contribute to the quality of life along the Maine coast. 
They are important for hunting, bird watching and other recreational 
activities, or as indicators of environmental contamination. 

American woodcock, Wilson's snipe, ruffed grouse, and ring-necked pheasant are 
hunted for sport in the characterization area. Woodcock and grouse hunting in 
Maine is among the best in the northeast. Nearly 30,000 people hunt woodcock 
and 12,000 people hunt grouse each year in Maine (Maine Department of Inland 
Fisheries and Wildlife statistics). Hunting and hunting-related activities 
contribute to local economies through the purchase of guns, ammunition, food, 
lodging, hunting dogs, and other supplies. 

Bird watching, bird feeding, and natural history studies are important 
recreational activities in Maine. An estimated 100,000 households maintain 
bird feeders and in 1972 almost 6 million pounds (2.7 million kg) of bird seed 
were purchased in Maine (Cross 1973). Participation on Christmas Bird Counts 
increased from 100 in 1969 to almost 400 in 1977. In addition, accessories 

16-31 

10-80 



used for bird watching, such as binoculars, cameras, and field guides, 
contribute to local economies. 

Some species of terrestrial birds accumulate high concentrations of toxic 
materials, such as heavy metals or persistent pesticides, as they pass through 
the food chain. For this reason birds can act as indicators of environmental 
contamination, particularly where large amounts of chemicals are used. The 
most vulnerable of Maine's birds are ospreys , bald eagles, shrikes, and 
Cooper's and sharp-shinned hawks, because they prey on high-level consumers, 
including fish and other birds. 

Birds may be pests on certain agricultural crops. Blueberry growers consider 
birds, especially gulls, robins, and blackbirds, a nuisance because they feed 
on blueberries (Ismail et al. 1974). The magnitude of this damage has 
increased in recent years. Growers in mid-coast regions (regions 3 to 5) 
believe the problem to be more serious than growers in eastern Maine (region 
6; Ismail et al. 1974). Small fields with good cover nearby are more often 
affected than larger fields. 

Grouse and many species of finches (primarily pine grosbeaks) feed on buds or 
flowers of commercially important trees during fall, winter, and spring. This 
reduces productivity and may cause adventitious buds which disfigure trees. 
Feeding activity by woodpeckers may damage trees, and woodpeckers serve as 
vectors for the chestnut blight and dutch elm disease (personal communication 
from Dr. Richard Campana, Department of Botany and Plant Pathology, University 
of Maine, Orono , ME.; June, 1972). 

MANAGEMENT RECOMMENDATIONS 

Migratory game birds (common snipe, American woodcock, Virginia and sora 
rails, crows, and American coots) are managed by the U.S. Fish and Wildlife 
Service and the Maine Department of Inland Fisheries and Wildlife. Non- 
migratory game birds (ruffed grouse and pheasant) are managed by the MDIFW. 
The State prepared long range management plans for woodcock, ruffed grouse, 
and pheasant (Corr et al. 1977a, b, and c). Nongame terrestrial birds are 
protected by State and Federal laws. With the exception of the bald eagle 
(see case study below) no active management of nongame birds is currently 
underway in Maine. 

The best recommendation for managing terrestrial birds is the maintainence of 
adequate amounts of habitats used by birds. Urban, suburban, rural, edge, and 
successional habitats can be expected to increase in the future in coastal 
Maine at the expense of forests and palustrine habitats. More emphasis should 
be directed to preserving mature forests and palustrine habitats, as well as 
coastal shoreline areas (beaches and salt marshes), and coastal islands and 
headlands used by nesting eagles and ospreys. Developed habitats can be 
enhanced for birds by leaving areas of natural and diverse vegetation in parks 
and along water courses and highway corridors. Hedgerows and fencerows should 
be encouraged in agricultural areas. Forest management alternatives 
benefiting birds include leaving cull trees for cavity nesters, cutting in 
small patches, and maintaining a diversity of successional stages in close 
proximity to one another. 



16-32 



CASE STUDY: THE BALD EAGLE 

Introduction 

Bald eagles ( Haliaeetus leucocephalus ) have been treasured as our national 
symbol in the United States since 1782. In the ecological community they have 
an additional value as high level consumers and indicators of environmental 
quality. A recent decline in their populations and the designation of eagles 
as an endangered species resulted in widespread concern for their status. 
Bald eagles nesting in Maine represent more than 90% of the known eagle 
population breeding in the northeastern United States. Maine's eagles, 
especially those inhabiting the characterization area, are more closely allied 
to those of the Canadian Maritime provinces. Eagles breeding in coastal Maine 
and Nova Scotia are the major remaining segments of a previously larger, 
continuous maritime eagle population. 

Bald eagles inhabit the characterization area throughout the year. The Maine 
coast supports more than 75% of the State's resident breeding and wintering 
eagle populations and is used by spring and fall migrants. Coastal Maine 
offers food chains capable of supporting eagles throughout the year, 
relatively isolated sites for nesting habitat, and ice-free waters that 
enhance eagle winter residence. 

Status 

Taxonomy . The American Ornithologists' Union (1957) recognizes two 
subspecies of bald eagles. Breeding eagles and most wintering eagles in Maine 
belong to the northern race (H. 1. alaskansus Townsend) . Southern bald eagles 
(H. 1_. leucocephalus Linnaeus) are irregular visitors to the State. Palmer 
(1949) cited a confirmed occurrence of the southern race in coastal Maine in 
1890. These divisions are now considered arbitrary but have influenced 
recognition of bald eagles as an endangered species. 

Historical distribution and abundance . No early appraisals of bald eagle 
distribution or abundance in Maine are available. References to eagles appear 
in the notes of James Rosier (1605), Captain John Smith (1614), and John 
Josselyn (1672; in Palmer 1949) during explorations of coastal Maine. The 
Abenaki Indians' word for eagle was "Sowangan" . The name "Swan Island" in 
coastal Maine (region 2 and 5) is an adaptation of this word and implies 
eagles were present, not swans, as commonly assumed (Palmer 1949). Names such 
as Eagle Island, Eagle Hill (regions 1, 4, and 5), Eagle Bluff (region 4), 
Eagle Lake, and Eagle Point (region 5), reinforce the historical importance of 
the eagle. 

Previous population estimates imply eagle abundance in Maine has been 
relatively low since the turn of the century. Knight (1908) suggested that 
the breeding population did not exceed 100 pairs at the close of the 19th 
century. Palmer (1949) considered 60 breeding pairs to be a liberal estimate 
in the late 1940s. Historical breeding sites in the characterization area 
documented prior to the initiation of State nesting surveys in 1962, are 
summarized in table 16-10. 



16-33 

10-80 



Table 16-10. Historical (pre-1960) Breeding Sites of the Bald Eagle in 
the Characterization Area. 



Region and associated 
water body 



Years 



References 



Region 1 

Casco Bay 



Region 2 

Kennebec River 

Merrymeeting Bay 



Region 3 

Damariscotta River 



Muscongus Bay 
Region 4 

Penobscot Bay 

Jericho Bay 
Patten Bay 
Penobscot River 
Region 5 

Blue Hill Bay 

Dyer Bay 
Frenchman Bay 
Mt. Desert Island 

Union River 
Region 6 

Dennys Bay 
Englishman Bay 
Machias River 
Narraguagus Bay 



1860s 


Rolfe 1908 


1900s 


Hardy 1908 


1950s 


Allen 1955 


1870s-1880s 


Spinney 1926 


1900s 


Bent 1937 


1890s 


Anonymous 1898 


1930s-1940s 


Anonymous 1949 and Townsend 1957 


1950s 


Packard 1955 


1860s 


Baird et al. 1874 


1890s 


Willard 1906 


1950s 


Anonymous 1953 


1930s 


Norton unpublished 


1890s 


Knight 1908 


1950s 


Hebard 1960 


1900s 


Bent 1937 


1940s 


Anthony 1947 


1940s 


MacDonald 1962 


1920s-1930s 


Tyson and Bond 1941 


1950s 


Townsend 1957 


1950s 


Spencer 1980 


1920s-1930s 


Tyson and Bond 1941 


1920s-1930s 


Tyson and Bond 1941 


1940s-1950s 


Long 1951 and Townsend 1957 


1890s 


Knight 1908 


1930s 


Norton unpublished 


1870s 


Longfellow 1876 


1900s 


Palmer 1914 


1940s 


Anonymous 1945 



16-34 



Local groups, ranging between 25 and 52 eagles, were noted historically in 
coastal Maine at a large fish kill in Casco Bay (region 1; Josselyn 1672), as 
well as at Damariscotta Lake (region 3; Bent 1937), Penobscot Bay (region 4), 
and the Narraguagus River (region 5) during migration. Wintering eagles in 
Maine formerly were characterized as common to occasionally numerous in some 
coastal regions (Palmer 1949). 

Breeding population . Nesting inventories from 1962 to 1979 identified 76 
bald eagle breeding sites in the characterization area. Their distribution 
and recent occupancy status are shown in figure 16-5. Fifty-two of these 
sites have been occupied at one time or another since 1975. Eighty-three 
percent of the State's breeding sites are in eastern Maine between the 
Penobscot River and St. Croix River drainages, primarily in regions 5 and 6 
and the interior portion of Washington County. Breeding sites for bald eagles 
in coastal Maine are included in atlas map 4. 

Surveys of bald eagles nesting in the characterization area since 1962 are 
summarized in table 16-11. These data provide the best estimates of the 
annual breeding population and production of young. The apparent population 
trends are not actual but are the product of variations in sampling 
methodology. The data suggest coastal Maine's breeding eagle population is 
increasing and the number of occupied breeding sites nearly tripled from 15 to 
40 between 1967 and 1978. Such apparent growth is primarily an artifact of 
improved survey coverage. The largest apparent advancement occurred during 
intensive search efforts of a recent study (Todd 1979; and Todd and Owen 
1979). A 43% increase in the number of occupied sites between 1976 and 1978 
paralleled 23% and 36% increases in the respective numbers of breeding sites 
and intact nests monitored in the characterization area. Discovery rates of 
new sites suggest the present survey efficiency does not exceed 80% of the 
total population. The apparent decrease from 1978 to 1979 reflects a loss of 
breeding pairs and/or the effects of a delayed survey in 1979. The latter 
probably underestimated the population size because some unsuccessful breeding 
pairs abandon their nests early. 

The known production of fledgling eaglets in coastal Maine increased more than 
ten-fold from a low of 2 in 1967 and 1972 to a high of 26 in 1979. The 
increase is less dramatic on a production rate basis but average recruitment 
since 1976 is significantly higher than it was in previous years. Both 
nesting success (the number of occupied sites where eaglets fledge) and 
fledgling brood size (the number of eaglets fledging from a successful nest) 
increased significantly. 

The recruiting of eagles in coastal Maine between 1977 and 1979 was 0.63 
fledglings for each occupied site and 0.73 fledglings for each apparent 
nesting attempt (excluding nonbreeding pairs), both of which remain below 
minimal numbers required for population stability. Eagles nesting on Cape 
Breton Island, Nova Scotia, Canada (the other major breeding area in the 
Northeast) averaged 1.35 fledglings for each apparent nesting attempt during 
1978 to 1979 (Smith, unpublished ) . The productivity of relatively healthy 
eagle populations in Michigan (Postupalsky , unpublished ) , Minnesota (Mathisen 
1979), and Kodiak Island, Alaska (Delaney, unpublished ) during 1977 to 1979 
ranged between 0.95 to 1.09 fledglings per occupied site and 0.97 to 1.22 
fledglings per apparent nesting attempt. The decline in fledgling recruitment 
of Maine eagles indicates its population is declining. 

16-35 

10-80 




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16-37 



10-80 



Regional differences in number of breeding sites and eagle production are 
manifest among Maine's breeding eagles (table 16-12). Nearly two-thirds of 
the State's known breeding population and eagle production is in coastal 
Maine. More than 50% of these state totals are in regions 5 and 6. Highest 
nesting densities occur in the Frenchman Bay (region 5) and Cobscook Bay 
(region 6) vicinities, although recruitment is significantly greater in the 
latter where 1977 to 1979 means were 0.44 and 0.88 fledglings per occupied 
site, respectively. Recruitment rates in all regions are below population 
maintenance levels. 

A striking decline in bald eagle breeding numbers in this century is apparent 
along the southwestern coast, especially in region 2. Fifteen occupied nests 
on the lower Kennebec River estuary dwindled to 3 by 1908 (Palmer 1949). 
Slightly upriver, the Merrymeeting Bay area was once characterized as having a 
"colony" of nesting eagles. These two areas were inhabited by only 1 and 2 
breeding pairs respectively in 1979. 

No occupied breeding sites have been found in region 1 since State nesting 
surveys began in 1962. A maximum of seven breeding pairs have been recorded 
in regions 2, 3, and 4 since 1977. Eagles nested successfully at only four of 
these sites. Early nesting surveys in Maine observed greater nesting activity 
in these western coastal and midcoastal areas. The contrast between past and 
present distribution patterns reveals a slight decline and/or shift of the 
State's resident breeding population. 

Wintering population . Aerial inventories of wintering eagles in the 
characterization area totaled 98 eagles in 1977; 88 in 1978; and 88 in 1979. 
Midwinter populations in coastal Maine averaged 82% of the Statewide totals. 
Previous estimates of wintering eagle numbers in Maine were based on limited 
ground counts and are considerably lower. Long term indices of the State's 
winter eagle population are limited to results of Christmas bird counts 
sponsored by the National Audubon Society, and midwinter waterfowl and eagle 
inventories by Maine Department of Inland Fisheries and Wildlife. Extreme 
annual fluctuations in these data indicate the inappropriateness of Christmas 
counts as a measure of abundance. 

The midwinter distribution of bald eagles in coastal Maine is summarized in 
table 16-13. Sixty-seven percent were found from the Penobscot River estuary 
eastward, almost evenly divided between regions 4, 5, and 6. Regions 1 and 3 
receive light, variable use by wintering eagles. 

Despite dispersion in the winter population, four areas of coastal Maine are 
significant wintering grounds. They are Cobscook Bay (region 6), Frenchman 
Bay (region 5), the Penobscot River estuary (region 4), and the Kennebec River 
estuary (region 2) . Combined midwinter counts in these areas averaged 42% of 
1977 to 1979 statewide populations. 

Cobscook Bay, Frenchman Bay, and the Kennebec River estuary once supported 
comparable numbers of wintering and nesting adult eagles. The consistently 
high year-round population levels in the two former coastal areas reaffirm 
their crucial importance to Maine's bald eagles. 



16-38 



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16-39 



Table 16-13. Number of Wintering Bald Eagles Counted and Percentage Mature 
in Maine During Mid-January 1977, 197S, and 1979. 



Area Year Number of ea gle s Percentage Mature/Inmatur ft 

Mature Immature Total Mature Immature 



Coastal Maine 1977 81 17 98 83 17 

1978 72 16 88 82 18 

1979 75 13 88 85 15 
Region 1 1977 3 14 75 25 

1978 2 13 67 33 

1979 10 1 100 
Region 2 1977 6 4 10 60 40 

1978 6 4 10 60 40 

1979 5 4 9 56 44 
Region 3 1977 8 19 89 11 

1978 2 2 100 

1979 4 15 80 20 
Region 4 1977 23 3 26 88 12 

1978 15 3 18 83 17 

1979 16 2 18 89 11 
Region 5 1977 19 5 24 79 21 

1978 28 4 32 87 13 

1979 26 4 30 87 13 
Region 6 1977 22 3 25 88 12 

1978 19 4 23 83 17 

1979 23 2 25 92 8 
Interior Maine 1977 16 2 18 89 11 

1978 17 4 21 81 19 

1979 18 3 21 86 14 
Statewide total 1977 97 19 116 84 16 

1978 89 20 109 82 18 

1979 93 16 109 85 15 



16-40 



The Penobscot River estuary winter eagle population is derived strictly from 
seasonal immigration. Winter occupancy levels there vary more than those of 
other coastal regions, where resident eagles may remain throughout the year. 
The Kennebec River estuary is notable for high proportion of immature eagles 
among its wintering eagle populations. The 1977 to 1979 mean was 45%. This 
fact is significant in view of the nearly complete nesting failure of eagles 
nesting in the Kennebec River watershed. It confirms the probability of a 
seasonal influx of nonresident eagles into coastal regions where resident 
breeding populations may also winter. 

The composition of coastal Maine's 1977 to 1979 midwinter eagle populations by 
age class averaged 83% adult and 17% immature eagles. Previous counts of 
eagles wintering in Maine also revealed a low percentage of immature birds, 
i.e., 11% in 1962 (Sprunt 1963), 21% in 1963 (Sprunt and Ligas 1964), and 
14% in 1975 (Cammack 1975). Data computed over a period of years, 1961 to 
1977 (Christmas Bird Counts) and 1963 to 1978 (Midwinter Waterfowl/Eagle 
Inventories), indicate only 21% immature eagles in Maine's wintering eagle 
population. 

The age ratio is biased against immature eagles because their relatively 
inconspicuous plumage makes them less visible to surveyors. Poor reproductive 
success in Maine's breeding eagle population also contributes to low 
percentages of immature eagles. Age ratios of wintering eagles in the Pacific 
Northwest indicate a range of 35% to 52% immature individuals (Hancock 1964; 
Servheen 1975; and Stalmaster 1976). The latter figures probably reflect 
greater recruitment among eagles nesting in the Pacific Northwest. 

Maine's midwinter eagle population is widely dispersed. The absence of large 
winter concentrations possibly reflects a lack of locally abundant foods which 
could result in a scarcity of immatures whose foraging skills are not well 
developed. 

Migration . No data are available on migration of adult bald eagles from 
Maine. Only 16 immature eagles among those banded as nestlings in Maine have 
been relocated after fledging. Seven first-year, one second-year, and one 
third-year bird were found within 90 miles (145 km) of their natal nests in 
the State. Three others were seen during their first fall or winter in Maine 
and two wintered in Massachusetts. A two-year-old eaglet was relocated 220 
miles (355 km) away in New Brunswick. The only documented case of dispersal 
out of the northeast was a juvenile observed in South Carolina, having 
traveled over 930 miles (1500 km) within 4 months of fledging in Maine. 

Adult eagles were observed on 1977 to 1979 midwinter surveys at 20 coastal 
nest sites that had been occupied the previous breeding season. At least 45% 
of the breeding sites in the characterization area known to be inhabited 
during the 1976 to 1978 breeding seasons also were occupied in winter. Many 
pairs nesting on the coast remain on breeding territory throughout the year. 
However, winter ranges are flexible and change to meet the food supply. 
Fidelity to nests by wintering eagles supports the belief that much of the 
eagle population nesting in Maine also winters in the State. 



16-41 

10-80 



Habitat 

Characteristics of eagle habitat . Bald eagle habitat is closely 
associated with bodies of water, which provide the preferred diet of fish. 
Coastal marine and estuarine systems contain 82% of all the eagle breeding 
sites known in the characterization area. Lacustrine and riverine habitats 
support only 17% and 1%, respectively, of the breeding areas in coastal Maine. 
Most nests are located on offshore islands and nearby headlands adjacent to 
bays. The relative isolation of these sites offers ideal breeding habitat to 
eagles . 

Bald eagles nest generally near large water bodies. The distance of 118 nest 
sites in Maine from open water averages only 149 yards (135 m) . Eighty-one 
percent are within 275 yards (250 m) . Mean distance from the shoreline varies 
significantly in different habitats from 44 yards (40 m) on coastal islands to 
253 yards (230 m) on nearby headlands. This contrast between adjacent areas 
probably results from greater shoreline development and greater human activity 
on the mainland. 

Nest locations near water provide both proximity to a food source and exposure 
of the site. Exposure allows maximum visibility from the nest, a clear flight 
path to and from the nest, and updrafts favorable for flight. The high 
proportion (88%) of supercanopy and dominant nest trees used by eagles in 
Maine also reflects exposure requirements. Seventy-three percent are old- 
growth white pines, which normally offer superior height and whorls of strong 
limbs to support nests. 

Eagle populations in coastal Maine are probably largest during winter. All 
eagles observed in the characterization area during midwinter surveys were 
found in marine and estuarine habitats. Inland lakes, ponds, and rivers are 
used infrequently, since winter ice cover limits foraging opportunities. 
Wintering eagles also favor undeveloped shoreline habitats although they 
appear to be more tolerant of human activities than breeding eagles. Tall 
white pines near open water are favored winter perches. They provide a wide 
panorama, are accessible, and have stout horizontal branches for secure 
perching. 

Food Habits 

Bald eagles are capable but often inefficient predators and generally adopt an 
opportunistic strategy that includes scavenging carrion. They forage 
primarily in areas of open water. Land-based feeding attempts also are 
limited to open areas rather than forested habitats. 

The diet of Maine eagles varies considerably in different habitats. More than 
90% of eagle food remains observed at nest sites during the breeding season in 
freshwater habitats were fish, primarily bottom-dwelling species, such as 
brown bullhead, chain pickerel, and white sucker. Fish represent only 35% of 
the food debris in marine and estuarine systems. Bottom-dwelling species, 
such as tomcod and sculpins, often are eaten but eagles also eat alewives, 
blueback herring, and American eels. 

Maine eagles increasingly depend on birds as a food source during winter. 
Avian remains constitute over 80% of eagle food debris in coastal Maine on a 

16-42 



year-round basis. Twenty different species of waterfowl and seabirds are 
represented in the food remains and more than 50% are black ducks and gulls. 
Food-debris data are biased somewhat and underrate the incidence of fish 
because fish remains are digested or decompose rapidly. 

Reproduction 

Bald eagles are believed to mate for life. They exhibit high fidelity to 
their breeding sites. An individual pair may have several alternate nests but 
the same nest frequently is used in successive years. The distance between 
nests within a breeding area averages 0.9 miles (1.5 km) in Maine. 

Some adult eagles are on territory by 25 February in coastal Maine. 
Prenesting activities include courtship flights and repairs or additions to 
the nest. The nest framework is constructed of limbs and branches of trees. 
Finer materials are used to line the nest interior. Over the years eagle 
nests become quite large. In Maine, nest size averages 5 feet (1.5 m) in 
diameter and 3 feet (1.0 m) in depth but ranges up to 10 feet (3m) and 17 feet 
(5m), respectively. Most eagle nests are built below the tops of trees but 
their bulk may eventually girdle and kill the treetop. 

Considerable intraregional and interregional variation in the timing of 
reproduction is evident among eagles breeding in Maine. In coastal areas a 
clutch of 1 to 3 eggs is laid between early March and mid-April. Both adults 
brood the eggs but the female predominates throughout the 35-day incubation 
period. Incubation begins with the first egg laid, so hatching is staggered 
and siblings may differ in age and size. The time of hatching ranges from 
mid-April to mid-May. Eaglets remain in the nest for 10 to 13 weeks before 
making their first flights. Fledging dates occur potentially from mid-June to 
early August on the coast. Family groups may remain together into the fall 
before the young disperse. 

Natural Factors of Abundance 

Considerable habitat is available to bald eagles in coastal Maine, as 
evidenced by nearly 263,417 acres (106,647 ha) of inland wetlands (preliminary 
data of National Wetlands Inventory) and 4000 miles (6400 km) of irregular 
coastline. Natural limitations on eagle abundance are exceeded by limitations 
resulting from human activities. For example, habitat and food availability 
generally are not limiting, but modifications of the environment by people 
lowered habitat quality and contaminated the diet of eagles. 

Inherent characteristics of the species, including recruitment, reproductive 
potential, and survivorship, limit the ability of bald eagles to recover from 
population declines. Field observations imply a lack of surplus nonbreeding 
adult eagles in Maine. A low reproductive potential, averaging only 1.3 
fledglings/nesting attempt, is characteristic of eagles even in relatively 
healthy Alaskan populations (Chrest 1964; Hensel and Troyer 1964; and Robards 
and King 1967). High postfledging juvenile mortality is indicated by 
estimates of only 10% to 20% survival through 3 years of life (Sherrod et al. 
1976; and Gerrard et al. 1978). Bald eagles do not attain maturity until the 
4th or 5th year of life. 



16-43 



10-80 



Human-caused Factors of Abundance 

Human activities such as shooting, habitat alteration, and environmental 
pollution have affected bald eagle populations. Bald eagles historically have 
suffered from human persecution in Maine. Early settlers apparently used 
eagles for food on occasion (Palmer 1949). Moorehead (1922) found eagle bones 
among Indian shell heaps in Lamoine (region 5). The town of Vinalhaven 
(region 4) approved a 20 cent/head bounty on bald eagles in 1806 (Lyons et al . 
1889) but this precedent was not adopted statewide. Eagle eggs were collected 
and offered for sale in the late 1800s. Spinney (1926) cited numerous 
instances in which pine trees supporting eagle nests were cut for timber. 

Shooting has been the most common cause of mortality among Maine eagles in 
recent years. Both adult and immature eagles are shot, indicating the problem 
is not solely one of recognition. The frequency of shooting deaths among 
known mortalities of Maine eagles is near the 407 o level observed nationwide. 
Shooting incidence declined nationally (Coon et al. 1970; and Prouty et al. 
1977) but not in Maine. At least five eagles have been shot in coastal Maine 
since 1963. Other direct losses of eagles in Maine attributable to people are 
trapping, electrocution, and lead poisoning (via ingestion of waterfowl 
containing lead pellets). The impact of human-related mortality on an eagle 
population may exceed that of the normal decline in recruitment (Young 1968) . 

Environmental contaminants found in Maine bald eagles and in their eggs 
include 13 organochlorines and 5 heavy metals. Foremost are pesticides such 
as DDT and dieldrin, industrial wastes such as PCBs (polychlorinated 
biphenyls), and mercury. Residues of DDE and DDD (metabolic by-products of 
DDT), dieldrin, PCBs, and mercury occur in all eagle egg and carcass samples 
from Maine. Other contaminants appear at lower levels. 

Contaminants at high levels are toxic to some animals but their persistence 
and cumulative effects at lower levels are not known for Maine eagles. They 
accumulate in eagles through contaminated foods and may be a threat to 
reproductive success. Reduced eggshell thickness and increased incidence of 
egg breakage are related to organochlorines, particularly DDE. Shell 
thickness of 34 eagle eggs collected in Maine between 1967 and 1979 averaged 
0.52 mm, 15% below normal. No significant reduction in levels of DDE, PCBs, 
mercury or associated thinning has occurred in Maine eagle eggs since 1967. 
These contaminants probably have additive effects and their total impact is 
unknown. Embryo mortality observed at various stages in unhatched eggs of 
Maine eagles may be caused by DDE, PCBs and/or mercury. 

The impact of organochlorines on bald eagle productivity in Maine becomes 
evident when the Maine eagle population is compared to those in other areas of 
the country. The amounts of residues of DDE, DDD, DDT, and dieldrin in Maine 
eagle eggs surpassed those of Florida and Wisconsin in 1968 (Krantz et al. 
1970). Levels of contamination in Maine eagle eggs in 1969 were higher than 
those in Minnesota and Alaska (Wiemeyer et al. 1972). Recruitment also is 
lower among Maine eagles than in these four populations. Organochlorine 
residues similar to those in Maine eagle eggs were reported in northwestern 
Ontario, where productivity also was declining (Grier 1974). Detrimental 
levels of mercury in bald eagle eggs are relatively unique to Maine (Wiemeyer, 
unpublished ) . 

16-44 



Regional and habitat differences exist in levels of contamination in Maine 
eagle eggs (table 16-14). Eggs from western coastal regions have higher mean 
residues of DDE, DDD, DDT, dieldrin, and PCBs than those of eastern coastal 
regions. This evidence concurs with the low productivity of bald eagles in 
western Maine. Residues in eggs from coastal nests tend to be higher than 
those in eggs from inland sites which may reflect greater contamination in 
estuarine habitats and/or the higher trophic position of eagles in coastal 
Maine . 

Limited sampling indicates Maine eagles receive these contaminants from food 
supplies within the State. Seven of 13 organochlorines present in Maine 
eagles and their eggs were found in fish and waterfowl samples collected 
throughout the State. Herring gull carcasses contained all 13 
organochlorines. DDE, PCBs, and mercury residues are significantly higher in 
fish-eating species, such as herring gulls and mergansers, than in black 
ducks. This trophic relationship demonstrates the bald eagle's vulnerability 
to receiving concentrated doses of contaminants as a result of its terminal 
position in many food webs. 

Four groups of eagle foods from Maine exhibited significant declines of DDE 
residues between 1966 and 1974. Trends in PCB exposure are uncertain but 
stable or increasing levels in fish and pooled black duck wings from Maine 
have been ci*:ed (White and Heath 1976; Wiemeyer et al. 1978). High mercury 
levels were detected in livers of mergansers from major eagle wintering areas 
on the Kennebec and Penobscot Rivers. Point sources of mercury pollution on 
the Penobscot River and PCBs on the Kennebec River have been cited (New 
England River Basins Commission 1977). 

The impact of human activity on nesting bald eagles has not been documented in 
Maine. Nesting success in other eagle populations has been correlated 
inversely to permanent, visible signs of human proximity. Examples are 
buildings, roads, boat landings, and timber harvests (Juenemann 1973; and 
Grubb 1976). Two types of human disturbance have been observed to adversely 
affect eagle nesting in Maine, i.e., climbing to an active nest, and felling 
of a nest tree. A dirt road and power line were constructed to within 654 
feet (20m) of a nest that was active in 1976 but which has since been 
abandoned. 

Other less visible human activities also may affect eagles. Diminishing 
quantities of old-growth timber, especially white pine which is preferred by 
eagles for nesting, may present future problems. Disturbances to nesting 
eagles are most harmful during incubation (Mathisen 1968) and as eaglets 
approach fledgling age (Harper 1974; and Weekes 1975). 

Increasing human activity and land development are encroaching upon favored 
eagle habitats in midcoastal and eastern coastal Maine (regions 4 to 6) and 
already have modified western coastal areas (regions 1 to 3) formerly occupied 
by a breeding population. Developmental projects potentially detrimental to 
the availablity or quality of bald eagle habitats or food supplies, merit 
careful evaluation, especially those affecting the population center and core 
of nesting in eastern coastal Maine. 



16-45 

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16-46 



Socioeconomic Importance 

The bald eagle has great aesthetic appeal to many people. The high level of 
interest in Maine eagles is evident from large-scale public participation in 
recent eagle count surveys. Citizens reported more than 5000 eagle sightings 
during a two-year period. Increasing demand is also reflected by the extent 
of press coverage of issues related to Maine eagles, public requests for slide 
shows and lecture programs, and a mailing list exceeding 1000 names for 
receipt of annual newsletters describing the status of Maine eagles. The 
recent designation of Maine's bald eagles as an endangered species should 
stimulate public interest further. 

Bald eagles have been revered traditionally as the national symbol 
representing greatness, strength, and our natural resources. They also have 
an important biological role in removing weak, diseased, or otherwise less-fit 
individuals from prey populations. Furthermore, bald eagle populations serve 
as a sensitive indicator of environmental quality because of their 
susceptibility to chemical contaminants and other human alterations of natural 
systems . 

Management 

Protection . The Federal Bald Eagle Protection Act of 1940 made illegal 
the taking, possessing, selling, purchasing, bartering, transporting, 
exporting, importing, or shooting of any bald eagle, or parts thereof. In 
1972 Congress established maximum penalties for shooting bald eagles as a 
$5000 fine and/or 1-year imprisonment. Convicted second offenders were 
penalized up to $10,000 and/or 2 years in prison. A further stipulation 
offered one-half of the fine to the person providing information leading to a 
conviction. 

The southern bald eagle was listed officially as an endangered species in the 
Federal Register on 11 March 1967. The endangered status was extended to 
northern bald eagles in all but five of the 48 contiguous states on 14 
February 1978. The latter designation included Maine, but excluded Michigan, 
Minnesota, Wisconsin, Oregon, and Washington, where eagles are listed as 
threatened. 

The Endangered Species Act of 1973 thus provides further protection to Maine's 
bald eagles. Section 7 of the Act states: 



The Secretary shall review other programs 
administered by him and utilize such programs in 
furtherance of the purposes of this Act. All 
other Federal departments and agencies shall, in 
consultation with and with the assistance of the 
Secretary, utilize their authorities in 
furtherance of the purposes of this Act by 
carrying out programs for the conservation of 
endangered species and threatened species listed 
pursuant to section 4 of this Act and by taking 
such action necessary to insure that actions 

16-47 



10-80 



authorized, funded, or carried out by them do not 
jeopardize the continued existence of such 
endangered species and threatened species or 
result in the destruction or modification of 
habitat of such species which is determined by 
the Secretary, after consultation as appropriate 
with the affected States, to be critical." 

Critical habitat for bald eagles has not been officially identified, but 
efforts are underway nationwide to establish criteria for this designation. 
Regional Bald Eagle Recovery Teams were formed in 1978 to identify critical 
habitat and coordinate other aspects of bald eagle research and management. A 
recent study of bald eagles in Maine, co-sponsored by the U.S. Fish and 
Wildlife Service, the Maine Department of Inland Fisheries and Wildlife, and 
the University of Maine at Orono Wildlife Department (Todd 1979; and Todd and 
Owen 1979) provided a basis for these evaluations within the State. 

Measures to protect Maine bald eagles were initiated prior to their 
designation as an endangered species since 1973. The U.S. Fish and Wildlife 
Service (FWS) coordinated a cooperative landowner agreement program to 
preserve eagle nest sites in the State (Gramlich 1975). FWS also conducted 
experimental transplants to bolster the depressed productivity of Maine eagles 
(U.S. Department of the Interior 1974, 1975, 1976, and 1979). A total of 18 
eggs and nestlings from captive breeding or wild populations in Minnesota and 
Wisconsin were substituted for eggs of traditionally unsuccessful breeding 
pairs in Maine. Seven fledglings resulted. Four of the removed eggs hatched 
and were reintroduced via fostering. Improved techniques should permit 
greater success rates in the future. 

Corr (1976) prepared a bald eagle management plan for the Maine Department of 
Inland Fisheries and Wildlife. He described basic population status, habitat 
availability, management concepts, and research needs. The latter were 
incorporated as basic research objectives of an intensive study conducted from 
1976 to 1978 (Todd 1979; and Todd and Owen 1979). Investigations focused on 
the ecology of Maine's breeding eagles (nesting habitat, breeding chronology, 
population size, productivity, and factors affecting the population), 
wintering eagles (population size, distribution and location of major 
wintering areas), and eagle food habits (diet composition and contamination of 
food supplies). The results of this research provided a basis for updating 
Maine's bald eagle management program (Todd, in preparation ) . Management 
objectives reflect minimum levels of recruitment essential for population 
stability and future growth to achieve an eventual goal of declassifying Maine 
eagles as endangered. Proposed programs are grouped into inventory, research, 
management, and education functions (figure 16-6). 

Guidelines for management of all known breeding sites in Maine are being 
developed on an individual basis, a policy initiated in national forests 
(Mathisen et al. 1977). Each plan summarizes all data available on physical 
habitat, nesting history, and research information at each site. Inquiries 
concerning possible site-specific impacts near important eagle habitats (see 
atlas map 4) should be directed to either (1) the appropriate regional 
biologist at the Maine Department of Inland Fisheries and Wildlife, (2) 



16-48 



Wildlife Division Office, Maine Department of Inland Fisheries and Wildlife, 
Augusta, Maine, or (3) U.S. Fish and Wildlife Service, Augusta, Maine. 

Research Needs 

Important data gaps on Maine eagles are reflected by the proposed research 
objectives in the State's eagle management plan. This research is dependent 
on continued inventories of breeding and wintering eagles and their habitats. 
These programs facilitate more effective management and are compatible with 
guidelines being developed by bald eagle recovery teams. 

The characteristics of suitable nesting and wintering habitat must be 
documented to permit critical habitat designations. Basic research is needed 
on winter habitat requirements in Maine (e.g., winter diet, tolerance to human 
activities, and the existence of nocturnal roosts). Studies of poorly 
understood aspects of eagle habitat use (e.g., feeding areas, home range, 
behavior, and tolerance to human proximity) are warranted in threatened 
habitats. Other life history data (longevity, recruitment, age at first 
breeding, juvenile dispersal, and age-specific survivorship) can be evaluated 
only on a long-term basis via banding. Evaluations of causes of mortality and 
contaminant levels in Maine eagles will be made as carcasses and unhatched 
eggs are found. Contaminants in food supplies and contributing sources need 
to be investigated periodically. 



16-49 

10-80 



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Nesting 
Survey 



Nesting 
Habitat 
Inventory 



Winter 
Survey 



Life 

History 

Study 



Contaminants 
Monitoring 



Dispersal 
and 

Survival 
Studies 



Causes of 
Mortality 



Habitat 
Management 



Population 
Management 



Management 
Strategy 



Information 

and 

Education 



Habitat 


Suitability 


Assessment 



Annually monitor the size and 
productivity of Maine's breeding 
population. 

Identify and characterize all known 
current breeding sites, historical 
breeding areas and suitable, potential 
nesting habitat of bald eagles in Maine. 

Periodically monitor distribution, size 
and age composition of bald eagles 
wintering in Maine. 

Conduct life history studies in bald 
eagle habitats threatened by development 
or other major alterations. 

Monitor organochlorine and heavy metal 
contaminants in Maine bald eagles and 
their foods. 

Identify the criteria for suitability of 
bald eagle breeding and wintering habitat 
in Maine. 

Obtain further data on dispersal and 
survivorship via banding of Maine bald 
eagles, especially juveniles. 

Continue investigations into causes of 
mortality in Maine bald eagles. 



Promote conservation of bald eagle nesting 
and wintering areas and enhancement of 
poten f ial habitats in Maine. 



— Enhance the viability of the bald eagle 
population breeding in Maine. 



Periodically update strategies for bald 
eagle management for the Maine Department 
of Inland Fisheries and Wildlife. 



Maintain public awareness and interest in 

the status and management of Maine bald eagles, 



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16-50 



REFERENCES 

Allen, N. F. I. Sighting file, 1955. Maine Audubon Society, Falmouth, ME. 

American Ornithologists' Union. 1957. Checklist of North American Birds. 
Lord Baltimore Press, Baltimore, MD. 

Anonymous. 1898. Eagles at Merrymeeting Bay. Maine Sportsman 5:20. 

. 1945. Bird notes. Maine Audubon Soc. Bull. 1:96-99. 

. 1949. Miscellaneous bird notes. Maine Audubon Soc. Bull. 5:58-60. 

. 1953. General bird lists. Maine Audubon Soc. Bull. 9:89-91. 

Anthony, E. F. 1947. Birds at "The Anchorage," Surry, Maine. Maine Audubon 
Soc. Bull. 3:25-27. 

Arbib, R. 1979 The blue list for 1979. Am. Birds 32:1106-1113. 

Avery, M. L. , ed. 1978. Impacts of Transmission Lines on Birds in Flight. 
78/48. U. S. Government Printing Office, Washington, D C. 

Bailey, R. S. 1967. An index of bird population changes in farm lands. Bird 
Study 14 (4) 195-209. 

Baird, S. F. , T. M. Brewer, and R. Ridgway. 1874. A history of North 
American birds: Land birds, vol. 3. Little, Brown, Boston, MA. 

Banks, R. C. 1979. Human related mortality of birds in the United States. 
U.S. Fish and Wild. Serv. Spec. Sci. Rep. Wildl. 215. 

Beaver, D. L. 1976. Avian populations in herbicide treated brush fields. 
Auk 93:543-553. 

Bent, A. C. 1937. Life histories of North American birds of prey, Part. 1. 
U.S. Nat. Mus. Bull. 167. 

Best, L. B. 1972. First-year effects of sagebrush control on two sparrows. 
J. Wildl. Manage 36:534-564. 

Black, C. P. 1976. The Ecology and Bioenergetics of the Northern Black- 
throated Blue Warbler ( Dendroica caerulescens caerulescens ) . Ph.D. 
Thesis. Dartmouth College, Hanover, NH. 

Bock, C. E. 1976. Synchronous eruptions of boreal seed-eating birds. Am. 
Midi. Nat. 110:559-571. 

Bond, J. 1947. What has happened to the vesper sparrow? Bull. Maine Audubon 
Soc. 3:10-11. 

. 1971. Native Birds of Mt. Desert Island and Acadia National Park. 

The Academy of Natural Sciences of Philadelphia, Philadelphia, PA. 

16-51 

10-80 



Burgason, B. N. 1977. Bird and Mammal Use of Old Commercial Clearcuts . M. 
S. Thesis. University of Maine, Orono, ME. 

Cammack, E. 1975. Winter Bald Eagle ( Haliaeetus leucocephalus ) study in 
Maine. Colby College, Waterville, ME. Unpublished report . 

Caslick, J. W. , and N. J. Cutright. 1973. Effects of Dylox on birds. Pages 
77-91 in Environmental Impact and Efficacy of Dylox Used for Gypsy Moth 
Suppression in New York State. Applied Forestry Research Institute 
College of Environmental Science and Forestry, State University of New 
York, Syracuse, NY. 

Chambers, R. E. 1972. Effects of Dylox on mammals and birds. Pages 58-77 in 
R. E. Chambers, H. H. Willcox, III, and D. G. Grimble, eds . Environmental 
Impact and Efficacy of Dylox Used for Gypsy Moth Control in New York 
State, Rep. No. 10 Appl. Forestry Res. Inst., State Univ. Coll. 
Forestry, Syracuse, NY. 

Chrest, H. R. 1964. Nesting of the Bald Eagle in the Karluk Lake Drainage on 
Kodiak Island, Alaska. M.S. Thesis. Colorado State University, Fort 
Collins, CO. 

Center for Natural Areas. 1978. Dickey/Lincoln School Lakes Project 
Ecological Resources Impact Study. U.S. Department of Energy, Bangor, 
ME. 1: Appendix E. 

Coon, N. C, L. N. Locke, E. Cromartie, and W. L. Reichel. 1970. Causes of 
bald eagle mortality, 1960-1965. J. Wildl. Dis. 6:72-76. 

Corr, P. 0. 1976. Bald eagle management plan. Maine Department of Inland 
Fisheries and Wildlife, Augusta, ME. 

, G. G. Donovan, and H. E. Spencer. 1977a. Woodcock Management Plan. 

Unpublished manuscript. Located at Maine Department of Inland Fisheries 
and Wildlife, Augusta, ME. 

, , . 1977b. Ruffed Grouse Management Plan. Unpublished 

manuscript. Maine Department of Inland Fisheries and Wildlife, Augusta 
ME. 

, , . 1977c. Ring-necked Pheasant Management Plan. 

Unpublished manuscript. Maine Department of Inland Fisheries and 
Wildlife, Augusta, ME. 

Crawford, H. S. , and R. W. Titterington. 1979. Effects of silvicultural 
practices on bird communities in upland spruce-fir stands. Pages 110-119 
in Management of North Central and Northeastern forests for nongame 
birds. U.S. For. Serv. Cen. Tech. Rep. NC-51. 

Cross, P. A. 1973. Bird seed is big business. Maine Fish and Game 15(4): 10- 
11. 

Cruickshank, A. D. 1950. Summer Birds of Lincoln County, Maine. National 
Audubon Society, New York. 

16-52 



Davis, R. B. 1960. The Spruce-fir Forests of the Coast of Maine. Ph.D. 
Thesis. Cornell University, Ithaca, NY. 

Delaney, R. L. Unpublished data. Kodiak National Wildlife Refuge, Kodiak, 
AK. 

Dwernychuk, L. W. , and D. A. Boag. 1973. Effects of herbicide induced 
changes in vegetation on nesting ducks. Canadian field-Nat. 87:155-165. 

Erskine, A. J. 1977. Birds in Boreal Canada. Rep. Ser. No. 41. Can. Wildl. 
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. 1978. The First Ten Years of the Co-operative Breeding Bird Survey in 

Canada. Rep. Ser. No. 42. Can. Wildl. Serv., Ottawa, Canada. 

Ferren, R. L. 1959. Mortality at the Dow Air Base ceilometer. Maine Field 
Nat. 15:113-114. 

Ferris, C. R. 1977. Effects of Interstate 95 on Songbirds and White-tailed 
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Fobes, C. B. 1956. Bird destruction at ceilometer light beam. Maine Field 
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Gerrard, J. M. , D. W. A. Whitfield, P. Gerrard, P. N. Gerrard, and W. J. 
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Gramlich, F. J. 1975. Maine's eagle nest sanctuary program. Pages 31-32 in 

Ingram, T. N. , ed. , Bald Eagle Land, Preservation and Acquisition. Proc. 

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Grier, J. W. 1974. Reproduction, organochlorines and mercury in northwestern 
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Grubb, T. G. 1976. A Survey and Analysis of Bald Eagle Nesting in Western 
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Hancock, D. 1964. Bald eagles wintering in the Southern Gulf Islands British 
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Hardy, M. 1908. Comment and query. Forest and Stream 71:411. 

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Hebard, F. V. 1960. The Land Birds of Penobscot Bay. Portland Society of 
Natural History, Portland, ME. 

Hensel, R. J., and W. A. Troyer. 1964. Nesting studies of the bald eagle in 
Alaska. Condor 66:282-286. 



16-53 

10-80 



Ismail, A. A., S. D. Schemnitz, and F. J. Gramlich. 1974. Bird damage to 
blueberry fields in Maine. Pages 1-13 in Research in the Life Sciences. 
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Josselyn, J. 1672. 1865 reprint of New England's Rarities Discovered in 
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Juenemann, B. G. 1973. Habitat Evaluations of Selected Bald Eagle Nest Sites 
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St. Paul, MN. 

Knight, A. W. 1908. The Birds of Maine. Charles H. Glass Co., Bangor, ME. 

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Long, R. H. 1951. A nesting barred owl on Mt. Desert Island. Maine Audubon 
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MacDonald, E. M. 1962. Bald eagle sighting file. Wildlife Resources, 
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McClelland, B. R. 1977. Relationships Between Hole-Nesting Birds, Forest 

Snags, and Decay in Western Larch-Douglas Fir Forests of the Northern 

Rocky Mountains. Ph.D. Dissertation. University of Montana, Missoula, 
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Mathisen, J. E. 1968. Effects of human disturbance on nesting of bald 
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. 1979. Bald Eagle - Osprey Status Report. Chippewa National Forest. 

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, D. L. Sorenson, L. D. Frenzel, and T. C. Dunstan. 1977. Management 

strategy for bald eagles. Trans. N. Am. Wildl. Nat. Resour. Conf. 
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Moorehead, W. K. 1922. A Report on the Archaeology of Maine. Andover Press, 
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Morse, D. H. 1968. A quantitative study of foraging of male and female 
spruce-fir woods warblers. Ecology 49:779-784. 

16-54 



. 1971a. The foraging of warblers isolated on small islands. Ecology 

52:216-228. 

. 1971b. Effects of the arrival of a new species upon habitat 

utilization by two forest thrushes in Maine. Wilson Bull. 83:57-65. 

. 1976. Variables affecting the density and territory size of breeding 

spruce-woods warblers. Ecology 57:290-301. 

. 1977. The occupation of small islands by passerine birds. Condor. 

79:399-417. 

Moulding, J. D. 1976. Effects of a low persistence insecticide on forest 
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Murton, R. K. , and N. J. Westwood. 1974. Some effects of agricultural change 
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Norton, A. V. Unpublished data. State of Maine Collection; Fogler Library, 
University of Maine, Orono, ME. 

Packard, C. M. 1958. Bird mortality during a migration. Maine Field Nat. 
14:83-85. 

. 1955. Field trip records. Maine Audubon Soc. Bull. 11:27-28. 



Palmer, R. S. 1949. Maine Birds. Bull. of Mus . of Comp. Zool. Harv. , 
Cambridge, MA. 102. 

Palmer, W. H. 1914. Our neighbor, the bald eagle. Bird Lore 16:281-282. 

Pearce, P. A. 1970. New Brunswick Spruce Budworm Control Program. In 
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Unpublished. Available from Department of Indian Affairs and Northern 
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Canada . 

, D- B. Peakall, and A. J. Erskine. 1976. Impact on Forest Birds of the 

1975 Spruce Budworm Spray Operation in New Brunswick. Progr. Note No. 62. 
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Peterson, S. R. 1975. Ecological distribution of breeding birds. Pages 22- 
38 in Proceedings of Symposium on Management of Forest and Range Habitats 
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PA. 

Postupalsky, S. Unpublished data. Department of Wildlife Ecology, University 
of Wisconsin, Madison, WI . 

Prouty, R. M. , W. L. Reichel, L. N. Locke, A. A. Belisle, E. Cromartie, T. E. 
Kaiser, T. G. Lamont, B. M. Mulhern, and D. M. Swineford. 1977. 

16-55 

10-80 



Residues of organochlorine pesticides and polychlorinated biphenyls and 
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bird communities of Appalachain spruce-fir forests. Ecol. Monogr. 
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Reitz, R. 1954. Birds meet with disaster at the Brunswick Naval Air Station. 
Bull. Me. Hud. Soc. 10:61-62. 

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Sport Fisheries and Wildlife, Juneau, AK. 

Robbins, C. S. 1970. Recommendations for an international standard for a 
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10:46-47. 

Rosier, J. 1605. A true relation of Captaine George Waymouth his voyage, 
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Virginia. Pages 100-152 in Winship, G. P., ed., Sailors Narratives of 
Voyages Along the New England Coast, 1524-1624. Houghton, Mifflin, 
Boston, MA. 

Servheen, C. W. 1975. Ecology of the wintering bald eagles on the Skagit 
River, Washington. M.S. Thesis, University of Washington, Seattle, WA. 

Sherrod, S. K. , C. M. White, and F. S. L. Williamson. 1976. Biology of the 
bald eagle on Akmchitka Island, Alaska. Living Bird 15:143-182. 

Smith, J. 1614. A description of New England. Pages 212-248 in Winship, G. 
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1624. Houghton, Mifflin, Boston, MA. 

Smith, P. A. Unpublished data. Department of Lands and Forests, Kentville, 
Nova Scotia, Canada. 

Spencer, H. E., Jr. 1980. Bald eagle sighting file. Wildlife Resources, 
University of Maine, Orono, ME. 

Spinney, H. L. 1926. Observations on the nesting of the bald eagle. Maine 
Nat. 6:102-109. 

Sprunt, A., IV. 1963. Bald eagles aren't producing enough young. Audubon 
Mag. 65:32-35. 

, and F. J. Ligas. 1964. The 1963 bald eagle count. Audubon Mag. 

66:45-46. 

16-56 



, W. B. Robertson, Jr., S. Postupalsky, R. J. Hensel, C. E. Knoder and F. 

J. Ligas. 1973. Comparative productivity of six bald eagle populations. 
Trans. N. Am. Wildl. Nat. Resour. Conf. 38:96-106. 

Stalmaster, M. V. 1976. Winter ecology and effects of human activity on bald 
eagles in the Nooksack River Valley, Washington. M.S. Thesis. Western 
Washington University, Bellingham, WA. 

Titterington, R. W. 1977. The Utilization of Northern Maine Clearcuts by 
Nesting and Wintering Birds. M. S. Thesis. University of Maine, Orono , 
ME. 

, H. Crawford, and B. N Burgason. 1979. Songbird responses to 

commercial clearcutting in Maine spruce-fir forests. J. Wildl. Manage. 
43:602-609. 

Todd, C. S. 1979. The Ecology of the Bald Eagle in Maine. M.S. Thesis. 
University of Maine, Orono, ME. 

. In preparation . Bald eagle management plan update. 



_, and R. B. Owen, Jr. 1979. The Ecology of the Bald Eagle in Maine. 
Final report, Jobs 240-245. Maine Department of Inland Fisheries and 
Wildlife, Augusta, ME. 

Townsend, F. C. 1957. Banding birds of prey in Maine. Maine Field Nat. 
13:8-13. 

Tyson, C. S., and J. Bond. 1941. Birds of Mt. Desert Island, Acadia National 
Park, Maine. Academy of Natural Science, Philadelphia, PA. 

U.S. Department of the Interior. 1974. Eagle 'Egg-plant' Successful. U.S. 
Fish and Wildlife Service News Release. 31 May 1974. 

. 1975. Egg Transplants Helping Bald Eagle Population. Fish and 

Wildlife Service News Release, 11 May 1975. 

. 1976. The bald eagle transplant program - status report. U.S. Fish 

and Wildlife Service, Washington, DC. 

. 1979. Regional briefs. Endangered Species Tech. Bull. 4(5):2-3. 



Vickery, P. D. 1978. Annotated Checklist of Maine Birds. P. D. Vickery 
Lincoln Center, ME. 

Weekes , F. M. 1975. Behavior of a young bald eagle at a southern Ontario 
nest. Can. Field-Nat. 89:35-40. 

Welty, J. C. 1975. The Life of Birds, 2nd ed. Saunders Co., Philadelphia, 
PA. 

White, D. H. , and R. G. Heath. 1976. Nationwide residues of organochlorines 
in wings of adult mallards and black ducks, 1972-73. Pestic. Monit. J. 
9:176-185. 

16-57 

10-80 



Wiemeyer, S. N. Unpublished data. Patuxent Wildlife Research Center, Laurel, 
MD. 

, A. A. Belisle, and F. J. Gramlich. 1978. Organochlorine residues in 
potential food items of Maine bald eagles ( Haliaeetus leucocephalus ) , 
1966 and 1974. Bull. Environ. Contam. Toxicol. 19:64-727" 

, B. M. Mulhern, F. J. Ligas , R. J. Hensel, J. E. Mathisen, F. C. 

Robards, and S. Postupalsky. 1972. Residues of organochlorine 
pesticides, polychlorinated biphenyls, and mercury in bald eagle eggs and 
changes in shell thickness - 1969 and 1970. Pestic. Monit. J. 6:50-55. 

Willard, B. G. 1906. Exceptional eggs of the bald eagle ( Haliaeetus 
leucocephalus ) . Auk 23:222. 

Willard, D. E. 1978. The impact of transmission lines on birds (and vice 
versa). Avery, M. L. Impacts of Transmission Lines on Birds in Flight. 
No. 78/48. U. S. Government Printing Office, Washington, DC. 

Young, H. 1968. A consideration of insecticide effects on hypothetical avian 
populations. Ecology 49:991-994. 

Zumeta, D. C, and R. T. Holmes. 1978. Habitat shift and roadside mortality 
of scarlet tanagers during a cold wet New England spring. Wilson Bull. 
90:575-586. 



16-58 



Chapter 17 

Terrestrial 

Mammals 



Author: Craig Ferris 




The group of mammals discussed in this chapter, collectively termed 
terrestrial mammals, includes 52 species representing several diverse orders: 
marsupials, bats, shrews and moles, rabbits and hares, rodents, carnivores, 
and hoofed mammals (table 17-1). Mammals are integral components of the 
terrestrial systems in the characterization area and are important to humanity 
for economic, recreational, and aesthetic reasons. No species are endangered 
or threatened but many are faced with shrinking habitats because of land 
development along the coast; their welfare should be an important 
consideration for regional planners. 

The term "terrestrial" mammals is not entirely correct, since several species 
(e.g., beaver, otter) spend much of their time in the water. The term is used 
to distinguish the species discussed in this chapter from the marine mammals 
(seals, whales and porpoises) discussed in chapter 13. Mammals use 
terrestrial habitats ranging from urban areas and rural farmland to mature 
forests and most freshwater wetlands (palustrine, lacustrine, riverine; table 
17-2). Mammals interact with other animals and plants through food chains, 
both as consumers and as prey. They influence plant species composition and 
distribution by consuming seeds and plant material; and they modify entire 
habitats (e.g., beavers). 

Forty-four species of mammals are found within all six regions of the 
characterization area, while eight others are found in only some of the 
regions (Godin 1977; table 17-3). With the exception of three species of bats 
that migrate south during winter, mammals are year round residents. 

Many species of terrestrial mammals found along the Maine coast have a direct 
relationship to humanity. Ten species are hunted for sport and 13 are trapped 
for fur. A few species (i.e., deer, bear, raccoon) cause economic losses from 
crop depredations. Mammals are also of aesthetic and scientific interest to 
humanity. In turn, people affect mammals. People alter the amount and 
quality of available habitat through, logging, agriculture, development, fire, 
wetland drainage, and stream channelization; and directly or indirectly alter 
mortality rates among mammals through hunting, trapping, poisoning, and 
accidental killing. 

17-1 



10-80 



Table 17-1. Mammals Known to Occur Within the Characterization Area. 
Listed by Order 3 



Marsupialia 

Virginia opossum* 

Insectivora 

Masked shrew 
Water shrew 
Smokey shrew 
Thompson's pygmy shrew 
Short-tailed shrew 
Hairy-tailed mole 
Star-nosed mole 

Chiroptera (Bats) 
Little brown bat 
Keen's myotis 
Small-footed myotis 
Silver-haired bat 
Eastern pipistrelle* 
Big brown bat 
Red bat 
Hoary bat 

Lagomorpha (Rabbits and Hares) 
New England cottontail* 
Snowshoe hare 

Rodent ia 

Eastern chipmunk 

Woodchuck 

Gray squirrel 

Red squirrel 

Southern flying squirrel 

Northern flying squirrel 

Beaver 



Rodentia (cont.) 
Deer mouse 
White-footed mouse 
Gapper's red-backed vole 
Meadow vole 
Pine vole* 
Muskrat 

Southern bog lemming 
Norway rat 
House mouse 
Meadow jumping mouse 
Woodland jumping mouse 
Porcupine 

Carnivora 
Coyote 
Red fox 
Gray fox* 
Black bear* 
Raccoon 
Marten* 
Fisher* 
Ermine 

Long -tailed weasel 
Mink 

Striped skunk 
River otter 
Bobcat 

Artiodactyla (Even-toed ungulates) 
White-tailed deer 
Moose 



a Species marked with asterisk (*) are not found in all regions (See 
table 17-3 ) . 



17-2 



Table 17-2. Amounts (square miles, except shoreline) of Major Habitat 

Types in Wildlife Management Units 6, 7, and 8, Which Encompass 
the Characterization Area 3 '" 3 



Habitat 




Wildlif< 


2 management 


unit 










6 


7 




8 


Total 


Terrestrial 














Coniferous forest 


941 


(37) a 


305 (14) 


688 


(24) 


1914 (26) 


Deciduous forest 


139 


(05) 


261 (12) 


337 


(12) 


737 (10) 


Mixed forest 






- 


38 


(01) 


38 (01) 


Successional forest 


1030 


(40) 


977 (46) 


897 


(32) 


2904 (39) 


Total forest 


2110 


(82) 


1543 (73) 


1940 


(69) 


5593 (75) 


Farmland 


139 


(05) 


277 (13) 


261 


(09) 


677 (09) 


Developed 


86 


(03) 


120 (06) 


354 


(13) 


560 (07) 


Palustrine 














Freshwater 


51 


(02) 


48 (02) 


49 


(02) 


148 (02) 


Saltwater 


60 


(02) 


23 (01) 


54 


(02) 


137 (02) 


Open fresh water 


128 


(05) 


99 (05) 


151 


(05) 


378 (05) 



Total area 



2574 



2110 



2809 



7493 



Linear miles of shoreline 

Lacustrine 641 

Riverine 3259 



511 

2616 



770 
2530 



1922 
8405 



a Numbers in brackets are percentages of unit totals, 
"Adapted from Anderson et al. 1975 a . 



17-3 



10-80 



Table 17-3. Regional Distribution of Species of Mammals Not Found in 
All Regions of the Characterization Area 



Species 



Regions 



Virginia opossum X 

Eastern pipistrelle X 
New England cottontail X 
Pine vole X 

Gray fox X 

Black bear 
Marten 
Fisher 



X 



X 



X 



X 
X 

X(?) 

X 



X 
X(?) 



a Godin 1977. 
The purpose of this chapter is to familiarize the reader with the ecological 
relationships of mammals within ecosystems along the coast, to describe the 
effects of people on mammals, and to provide information to help lessen 
adverse effects. Species found in specific regions, the habitats in which 
each species is likely to be found, and the abundance of the different habitat 
types important to mammals are addressed first. Following is a discussion of 
the the ecological relationships of mammals, the role of mammals in their 
communities, and the natural factors affecting abundance. These provide a 
background for a description of the effects of people on mammals, which is 
followed by a discussion of the importance of mammals to humanity. Finally, a 
summary is given of some management procedures that can be used to mitigate 
the detrimental effects of human activity. Common names of species are used 
except where accepted common names do not exist. Taxonomic names of all 
species mentioned are given in the appendix to chapter 1. 

DATA SOURCES 

The information used to prepare this report came from books, published 
research reports, theses, personal communications, and unpublished 
manuscripts. The latter includes species management plans, which have been 
prepared by the Maine Department of Inland Fisheries and Wildlife (MDIFW) on 
most species of game and furbearing mammals. These plans provide historical 
perspectives, estimates of current populations, demand by hunters and 
trappers, current harvest levels, and habitat preference and abundance. Most 
of the information contained in species management plans is summarized on the 
basis of Wildlife Management Units (WMU) , which are designated areas within 
which uniform wildlife management practices are appropriate. Wildlife 
Management Units 6, 7, and 8 contain most of the characterization area (figure 
17-1) but extend farther inland so that some information may not represent the 



17-4 



coastal area in detail. In many instances no other information is available. 
Points at which the data becomes less representative of the immediate coast 
will be noted. Unit 6 is perhaps best representative of the corresponding 
characterization regions (5, 6, and part of 4), since 64% of Unit 6 lies 
within the characterization area. Forty-nine percent of Unit 7 (regions 2, 3, 
and 4) and only 8% of Unit 8 (regions 1 and 2) lie within the characterization 
area . 

DISTRIBUTION AND ABUNDANCE 

The abundance of each species varies regionally, due primarily to the amounts 
of suitable habitat available. This section discusses general distribution 
and abundance of mammals in the six regions, describes the specific habitat 
preferences of each species, and summarizes the availability of those habitats 
along the coast. Finally, population estimates are given for selected game 
and furbearing species, based on habitat quantity and species densities for 
those habitats. 



Regional Distribution 

Forty-four species (85%) of mammals are found in all six regions of the 
characterization area (table 17-1). It is difficult to delineate the exact 
boundaries of a species' range, particularly if the range is changing. At the 
edge of a species' range populations are usually low and the number of 
observations of the species, on which the range is based, is low. This is 
confounded by the natural fluctuations that all species undergo. For species 
with very low numbers these fluctuations may cause the population to disappear 
altogether. The result is a constantly changing boundary, based on population 
levels. The distributions presented in table 17-3 are based on published data 
and, while they are the best available information to date, they should not be 
regarded as absolute. 

Five species of mammals are found only in the southern regions and reach the 
northern limits of their distribution within the characterization area: 
Virginia opossum, eastern pipistrelle, New England cottontail, pine vole, and 
gray fox. All but the pipistrelle (a bat) are expanding their ranges 
northward. The opossum seems to be limited by cold temperatures, because its 
fur is a poor insulator and it must remain in its den during severe winter 
weather (Scholander et al. 1950; and Godin 1977). Populations of the New 
England cottontail are increasing and the range is expanding, perhaps in 
response to changes in habitat. Because the cottontail is the preferred prey 
of the gray fox, it, too, is increasing (Palmer 1956; and Stanton 1960). 

Three other species are absent from portions of the characterization region: 
black bear, marten, and fisher (table 17-3). The black bear is fairly 
abundant in eastern Maine (regions 5 and 6) but is scarce in regions 3 and 4 
and absent from regions 1 and 2. Marten were formerly found in much of Maine 
but were reduced by trapping and habitat loss (Coulter 1959). Recently they 
have been expanding their range eastward and southward and may be present in 
the northern extensions of regions 4 and 5. Fishers are abundant in the mid- 
coast area (regions 3 and 4) but have never been numerous east of the 
Penobscot River. They may be absent from along the coast in extreme southern 
Maine because of the lack of suitable habitat. 

17-5 



10-80 




17-6 



Excluding the eight species mentioned above, each species of terrestrial 
mammal should be present in suitable habitat throughout the characterization 
area, with the exception of the offshore islands. Expanses of salt water 
present a formidable barrier to most species of mammals, so they are absent 
from all but the nearest or largest offshore islands. Mammals reach islands 
by swimming, rafting on debris, crossing ice bridges, or by coming with 
people. Two deer reportedly swam over 2 miles (3.2 km) and another swam 
nearly 7 miles (11.3 km) to the mainland from islands on which they had been 
released (Schemnitz 1975). Morse (1966) also reported deer swimming freely 
between Hog Island and the mainland but this was only a distance of a few 
hundred yards. Rafting is used most likely by small mammals that get trapped 
on pieces of earth or debris that break loose from the mainland during storms. 
Ice bridges are used by wide-ranging species such as deer, fox (Morse 1966), 
and raccoon. Mammals brought by people probably include mice, rats, and 
voles that are small enough to stow away on boats, and domestic animals (dogs, 
cats, sheep). Species lists of mammals present on some of the larger islands 
have been compiled and are summarized in appendix table 10. 

Islands also present problems other than accessibility that prevent species 
from becoming established. Populations of colonizing species are small 
initially and natural fluctuations may cause their extinction (Crowell 1973) . 
Colonizing individuals may have to compete with closely-related species that 
are already present. Native species seem to have an advantage in these 
situations, perhaps because of their larger numbers (Crowell and Pimm 1976). 
Some of these factors were seen among the small mammals that were studied by 
Crowell (1973) and Crowell and Pimm (1976) on the islands off Deer Isle 
(region 4). Meadow voles are the most abundant species on small islands; they 
seem more capable of reaching islands and they reproduce rapidly once 
established. Deer mice are present only on larger islands, where their 
populations can build up sufficiently to preclude chance extinctions. Red- 
backed voles seem to have a poor dispersal capability, low reproductive 
potential initially, and little or no ability to compete successfully with 
meadow voles . 

Habitat Preferences 

Within its geographical range each species has preferred or optimal habitats 
in which it will most likely be found. Each species also has less-preferred 
or marginal habitats in which it will be found less frequently and usually in 
fewer numbers (figure 17-2). Some species, such as beaver, otter, or flying 
squirrels, occupy only a few habitat types, while others (i.e., coyote, red 
fox, short-tailed shrew) inhabit a wide range of habitat types. Species with 
restricted habitat preferences are generally less adaptable and do not 
tolerate disturbance as well (Gill and Bonnet 1973). Planners need to be 
aware of species with restricted habitat preferences so that if these species 
are found within areas scheduled for development the impact of the habitat 
loss on their populations can be assessed. Critical habitats in a region 
need to be identified, and protected. The number of preferred and acceptable 
habitats is summarized in figure 17-2. Species that may be of concern 
ecologically, because of their narrow habitat preferences, are the water 
shrew, some of the bats, and the aquatic furbearers. 



17-7 



10-80 





IN OR NEAR 
LAKES, PONDS, 
RIVERS, STREAMS 


O 

o 

CO 

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rr i- 

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i e 


CO 

o 

LU H 

t JS 

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O LL 


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< 

cr 

rr 


< 

CD 

cr 

3 


NUMBER OF 
PREFERRED OR 
ACCEPTABLE HABITATS 


LAKES, PONDS. RIVERS, 
STREAMS 

Virginia opossum 

Water shrew 
Little brown bat* 
Keen's myotis* 
Silver-haired bat* 
Beaver 
Raccoon* 
Mink 
Otter 


• 
• 
• 
• 
• 
• 
• 
• 
• 


• 


• 
• 




o 


• 

o 
o 
• 
o 
• 
o 


• 
o 
o 
• 

• 
o 


• 
o 
o 
• 

O 


• 
• 

o 


o 


2 
4 

7 
7 
4 
3 
7 
5 
2 


MARSHES, BOGS, 
WETLANDS 

Star-nosed mole 

Muskrat 

Southern bog lemming 

Meadow jumping mouse 


O 
• 

• 




• 

o 
• 


• 




o 


o„ 


O 


o 




3 
2 
6 
4 


FORESTED UPLANDS 
(INCLUDING OLD FIELD) 

Masked shrew 
Smokey shrew 
Thompson's pygmy shrew 
Short-tailed shrew 
Silver-haired bat* 
Eastern pipistrelle 
Red bat 
Hoary bat 

New England cottontail 
Snowshow hare 


• 
O 
O 
• 
• 
• 


• 


o 


o 


o 
o 
o 




• 
• 
• 

• 
• 

o 
• 


• 
• 
• 

o 
• 

• 
• 


• 

o 
o 
o 


o 
o 


4 
5 
4 
8 
4 
4 
4 
6 
6 
5 



preferred 



Q acceptable 



Figure 17-2. 



Habitat preferences of terrestrial mammals found in the 
characterization area (after Godin 1977) . 



(Continued) 
17-8 





IN OR NEAR 
LAKES, PONDS 
RIVERS, STREAMS 


co 
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NUMBER OF 
PREFERRED OR 
ACCEPTABLE HABITAT 


FORESTED UPLANDS 
























Eastern chipmunk 








o 


• 


• 


o 




o 


o 


6 


Gray squirrel 










O 


• 


• 




o 


o 


5 


Red squirrel 










O 


o 


o 


• 


o 




5 


Northern flying squirrel 














• 


• 






2 


Southern flying squirrel 


O 










• 


o 




o 




4 


Deer mouse 










O 


• 




• 


o 




4 


White-footed mouse 








• 


• 


o 


o 








4 


Red-back vole 














o 


• 






2 


Pine vole 




o 


• 






• 


• 


• 






5 


Woodland jumping mouse 


• 










• 


• 


• 






4 


Porcupine 












o 


• 


o 






3 


Coyote 




o 




• 


• 


• 










4 


Red fox 


















o 




6 


Gray fox 








o 


O 


• 


• 








4 


Black bear 


O 


o 








o 


• 


o 






5 


Raccoon* 


• 


• 






O 


• 


• 




o 


o 


7 


Marten 














o 


• 






2 


Fisher 










o 


o 


• 


o 






4 


Ermine 


O 






• 


• 












3 


Long-tailed weasel 


*o 






• 


• 


o 










4 


Striped skunk 






• 


• 


• 








o 




4 


Bobcat 






o 


o 


• 


• 


• 


• 


o 




7 


White-tailed deer 


O 


o 




• 


• 


o 


o 


o 


o 




8 


Moose 


• 


• 






o 


o 


o 


o 






6 



preferred 



O acceptable 



Figure 17-2, 



(Continued) 



17-9 



10-80 

























1— 
























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AGRICULTURAL LANDS 
























Short-tailed shrew* 


• 














o 


• 




8 


Hairy-tailed mole 












• 


• 








3 


Woodchuck 


O 






• 


• 


o 






o 




6 


Meadow vole 


O 


o 




o 


o 


o 






o 




7 


Pine vole* 




o 








• 


• 


• 






5 


House mouse* 


















• 


• 


3 


Meadow jumping mouse* 


• 


• 




• 














4 


Red fox* 


















o 




6 


RURAL AND URBAN LANDS 
























Little brown bat* 


• 










O 


o 


o 


• 


o 


7 


Keen's myotis 


• 










o 


o 





• 


o 


7 


Small-footed myotis 


















• 


o 


2 


Big brown bat 


















o 


o 


2 


Norway rat 


O 


o 














• 


• 


4 


House mouse* 






o 












• 


• 


3 



TOTAL NUMBER OF 
SPECIES PER HABITAT 



27 17 14 

A preferred 



16 23 38 33 26 

O acceptable 



23 



11 



■ appears more than 
once on the chart 



Figure 17-2. (Concluded) 



17-10 



At the other end ot the spectrum are species that occupy a wide range of 
environments. Generally, these species have adapted to human presence and can 
often thrive in altered habitats. These species are less likely to be 
eliminated through habitat alteration. 

A few species have seasonal habitat preferences, or requirements; consequently 
more than one habitat must be available within the home range of individual 
animals. For example, deer require dense coniferous forest in winter, because 
it provides reduced snow depth and protection from wind (Glasgow 1949; Gill 
1957; and Day 1963). Deer concentrate in particular locations within this 
habitat type year after year during severe winter conditions. The locations 
of many of these areas, called deer "yards", are known and are plotted on 
atlas map 4. Since most of the coastal zone is subject to severe winters 
periodically (Banasiak and Hugie 1975), this habitat type must be preserved in 
sufficient quantity and distribution to ensure survival of deer. Coniferous 
forest provides little food, so habitats that contain abundant herbaceous and 
woody browse (such as old fields, second growth hardwoods, meadows, and 
wetlands) are needed. Adequate year-round deer habitat must include a mixture 
of both of these types of habitat in close proximity. This illustrates the 
concept of interspersion of habitats, which is very important for species of 
wildlife that require more than one habitat type. If necessary habitats are 
not present within the home range or cruising radius of a mammal, it cannot 
survive. Therefore, a sufficient amount of a particular habitat type on a 
regional basis is not enough. If a habitat exists in large uniform blocks it 
will not be suitable for those species requiring an interspersion of two or 
more habitats. Size must be considered in relationship to the home range of 
each species. For small mammals (mice, shrews, voles) an area of 10 to 15 
acres (4 to 6 ha) would far exceed the normal home range of an individual, 
while foxes or coyotes may range over an area of several square miles. 
Banasiak and Hugie (1975) regard the degree of interspersion of habitats 
relative to deer (which range 1/4 to 1/2 mile; 0.4 to 0.8 km) as moderate in 
regions 5 and 6 and high in regions 1 to 4. Black bears, which also require 
several habitat types, range over a much larger area, as much as 20 sq mi (51 
sq km) or more. Within their home range they require township-sized blocks 
(36 sq mi; 92 sq km) of forest habitat. These conditions are not present in 
regions 1 to 4 of the characterization area, which is one reason that black 
bears are not abundant there (Hugie and Banasiak 1975). 

The relative importance of each community type to mammals as a group is 
indicated by the total number of species utilizing each type (figure 17-2). 
All species of mammals found within the same habitat may be said to constitute 
the "mammal community" of that habitat. Forest systems (deciduous, 
coniferous, and mixed) and aquatic habitats (palustrine, lacustrine, and 
riverine) are preferred habitat for the greatest numbers of species and 
acceptable habitats for many others. Urban areas and open meadows support 
fewest species. Land development on shorelines and watercourses, draining 
wetlands, and removing forest habitat has a greater impact on mammals, in 
terms of the number of species affected, than alterations in other habitats. 
On the other hand, providing small patches of these habitats, particularly 
forests and wetlands, within urban areas can increase the diversity of mammal 
communities significantly (Leedy et al. 1978). 



17-11 

10-80 



ROLE OF MAMMALS IN THE ECOSYSTEM 

Mammals have a major role in their communities, primarily in the transfer of 
energy and nutrients through food chains. As a result of their role mammals 
can sometimes exert significant influences on other groups within their 
communities. Herbivores may assist in the distribution of plants by 
disseminating seeds or limit the distribution of other plants by overutilizing 
them. Carnivores may influence the abundance of their prey and beavers can 
alter entire communities to their liking. Knowledge of the food habits of 
mammals is important for an understanding of the effects of people on mammals, 
because people can affect mammals indirectly through their food supply. For 
example, spraying a forest stand to control spruce budworm may reduce 
populations of other insects that serve as food for small mammals. 

Mammals found within the characterization area range from strict herbivores 
(e.g., deer, moose, snowshoe hares), which consume only plant material, to 
insectivores (e.g., bats and shrews), and carnivores (e.g., bobcat and otter) 
that rely solely on invertebrates or meat, respectively. The majority of 
species, however, are omnivorous; that is, they consume both plant and animal 
matter. The food preferences of the mammals found in coastal Maine are shown 
in figure 17-3. The role of herbivores is to convert the energy stored in 
plants into animal tissue. Mammals that consume twigs, stems, and bark (e.g., 
deer, moose, hares) have special adaptations in their digestive systems (rumen 
or large caeca) and host symbiotic microorganisms that aid the breakdown of 
complex structural carbohydrates (cellulose and lignin) and release the energy 
stored in chemical bonds. Other herbivores do not possess this ability and 
consume more digestible plant material, such a fruits, seeds, nuts, leaves, 
and tender shoots. 

Usually only a relatively small amount of the total plant material in a 
community is consumed by mammals. Browsing mammals can kill individual 
plants by repeated cropping of twigs, stems, and foliage. For example, heavy 
browsing by deer on Canada yew has virtually eliminated this plant from 
portions of its former range in New York. In the northern hardwood forests of 
the Adirondack Mountains, deer have caused a shift in the plant species 
composition by selectively browsing maple, birch, and ash seedlings, which 
allowed the less desirable beech to become dominant in the understory (Tierson 
et al. 1966). Areas protected from deer had a more even distribution of plant 
species. Herbaceous vegetation showed similar effect. Biologists have 
recognized the ability of certain plants, such as mountain maple, to withstand 
repeated cropping of current growth and still survive. These plants can be 
encouraged where food production for browsing animals is desired. 

Small mammals can affect the regeneration of plants by eating seeds or nuts. 
Squirrels can consume the entire crop of acorns or hickory nuts in most years. 
However, during the occasional years with "bumper" crops, enough seeds escape 
to ensure sufficient regeneration (Barnett 1977). 

Sometimes mammals aid the dispersal of plants by consuming fruits and later 
passing the seeds in their feces. In the characterization area, bears, 
raccoons, foxes, and other mammals distribute the seeds of such plants as 
raspberries and cherries in their feces and beggars ticks in their fur. 
Recent research in New Hampshire suggests that gray squirrels are perhaps the 
most important factor affecting establishment of white pine regeneration 

17-12 



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O acceptable 


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NUMBER OF 
PREFERRED OR 
ACCEPTABLE FOODS 


HERBIVORES 






























New England Cottontail 




• 


• 






















2 


Snowshoe hare 




• 


• 






















2 


Woodchuck 




• 


• 




O 


















3 


Beaver 




• 


o 






















2 


Meadow vole 


o 


• 


• 






















3 


Pine vole 


• 


• 






O 


















3 


Southern bog lemming 




O 


• 


o 


o 


















4 


Muskrat 






• 






O 


o 


o 


o 








o 


6 


Porcupine 


• 


• 


• 






















3 


White-tailed deer 


o 


• 


• 


o 




















4 


Moose 




• 


• 


o 




















3 


OMNIVORES 






























Virginia opossum 


• 


o 


o 


o 


• 


• 














• 


7 


Short-tailed shrew 


o 








• 


O 


o 




o 


o 






o 


7 


Eastern chipmunk 


• 


• 


• 


• 


o 




o 




o 


o 








8 


Gray squirrel 


• 






• 


o 








o 










4 


Red squirrel 


• 


• 


o 


o 


o 








o 











7 


Northern flying squirrel 


• 






o 


o 








o 


o 








5 


Southern flying squirrel 


• 






o 


o 








o 










4 


Deer mouse 


• 








• 
















o 


3 


White-footed mouse 


• 








• 
















o 


3 


Red-backed vole 


• 


o 


• 


• 


o 


















5 


Norway rat 


o 












o 


o 


c 


o 


o 




o 


7 


House mouse 


o 



























2 


Meadow jumping mouse 


• 






• 


• 


















3 


Woodland lumping mouse 


• 




• 


• 


• 


















4 


Coyote 


o 








o 1 o 


o 


o 


o 


o 


o 


O 


• 


10 



Figure 17-3. Food preferences 
characterization 



of terrestrial mammals found in 
area (Godin 1977). 
(Continued) 
17-13 



the 



10-80 



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NUMBER OF 
PREFERRED OR 
ACCEPTABLE HABITAT 


OMNIVORES 






























Red fox 


















• 










6 


Gray fox 


















• 










6 


Black bear 
















• 












6 


Raccoon 












• 






• 










7 


Skunk 


















• 










6 


INSECTIVORES 






























Masked shrew 












• 




o 












2 


Water shrew 


o 
























o 


3 


Smokey shrew 














o 




o 


o 








4 


Pygmy shrew 


























o 


2 


Hairy-tailed mole 




























1 


Star-nosed mole 












• 




o 












2 


Little brown bat 






























Keen's myotis 






























Small-footed myotis 






























Silver-haired bat 






























Eastern pipistrelle 






























Big brown bat 




















o 








2 


Red bat 




























1 


Hoary bat 




















o 








2 


CARNIVORES 






























Marten 


o 








o 




o 


o 


o 


• 






o 


7 


Fisher 


o 








o 




o 


o 


o 


• 


• 




• 


8 


Ermine 










o 




o 




o 


• 


• 




o 


6 


Long-tailed weasel 










o 




O 




o 


• 


• 




o 


6 
8 

7 


Mink 












• 


• 


• 


o 


• 


• 




o 


River Otter 












• 


• 


• 


o 










4 


Bobcat 










o 


o 


O 




o 


o 


• 


• 


o 


6 



Figure 17-3. (Concluded) 



17-14 



(personal communication from L. Alexander, Forestry Department, University of 
New Hampshire, Durham, NH.; February, 1979). Squirrels digging under oaks and 
hickories expose mineral soil that is required for germination of white pine 
seeds . 

Insectivorous or carnivorous mammals consume a wide variety of animal tissue, 
including insects and other invertebrates, fish, reptiles and amphibians, 
birds, and other mammals (figure 17-3). Mammals in turn are preyed upon by 
fish (e.g., bass), reptiles (snakes and turtles), and birds (hawks and owls). 

Just as there are habitat generalists and specialists among mammals there are 
also diet generalists and specialists. Some generalists are the coyote, fox, 
raccoon, black bear, and opossum. Specialists include the bobcat, water 
shrew, and most bats. Diet specialists are more susceptible to disruptions in 
their food supply, both natural and human- induced, because they are not 
capable of changing to other food sources if their preferred food is not 
available. Diet specialists are also vulnerable to the effects of pollution 
and pesticides, because if their food becomes contaminated they may acquire 
large concentrations through repeated small doses. 

Beavers have a unique role in their communities. Beaver dams create habitat 
for many other species of mammals, as well as fish, reptiles, amphibians, 
invertebrates, and birds. Beaver flowages are particularly important for 
moose (Dunn et al. 1975) and are used by deer (Banasiak and Hugie 1975), bear 
(Hugie and Banasiak 1975), and aquatic mammals (e.g., muskrat, mink, otter, 
etc.) . 

FACTORS OF ABUNDANCE 

The distribution and abundance of mammals on a regional basis is affected most 
by the amount and quality of their preferred habitats. There are no data on 
habitat availability within the six characterization regions but information 
does exist for the three Wildlife Management Units that encompass the coastal 
zone. A summary of the major habitat types is presented in table 17-2, while 
a more detailed description can be found in appendix tables 1 to 9 . Overall, 
75% of the total area of Wildlife Management Units 6, 7, and 8 is covered with 
forest habitat, ranging from 69% in Unit 8 to 82% in Unit 6. While this is 
less than the overall State total of 90% (Ferguson and Kingsley 1972), there 
unquestionably is an abundance of forest habitat. The combined amount of 
urban and rural land constitutes 16% of the total area, ranging from 8% in 
Unit 6 to 22% in Unit 8. Since the majority of developed land is along the 
immediate coast, the proportion within the characterization area is much 
higher. Open fresh water (lakes and ponds) constitutes 5% of the area, and 
wetlands (both fresh and saltwater) occupy only 3% to U%. 

The importance of a habitat type to mammals usually should not be judged on 
the basis of acreage alone. As was pointed out earlier, wetland habitats 
support some of the most diverse mammal communities and yet constitute only a 
small portion of the total characterization area. Habitats such as these that 
are in short supply are often critical for the survival of some species. 

In order to show how these habitat figures relate to animal abundance, table 
17-4 summarizes the available habitat, species densities (animals per unit of 
habitat), and total populations for a number of game and furbearing species in 

17-15 

10-80 



each of the three Wildlife Management Units along the coast. These data were 
obtained from species management plans, described earlier, and are 
approximations at best. The data concerning animal densities, in particular, 
should be considered only as very rough approximations, and only be used for 
comparing relative abundance between regions. More detailed data are 
available in appendix tables 1 to 9. In most instances the density figures 
are different for each of the three units, because the total habitat figure is 
made up of differing amounts of habitat types, each with a corresponding 
density figure. Also, animal abundance in the same habitat may vary from one 
unit to the next, because of the quality of the habitat, its interspersion 
with other required types, its positon in the species range, or other factors 
described below. 



Natural Factors Affecting Abundance 

A unit of habitat is capable of supporting only a given number of individuals 
of one species. This is often called the carrying capacity of the habitat. 
The size of a population results from increases due to birth and immigration 
and losses due to death or emigration. For populations below carrying 
capacity, gains usually exceed losses and the population increases. As it 
approaches saturation levels, several factors can enter to reduce population 
growth by affecting reproductive rates, increasing mortality, or increasing 
emigration. 

Each species has a maximum inherent reproductive rate, which is determined by 
(1) the number of young per litter, (2) the number of litters per year, and 
(3) the minimum age of first breeding (appendix table 11). Some species 
(e.g., bats, black bears) have low rates of reproduction, producing only one 
or a few young each year. Others, like the meadow vole, are capable of 
producing up to 40 to 50 young in a single year. Species with high 
reproductive potentials are capable of rapid population increases following 
depletion of their numbers or upon encountering unoccupied habitats. 
Conversely, species with low reproductive rates will rebound slowly from 
reductions in population size and are therefore more susceptible to 
exploitation. 

Reproductive rates may be reduced to a level lower than their maximum 
potential by inadequate nutrition. Deer on poor range have a lower incidence 
of twins or triplets, and first year does on poor range are less likely to 
produce fawns than deer on good range. Snowshoe hares, mice, and voles may 
have fewer litters per season, as well as a delay until first breeding, due to 
food shortage. Social stress, brought about by high population densities, may 
have similar consequences. The mechanics of stress are not entirely clear, 
but apparently, increased contacts between individuals causes changes in 
hormone levels that in turn affect reproduction. 

Territorial behavior also limits the density of animals in a given unit of 
habitat. Many species, including mice, beavers, and most carnivores, are 
territorial and individuals exclude other members of their species from the 
particular area they occupy. This limits population size by (1) spacing out 
individuals, (2) reducing immigration, and (3) preventing some individuals 
from breeding. Young produced within a territory are tolerated until they 
become independent, at which time they are forced to disperse. If these 

17-16 



individuals are not able to establish a territory in some other part of the 
habitat they may become part of a floating, nonbreeding segment of the 
population, which wanders from one territory to the next until a vacant area 
is found. 

This dispersal is an important mechanism of population regulation for many 
species of mammals (e.g., bears, voles, hares, beavers). The fate of 
dispersing individuals is (1) they settle in unoccupied territories when 
available, (2) they try to survive in suboptimal habitats, or (3) they die 
from lack of suitable habitat. Dispersing individuals suffer higher mortality 
from predation and accidents than resident animals because they are less 
familiar with their surroundings and their increased movement brings them into 
contact with a greater number of hazards (Ambrose 1977). 

Species of mammals that are not territorial, such as deer and moose, do not 
possess a dispersal mechanism for controlling abundance. Although passive 
dispersal may occur populations that are increasing continue to do so until 
some resource, usually food, becomes limiting. Mortality from starvation 
usually occurs during the winter, when energy requirements are highest. This 
may be due to inadequate food supplies in late summer or fall when fat stores 
necessary for winter survival must be built up. Winter mortality can be an 
important mechanism of control for deer populations in Maine. Mild winters 
allow the population to increase above the ability of the habitat to support 
it through normal winters. Widespread deaths then occur when normal or severe 
winters follow. This is illustrated by the deer harvest in the coastal 
regions, which, when adjusted for season length and hunting effort, reflects 
the status of the deer population. Figure 17-4 shows the adjusted harvest of 
deer in each of the six coastal regions for the years 1959 to 1977. In almost 
all instances the harvest is low after severe winters and high after mild 
winters. This is complicated in some cases (i.e., 1973 and 1976) when mild 
winters were followed by hunting seasons in which poor hunting conditions 
existed due to lack of tracking snow. 

Mammals experience other forms of mortality such as predation, diseases, 
parasites, and weather-related mortality. The importance of these factors 
among mammal populations along the coast of Maine generally is unknown. The 
importance of natural predation in controlling small mammal populations has 
been studied extensively outside Maine. Some authors (Craighead and Craighead 
1969) have suggested that predation can control populations but it is 
generally accepted that predation alone is not sufficient (Pearson 1964; and 
Errington 1963). Keith (1974), studying the 10-year cycle of snowshoe hares 
in Alberta, has shown that predation can keep numbers low after they have 
declined (crashed), but it is not responsible for the significant rapid 
population declines (which may be due to food shortage caused by 
overpopulation) . 

Predation has been shown to be important in controlling populations of some 
large mammals, such as moose in Michigan (Mech 1966) and Dall sheep in Alaska 
(Murie 1944). In Maine, however, there are no serious predators of moose or 
deer and losses due to bobcats, coyotes, and dogs seem to be relatively low. 
During the years 1969 to 1977 an average of 256 deer and less than one moose 
were reported killed by predators. These figures do not represent total 
losses for the entire State but only reported losses. 



17-17 

10-80 



Table 17-4. Available Habitat, Species Densities, and Total Population 

Estimates for Selected Species of Game and Furbearing Mammals 
in Wildlife Management Units 6, 7, and 8 a ' ' c 



Species 



Wildlife management unit 



Total 



Aquatic furbearers 



Beaver 



Habitat (stream miles) 1375 
Density/100 miles 115 

Total population 1575 



1062 

104 

1109 



1027 

81 

834 



34 64 

102 

3518 



Mink 



Habitat (miles of 

shore and stream) 
Mink/ 100 miles 
Total population 



Muskrat 



Habitat (sq. mi) 
Muskrat/sq. mi. 
Total population 



Otter 



Habitat (miles) 
Otter/1000 miles 
Total population 



3900 


3127 


3300 


10,327 


60 


51 


27 


47 


2352 


1604 


900 


4856 


50 


43 


60 


153 


514 


881 


810 


733 


25,700 


37,900 


48,600 


112,200 


3900 


3127 


3300 


10,327 


90 


84 


59 


79 


353 


262 


196 


811 



Upland furbearers 



Fisher 

Habitat (sq.mi.) 
Fisher/10 sq. miles 
Total population 



2121 


1546 


1896 


5563 


<1 


15 


9 


7 


30 


2320 


1680 


4030 



Marten 



Habitat (sq.mi.) 

Density 

Total population 



226 



66 



92 



384 



Wildlife management units 6, 7, and 8 encompass the chacterization area, 
From Anderson et al . 1975 a,b,c, and d. 
c Counts 1 stream mile = 1 acre habitat. 

(Continued) 



17-18 



Table 17-4. (Concluded) 

Species Wildlife management unit Total 



^Ipland furbearers (cont.) 

I Bobcat 

Habitat (sq.mi.) 
Density/100 sq.mi. 
Total population 



> 



Coyote 

Habitat (sq.mi.) 
Density/100 sq.mi. 
Total population 
(*potential) 

Red fox 

Habitat (sq.mi.) 
Density/100 sq.mi. 
Total population 

Raccoon 

Habitat (sq.mi.) 
Density/sq.mi. 
Total population 



Big Game Species 

White-tailed deer 

Habitat (sq. miles) 
Deer/10 sq. miles 
Total population 

Moose 

Habitat 

Moose/100 sq. miles 

Total population 

Black bear 
Habitat 

Bear/ 100 sq. miles 
Total population 



> 



> 



> 



2110 


1541 


1902 


5553 


22 


13 


8 


15 


464 


199 


148 


811 


2312 


1845 


2176 


6333 


13 


11 


11 


12 


290 


210 


240 


740 



2345 


2429 


2209 


6983 


77 


66 


78 


73 


1802 


1606 


1714 


5122 


695 


1163 


1799 


3657 


8 


9 


9 


9 


5900 


9900 


15,400 


31,200 



2207 


1649 


1986 


5842 


27 


105 


96 


89 


16,000 


17,000 


19,000 


52,000 


2223 


1615 


1964 


5802 


14 


13 


10 


12 


311 


210 


196 


717 


1670 


75 


100 


1845 


38 


35 


30 


38 


646 


26 


30 


702 



17-19 



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17-20 



The role of diseases and parasites is occasionally of some significance to 
mammals in Maine. The most important example is the brain worm parasite 
( Paraelaphostrongylus tenuis ) and its effect on moose populations. The 
natural host of the brain worm is the white-tailed deer, in which it 
apparently causes no harm. However, it is also capable of infecting moose 
when it is ingested with its alternate host, one of several species of 
molluscs. The brain worm damages the central nervous system, sometimes 
killing moose outright but also affecting their behavior, which subjects them 
to other forms of mortality (such as roadkills, poachers, and accidents). 
Gilbert (1974) studied the incidence of brain worm in Maine moose and found 
that where moose occurred with high deer populations the rate of infection was 
high enough to reduce moose populations significantly. The incidence of brain 
worm in a sample of illegally killed moose was 50%, 80%, and 64% in Wildlife 
Management Units 6, 7, and 8, respectively. 

Other diseases and parasites that are important to mammals are rabies virus in 
carnivores (fox, skunk, coyote, bobcat) and sarcoptic mange caused by 
mites , ( Acari ) . These may become manifest when host populations are high 
because they are transmitted more easily then and overpopulation often results 
in less vigorous animals that are more susceptible to infection (see below for 
incidence of rabies in the characterization area). 

Human Factors 

People affect mammals directly, through mortality factors such as hunting, 
trapping, roadkills and environmental contaminants, and by affecting the 
amount and quality of habitat that is available. In any situation involving 
habitat change some species will be adversely affected, and others will 
benefit. 

The major land uses influencing mammal habitat in the characterization area 
are logging, agriculture, and development (housing, industrial, commercial, 
highways). The latter has the most significant impact because the habitat 
loss is permanent and developed areas support very few mammal species (figure 
17-2). On the basis of Wildlife Management Units, developed land is most 
abundant in the southwestern coastal regions. In Wildlife Management Unit 8, 
13% of the land falls in this category, compared to 6% of Unit 7 and only 2% 
of Unit 6 (table 17-2). Species of mammals that can be expected to benefit 
from further urbanization include some species of bats, gray squirrels, Norway 
rats, house mice, and perhaps raccoons (figure 17-2). Additional species that 
may benefit from suburban or rural developments (farms) include foxes, skunks, 
chipmunks, short-tailed shrews, woodchucks, meadow voles, and coyotes. Most 
other species, if not all, will be adversely affected by land development. 

Although little can be done to slow the rate of urbanization, steps can be 
taken to mitigate its environmental effects. Habitats to be replaced should 
be those that are most abundant, such as forest habitats, and not those in 
short supply, such as wetlands. If possible, new developments should be 
located where old ones have been allowed to deteriorate so no net loss of 
habitat results. The welfare of mammals should be made an important aspect of 
the planning stages, so that allowances can be made to leave parks and patches 
of habitat and to provide corridors between these patches (Leedy et al. 1978). 
In the recent past the loss of habitat to development in Wildlife Management 
Units 7 and 8 was compensated by increases from farmland abandonment (Banasiak 

17-21 



10-80 



and Hugie 1975). This trend is not expected to continue, however, as losses 
will exceed gains in the future. Unit 6 is expected to maintain its present 
habitat composition. 

Land development includes roads, highways, and power lines. The effects of 
these developments on mammals have been studied in Maine (Ferris 1977 and 
Palman 1977) and elsewhere (Michael 1975; and Schrieber and Graves 1977), and 
generally are limited to loss of habitat. Some evidence exists that fishers 
may shy away from habitat adjacent to highways (Palman 1977) and this response 
might be expected from other species that are easily disturbed by human 
presence (e.g., bears, marten, and bobcat). Oxley and his colleagues (1974) 
felt that four-lane highways were a barrier to movements of small mammals but 
additional evidence of this is lacking. Schrieber and Graves (1977) studied 
the movements of small mammals across power lines in New Hampshire and found 
that neither 164 feet (50 m) nor 328 feet (100 m) wide rights-of-way prevented 
movements of white-footed mice or short-tailed shrews. The concern of 
planners with regard to highways and transmission lines should be to place 
them through habitats that are least desirable for mammals (Leedy et al. 
1978). 

Agricultural land is most abundant in the mid-coast regions. Thirteen percent 
of Wildlife Management Unit 7 is agricultural, compared with 9% of Unit 8 and 
only 5% of Unit 6 (table 17-2). Land in production is primarily crop land, 
pasture land, and blueberry barrens. These lands may be used by mammals as 
feeding areas, particularly if individual fields are small and interspersed 
with forest land, abandoned fields, or hedgerows that provide cover. 
Agricultural lands are least desirable when they encompass large uniform 
tracts providing a minimum amount of edge habitat and interspersion of 
habitats . 

Logging is most significant in regions 5 and 6 where commercial timber 
operations still exist. Habitat modifications resulting from timber 
harvesting range from very slight in single-tree selection to severe in 
clearcutting. However, recent increases in firewood consumption will result 
in more intensive harvesting on small forest lands in all regions of the 
characterization area. 

The effects of timber harvesting on mammals have been studied since 1974 in a 
section of northern Maine near Moosehead Lake. This area lies well north of 
the characterization area but the conclusions are applicable here and anywhere 
that similar logging practices are employed. The results indicate that the 
effects on a particular species depend on the extent to which its preferred 
habitat is increased or decreased by the logging operation. For example, 
populations of the marten, a species preferring mature softwood and softwood- 
dominated mixed forests, were reduced 65% to 75% in an area subjected to 
commercial clearcutting, but were unaffected by a partial cut (Soutiere 1978). 
In the clearcut area marten moved freely through cuts and hunted in them; 
however, they used residual uncut softwood patches and partial cut hardwood 
stands more frequently. 

Moose, on the other hand, responded favorably to clearcutting near Moosehead 
Lake (Burgason 1977; Monthey 1978; and Schoultz 1978). Schoultz (1978) 
reported that moose preferred clearcut softwood stands, followed by partial 
cut mixed stands and uncut forest. He attributed this to the availability of 

17-22 



browse in clearcuts. This supports the findings of Stone (1977) that 
production of all classes of vegetation (herbaceous, raspberries, hardwood and 
softwood browse) was higher in clearcuts than in uncut habitats. The amount 
and quality of this vegetation are sometimes affected by the age of the 
clearcut. Burgason (1977) found that lands cut 20 to 25 years before were 
used more than those cut only 6 to 10 years before. He attributed this to a 
better combination of food and cover in the prior cut lands. 

Deer populations usually respond favorably also to increases in herbaceous and 
woody vegetation following clearcutting. However, in the area studied by 
Schoultz (1978) access to cuts was limited during the winter by deep snow. 
Deer were forced into areas with dense softwood cover where snowfall is 
intercepted by the canopy. Only those areas of the cutover lands directly 
adjacent to softwood patches could be utilized for food in winter. 

Thus, while populations of species that require mature forests may be reduced 
significantly in areas subject to clearcutting, other species will find ideal 
conditions in the successional stages following cutting. To minimize the 
effects of logging on mammals it is perhaps best to leave a mosaic of cut and 
uncut areas, which provides a diversity of habitats. 

Another aspect of logging that affects mammals is reforestation. In the 
characterization area this includes the planting of seedlings and the use of 
herbicides. The aim of reforestation efforts by the commercial paper industry 
is to establish coniferous regeneration as rapidly as possible (see chapter 
19, "Commercially Important Forest Types"). Herbaceous and hardwood 
regeneration may compete successfully with the seedlings of desirable species 
and may dominate a site for many years. Herbicides are sometimes used to kill 
the competing hardwood and herbaceous vegetation. Unfortunately these "weed" 
species, as they are called by foresters, are also the most beneficial species 
for wildlife in terms of food production. Eliminating them from large tracts 
of regenerating forest land will obviously affect mammal populations as well, 
although these effects have not been measured. 

An important cause of habitat alteration, albeit unintentional, is fire. The 
extent to which the habitat is changed depends on the severity of the fire. 
Cool fires remove dead vegetation and accumulated litter, release nutrients, 
and often result in enhanced production of herbaceous and woody vegetation 
within a few weeks. Severe fires, on the other hand, destroy not only litter 
but also the organic matter in the soil. All vegetation may be killed and 
excessive soil erosion often results because there is no vegetation to hold 
the soil. In such cases it may be years before the site is suitable for 
wildlife . 

Direct mortality . In addition to affecting mammal habitat people also 
kill mammals. Some of this is intentional, such as hunting and trapping, and 
is controlled so as not to reduce populations excessively. Other forms are 
either unintentional (e.g., roadkills) or are hard to control (e.g., illegal 
hunting and dogs) . 

Ten species of mammals are hunted for sport in Maine: deer, bear, snowshoe 
hare, squirrel, fox, coyote, bobcat, raccoon, woodchuck, and New England 
cottontail. Each deer and bear legally harvested must be tagged and recorded 
at an official State check station. This provides accurate harvest data for 

17-23 

10-80 



these two species. The average annual legal harvest of deer for the years 
1959 to 1977 is summarized in table 17-5 for each of the six regions. The 
highest kill occurred in region 4 where an average of 2094 deer were killed 
each year. More importantly for comparative purposes, the highest kill per 
square mile (2.3) also occurred there. The lowest kill (89) and kill per 
square mile (0.4) was in region 1. This is to be expected as much of this 
region is urban (Portland and South Portland) and is not optimal deer habitat. 
Hunting losses constitute a significant portion of the annual mortality for 
deer populations. Depending on the productivity of the population, deer in 
Maine can withstand an all-cause removal of 25% to 35% (Banasiak and Hugie 
1975). Present harvest levels are approximately equal to the removable 
supply. The all-cause removal takes into account the illegal harvest. 
Between 1969 and 1977 an average of 180 illegal kills was reported annually. 
However, a study by Vilkitis (1971) indicated that the reported losses 
constituted only about 1.2% of the actual illegal harvest, which was probably 
closer to 15,000 to 18,000 annually. 

The black bear kill for the townships in the characterization area is also 
summarized in table 17-5, for the years 1969 to 1977. No bears were killed in 
either region 1 or 3, and only one bear was killed in region 2. The highest 
bear kill was in region 5, where an average of 3 bears/100 sq mi were taken. 

Harvest data for the other game species (except woodchuck and cottontail) are 
estimated by MDIFW by surveying a sample of licensed hunters each year. The 
accuracy of these harvest estimates is questionable, since the sample size is 
very small and hunters tend to exaggerate. For example, Hunt (1975) suggests 
the estimated harvest of red fox could be as much as twice the actual kill. 
One test of the accuracy of the survey is the estimate of the deer kill, which 
can be verified through tagging procedures. The survey estimate is 
consistently high, sometimes as much as 50%. Until more accurate data are 
available the estimates have little use except for comparative purposes, since 
biases should be consistent from one part of the State to another. 

Estimates of the harvest of furbearing mammals are derived from two sources. 
One is a trapper survey conducted by the MDIFW. The trapper survey, which is 
similar to the hunter survey, is subject to the same biases, except that the 
percentage of trappers sampled is much larger. Nearly all licensed trappers 
received a questionnaire and approximately 60% were filled out and returned. 
Again, the harvests seem to be overestimated. The second method of 
determining the trapping harvest is by a tagging procedure similar to that 
used for deer and bear. Each beaver, otter, fisher, fox, marten, coyote, 
bobcat, and raccoon legally killed must be tagged by a State game warden 
before it can be sold. Beaver and otter have been tagged for several years 
but tagging of the other species began only a few years ago. Tagging is not 
required for muskrat, mink, skunk, or weasel, so accurate information is not 
available for these species. The number of animals tagged in the 
characterization area is summarized in table 17-6. Determination of the 
extent to which these harvests approach the current supply must await more 
accurate estimates of population sizes. 



17-24 



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17-25 



10-80 



Table 17-6. Annual Harvest (Number of Pelts Tagged) and Average Price per 
Pelt (1976 to 1977 average) of 7 Species of Furbearers in 
Coastal Maine a . 



Species 



Region 



Total 



Aver- 
age 
price 
($) 



Raccoon (1 yr.) 200 1331 596 878 448 303 3816 19 

Beaver (6 yr . avg.) 19 123 83 162 333 350 1070 28 

Fox (1 yr.) 62 236 36 229 255 68 886 55 

Fisher (5 yr. avg.) CI 105 48 98 2 <1 253 89 

Bobcat (4 yr. avg.) 1 1 7 37 41 87 82 

Otter (2 yr. avg.) 1 11 6 9 18 19 64 55 

Coyote (1 yr.) 1 3 3 12 19 34 

a Maine Department of Inland Fisheries and Wildlife, MIDAS Files, Augusta, ME. 



Other forms of direct mortality caused by man include illegal harvest 
(poaching), crippling losses during the hunting season, traffic and train 
accidents, intentional nuisance removals, predation by dogs, and environmental 
contaminants. Unfortunately, information on some of these losses is only 
available for deer and moose. 

A 9-year summary of death due to factors other than hunting is presented in 
table 17-7 for deer and table 17-8 for moose. An average of 1917 deer were 
reported killed per year during this time (Lavigne 1978b). Most (64%) losses 
were due to accidents with cars and trucks, followed by dog kills (10%), 
illegal kills (9%), and unknown (4%) and miscellaneous (3%) causes. On a WMU 
basis total losses were correlated with the density of deer populations, and 
losses due to roadkills were correlated with the amount of rural roads/100 sq 
mi of deer habitat. For moose, total losses due to illegal hunting were most 
important (42%), followed by cars and trucks (34%), miscellaneous causes (9%) , 
unknown losses (8%), and trains (6%) (Lavigne 1978a). 



17-26 



Table 17-7. Number of Deer Killed by Causes Other than Legal Hunting in 
Maine, 1969 to 1977 a . 



Year Cars or Illegal Dog Misc. Wild Crop Trains Total 

trucks 



Misc. 


Wild 


Crop 


Trains 


or un- 


preda- 


prot ect- 




known 


tors 


ion 





1969 1109 100 241 229 42 37 19 1777 

1970 1275 198 145 186 28 64 — 1896 

1971 976 145 487 237 36 28 — 1909 

1972 1281 209 131 124 63 28 23 1859 



1973 


1216 


226 


202 


119 


50 


41 


10 


1882 


1974 


1322 


265 


53 


72 


26 


30 


9 


1780 


1975 


1479 


269 


98 


115 


44 


33 


9 


2047 


1976 


1160 


154 


131 


118 


55 


23 


7 


1648 


1977 


1604 


276 


316 


129 


68 


48 


18 


24 59 



Mean 1279 217 200 148 56 37 15 1917 



a Lavigne 1978b. 



Table 17-8. Number of Moose Killed by Causes Other than Legal'Hunting in 
Maine, 1969 to 1977 a . 



Year 


Illegal 
kill 


Car or 
truck 


Misc. 
or un- 
known 


Train 


Predator 


Total 


1969 


71 


62 


31 


19 


1 


184 


1970 


96 


65 


45 


10 





216 


1971 


95 


57 


41 


12 





205 


1972 


70 


60 


50 


13 





193 


1973 


139 


84 


27 


20 





270 


1974 


121 


90 


41 


19 





271 


1975 


115 


94 


33 


6 


1 


249 


1976 


110 


95 


38 


8 





2 51 


1977 


93 


130 


58 


15 


1 


297 



Mean 102 82 41 14 <1 237 



l Lavigne 1978a. 



17-27 



10-80 



Environmental contaminants . Humans also affect mammals by applying 
chemical pesticides to control agricultural and forest insect pests. Some of 
the chemicals sprayed on agricultural lands in the characterization area 
include Guthion, Diazinon, Benlate, Ferbam, Thrithion, Sevin, Systox, 
Disyston, Dithane, Monitor, Bladex, and Lasso. Chemicals sprayed for control 
of forest insect pests (primarily spruce budworm) include Sevin, Orthene , and 
Dylox, as well as experimental sprayings of Matacil and Lannate. Bacillus 
thuringiensis , a biological control bacteria, is also used. The persistent 
pesticides, such as DDT, have not been used since the early 1970s. The extent 
of pesticide use in the coastal zone and known impacts are discussed in 
chapter 3, "Human Impacts on the Ecosystem." The effects on mammals of the 
chemicals currently used seem to be minor. They break down rapidly (within a 
few days or weeks) and are not concentrated in animal tissues. Populations of 
nontarget insects may be reduced temporarily but this has not seemed to affect 
small mammal populations and no acute toxic effects have been noted (Conner 
1960; Barrett 1968; Buckner et al. 1973, 1974, andl975; Caslick and Smith 
1973; Buckner and Sarrazin 1975; and Stehn and Stone 1975). 

Residues of DDT and its metabolites may still be present in some species of 
terrestrial mammals, as Dimond and Sherburne (1969) reported residues of DDT 
in shrews 9 years after application. The pattern of accumulation in mammal 
species was based on the food habits, as expected. Voles and mice (mainly 
herbivores) had low levels and were approaching pretreatment levels after 9 
years. Shrews had 10 to 40 times as much as mice and voles and were still 
well above pre-spray levels after 9 years. The highest levels, 41 ppm, were 
high enough to cause acute mortality, which could result in local extinctions. 
Sherburne and Dimond (1969) also examined residues in snowshoe hares and mink. 
Hares had low levels which did not differ from hares on untreated areas. Mink 
had levels 10 to 90 times those found in hares and levels were still above 
pretreatment concentrations after 7 to 9 years. 

IMPORTANCE TO HUMANITY 

Mammals are valuable for recreational, economic, aesthetic, and scientific 
reasons. The most obvious values are those associated with recreation, i.e. 
hunting and trapping. There were over 218,000 licensed hunters in Maine in 
1977, of which about 30,000 were nonresidents. While some of these may have 
been interested only in hunting game birds, it is estimated that over 80% of 
those holding hunting licenses hunted deer. The recreational importance of 
seven of the ten game species hunted for sport (no data for cottontail, 
woodchuck, or coyote) is indicated by the number of man-days effort expended 
in pursuit of these species (table 17-9). Deer provide the greatest amount of 
recreational value, with approximately 580,000 man-days of effort expended in 
Wildlife Management Units 6, 7, and 8. Following deer, in decreasing order of 
effort, are snowshoe hare (222,000), gray squirrel (38,000), black bear 
(32,000), raccoon (27,000), fox (21,000), and bobcat (13,000). The three 
Wilflife Management Units along the coast provide a large share of the total 
recreational value in hunting in the State. This proportion is highest for 
gray squirrel (69% of total man-days for the State), followed by snowshoe hare 
(57%), raccoon (51%), fox (46%), deer (45%), bobcat (31%), and bear (16%). 

Furbearing mammals also provide recreational opportunity. The number of 
trappers pursuing each species of furbearers in WMUs 6, 7, and 8 is shown in 
table 17-10. Also shown is the number of trap-days effort (number of traps x 

17-28 



Table 17-9. Average Number of Man-days of Hunting Expended on 7 Species 
of Game Mammals in Wildlife Management Units 6, 7, and 8 
During 1971 to 1972 Through 1976 to 1977 a 



Species 


Wildlife 


management 


unit 




Total 


% 




6 


7 




8 


of 
















State 
















total 


White-tailed deer 


125,228 


177,528 


275 


,723 


578, 


,479 


45 


Snowshoe hare 


32,123 


63,015 


126 


,874 


222, 


,012 


57 


Gray squirrel 


2310 


10,748 


25 


,409 


38, 


,467 


69 


Bear 


17,032 


2890 


12 


,427 


32 


,349 


16 


Raccoon 


3341 


9821 


13 


,498 


26 


,660 


51 


Red fox 


3998 


7813 




9435 


21 


,246 


46 


Bobcat 


4829 


2255 




6350 


13 


,434 


31 



Data from Anderson et al . 1975a and b. 



the number of days set) spent in pursuit of each species. More tappers 
pursued raccoon (406) than any other species, followed in decreasing order by 
fox (364), muskrat (329), fisher (311), beaver (292), mink (270), otter (114), 
skunk (83), weasel (55), bobcat (49), and coyote (27). In terms of trap-days 
effort, however, muskrat was highest (137,000 in the fall season, 99,000 in 
the spring season), followed by beaver (121,000), fox (75,000), raccoon 
(59,000), otter (17,000), skunk (11,000), bobcat (9000), weasel (8000), and 
coyote (3000). The importance of the coastal units in providing trapping 
recreation is indicated by the proportion of the total trap-days expended on 
each species within the coastal units. This ranges from 50% for muskrat to 
only 12% for coyote (table 17-10). 

Mammals have economic values but cause economic losses also. The economic 
values associated with hunting and trapping include the money spent for 
license fees, firearms and ammunition, traps, guides, gasoline, food, and 
lodging. Also, trappers realize a direct return from furs sold on the market. 
As an indication of the importance of furbearers in the coastal regions, table 
17-6 summarizes the number of furs tagged for each of seven furbearing species 
in the six coastal regions and the average price per pelt paid during 1976 to 
1977. While this table does not include those species that need not be tagged 
(muskrat, mink, skunk, weasel), the value for just these species was over 
$180,000. 



17-29 

10-80 



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Mammals sometimes destroy crops and livestock. Between 1946 and 1960 an 
average of $7600 was paid by MDIFW and landowners for damage caused by bears. 
This ranged from $2600 to $15,000 (Hugie and Banasiak 1975). There are no 
data on the costs associated with deer depredations but between 1969 and 1977, 
an average of 37 deer were killed each year as a result of complaints of crop 
damage (table 17-7). Other species of mammals that cause problems include 
beavers, bats, rats, mice, squirrels, and raccoons. Mammals are also 
important aesthetically, although quantifying aesthetic values is difficult. 
Most people enjoy watching mammals and the opportunity to view some of the 
more elusive mammals (such as mink, fisher, marten, and black bear) is an 
added reward to any outdoor activity. Acutal excursions to view mammals are 
probably limited to moose, deer, or beavers. Dunn and his colleagues (1975) 
identified 57 frequently used sites for watching moose in Maine. Only two are 
in the coastal WMUs , both in Unit 6, in Centerville and Northfield. While 
many people make day trips to view moose, it is doubtful that anyone comes to 
Maine specifically for that reason. 

Finally, mammals are of concern to humanity as a source of diseases, the most 
obvious of these being rabies virus. The incidence of rabies among mammals in 
Maine averaged 73 cases per year during 1971 to 1977. The seven counties 
along the coast averaged 24 cases per year (32% of the State total; table 17- 
11). Of the wild mammals affected, foxes account for 64% of the positive 
cases. Most other species of wild mammals have relatively low incidences of 
rabies (table 17-12). Not only people but domestic animals also are 
susceptible to rabies. Domestic animals most affected are (in decreasing 
order) cattle, cats, dogs, sheep, goats, horses, and pigs (table 17-12). 
Since animals suspected of having rabies must be destroyed, the economic loss 
may be considerable. 

MANAGEMENT 

Management of terrestrial mammals is the responsibility of the Maine 
Department of Inland Fisheries and Wildlife. Management strategies for game 
and furbearing mammals are determined by assessing the present status of, and 
alternative goals and objectives for, each species. This information is 
compiled in species management plans, which then form the basis for management 
decisions. Periodically, these plans are updated and revised as necessary. 

More important are management alternatives that can be employed by persons 
involved in making land-use decisions. As stated earlier, the most important 
influence man has on mammals concerns habitat quality and quantity. Persons 
proposing activities that will alter natural habitats should consider (1) the 
species of mammals using the habitats (figure 17-2), (2) the amount of that 
habitat type available (i.e., is it in short supply; see table 17-2 and 
appendix tables 1 to 9), and (3) whether that habitat is necessary for any 
species (figure 17-2). Increased awareness of particularly unique or rare 
habitats can be achieved by registering them with the Critical Areas Program 
of the Maine State Planning Office. 

More specifically, logging effects can be mitigated by leaving deer wintering 
areas uncut; cutting in patterns that create a mosaic of successional stages 
in close proximity to one another (i.e., prevent large tracts of uniform 
habitat) ; using selective or partial cutting practices to preserve mature 
forest habitats; leaving large undesirable "cull" trees for den sites; 

17-31 



10-80 



limiting planting and herbicide treatment to sites that are most productive 
for timber production; and leaving less productive sites to follow natural 
succession. 

In agricultural areas large fields with a minimum of edge should be avoided; 
hedgerows and natural vegetation in corners and damp spots should be 
encouraged; and some crops should be left unharvested (i.e., corn or alfalfa) 
as food. Effective means of biological control should be used to minimize 
spraying of pesticides. 

The opportunity for managing mammals is perhaps greatest in developed areas. 
Leedy and his colleagues (1978) have written an excellent guide to wildlife 
management in urban and suburban areas. They stress the importance of 
considering wildlife in the planning stages but also give management 
recommendations for existing developed habitats. These include: attempt to 
maintain entire ecosystems; use native plants for ornamental plantings; allow 
as many trees as possible, both alive and dead; provide multilayered habitats 
as opposed to monocultures; use natural drainage systems; avoid filling and 
dredging wetlands; provide continuous lanes of vegetation between parks; plan 
roads to minimize habitat loss; convert vacant lots to small parks or refuges; 
provide a diversity of plant species; consider biological control over 
pesticides; and, above all, retain natural habitat whenever possible. 



Table 17-11. Incidence of Rabies in Coastal Counties, Listed West to East, 
of Maine from 1971 through 1977 



County Number uf cases 



Cumberland 

Sagadahoc 

Lincoln 

Knox 

Waldo 

Hancock 

Washington 



Minimum 


Max imum 


Av 


erage 





23 




5 





10 




4 





16 




5 





10 




3 





20 




6 





5 




1 





4 




1 



17-32 



Table 17-12. 



Incidence of Rabies in Wild and Domestic Mammals in Maine 
from 1971 through 1978 



Species 



Average number of 
confirmed cases 



Average number of 
suspected cases 



Wild mammals 



Red fox 

Bat spp. 

Skunk 

Raccoon 

Deer 

Fisher 

Coyote 

Other (mainly rodents) 



49 (2-93) 

2 (1-4) 

1 (0-6) 

1 (0-8) 

<1 (0-2) 

<1 (0-1) 

<--l (0-1) 

■I (0-2) 



67 

46 
7 

39 
2 
1 


57 



Domestic mammals 



Cattle 

Cat 

Dog 

Sheep 

Horse 

Goat 

Pig 



7 


(1-30) 


4 


(0-21) 


3 


(1-10) 


2 


(0-13) 


1 


(0-4) 


1 


(0-3) 


1 


(0-3) 



Total 



73 



33 
95 

49 
6 
4 
4 
4 

414 



17-33 



10-80 



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10-80 



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17-35 



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Vilkitis, J. R. 1971. The violation simulation formula proves as reliable as 
field research in estimating closed-season illegal big game kill in 
Maine. Trans. Northeast Sect. Wildl. Soc. 28:141-144. 



17-37 



Chapter 18 
Reptiles and 
Amphibians 



Authors: Craig Ferris , Sally Rooney 




Resident reptiles and amphibians (collectively called herptiles) are not 
abundant in coastal Maine when compared to other eastern United States coastal 
areas probably because of the low winter temperatures and/or the short cool 
summers. However, certain habitats, such as marshes, bogs, and rivers, may 
support high numbers of some species . Sixteen amphibian species inhabit 
coastal Maine: eight salamander species, one toad species, and seven frog 
species. Fourteen resident reptile species are represented: five turtle 
species and nine snake species (table 18-1). In addition, there is one 
species of sea turtle, the leatherback (an endangered species), that is found 
regularly in low numbers in the marine system of coastal Maine. There are no 
native lizards in Maine. 

Amphibians are poikilothermic (cold blooded) vertebrates with moist skins, and 
lungs or gills, through which they respire. They inhabit damp terrestrial 
habitats and freshwater aquatic environments. Several salamanders are 
primarily terrestrial but require moist microhabitats , e.g., under logs or in 
wet leaf-litter. Adult toads, although terrestrial, breed in aquatic 
habitats. All amphibian species have an amphibious larval stage. 

Reptiles have dry, scaly skins, which help prevent desiccation, and respire 
through lungs. Snakes inhabit terrestrial systems mostly, while turtles are 
found primarily in or near freshwater systems. Reptiles have no larval 
stages . 

Reptiles and amphibians are important to humanity scientifically and 
aesthetically. It has been suggested that amphibians could serve as 
indicators of environmental contamination, because their moist skins may 
concentrate toxic substances trapped during respiration (Porter 1972). 
Neither group has economic value in Maine, although bullfrogs and snapping 
turtles are used locally as food. High concentrations of snapping turtles can 
be a problem if they prey on young waterfowl and fish. 



18-1 



10-80 



Table 18-1. Habitats and Distribution of Herptiles in Coastal Maine 



Species 



Habitat 

or system 



Region 



Salamanders 

Blue-spotted salamander 
Spotted salamander 
Red-spotted newt 
Northern dusky salamander 
Red-backed salamander 
Four-toed salamander 
Spring salamander 
Northern two-lined salamanader 



LPT 

LPT 

LPT 

RP 

PT 

PT 

R 

R 



all 

all 

all 

all 

all 

4 

1 

all 



Frogs and toads 
American toad 
Spring peeper 
Gray tree frog 
Bullfrog 
Green frog 

Northern leopard frog 
Pickerel frog 
Mink frog 
Wood frog 

Turtles 

Snapping turtle 

Stinkpot 

Spotted turtle 

Wood turtle 

Eastern painted turtle 

Sea turtle 

Leatherback 

Snakes 

Northern water snake 
Northern brown snake 
Red-bellied snake 
Eastern garter snake 
Northern ringneck snake 
Northern black racer 
Smooth green snake 
Eastern milk snake 



LPT 

LP 

LP 

RLP 

RLP 

RLP 

RLP 

LP 

PT 



RLP 

RL 

LP 

PT 

RLP 



M 

RLP 

T 
T 
T 
T 
T 
T 
T 



all 

all 

all 

all 

all 

all 

all 

6 

all 



all 

1-4 

1 

all 

all 



all 

6 

all 

all 

all 

all 

all 

all 

all 



a Includes breeding habitats. 

bR=Riverine; L=Lacustrine; P=Palustrine; T=Terrestrial ; M=Marine. 



18-2 



This chapter describes the status of reptile and amphibian species along the 
coast of Maine; their species associations, food requirements, and 
reproductive biology; the factors that affect their distribution and 
abundance; and their importance to humanity. Data gaps and research 
priorities are indicated and current management practices applicable to 
herptiles are discussed. 

DISTRIBUTION AND ABUNDANCE 

Most species of amphibians and reptiles are found throughout the six coastal 
regions in the habitats listed in table 18-1. Exceptions are the spring 
salamander and the spotted turtle, which reach the northernmost extent of 
their ranges in the area of regions 1 or 2 (Pope 1915; and Babcock 1919). The 
abundance of herptile species in coastal Maine is not known. The eastern 
region, particularly the coastal area, has not been surveyed comprehensively. 
The limited distributions indicated in table 18-1 for the four-toed 
salamander, mink frog, stinkpot turtle, and northern water snake probably 
result from lack of adequate information. Information from northern Maine and 
other States indicates that reptiles and amphibians may be abundant, although 
inconspicuous. For example, a deciduous forest in New Hampshire supported 
approximately 3000 salamanders per hectare, with a biomass of 1770g/ha (wet 
weight; Burton and Likens 1975). This biomass is approximately twice that of 
breeding birds, and nearly equal to that of small mammals. These densities 
are comparable to those found elsewhere (Michigan, Pennsylvania, and 
Virginia). In northern Maine, populations of the red-backed salamander 
averaged 1100/ha in mixed hardwood-spruce fir forests (Banasiak 1974). More 
studies are needed to determine populations of these and other herptiles in 
coastal Maine. The importance of herptiles in the functioning of ecosystems 
probably has been underestimated (Burton and Likens 1975). 

The leatherback turtle is an endangered species. The distribution of the 
leatherback turtle, as well as other species of sea turtles, is currently 
being investigated along the Atlantic coast from Cape Hatteras, North 
Carolina, to Nova Scotia (Shoop et al. 1979). During the first year of 
observation (1979) four leatherbacks were sighted in marine waters off the 
Maine coast. Leatherbacks appear rather suddenly along the Maine coast in 
late spring, and it is thought they move northward using the Gulf Stream for 
transport. Unlike other species of sea turtle^, leatherbacks are capable of 
regulating their body temperture at about 80 F (27 ° C) , and are thus able to 
survive in the cold marine waters along the Maine coast. 

HABITAT PREFERENCES 

The preferred habitats of many species of reptiles and amphibians differ 
according to the stages of their annual cycle. Many species that spend much 
of the year in terrestrial habitats move to aquatic habitats for breeding and 
egg laying. In addition, all reptiles and amphibians indigenous to the 
coastal zone must hibernate during the winter. Many species (e.g., 
terrestrial amphibians) hibernate in the mud on the bottoms of lakes and 
ponds. Others (i.e., aquatic amphibians) burrow in the ground. Snakes 
hibernate under rocks, tree roots, or underground. Snake dens are usually 
occupied by a number of individuals. 



18-3 



10-80 



Among the salamanders found in coastal Maine, five are primarily terrestrial 
(table 18-2). These are the spotted, blue-spotted, red-backed, four-toed, and 
dusky salamanders (the red-backed is entirely terrestrial). Except during the 
breeding season these species are found in damp leaf-litter and under rocks 
and logs in moist woodland habitats. The four-toed salamander prefers swampy 
woods or peat bogs (Bleakney 1953). Two species, the spring and two-lined 
salamanders, are entirely aquatic. They remain in fast-moving riverine 
habitats throughout the year. 

The red-spotted newt has three stages: one terrestrial and two aquatic. The 
red-spotted newt is found in moist woodland environments during the eft 
(between larvae and adult) stage. When the time comes for their 
transformation from eft to the adult stage, the efts migrate to emergent 
wetlands and shallow waters of ponds and lakes, the preferred habitats of the 
adult newt. 

The American toad, the gray tree frog, and the wood frog are primarily 
terrestrial species that return to the water to breed (table 18-2). The true 
frogs (genus Rana ) include species that range from almost totally aquatic 
(e.g., bullfrog and green frog) to almost entirely terrestrial (e.g., wood 
frog). The leopard frog is in the middle of this range, preferring grassy 
meadows and marshes. 

Turtles found in the coastal zone are aquatic animals, occupying a variety of 
lacustrine, riverine, and palustrine habitats throughout the year. The one 
exception to this rule is the wood turtle, which is a terrestrial species. 
The snapping and stinkpot turtles prefer sluggish streams. The leatherback 
turtle prefers deep water marine habitats. 

Snakes are found in a variety of terrestrial habitats, including forests, old 
fields, and agricultural land. The water snake is a semiaquatic species and 
is found usually in or near water. 

BREEDING HABITS 

The breeding seasons of amphibian species differ considerably. Most breed in 
spring or early summer but a few (such as the bullfrog and spring salamander) 
breed in late summer or early fall (table 18-2). In spring, blue-spotted and 
spotted salamanders seek the shallow waters of small ponds and lakes or small 
temporary bodies of water to begin breeding displays and egg laying. The 
four-toed salamander lays its eggs singly, dropping them into the water 
(Oliver and Bailey 1939). The red-backed salamander completes its breeding 
cycle within moist woodland habitat, where it deposits its eggs under rocks or 
rotten logs. The dusky salamander lays its eggs on land and the larvae may 
develop on land or migrate to nearby water, where development continues. The 
more aquatic species (spring and two-lined salamanders) lay their eggs under 
rocks and stones in fast-moving riverine habitats. The red-spotted newt is 
unique among the salamanders found in coastal Maine because it is aquatic in 
both the adult and larval stages. The eft stage is terrestrial and lasts from 
1 to 3 years (usually 2). 

Upon hatching from the egg most salamanders undergo a gilled larval 
development period, the length of which varies among species. An exception is 
the red-backed salamander, which hatches from the egg as a miniature adult. 

18-4 



Table 18-2. Herptile Breeding Seasons and Habitats 



Species 



Months 



JFMAMJJASOND 



Amphibians 
Blue-spotted salamander 
Spotted salamander 
Red-spotted newt 
Dusky salamander 
Red -backed salamander 
Four-toed salamander 
Spring salamander 
Two-lined salamander 
American toad 
Spring peeper 
Gray tree frog 
Green frog 
Bullfrog 
Leopard frog 
Pickerel frog 
Mink frog 
Wood frog 



P a 


P 


T 


T 


T 


T ~ 


P 


P 


T 


T 


T 


T - 


p 


P 


P 


P 


P 


P - 


T 


T 


R 


R 


T 


T - 


T 


T 


T 


T 


T 


T - 


P 


P 


P 


P 


P 


P - 


R 


R 


R 


R 


R 


R - 


R 


R 


R 


R 


R 


R - 


P 


P 


P 


T 


T 


T - 


T> 


P 


P 


P 


P 


P - 


T 


P 


P 


T 


T 


T - 


P 


P 


P 


P 


P 


P - 


PR 


PR 


PR 


PR 


PR 


PR - 


P 


P 


P 


P 


P 


P - 


P 


P 


P 


P 


P 


P - 


P 


P 


P 


P 


P 


P - 


P 


P 


T 


T 


T 


T - 



Reptiles 
Snapping turtle 
Stinkpot 
Spotted turtle 
Wood turtle 
Painted turtle 
Water snake 
Brown snake 
Red-bellied snake 
Garter snake 
Ribbon snake 
Ringneck snake 
Black racer 
Smooth green snake 
Milk snake 



PR PR PR PR PR PR 
PR PR PR PR PR PR 
P P P P P P 



T 
P 
P 
T 
T 
T 
T 
T 
T 
T 
T 



T 
P 
P 
T 

T 
T 
T 
T 
T 
T 
T 



T 
P 
P 



T 
P 
P 



T 
P 
P 



T 
P 
P 



T T T T 

T T T T 

T T T T 

T T T T 

T T T T 

T T T T 

T T T T 

T T T T 



a P=Palustrine; R=Riverine; T=Terrestrial; ^Hibernation (varies with 
region) . 
Habitat symbols underlined indicate months of breeding. 



18-5 



10-80 



Among the frogs and toads, the American toad, gray tree frog, and the wood 
frog are primarily terrestrial but migrate to a variety of palustrine habitats 
during the breeding season (spring and early summer) to lay their eggs in 
shallow water. The spring peeper and the remaining frog species found in 
coastal Maine occupy palustrine and riverine habitats throughout the year. 
Breeding takes place from June through July (personal communication from B. 
Burgason, Maine Department of Inland Fish and Wildlife, Bingham, ME; March, 
1979). Among all species of toads and frogs the eggs hatch into a "tadpole," 
or larval stage. Tadpoles metamorphose into adults after periods of time that 
vary with species. Bullfrog tadpoles overwinter before metamorphosing into 
adults . 

Turtles in coastal Maine breed in spring and summer. The females lay their 
eggs in cavities dug in sandy soil or in humus along river banks, shores of 
ponds, lakes, or palustrine wetlands. The eggs usually hatch by September. 
Turtles have no larval stages. 

The snakes found along the coast of Maine fall into two reproductive 
categories: those that give birth to living young (water, brown, red-bellied, 
ribbon, and garter snakes) and those that lay eggs (ring-necked, green, black 
racer, and milk snakes). The living young are born in late summer, the eggs 
hatch usually in August or September (Oliver and Bailey 1939). Snakes have no 
larval stages. 

FOOD HABITS 

Reptiles and amphibians of coastal Maine are primarily carnivorous, feeding on 
a variety of animal life, principally invertebrates. The major exceptions are 
the turtles, which consume both plant and animal matter. Adult terrestrial 
salamanders eat terrestrial insects (adults and larvae), as well as other 
available invertebrate fauna, including spiders, mites, and various worms. 
Larvae of all terrestrial salamanders feed on insects. Aquatic larval 
salamanders prey on aquatic insect larvae, supplementing their diets with 
other available animal material. 

Adult American toads, tree frogs (spring peeper and gray tree frog), and the 
more terrestrial frogs (pickerel, leopard, mink, and wood) eat insects 
primarily, and a wide variety of other invertebrates. The more aquatic frogs 
(green frog and bullfrog) eat aquatic insects principally, and other available 
invertebrate foods. The bullfrog also consumes some vertebrate prey, 
including small fish, and other herptiles (Oliver and Bailey 1939). The 
larvae of toads and frogs are herbivores and detrivores, feeding on algae and 
decomposing material from the surfaces of their aquatic environments. 

Turtles in the coastal zone are generally omnivorous, eating a variety of 
invertebrates, a few vertebrates, and vegetable material. Snapping turtles 
occasionally may eat fish and become a nuisance in proximity to fish 
hatcheries and natural spawning areas. Under certain circumstances the 
snapping turtle may be a serious threat to fish fry and ducklings (Coulter 
1957 and 1958). The leatherback turtle feeds primarily on jellyfish. 

Snakes indigenous to the Maine coast are predators. The larger species 
(water, garter, ribbon, black racer, and milk) eat small vertebrates (mice, 
birds, and shrews) as well as insects and other invertebrates. The 

18-6 



semiaquatic water snake preys upon small fish and frogs. The smaller snakes 
(brown, red-bellied, ring-necked, and smooth green) eat insects, earthworms, 
slugs, and other invertebrates. The green snake eats adult and larval insects 
almost exclusively (Oliver and Bailey 1939). 

FACTORS OF ABUNDANCE 

Although natural factors largely determine the distribution and abundance of 
most animals, human-induced factors increasingly alter the ecosystem and their 
inhabitants. Some of the major factors that affect herptiles are discussed 
below. 

Natural Factors 

The relatively long, cold winters and short, cool summers of coastal Maine are 
probably the most influential natural limiting factor to reptiles and 
amphibians. Other natural factors affecting abundance of herptiles are forest 
and ground fires, beaver dams, predation, and the degree of abundance of food 
and cover. The extent to which these factors affect populations of amphibians 
and reptiles on the Maine coast is not known, but none appears to be 
particularly limiting. 

Human Factors 

Agriculture . Erosion from cultivated fields may damage herptile habitats 
seriously by causing siltation of nearby streams, rivers, and ponds (see 
"Agricultural and Developed Land," chapter 10 and "Human Impacts On the 
Ecosystem," chapter 3). However, farm ponds generally benefit most species of 
herptiles, especially frogs, and salamanders, through the creation of 
freshwater aquatic habitat. The fact that large acreages of blueberry barrens 
are routinely burned may affect populations of herptiles living in these 
habitats adversely, especially the blue-spotted, spotted, red-backed, and 
dusky salamanders, and several species of snakes, including the black racer, 
garter, and green snakes. The American toad, once abundant on Mount Desert 
Island (region 4) was virtually eliminated during the massive fire of 1947 
that swept the island (Davis 1959) . 

Pollution . The introduction of toxic chemicals and sediments from soil 
erosion into coastal Maine could play major roles in reducing the abundance of 
herptiles (Porter 1972). An average of 10,000 to 12,000 lb (4500 to 5500 kg) 
of Guthion was sprayed on blueberry fields in Washington County between 1971 
and 1976 (Maine Soil and Water Conservation Commission 1978). Air pollution 
and acid rain could have an adverse effect on populations of terrestrial 
salamanders, which respire through their skins. 

Bart and Hunter (1978) have compiled an annotated bibliography on the 
biological impact of selected insecticides on vertebrates and invertebrates. 
According to these authors no significant impact on populations of herptiles 
was noted in experiments with various dilutions of the insecticides commonly 
used in Maine (e.g., Zectran, Dylox, and Guthion) against spruce budworm or on 
agricultural crops, but populations of aquatic insects (e.g., mayflies, 
stoneflies, and various fly larvae) were reduced by some of these chemicals. 
Certain insects used by aquatic herptiles as food were among these. In 
addition, pesticide and oil films on pond surfaces may interfere with the 

18-7 

10-80 



dermal oxygen exchange of transforming amphibians (Porter 1972) . Insects 
dying from pesticides often go into convulsions, and adult toads and frogs may 
orient towards these struggling insects (Sassamon 1978). Frogs and toads were 
found to have concentrations of 6 to 222 ppb Orthene (Acephate) immediately 
following a spray to kill spruce budworm, but after 30 days there were no 
detectable residues (Sassamon 1978). 

Impoundments . Small artificial dams have created new ponds and wetlands 
in coastal Maine. Cook (1967) discovered that many salamander and frog 
species had increased in abundance on Prince Edward Island, Canada, because of 
these dams. Millponds used by the logging industry have formed new habitat 
for several species, principally the red-spotted newt, green and leopard 
frogs, and the American toad. The adverse effects such structures would have 
on species such as the dusky and two-lined salamanders, which prefer small, 
flowing streams have not been investigated. Similar structures in coastal 
Maine may provide additional habitat for aquatic herptiles. 

Land, water, and forest disturbances . Many small gravel extraction 
operations are present in coastal Maine, especially in region 6. When gravel 
eskers are mined near bodies of water the quality of herptile habitat may be 
reduced through erosion and siltation. 

Peat mining, conducted principally in Washington County (region 6), probably 
does not reduce significantly the preferred habitat (sphagnum bog) of most 
herptile species, with the possible exception of the four-toed salamander. 
However, increased siltation due to peat mining could reduce water quality. 

Rights-of-way maintained along highways and beneath power lines or pipelines 
may provide brushy habitat for species such as the black racer (personal 
communication from D. F. Mairs, Pesticide Control Board, Augusta, ME; 
February, 1979). Transmission corridors may alter the abundance of herptiles 
locally, by changing drainage patterns in adjacent areas, and thereby creating 
small, temporary palustrine areas that may serve as breeding areas for 
herptiles (blue-spotted and spotted salamanders and most frogs). 

Forest cutting practices have great potential for altering habitats. Clearcut 
or strip harvesting methods expose areas of the forest floor that have been 
shaded previously, causing them to dry out. Such activities destroy preferred 
habitat of many terrestrial salamanders and the wood frog. Subsequent brushy 
growth in these clearings provides new habitat for black racer and garter 
snakes. As a result of these logging practices adjacent bodies of water may 
be subject to silting and lowering of pH. These processes could reduce the 
abundance of herptiles (Porter 1972). 

Road construction adjacent to breeding areas increases the hazard of roadkills 
for some herptile species, especially those that move in large numbers to 
breeding ponds (blue-spotted and spotted salamanders, the American toad, and 
all frog species and turtles). Brush removal and landscaping in suburban 
areas can have an adverse effect on many herps because they depend on brush 
and fallen logs for their shelter and habitat. 



18-8 



IMPORTANCE TO HUMANITY 

People use small numbers of bullfrogs and snapping turtles as food. Some 
smaller species of frogs (pickerel, leopard, and green) are used as fish bait. 

Amphibians could serve as indicators of environmental contamination. Their 
moist skins may hold concentrations of toxic chemicals and other environmental 
pollutants trapped during respiration (Porter 1972) . No data are available on 
this subject, however. 

MANAGEMENT 

The integrity of freshwater aquatic and terrestrial habitats important to 
reptiles and amphibians needs to be maintained in coastal Maine. No laws 
exist at present governing the collecting or possession of herptiles in the 
State of Maine (personal communication from B. Burgason, Maine Department of 
Inland Fisheries and Wildlife, Bingham, ME; March, 1979). Such laws may be 
necessary for the preservation of these animals if the magnitude of collecting 
increases . 

RESEARCH NEEDS 

Very little information is available on reptiles and amphibians along the 
coast of Maine. The only available distributional information that is 
specific to coastal Maine is local. Some data on food habits of the snapping 
turtle (Coulter 1957, 1958, and 1968) are available. 

Population studies of herptiles in coastal Maine are needed to provide 
information on the role of herptiles within ecosystems. Information is needed 
on the impact of pesticides on herptiles. Further research is needed to 
determine if sphagnum-peat bogs are the preferred habitat of the four-toed 
salamander, as suggested by Bleakney (1953) and Burgason and Davis (1978). If 
so, the effects of peat mining on this rare species will need to be 
determined. Studies also need to be conducted to determine the effects of 
regular burning of blueberry barrens on the abundance of reptiles and 
amphibians . 



18-9 

10-80 



REFERENCES 



Babcock, H. L. 1919. Turtles of the Northeastern States. Dover, New York. 

Banasiak, C. F. 1974. Population Structure and Reproductive Ecology of the 
Red-backed Salamander in DDT-treated Forests of Northern Maine. Ph.D. 
Thesis. University of Maine at Orono, Orono, ME. 

Bart, J., and L. Hunter. 1978. Ecological Impacts of Forest Insecticides: 
An Annotated Bibliography. New York Cooperative Wildlife Research Unit. 
Cornell University, Ithaca, NY. 

Bleakney, S. 1953. The four-toed salamander, Hemidactylium scutatum, in Nova 
Scotia. Copeia 3:180. 

Burgason, B. , and S. Davis. 1978. Hemidactylium scutatum (Four-toed 
Salamander). Herp. Review 9(1) :21. 

Burton, T. M. 1975. Energy flow and nutrient cycling in salamander 
populations in the Hubbard Brook Experimental Forest, New Hampshire. 
Ecology 56(5): 1068-1080. 

, and G. E. Likens. 1975. Salamander populations and biomass in Hubbard 



Brook Experimental Forest, New Hampshire. Copeia (3):54l-546. 

Cook, F. R. 1967. An Analysis of the Herptofauna of Prince Edward Island. 
M.S. Thesis. Acadia University, Wolfville, Nova Scotia. 

Coulter, M. W. 1957. Predation by snapping turtles upon aquatic birds in 
Maine marshes. J. Wildl. Manage. 21(1): 17-21 . 

1958. Distribution, food and weight of the snapping turtle in Maine. 



Maine Field Nat. l4(3):53-62. 

_. 1968. The ancient snapper. Maine Fish and Game. Summer 1968, 



Davis, S. L. 1959. Notes on the Amphibians in Acadia National Park, Maine. 
M.S. Thesis. Cornell University, Ithaca, NY. 

Maine Soil and Water Conservation Comm. , with Soil Conservation Service (SCS) 
and Department of Environmental Protection (DEP) cooperating. 1978. 
Study of Non-point Agricultural Pollution in Washington County, U.S. 
Department of Agriculture, Soil Conservation Service, Machias, ME. 

Oliver, J. A., and J. R. Bailey. 1939. Amphibians and reptiles of New 

Hampshire. Pages 195-217 in Herbert E. Warful, ed., Biological Survey of 

the Connecticut Watershed, Survey Report No. 43 New Hampshire Fish and 
Game Department, Concord, NH. 

Pope, P. H. 1915. Some new records for Gyrinophilus porphyriticus (Green). 
Copeia 19:14-15. 

Porter, K. R. 1972. Herpetology. W. B. Saunders Co., Philadelphia. 

18-10 



10-80 



Sassamon, J. F. 1978. Post-spray monitoring of amphibians (Orthene: 
Acephate). In Environmental monitoring of cooperative spruce budworm 
control projects, ME. 1976:1977. 

Shoop, C. R., T. L. Doty, and N. E. Bray. 1979. Sea turtle sighting, 
strandings, and nesting activity, January - June, 1979; Cape Hatteras, 
North Carolina, to Nova Scotia. Pages 313 to 341 in Cetacean and Turtle 
Assessment Program (CETAP) . Quart. Summary Rept. , Naragansett Marine 
Laboratory, Univeristy of Rhode Island, Kingston, RI . 



18-11 



Chapter 19 

Commercially Important 
Forest Types 

Author: David Canavera 




Trees occur in abundance on virtually all of the terrestrial habitats in the 
characterization area. They are present on all types of terrestrial habitat, 
from open pine barrens to urban centers and provide suitable habitat for many 
plant and animal communities. Due to diverse habitat and reproductive 
requirements, trees of the coastal zones, (a term that will be used 
synonymously with "characterization area" here) evolved unique adaptive 
mechanisms to help guarantee their survival (e.g., closed cones in jack pine 
that open and disperse seeds after fire) . 

Trees have direct economic importance to people. Collectively, the 43 tree 
species (table 19-1) found in the region are its most important commercial 
plant crop (see also chapter 9, "The Forest System"). Examples of wood- 
product industries supplied with raw materials from the coastal zone include: 
pulp and paper, lumber, veneer, turnings (including lobster traps, pallet 
stock, and box boards), slack cooperage, fencing, shingles, Christmas trees, 
wreaths and greens, spruce gum, salad bowls, paddles, bowling pins, log 
cabins, maple syrup and firewood (Ferguson and Kingsley 1972). 

People have influenced the number and diversity of tree species in the coastal 
zone by altering habitat conditions (through agriculture, construction, 
logging, soil moisture drainage, and fire among others) and by harvesting some 
species (e.g., eastern white pine, red spruce, and paper birch) in greater 
quantity than others. 

This chapter is designed to familiarize the reader with the commercial forests 
and common tree species of the coastal zone and to discuss current forestry 
practices within this region. Emphasis is placed on the impacts (silvicultural 
and environmental) of these practices. The term forest type as used here is 
"a descriptive term used to group stands of trees of similar character in 
regards to composition and development due to certain ecological factors, by 
which they may be differentiated from other groups of stands" (Society of 
American Foresters 1964). 



19-1 



10-80 



Table 19-1. Common Commercial Tree Species of the Characterization Area 



ab 



Common name 



Taxonomic name 



Atlantic white-cedar 

Eastern red cedar 

Tana rack 

Norway spruce (exotic) 

White spruce 

Black spruce 

Red spruce 

Jack pine 

Red pine 

Pitch pine 

Eastern white pine 

Scotch pine (exotic) 

Douglas fir 

Northern white cedar 

Eastern hemlock 

Balsam fir 



Red 

Silv 

Suga 

Yell 

Swee 

Pape 

Gray 

Amer 

Shag 

Amer 

Whit 

Blac 

Gree 

Butt 

East 

Bals 

Bigt 

Quak 

Blac 

Whit 

Bar 

Nort 

Blac 

Amer 

Amer 

Slip 



mapl 
er m 
r ira 
ow b 
t bi 
r bi 
bir 
ican 
bark 
ican 
e as 
k as 
n as 
ernu 
ern 
air p 
ooth 
ing 
k ch 
e oa 
oak 
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.Maine Forestry Department 19 7 3. 
Names according to Little 195 3, 



19-2 



The forest communities are divided into three main forest types: spruce-fir; 
maple-beech-birch; and white pine-hemlock-hardwood. Each forest type will be 
analyzed for habitat conditions, reproduction and growth, management methods, 
and occurrence of natural enemies. Analysis by this method readily 
facilitates discussion of ecological interactions. The grouping of forest 
types here necessitated the inclusion of several minor forest types recognized 
by the United States Forest Service as occurring in the coastal zone (table 
19-2) . Separate sections in the chapter are devoted to fuel wood production 
and Christmas tree production. 

Biological and silvicultural knowledge of tree species in the characterization 
area is relatively widespread because the species are all common in Eastern 
North America and have been well studied in various parts of their botanical 
ranges. However, they have not been well studied in coastal areas and facts 
such as species' modifications and adaptations to the maritime climate are 
little known. 

The information used to prepare this chapter has been compiled from research 
conducted by: universities in the Northeast (Maine, New Hampshire, Vermont, 
Massachusetts, Connecticut, and New York), the North Central States (Michigan, 
Wisconsin, and Minnesota), and Canada (Ontario, Quebec, New Brunswick, Nova 
Scotia, and Newfoundland), the U.S. Forest Service, the Canadian Forest 
Service, and individual State and Provincial forest service organizations. 

Precise statistical data (e.g., sawtimber volume, forest land area by 
ownership class, timber growth, and available cut projections) for the coastal 
zone are not available. However, the Forest Survey unit of the United States 
Forest Service inventoried the timber resources of Maine during 1968 to 1970 
(Ferguson and Kingsley 1972), so some information on forest conditions and 
production (table 19-3 and figure 19-1) is available. See atlas map 2 for 
types of land cover found in the characterization area. Geographic sampling 
units in Maine, as presented by Ferguson and Kingsley (1972), are shown in 
figure 19-1. The Casco Bay Unit, the Capitol Unit, and the Hancock and 
Washington Units encompass most of the characterization area. Units are 
delineated on the basis of homogeneity of tree species in so far as possible. 
Common names of species are used except where accepted scientific names do not 
exist. Taxonomic names of all species mentioned are given in the appendix to 
chapter 1. 

The 1968 to 1970 Forest Survey points out the following general trends in 
Maine's timber resource that deserve attention: 

1 . Softwood (one of the botanical group of trees that have needle or 
scale-like leaves) growing-stock is increasing at a much greater rate 
than that of hardwood (one of the botanical group of trees that have 
broad leaves) . 

2. About two-thirds of the sawtimber volume is in trees <15.0 inches, or 
38 cm, diameter at breast height (dbh; 4.5 feet, or 1.4 m, above 
average ground level). 

3. Although growth exceeds removal for total growing-stock, the growth- 
to-removal ratios of northern white cedar, northern red oak, white 
ash, yellow birch, white pine, sugar maple, and beech show 
overcutting. 

19-3 



10-80 



4. Projections of future timber supply show that, if present removal 
trends continue, hardwood removals will exceed growth within a few 
years, and softwood removals will exceed growth before the turn of 
the century. 

These observations illustrate an increased effort must be made to encourage 
landowners to practice good forest management. These efforts must be directed 
to hardwoods, particularly if growth is to keep pace with demand. 

SPRUCE-FIR TYPE 

Habitat Conditions 

Red spruce, white spruce, and balsam fir are the predominant species in the 
spruce-fir type. Black spruce is also a minor component. Depending on site 
conditions, stands (aggregations of trees occupying a specific area and 
sufficiently uniform in composition, age arrangement, and condition as to be 
distinguishable from the forest on adjoining areas) may contain only spruce 
and fir or spruce-fir in various combinations with other conifers and 
hardwoods. Other conifers include northern white cedar, eastern hemlock, 
eastern white pine, and tamarack; and the hardwoods include red maple, paper 
birch, the aspens, white ash, American beech, sugar maple, and yellow birch 
(Hart 1964). Red spruce, white spruce, and balsam fir will grow on a variety 
of soils, including those that are poorly drained (McLintock 1954). The soils 
where spruce-fir grow are mostly acid podzol with a thick mor humus and well- 
defined A2 horizon, characteristics commonly associated with abundant 
rainfall, cool climate, and coniferous cover. Black spruce is generally 
confined to bogs and muck soils. 

The shade tolerance of spruce and fir and the multiple-aged condition of the 
stands in which they normally occur make the identification of "good" and 
"poor" growing areas difficult. Westveld (1941) devised a system whereby the 
ireas can be classified either as primary softwood sites or secondary softwood 
sites. These classes are meaningful in terms of potential stand composition, 
growth, and reproduction. 

Primary softwood sites usually occur in areas with poor or impeded drainages 
in the so-called spruce-fir swamps, flats, and other lower topographic 
positions. Spruce-fir also is common on the thin soils of upper slopes. 
Characteristic shallow rooting on these soils makes open stands susceptible to 
windthrow. These sites are composed mostly of softwood species. Hardwoods 
comprise less than 25% of the stands and are mostly paper birch, yellow birch, 
aspen, red maple, and an occasional beech or sugar maple. 

Secondary softwood sites occur on the better-drained areas of higher 
topographic elevation and on medium-elevation ridge lands. Hardwoods may 
comprise from 25% to as much as 70% of the stands on these sites, often 
competing sharply with spruce-fir. The tolerant red spruce and balsam fir may 
become established in the understory, responding to release if the overstory 
is removed. On such sites, the hardwoods usually are beech, sugar maple, and 
yellow birch. Herbaceous vegetation is less common than shrubs such as witch 
hobble, striped maple, and mountain maple. 

19-4 



a 



Table 19-2. Forest Types of the Characterization Area c 



Forest type 



Descr ipt ion 



Spruce-F ir 



Forests in which balsam iir or 
spruce (black, red, white), 
singly or in combination, irake up 
a plurality of the stockinq. 
h orthern white-cedar swair. ds are 
also included. Common associates 
include tamarack, red maple, 
white birch, and eastern hemlock. 



Maple-Be ech-Birch 



lorests in which sucjar maple, 
American beech and yellow birch, 
singly or in combination, are the 
major components. Associated are 
various admixtures of basswood, 
red maple, northern red oak, 
white ash, eastern white fine, 
balsam fir, black cherry, paper 
birch, gray birch, American elm, 
slippery elm, eastern 
hophornbeam, red spruce, and 
white spruce. 



White Pi tie -Hemlock-Ha rd wood 



Forests in which eastern white 
fine and eastern hemlock are 
predominant. The hardwood 
associates are numerous but none 
ere particularly characteristic. 
The principal ones are American 
beech, sugar maple, basswood, red 
maple, yellow birch, paper birch, 
white ash, and northern red oak. 



a Adapted from Ferguson and Kingsley 
conform to Barrett 1962. 



1972 and modified to 



19-5 



10-80 



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10-80 



Reproduction and Early Growth 

Red spruce produces good seed crops every 4 to 8 years, white spruce every 2 
to 6 years, and balsam fir every 2 to 4 years (Fowells 1965). Seed production 
may begin when trees are about 15 years, but significant production usually 
does not begin until the trees are 25 to 30 years or older. Very few viable 
seeds are stored in the forest floor for more than one year. Some of the 
silvical characteristics of the major species are given in table 19-4. All 
three spruce species are tolerant of shade but require considerable light for 
rapid growth and development. In the coastal zone, white spruce develops pure 
stands on oldfield sites. These stands exhibit the same characteristics of 
growth and form that are expected in plantation-grown trees. All three 
species may form physiographic climaxes on poorly drained sites but on the 
better soils are subclimax to, and often mixed with, hardwoods such as sugar 
maple and beech (Westveld 1953) . 

Spruce-fir stands normally reproduce readily and have remarkable recuperative 
capacity (Barrett 1962). Advanced spruce-fir reproduction under many older 
stands may assure new spruce-fir stands after the overstory is harvested, 
unless fire occurs. Favorable seedling development is greatly affected by 
light, temperature, and moisture conditions. Initially, the light 
requirements conducive to early establishment seem not to exceed 10% of full 
sunlight (Vezina and Peck 1964). However as the seedling develops, light 
intensities of 50% or more are necessary for optimum growth (Shirley 1943) . 
Soil surface temperatures between 115°F (46°C) and 130°F (54°C) result in the 
death of most young conifer seedlings even when they are exposed for very 
short periods of time (Baker 1929). Damage caused by late frost to leaders 
and new lateral growth is seldom severe. 

Spruce seedlings are weaker and more fragile than fir and grow slower during 
the establishment phase (Fowells 1965). Seedlings that have obtained a height 
of 6 inches (15 cm) are considered to be established. Once a seedling becomes 
established, early growth is determined largely by the amount and character of 
overhead competition. Dense growth of bracken fern, raspberry, and hardwood 
sprouts are the chief competitors of seedlings on heavily cutover lands, but 
both fir and the spruces will survive many years of suppression and still 
respond to release. If left undisturbed, most stands of this type will 
contain a number of age classes because most species will survive under heavy 
shade; however, the main canopy of many stands is even-aged because they 
developed after depredation by insects, hurricanes, fire, and clear-cutting of 
mature stands around 1900 (Coolidge 1963) . 

Management Methods 

The spruce-fir tree species in the characterization area are suited to 
management in either even-aged or uneven-aged stands (Frank and Bjorkbom 
1973). Both types of management are commonly used although the exact acreages 
of each are unknown. Since the ecological interactions resulting from use of 
each type are so clearly different, a detailed description of each follows. 



19-8 



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19-9 



Uneven-aged stands are those in which the trees are of at least three distinct 
age classes irregularly mixed (Society of American Foresters 1964) . Except 
for very old stands, uneven-aged stands are distinctly irregular in height and 
tree size. These stands are developed or maintained by relatively frequent 
harvests made throughout the rotation age (the number of years required to 
establish and grow timber crops to a specified condition of maturity) . The 
distribution of diameter measurements in a balanced uneven-aged stand will 
plot into a characteristically inverted J-shaped curve. 

Even-aged stands are those in which the difference between the oldest and the 
youngest trees does not exceed 10 to 20 years or 25% of the length of the 
rotation age. Trees in these stands tend to be uniform in height, but 
frequently they cover a wide range of diameter widths. These stands usually 
develop after the sudden removal of previous stands by logging, fire, insect 
epidemic, or other cause. A plotting of diameter widths will usually result 
in a normal curve. 

Management of uneven-aged stands . In uneven-aged stands mature trees are 
removed as scattered individuals or in small groups at relatively short time 
intervals (10 to 15 years on primary softwood sites and 20 to 25 years on 
secondary softwood sites). The interval between cuts is based on growth 
rates, stand conditions, and size of the intended harvest. Individual trees 
or groups of trees are marked before cutting. The criteria used for marking 
trees for removal are: (1) poor-risk trees (those assumed to be doomed before 
the next harvest), (2) poor quality trees, (3) slow-growing trees, (4) trees 
of less desirable species, (5) trees whose removal will improve spacing in the 
residual stand, and (6) mature trees of good quality, good risk, desirable 
species, and fast growth. The term "selection system" is applied to any 
silvicultural program that is aimed at the creation or maintenance of uneven- 
aged stands and that includes some form of periodic harvesting. Because 
spruce and fir are usually able to reproduce and grow under overhead shade, 
uneven-aged stands will develop in areas not drastically disturbed by nature 
or people. Advantages of using the selection system of cutting in the spruce- 
fir type are: 

1. Periodic harvests guarantee that a continuous forest cover is 
maintained. 

2. The retention of spruce trees can favor the regeneration of this 
species with a corresponding reduction in fir. 

3. Environmental conditions are stable so that plant and animal 
populations do not fluctuate much. 

4. Fire hazard from slash accumulation (fallen branches and twigs) is 
not severe. 

5. There is less chance of losing an entire stand at one time to insect 
attack, infectious disease, or other natural catastrophies . 

6. The stands, except for the period immediately after a cut, appear 
attractive to the esthetic-conscious public. 

Management of uneven-aged stands is complex. Because operations are conducted 
in mixtures of different age classes logging damage to, and death of, some 
uncut trees is difficult to prevent. Harvesting operations usually are 
difficult and expensive in that large land areas must be covered to obtain a 
given volume of wood. 

19-10 



The criteria for wise removal of trees are not adhered to in the coastal zone. 
Instead, a selection method known as diameter-limit harvesting is employed. 
Under this method all trees over a specified minimum diameter are removed. 
Diameter limits range from 8 to 15 inches (20 to 38 cm) for the spruces and 
over 6 inches (15 cm) for balsam fir. This method of cutting is conducive to 
future stand development and keeps the cost of harvesting reasonably low, 
however, diameter-limit harvesting removes large vigorous trees and leaves 
small, poor-risk and defective trees. In some areas too many trees per acre 
are removed, while too few are removed in other areas. The overall effect of 
the diameter-limit method is to lower the quality of the stand. The long-term 
genetic makeup of the forest is also affected adversely since only the best 
trees are removed with each cutting, and the poorer trees remain to disperse 
seeds and repopulate the area. Positive responses to selection for several 
traits have been shown for most tree species growing in the spruce-fir type 
(Wright 1976). Negative responses due to diameter-limit cutting practices are 
to be expected but no confirmed dysgenic effects (detrimental to the genetic 
quality) have been shown to date in the coastal zone. Diameter-limit cutting 
is also frequently applied to the northern hardwood and white pine-hemlock- 
hardwood types under the guise of selective harvesting. 

Mana gement of even-aged stands . Development of highly mechanized 
harvesting systems has prompted the use of even-aged stands in the management 
of the spruce-fir type. Although various methods of establishing even-aged 
forest stands have found application, the method most frequently used in the 
characterization area is the Clearcutting method. In clearcutting, all trees 
on an area are removed in one cutting, with subsequent regeneration being 
obtained from seed disseminated by adjacent forest stands and/or by the trees 
being removed in the harvesting operation. Different methods of clearcutting 
are discussed in "White Pine-Hemlock-Hardwbod Forest Type." Cutting areas may 
also be artificially regenerated by planting seedlings or sowing seed. 

It is difficult to characterize all of the clearcutting operations that are 
presently taking place in or near the characterization area. A typical 
operation would have these component parts: (1) mature trees are cut either 
mechanically or by hand; (2) they are delimbed in the woods or are dragged to 
the roadside and then delimbed; (3) a reproduction survey is performed on the 
area and if adequate reproduction of desired species is expected to take 
place, no additional reforestation steps are taken; if an adequate 
reproduction is not expected, planting is done; (4) 2 to 3 years after 
clearcutting, the area is aerially sprayed with herbicide to kill hardwoods, 
raspberries, and other competing vegetative growth. 

Major ecological implications of clearcutting are as follows: 

1. The effect of mechanical harvesting on soil quality. Holman (1977) 
found that no permanent compaction of soils was present in clearcut 
areas as bulk densities returned to preharvest levels after one 
complete overwintering period. The most compaction observed was on 
skid trails that had been used in the summer. Several different 
types of mechanical harvesting systems are currently in use in the 
coastal zone, however, and different levels of compaction could be 
expected with different systems. 



19-11 



10-80 



2. The effect of redistribution of logging slash (unwanted portions) and 
removal of all above-ground portions of trees on nutrient levels. 
Weetman and Webber (1972) found that full-tree logging will not cause 
any reduction in growth from nutrient removal during the second 
rotation of trees. However, nutrient depletion due to full-tree 
logging, particularly calcium, potassium, and nitrogen depletion, may 
require correction in forest ecosystems of marginal fertility. These 
sites are usually either dry, with low reserves of organic matter and 
low exchange capacity, or wet, with excessive accumulations of 
organic matter. No work with nutrient depletion has been done on 
logging areas in the characterization area. 

3. The change in vegetation that occurs in an area is a result of 
increased light and decreased soil moisture. Bird and mammal 
populations are also affected when vegetation changes. See chapter 
9, "The Forest System," for a discussion of these factors. 

4. Soil erosion and siltation of streams are dependent upon soil types, 
slope, and the time of year the clearcutting operation is performed. 
Usually, clearcutting should not cause serious erosion of sites or 
siltation of streams if proper harvesting procedures are followed; 
however, no relevant data on the characterization area are available 
and it must be obtained if the extent of erosion and siltation due to 
clearcutting is to be measured. 

5. The effects of spraying herbicides on the forest ecosystem are not 
completely understood (see chapter 3, "Human Impacts on the 
Ecosystem") . This topic is of national concern and has been the 
subject of heated debate in recent months. The Environmental 
Protection Agency (EPA) banned the use of 2,4,5-T (which had been 
used in coastal Maine) on forest lands in March, 1979. 

Cubic foot yields per acre from fully stocked, even-aged stands of second- 
growth red spruce in the northeast are given in table 19-5. Because yield 
relationships between sites and for stands within sites are not distinct, 
there is an overlapping of various sites and stand types for specific yield 
values. The yield values in the table are given for four combinations of 
sites and stand types. These yields are from so called normal unmanaged 
stands. Yields from stands under a management scheme, including periodic 
harvests or thinnings, would be substantially higher over a rotation. No 
yield information on other species in even-aged stands is available. 

Management practices, including silvicultural manipulation, have a strong 
influence on net annual growth. For example, experimental data have shown 
that well-managed stands on reasonably productive sites can produce nearly 
twice as much merchantable wood as unmanaged stands over the course of a 
rotation age (Frank and Bjorkbom 1973). Net annual growth during the first 10 
years after selective cutting in primary softwood stands ranged from 47 to 82 
cu ft/acre annually in several experiments in northern Maine (Frank and 
Bjorkbom 1973). Similar data for softwood sites in the characterization area 
are not available. 



19-12 



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10-80 



Natural Enemies 

Although many insects and diseases damage spruce and fir, spruce is relatively 
free from these hazards until it matures. Fir, at all ages, is subject to 
insect and disease attack. 

The most destructive insect is the spruce budworm. This insect is a 
defoliator that attacks both spruce and fir, but prefers fir. Many millions 
of cords of pulpwood have been lost due to large outbreaks of this insect in 
the past, primarily in stands containing mature and over-mature fir. Large 
aerial spraying programs in northern and western Maine have been directed 
against the spruce budworm in the last several years. Epidemics have not been 
severe in the characterization area. 

The balsam woolly aphid is an introduced insect that is becomming increasingly 
damaging to fir. The salivary injections of the aphid kill or deform trees. 

The important fungal diseases of spruce include red ring rot, which enters 
through dead branch stubs, and red-brown butt rot, which enters largely 
through basal wounds (wounds in the lower trunk) . These diseases are usually 
confined to overmature or damaged trees. One fungus, Stereum sanguinalentum , 
causes over 90% of all trunk rot in living balsam fir trees. Often referred 
to as "red heart," this disease enters the tree through broken tops, broken 
branches, and other injuries. 

In stands where diseases are serious, commercial thinning should begin when 
tree diameters are about 8 inches (20 cm). The pathological rotation of fir 
and spruce-fir is 50 to 60 years. 

Spruce and fir are shallow rooted. Most of the feeding roots are in the duff 
(pre-humus ground litter) and the top few inches of mineral soil. Because of 
their shallow root systems, thin bark, and flammable needles, spruce and fir 
trees of all ages are easily killed by fire. Their shallow root systems also 
make them subject to windfall. Caution is necessary in stands subjected to 
harvesting operations and in areas where windfall is known to be a problem 
(i.e., coastal peninsulas). Damage can be reduced by leaving uncut portions 
along the windward edges of the stand. Depth of these protective strips 
should be a minimum of one-half the height of the trees to be harvested. 

MAPLE-BEECH-BIRCH TYPE 

Habitat Conditions 

Sugar maple, yellow birch, and American beech are the primary timber species 
in the northern hardwood forests. In older stands, these three species 
dominate, but younger stands also contain paper birch, white ash, and red 
maple. Conifers such as eastern hemlock, balsam fir, and red spruce grow with 
the hardwoods, especially on cool steep slopes and on poorly drained soils at 
the lower elevations. Repeated cuttings, sometimes followed by wildfires, 
have favored a variety of stand conditions. Consequently, numerous 
combinations of stocking levels, age classes, and species are present. 
Hardwood soils are usually stony and podzolic, but the most productive soils 
are deep and well to moderately well drained. 

19-14 



Reproduction and Growth 

Species in this forest type differ in shade tolerance, longevity, and growth 
rate. Yellow birch tolerates shade moderately well but usually has the 
slowest growth. White ash and red maple are also intermediate in shade 
tolerance but have moderately fast growth rates. Paper birch is one of the 
fastest growing commercial species but the typical variety is short-lived and 
very intolerant of shade. Sugar maple, beech, hemlock, and red spruce are all 
shade-tolerant, long-lived species. Sugar maple and beech have moderate 
growth rates, whereas hemlock and red spruce are slow growing. Sugar maple, 
beech, and hemlock are the principal components of the northern hardwood 
climax forest (Society of American Forester 1967). 

The highly shade-tolerant sugar maple and beech dominate the understories of 
most northern hardwood stands. In contrast, yellow and paper birches need 
some overhead light and seedbeds of humus or mineral soil for their early 
establishment and development (Fowells 1965). Paper birch must become 
dominant in the stand early in life in order to survive to maturity. 

Management Methods 

Management methods require that a landowner must first decide whether he wants 
his growing stock to yield top grade products such as veneer logs, sawlogs , 
and millwood or to yield mostly pulpwood, fuelwood, or other less-valued 
products. A second basic decision he must make is whether to manage for a 
high proportion of shade-tolerant species, intermediates, or intolerants. 
This would have a controlling influence over the silvicultural system used. 

Management of uneven-aged stands . Management by uneven-aged stands 
implemented through selective cutting of individual trees or harvesting of 
trees in groups of two or three, is recommended for growing a high proportion 
of shade-tolerant species (i.e., sugar maple, beech, hemlock, and spruce) 
(Leak et al. 1970; and Tubbs 1968). Selective cutting will produce veneer 
logs, sawlogs, and millwood, with pulpwood as a byproduct. The public 
generally accepts selection cutting esthetically because a residual stand 
always covers the site and disturbance from logging is not as apparent. 

To achieve maximum yields, the cuttings are repeated at 10-to 20-year 
intervals. To develop and maintain a balanced stand structure, a deliberate 
attempt must be made to mark trees in all diameter classes for cutting. This 
is not always done because diameter-limit cutting is practiced extensively in 
the maple-beech-birch forest type in the characterization area. 

In many of today's uneven-aged stands, past preferences for certain species in 
cutting operations and heavy mortality or deterioration in some species (such 
as beech) from disease attacks have caused considerable variation in 
structure, stocking, composition, and grade. It may take three or more cyclic 
cuts (over a given rotational cycle) to improve the productivity of such 
stands. Yields from improvement cuttings may contain 55% or more low-value 
products (Filip 1967). In subsequent cuttings the yield should be mostly top- 
grade products (see "Fuelwood," below). 



19-15 



Often unmerchantable sized classes need additional cultural work to improve 
species composition, especially to reduce the over-abundance of beech in favor 
of the higher-value sugar maple. Removing trees above 2 inches (5 cm) dbh may 
be necessary. 

Management of even-aged stands . Management of even-aged stands is 
recommended for growing a high proportion of intermediate and intolerant 
northern hardwoods. Among these the commercially important species are yellow 
birch and white ash (intermediates), and paper birch (intolerant). When 
managed appropriately, even-aged stands will produce top-grade products. This 
form of management, as stated previously, is also well suited for pulpwood 
production, particularly in view of the trend toward more mechanization in 
harvesting. 

Special attention must be given to cutting and cultural practices where high 
proportions of birches are to be naturally regenerated. Generally, complete 
stand removal is necessary for successful stand establishment. Complete stand 
removal can be done in patches, strips or blocks. In each case, the 
harvesting of merchantable trees is followed by mechanical or chemical removal 
of all unmerchantable trees above 2 inches (5 cm) dbh. 

Patches range from 0.1 to 0.75 acre (0.04 to 0.3 ha) in size. Patch cuttings 
encourage the regeneration of both yellow and white birch and are appropriate 
when used in combination with selective cutting under uneven-aged stand 
management. Groups of mature, overmature, or defective trees are used as 
nuclei for the patches (Gilbert and Jensen 1958) . 

Optimum conditions for regenerating white ash have not been determined 
experimentally; however, conditions that are favorable for yellow birch 
regeneration tend to be favorable for white ash regeneration, also. 

Strip cutting is similar to patch cutting, but is more feasible to apply over 
large areas. Strips are particularly favorable for regenerating yellow birch 
(ratios as high as 10 yellow birch to 1 paper birch have been obtained). 
Strips can be 50 to 100 feet (15 to 30 m) wide. For best yellow birch 
regeneration, they should be about 50 feet (15 m) wide and oriented in an 
east-west direction. 

Block cutting is more favorable for regenerating paper birch than yellow 
birch. This cutting method results in regeneration composed of approximately 
2/5 paper birch, 1/5 yellow birch and white ash, and 2/5 sugar maple and beech 
(Leak and Wilson 1958) . A seed source must be available to insure prompt and 
adequate natural birch regeneration. Adjacent stands can provide the seed 
source in block cuttings up to 10 acres (4 ha). In larger blocks the cutting 
should be done between September and April during a good seed year to take 
advantage of the seed from harvested trees. Birch seeds usually do not remain 
viable beyond the first growing season (Fowells 1965). 

Birch regenerates best on disturbed seedbeds where mineral soil is partially 
exposed or mixed with humus (Barrett 1962; Marquis 1965; and Filip 1967). If 
about 50% of the soil surface is not disturbed during the logging operation, 
additional scarification (breaking up the surface) should be considered. 
Seedbed preparation with power equipment provides the desired mineral soil- 

19-16 



humus mixture, and also removes much unwanted vegetation that can suppress 
newly established birch seedlings. 

Productivity of even-aged stands is increased considerably and rotations are 
shortened by periodic thinnings (see "Fuelwood," below). Stocking guides, 
based on mean stand diameter and basal area per acre, coupled with stand 
prescriptions, are used to determine when and how much to thin and when to 
make the final harvest cutting (Leak et al. 1970; and Solomon and Leak 1969). 
Basal area, the area in cross section at breast height of a single tree or of 
all the trees in a stand, is usually expressed in square feet. 

Natural Enemies 

Northern hardwoods have several natural enemies. One of these is beech bark 
disease caused by beech scale insect infestation, which may be followed by 
infection by the parasitic bark fungus Nectria coccinea var. faginata . This 
is a lethal disease and is the chief obstacle to producing high quality beech 
logs. 

Birch dieback is an unidentified disease that destroyed thousands of square 
miles of yellow and paper birch in the New England States and Eastern Canada 
during the 1930s and 1940s. Dieback has caused the virtual disappearance of 
birches in some areas (Hepting 1971). Although the disease has subsided in 
recent years, a recurrence is possible. A similar condition, postlogging 
decadence, often develops in birches excessively exposed by heavy partial 
cutting. 

The saddled prominent caterpillar has defoliated large areas of northern 
hardwood stands in the characterization area in recent years. Most hardwoods 
can withstand 2 to 3 years of moderate defoliation and still recover 
(Houseweart and Dixon 1977) but severe defoliation can kill trees in one 
season. 

Most fungi that cause decay in living trees are found only in heartwood. A 
number of such organisms cause cull in birch but some grow outward from 
heartwood into sapwood and cambium. These decay fungi cause trunk cankers. 
Several wood-rotting fungi are possible causes of cankers on birches. Among 
them is Poria obliqua . Birch is also susceptible to several fungi that are 
known to be canker-producing, especially Nectria galligena . A number of 
canker diseases also occur on the various species of maple. The most common 
ones are caused by Nectria strummela , and Eutypelaa parasitica . 

WHITE PINE-HEMLOCK-HARDWOOD TYPE 

Habitat Conditions 

This forest type is composed chiefly of eastern white pine, eastern hemlock, 
beech, sugar maple, red maple, yellow birch, white ash, paper birch, red 
spruce, and northern red oak. White pine was the species most eagerly sought 
by loggers in the original forests of the coastal zone and economically is 
still the most important forest species. 



19-17 



10-80 



In the virgin forest white pine was dominant on soils inclined to he droughty, 
such as eskers , kames , outwash plains, and shores and terraces of old glacial 
lakes (Braun 1950) . Elsewhere the development of stands heavily stocked with 
white pine was the consequence of forest catastrophies . Fire played a major 
role in establishing essentially even-aged stands of white pine in the 
original forest by eliminating competition (Cline and Spurr 1942) . People 
also were greatly responsible for the creation of the white pine region along 
the coast. The farm clearings which they carved out of the wilderness and 
subsequently abandoned were often reclaimed by white pine forests . 

On sandy relatively dry sites, white pine stands may form a climax forest. On 
fertile and relatively moist soils white pine eventually is displaced by more 
shade-tolerant species, usually hardwoods. Although white pine may play an 
ecological role similar to that of some of the most light-demanding species, 
it is in fact intermediate in shade tolerance. 

Reproduction and Growth 

White pine begins to bear cones before it is 20 years old, but optimum seed- 
bearing age is not until 50 to 150 years (Fowells 1965). Condition of the 
seedbed is an important factor in regenerating white pine. In full sunlight 
favorable seedbeds are moist mineral soil, moss, or short grass cover of 
light-to-medium density. Unfavorable seedbeds include dry soil, coniferous 
litter, lichen, and very thin or very dense grass covers (Smith 1951; and 
Fowells 1965). 

White pine has several attributes that enable it to take advantage of certain 
conditions and endure in the forest community. First, its seed will germinate 
well and survive on almost any type of seedbed under shade (Smith 1951). 
Following establishment the young plants must be given abundant overhead light 
for best development. They have the ability to withstand exposure without 
suffering undue mortality. Second, young seedlings are exceptionally drought 
resistant, having the capacity to survive extended periods of drought (Smith 
1951). Third, height growth may be very rapid once the seedling is 
established and in the open. On the best sites, annual height growth of 2 to 
3 feet (0.6 to 1 m) or more has been observed after trees have reached breast 
height. 

Management Practices 

Growth characteristics of white pine are such that it is best grown under 
even-aged stand conditions but considerable flexibility may be exercised in 
choosing regeneration methods. The method most successfully employed is known 
as a two-cut shelterwood system. The following steps are taken in this 
system: 

1. An initial cut is made in an established stand of trees during, or 
immediately after, an abundant seed year. This cut consists of 
removing 40% to 60% of the overstory. It is important that the first 
cut result in the disturbance of accumulated litter and the exposure 
of mineral soil so that the seed can germinate and grow. 



19-18 



2. A second cut is made to remove the shelter trees, usually 5 to 10 
years after the first cut. Seedlings by this time have become 
established and have entered their rapid growth period. 

Corrective measures must accompany the harvest of trees if pine is to be 
perpetuated in a stand. Before the first cut, hardwood saplings must be 
removed. This has been done in the past most economically by spraying 2,4,5-T 
(see discussion in "Spruce-Fir Forest Type" for alternative herbicides). If 
this measure is not taken, hardwoods will be released, will grow very rapidly, 
and will shade out young pine seedlings when the stand is opened. Before or 
immediately after the second cut the area must be examined to determine 
whether white pine has become adequately established. Hardwood seedlings 
should be removed at this time if they have become established to an extent 
that would interfere with the rapid growth of, or threaten the survival of, 
pine. Light to moderate livestock grazing served these purposes inadvertently 
in the past. White pine can be grown on every soil type in the Maine coastal 
zone with the exception of heavy clay soils. Since competition from hardwoods 
is an important factor in establishing pine, it must be considered in choosing 
to manage pine. Hardwood offers the least competition on excessively-drained 
and well-drained sandy soils and on droughty, loamy sands. 

No firm rules exist for selecting a forest site for hardwood or white pine 
management. Over a rotation white pine will outgrow hardwood on the good and 
poor sites but if growing pine on good hardwood sites is unprofitable 
economically, growing it on poor or light soils may be a wiser choice. This 
practice not only provides for sufficient representation of both hardwood and 
white pine, but also facilitates the task of developing a greater proportion 
of white pine (Lutz and Cline 1947). 

Yields of white pine stands vary with soil condition and other factors that 
influence overall site quality. Site quality is determined from site-index 
curves shown in figure 19-2, which shows the height of dominant trees plotted 
over age for several site-index classes. 

Volumes (by stand age and site indexes) for pure white pine stands near the 
upper limit (for practical management) of stocking are given in table 19-6 
(Leak et al. 1970). Yields increase markedly with age and site index and will 
be higher or lower depending on stand stocking. Yields of white pine will 
drop as the proportion of hardwood increases. 

Growth rates in white pine stands may vary greatly with site condition and 
stocking density. The average white pine stand will grow from 300 to 800 
board feet (1" x 12" x 12")/acre/year . Study plots on exceptionally good 
sites have shown yearly growth rates as high as 1200 board feet/acre for site 
index 60, and as high as 1600 board feet/acre for site index 80. These growth 
rates represent optimum conditions in small, well-stocked stands (Leak et al. 
1970). 

Natural Enemies 

Quality white pine is always in commercial demand but finding high quality 
material is difficult in the characterization area, as it is in most of the 
white pine range. 

19-19 



10-80 



One of the major limiting factors affe 
white pine weevil. This insect attacks 
of the tree. The resulting injury 
lateral branches competing for the posit 
leader inevitably produce a crook in 
quality. The rapidity with which one la 
the others determines the degree of 
long enough to establish a forked tree, 
injury also causes a loss in stem len 
Lumber defects caused by weevil injury a 
knots, and loose knots. 



cting the quality of white pine is the 
and kills the terminal (central) shoot 
seldom causes deaths of the trees, but 
ion formerly held by the terminal 

the stem, which ultimately lowers log 
teral shoot asserts its dominance over 
the crook. Often two laterals compete 

In addition to causing crooks, weevil 
gth, affecting 2 or 3 years of growth, 
re cross-grain, red rot, large branch 



Several techniques are used for controlling white pine weevil damage. 
Chemical sprays can be used safely provided that precautions are observed with 
applications and dosage, and that only properly registered insecticides are 
used. Spraying from the ground is expensive and aerial spraying in the spring 
has not proved successful. Recent research performed on young white pine 
plantations in Penobscot County by the University of Maine's School of Forest 
Resources indicates that fall spraying may offer promise to greatly reduce 
insect numbers (Cooperative Forestry Research Unit 1979). 



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BREAST-HEIGHT AGE (YEARS) 



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Site index curves for eastern white pine in New England 
(curves corrected to breast-height age of 50) (Frothingham 
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19-20 



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10-80 



The major tree disease in the coastal zone is the blister rust which occurs 
when white pine is grown near Ribes species, such as currants or gooseberries. 
The fungus grows through the needle or new shoot into the branch and from 
there into the trunk where it produces a girdling, killing canker. Orange 
blisters filled with spores appear on these cankers in the spring and spores 
are liberated when the blisters break. The spores then infect Ribes leaves 
and the cycle begins again. 

White pine should not be planted in an area where Ribes grow unless the Ribes 
bushes are removed from the planting site and from an area 900 feet (273 m) 
wide around it. Ribes should be removed in stands of white pine where blister 
rust occurs. Losses in infected stands can be minimized by removing stem- 
cankered trees and pruning the others to reduce the possibility of the rust 
reaching the trunk through one or more lower branches. 

FUELW00D 

Recent price increases and scarcity of fuel oil has stirred interest in 
heating with wood. A 1978 survey by the Maine Audubon Society revealed that 
46% of Maine's households are currently heating entirely or partially with 
wood and the average annual consumption of wood per household was 3.6 cords. 
This use of wood for heating represents a net increase in the State's total 
wood consumption. 

Species Used 

The species most used for heating are those with the highest BTU values, such 
as oak and maple (table 19-7). The species are present in all of the forest 
types previously described, but they are most indigenous to the northern 
hardwood type. Silviculturally , the ideal way to produce fuelwood is by 
selectively thinning hardwood stands. This method, when properly applied 
throughout the life of the stand, will yield adequate amounts of fuelwood and 
permit the most valuable species in a stand to grow rapidly throughout their 
lives. Removal of less valuable competing trees enables the stand to 
ultimately produce large, high quality trees that can be sold at rotation age 
for veneer, sawlogs, and other valuable products. 

The monetary value of the species in a stand must be known before thinning can 
begin (table 19-8). Sugar maple, white ash, yellow birch, and white birch, 
usually, are more valuable than red maple, beech, and aspen. The higher- 
valued species should be favored to remain uncut in the stands. 

Silvicultural Methods 

Thinnings should begin as early as possible so that the benefits of repeated 
thinnings may be gained. The best time to begin thinning a hardwood stand is 
when the trees average 4 to 10 inches (10 to 25 cm) in dbh. Trees of this 
size class, commonly referred to as poles, respond rapidly to thinning because 
intense competition from surrounding trees has begun to slow their growth. 
Even larger trees, averaging 10 to 12 inches (25 to 50 cm) dbh, should 
sometimes be thinned. These hardwood stands are approaching commercial 
sawtimber size and some of the high quality thinned trees can probably be sold 
as sawlogs. 

19-22 



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10-80 



Table 19-8. Average Stumpage Price by Species for Sawtimber and Pulpwood, 



March 1979 a 



Sa w.t^i!2.fc.£.£ Eii.lp_ii.ood 

Species S/1000 bd ft $/cord 



Softwoods 



White pine 56 4.25 

Red pine 42 4.00 

Pitch pine 37 

Hemlock 33 5.25 

Spruce 43 7.95 

Balsam fit 40 7.95 

Northern white cedar 29 

Tanar ack 27 5.25 



Hard woods 



White birch 54 5.00 

Yellow birch 49 5.00 

Sugar maple 52 5.00 

Oak 65 5.00 

Beech 30 5.00 

Aspen 29 4.75 

Basswood 24 5.00 

Elm 26 5.00 

Red maple 28 5.00 

White ash 74 5.00 

Brown ash 18 5.00 



a 



Maine Bureau of Forestry. 



19-24 



The preferred way to thin a young pole stand is the "crop tree selection 
method." This is a simple method of thinning stands to the advantage of the 
best trees (i.e., crop trees) in the stand. First, trees selected as crop 
trees should be a valuable species. They should be straight, tall, have 
relatively small branches, and should show signs of self-pruning (the lower 10 
to 16 feet, or 3 to 5 m, of the tree should have few or no branches). The 
crown of a crop tree needs 3 to 4 feet (1 to 1.2 m) of open space on at least 
two sides. Trees touching the crown of crop trees are competitors. In 
harvesting fuelwood these should be the first trees removed since they are 
direct competitors. The trees to be removed in some stands may be as high 
quality as the crop trees. But, they would be shaded out by crop trees in the 
future and die anyway. Furthermore, the crop trees released will grow faster 
and will regain some of the growth lost by removing competitors. 

Small understory trees are abundant in most pole stands. Their crowns are 
lower than the crowns of larger trees so they are usually deprived of direct 
sunlight. The larger understory trees may be cut for fuelwood. Their removal 
will have little effect on the growth of crop trees but they are useful as 
fuelwood supplies. 

After releasing the crop trees any remaining dead, dying, and deformed trees 
which hinder development of the stand should also be harvested for fuelwood. 

CHRISTMAS TREE PRODUCTION 

The Christmas tree and wreath businesses are important sources of income for 
many people in the Maine coastal zone. Christmas trees, brush for 
decorations, and tips for wreaths are cut in natural stands and plantations 
each fall. Reliable production and cost data by species and geographic region 
within Maine are not available. 

The primary species used is balsam fir because of its strong fragrance, soft 
dark-green foliage, good shape, and excellent needle-retention capacity. 

RESEARCH NEEDS 

The increasing demand for paper, paper products, and building materials, 
relatively heavy recreational use, suburban development, and the high cost of 
land ownership, results in the need for growing more and better quality trees 
on less land while still considering wise environmental protection practices. 
It is imperative that new, environmentally sound methods of shortening 
rotations and raising tree quality be developed and used. 

The following is a list of basic silvicutural considerations and data gaps to 
be investigated for the coastal zone: 

1. Acreages and land ownership patterns by forest type and intensity of 
management practices should be determined. 

2. The effect of redistributing logging slash and removing above-ground 
portions of the tree on nutrient levels. 

3. The environmental implications of spraying 2,4,5-T. Perhaps even 
more important, the environmental impacts of spraying substitute 



19-25 



10-80 



herbicides if 2,4,5-T is permanently banned for use in forestry 
practice. 

4. The amount of erosion and stream siltation resulting from different 
harvesting and cutting methods. 

5. The effect of spraying insecticides to suppress spruce budworm on the 
total insect population and their predators. 

6. The effect of monocultures (single species stands), especially tree 
plantations that may include introduced species, on native flora and 
fauna populations. 

7. The effect of fuelwood harvesting on total forest resources. 



19-26 



REFERENCES 

Baker, F. S. 1929. Effect of excessively high temperatures on coniferous 
reproduction. J. For. 27:949-975. 

Barrett, J. W. 1962. Regional Silviculture of the United States. Ronald 
Press , New York. 

Braun, E. L. 1950. Deciduous Forests of Eastern North America. The 
Blakiston Co., Philadelphia. 

Canavera, D. S. 1977. The status of tree improvement programs for northern 
tree species. U.S. For. Serv. Gen. Tech. Rep. NE-29. 

Cline, A. C, and S. H. Spurr. 1942. The virgin upland forest of central New 
England. Harv. For. Bull. 21. 

Coolidge, P. T. 1963. History of the Maine Woods. Furbush-Roberts Printing 
Co. , Bangor, ME . 

Cooperative Forestry Research Unit. 1979. Annual Report 1978. Misc. Rep. 
No. 212. School of Forest Resources, University of Maine, Orono , ME. 

Ferguson, R. H. , and N. P. Kingsley. 1972. The timber resources of Maine. 
U.S. For. Serv. Resour. Bull. NE-26. 

Filip, S. M. 1967. Harvesting costs and returns under 4 cutting methods in 
mature beech-birch-maple stands in New England. U.S. For. Serv. Res. Pap. 
NE-87. 

Fowells, H. A. 1965. Silvics of Forest Trees of the United States. U.S. 
Dept. Agric. Agric. Handb. 271. 

Frank, R. M. , and J. C. Bjorkbom. 1973. A silivicultural guide for spruce- 
fir in the northeast. U.S. For. Serv. Gen. Tech. Rep. NE-6. 

Frothingham, E. H. 1914. White pine under forest management. U. S. Dept. 
Agric. Bull. 13. 

Gilbert, A. M. , and V. S. Jensen. 1958. A management guide for northern 
hardwoods in New England. U.S. For. Serv. Res. Pap. 112. ( Formerly U.S. 
For. Serv. Northeast For. Exp. Stn. Pap.) 

Hart, A. C. 1964. Spruce-fir silviculture in northern New England. Proc. 
Soc. Am. For. 1963:107-110. 

Hepting, G. H. 1971. Diseases of Forest and Shade Trees of the United 
States. U.S. Dep . Agric. Handb. 386. 

Holman, G. T. 1977. The Effects of Mechanized Harvesting on Site and Soil 
Conditions in the Spruce-fir Regions of North Central Maine. M.S. Thesis. 
School of Forest Resources, University of Maine, Orono, ME. 



19-27 



10-80 



Houseweart, M. W. , and W. M. Dixon. 1977. Update on the Saddle Prominent. 
CRFU Information Rep. 1. School of Forest Resources, University of Maine, 
Orono, ME. 

Leak, W. B. , and R. W. Wilson, Jr. 1958. Regeneration after clearcutting of 
old-growth northern hardwoods in New Hampshire. U.S. For. Serv. Res. Pap. 
NE-103. ( Formerly U.S. For. Serv. Northeast For. Exp. Stn. Pap.). 

, P. H. Allen, J. P. Barrett, F. K. Beyer, D. L. Mader, J. C. Mawson, and 



R. K. Wilson. 1970. Yields of eastern white pine in New England related 
to age, site, and stocking. U. S. For. Serv. Res. Pap. NE 176. 

Little E. L., Jr. 1953. Check List of Native and Naturalized Trees of the 
United States (including Alaska). U.S. Dept. Agric. Handb. 41. 

Lutz, R. J., and A. C. Cline. 1947. Results of the first thirty years of 
experimentation in silviculture in the Harvard forest. 1908-1938-Part I. 
Harv. For. Bull. 23. 

Maine Bureau of Forestry. 1979. Stumpage Prices, Spring 79. Augusta, ME. 

Maine Forestry Department. 1973. Forest trees of Maine. Bull. 240. Maine 
Forestry Department, Augusta, ME. 

Marquis, D. A. 1965. Regeneration of birch and associated hardwoods after 
patch cutting. U.S. For. Serv. Res. Pap. NE-32. 

McLintock, T. F. 1954. Factors affecting wind damage in selectively cut 
stands of spruce and fir in Maine and northern New Hampshire. U.S. For. 
Serv. Res. Pap. 70 ( Formerly U.S. For. Serv. Northeast For. Exp. Stn. 
Pap.) 

Shirley, H. L. 1943. Is tolerance the capacity to endure shade? J. For. 
41:339-345. 

Smith, D. M. 1951. The influence of seedbed conditions on the regeneration 
of eastern white pine. Conn. Agric. Exp. Stn. Bull. (New Haven) 545. 

Society of American Foresters. 1955. Silviculture. Pages 6.1-6.67 in 
Forestry Handbook. Ronald Press, New York. 

. 1964. Forestry Terminology. 3rd. ed. Society of American Foresters, 



Washington, DC. 

1967. Forest Cover Types of North America (exclusive of Mexico). 
Soc. Am. For., Washington, DC. 

Solomon, D. S., and W. B. Leak. 1969. Stocking, growth, and yield of birch 
stnds. U.S. For. Serv. Northeast For. Exp. Stn. Birch Symp. Proc: 106- 
118. U.S. Forest Service, Upper Darby. PA. 



19-28 



Tubbs, C. H. 1968. Natural regeneration. U.S. For. Serv. North Central For. 
Exp. Stn. Sugar Maple Conf. Proc: 75-81. U.S. Forest Service, St. Paul, 

MN. 

University of Wisconsin Extension. 1977. Wood Energy for Domestic Space 
Heating. G2874. Wisconsin Board of Vocational and Adult Education, 
Madison, WI . 

Vezina, P. E., and G. Y. Peck. 1964. Solar radiation beneath conifer 
canopies in relation to crown closure. For. Sci. 10(4): 443-451. 

Weetman, G. F. , and B. Webber. 1972. The influence of wood harvesting on the 
nutrient status of two spruce stands. Can. J. For. Res. 2:351-369. 

Westveld, M. 1941. Yield tables for Cut-over Spruce-fir Stands in the 
Northeast. U.S. For. Serv. Northeast For. Exp. Stn. Occas. Pap. 12. U.S. 
Forest Service, Upper Darby, PA. 

1953. Ecology and silviculture of the spruce-fir forests of Eastern 



North America. J. For. 51:422-430. 

Wright, J. W. 1976. Introduction to Forest Genetics. Academic Press, New 
York. 



19-29 



10-80 



Chapter 20 
Endangered, Threatened 

and Rare Plants 



Authors: Norman Famous, Craig Ferris 




Endangered species are those considered in danger of extinction throughout all 
or a significant portion of their range. Threatened species are those likely 
to become endangered within the forseeable future throughout significant 
portions of their ranges and rare plants are those having small or restricted 
populations in particular areas of their ranges, but are not endangered. 

A variety of the estuary monkey flower (Mimulus ringens var. colpophilus) , 
found in some estuaries in coastal Maine and Canada, was recently considered 
endangered by the U.S. Fish and Wildlife Service (FWS) . Six other plants 
found in coastal Maine were listed as threatened by the Smithsonian Institute 
(table 20-1; Ayensu and DeFilipps 1978). These species are no longer listed 
as endangered or threated because critical habitats in which they are found 
were not identified (see "Protection of Endangered, Threatened, and Rare Plant 
Species" below). Another 84 plant species are considered rare in Maine by 
either the Maine State Planning Office, the New England Botanical Club, or 
plant taxonomists familiar with the species (table 20-2). 

Plants are usually considered endangered if they have very limited 
distributions, or if they are found in restricted or fragile habitats. Plants 
also may be endangered because of destruction, alteration, or curtailment of 
their habitat, or because of exploitation, disease, or unknown causes. Rare 
plants may be rare throughout their ranges, or they may be rare only on the 
fringes of their ranges. Most species considered rare in Maine are on the 
periphery of their normal ranges and may be relatively common elsewhere. 

Endangered, threatened, and rare plants may occur in relatively 
undifferentiated habitats, such as mature deciduous forests and mature spruce- 
fir forests, or they may be found in locally unique, unusual, or isolated 
habitats (Ayensu and DeFilipps 1978). The latter habitats may be ecologically 
or geographically restricted, fragile, or otherwise specialized due to various 
combinations of climatological, geological, hydrological , and biological 
factors. Unique or specialized habitats in coastal Maine that support rare 
plants include plateau bogs, forested wetlands dominated by Atlantic white 
cedar or northern white cedar, coastal headlands and islands, palustrine and 
riverine wetlands, and estuaries. 



20-1 



10-80 



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20-2 



Table 20-2. Rare Plant Species of Coastal Maine 1 



Common and Taxonomic names 



Family name 



Atlas 
Number 



Habitat 



Calvpso bulbosa (L.) Oakes 
Calypso 

Lvcopodium selapc L. 
Mountain club-moss 

Botrvchiuro lunar ia ( L . ) SK . 
Moonwort 



Ophioglossum vulgatum L. 

var. pseudopodum (Blake) Farv. 
Adder's tongue 

Asplenium trichomanes L. 
Maiden-hair spleenwort 

Dryopteris fragrans (L.) Scott 
var. rojnot iuscula Kamarov 
Fragrant cliff-fern 



Orchidaceae 

Lycopodiaceae 

Ophioglossaceae 

Ophioglossaceae 

Polypodiaceae 
Polypodiaceae 



Athyrium thelypterioides (Michx . ) Polypodiaceae 
Desv. 
Silvery spleenwort 



Pinus banksiana Lamb 



Jack pine 

Chamaecyparis thyoides (L.) BSP. 
Atlantic white cedar 

Juniperus horizontalis 

Moehch, X J^ Virginiana L, 
Hybrid juniper 

Zannichellia palustris L. 

var. llajor (Boenn.) D.J. Koch 
Horned pondweed 

Scirpus cvliniirinn (Torr.) 
Britt. 
Bulrush 

Eleocharis rostellata Torr. 
Spike-rush 



P ina c ea e 

Cupressaceae 

Cupressaceae 

Najadaceae 

Cyperaceae 

Cyperaceae 



9"- 



10 
11 
132 

n 2 

15 

16 

173 
18 

19 



20 



21 



Deep, moist coniferous 
woods 

Mossy rocks, barrens, 
cold woods 

Open turfy, gravelly, 
or ledgy slopes and 
shores 

Peaty or grassy 
patures, meadows 
and wet thickets 

Shaded rock crevices 



Dry cliffs and rocky 
banks 



Rich woods, bottom 
lands, and shaded 
plots 

Barren, sandy, or 
rocky soil 

Palustrine forested 
wetlands 

Coastal rocky ledges 



Fresh, brackish or 
alkaline waters 



Brackish emergent 
wetlands and brackish 
shorelines 

Brackish and salin<=- 
emergent wetlands 



Nomenclature after Fernald 1950. 
^Botanical fact sheets available from Critical Areas Program 
Planning reports available from Critical Programs 

(continued) 



20-3 



10-80 



Table 20-2. (continued), 



Common and taxonomic names 



Family name 



Atlas 
Numbers 



Habitat 



Car ex atherodes Spreng. 
Sedge 



C. rariflora (Wahlenb.) Sm. 
Sedge 

Wo 1 f f ia columbiana Karst. 
Water -meal 

Eriocaulon parkeri Robins. 
Pipewort 



Cyperaceae 



Cyperaceae 



-emnaceae 



Eriocaulaceae 



22 



23 



24 



25- 



Calcareous meadows> 
shores palustrine 
emergent meadows 

Bogs and pond margins, 
peaty barrens 

Floating beneath quiet 
wa t er s 

Brackish and saline 
tidal mud 



Juncus dudleyi Wieg. 
Rush 

J. alpinus Vill. 
Rush 

Allium canadense L. 
Wild garlic 

A le tris farinosa L. 
Unicorn-root 

Iris hooker i Penny 
Beachhead iris 



I. prismatica Pursh 
Slender blue flag 



Goodyera pubescens (Willd.) 
R.Br. 
Dovmy rattlesnake plantain 

Arethusa bulbosa L. 
Dragon's mouth 

A. bulbosa forma albif lora 
Rand S. Redfield 
Dragon's mouth 

A. bulbosa forma subsaerulea 



Juncaceae 



Juncaceae 



Li 1 ia c ea e 



Liliaceae 



Iridaceae 



Iridaceae 



Orchidaceae 



Orchidaceae 



Orchidaceae 



Orchidaceae 



Rand £. Redfield 
Dragon's mouth 



26 Damp calcareous soils 



27 Wet shores, emergent 
wetlands (palustrine) 

28 Low woods, thickets 
and meadows 

29 Dry or moist peats, 
sands and gravels 

2 

30 Headlands, rocky slopes 

beaches, dunes within 
reach of salt-spray 

31 Brackish or saline 
emergent wetlands 
near coast 

32 Dry or moist woods 



33a Sphagnous bogs and 

peaty emergent meadows 

33b Sphagnous bogs and 

peaty emergent wetlands 
(scrub-shrub) 

33c Sphagnous bogs and 

peaty emergent wetlands 
(scrub-shrub) 



20-4 



Table 20-2. (continued) 



Common and taxonomic names 



Family name 



Atlas 
Number 



Habitat 



Spiranthes gracilis (Bigel.) Orchidaceae 

Beck 
Southern slender ladies' tresses 

Betula caerulea-grandis Blanch. Betulaceae 
Blue birch 



34 



35 



Sterile open soil, 
thickets, open woods 

Drv woods 



Castanea dentata (Marsh.) 
Borskh. 
American chestnut 



Fagaceae 



36 



Dry, rocky acid 
deciduous woods 



Geocaulon lividum (Richards.) Santalaceae 
Fern. 
Northern comandra 



37 Moss or damp humus, 
coastal plateau "bogs 



Montia lamprosperraa Cham. 
Blinks 



Portulacaceae 



38 



Springy wet shores, 
brackish shores 



Arenaria groenlandica (Rentz.) Caryophyllaceae 

Spreng. 

Mountain sandwort 



Nuphar microphyllum (Pers.) Nymphaeaceae 
Fern. 
Yellow pond-lily 



Ranunculus ambigens S. Wats. Ranunculaceae 
Water plantain or 
spearwort 



Clematis verticillaris DC . 
Purple clematis 



Ranunculaceae- 



Sassafras albidum (Nutt.) Nees. Lauraceae 
Sassafras 



39" Granitic ledges and 
gravels on coastal 
headlands, islands and 
mountain tops 

40 Pond-margins and 
deadwaters (palustrine, 
lacustrine, and 
riverine) 

41 Sloughs, ditches and 
muddy palustrine 
emergent wetlands 

42 Rock slopes and 
open woods 

43 Woods and thickets 



Adlumia fungosa (Ait.) Greene Fumariaceae 
Climbing fumitory 



Dentaria maxima Nutt. 
Toothwort 



Subularia aquatica L. 
Awlwort 

Arabis missouriensis Greene 
Rock cress 



Brassicaceae 



arassicaceae 



Brassicaceae 



44 Recently burned woods 
and rocky wooded slopes 

45 Wooded streams and 
calcareous wooded slopes 
(riverine and lacustrine) 

46 Slow streams and sandy 
margines of lakes 

47 Bluffs, ledges, and 
rocky woods (northern) 



20-5 



10-80 



Table 20-2 (continued) 



Common and taxonomic names 



Family name 



Adas 
Number 



Habitat 



Podostemum ceratophvllum Michx. Podostemaceae 
Thredf oot 



48 



On rocks in streams 
(riverine) 



Sedum ternatum Michx. 
Stonecrop 

Sedum rosea (L. ) Scop. 
Roseroot 



Crassulaceae 



Crassulaceae 



49 Damp, often calcareous 
rocks, brooksides, etc. 

50 Along rocky coast and 
cliffs 



Saxif raga pensylvanica L. 
Swamp thickets 



Saxif ragaceae 



51 Sphagnous palustrine 
scrub-shrub emergent 
wetlands (boggy thickets 
and swamps) 



Amelanchier interior Nielson. 
Shadbush or Juneberrv 



Rosaceae 



52 



Hillsides and banks 
of streams 



Crataegus ideae Sarg. 
Hawthorn 



Rosaceae 



53 



Old fields, thickets, 
and open woods 



Rubus chamaemorus L. 
Baked -apple-berry 



Astragalus alpinus L. 
var. bronetianus Fern. 
Milk-vetch 



Rosaceae 



Fabaceae 



54 



55 



Coastal plateau bogs 
(palustrine emergent 
scrub-shrub wetland) 

Gravellv river banks 



Polygala cruciata L. var. 
aquilonia Fern & Schub. 



Polygalaceae 



56 Damp peat, sands, 

sterile meadows near 
coast 



Empetrum atropurpureum 
Fern. & Wieg. 
Purple crowberry 



Ilex glabra (L.) Gray 
Inkberry 



Empetraceae 



Aquif oliaceae 



57 



58" 



Granitic or acidic 
gravel £> sands along 
coast (coastal plateau 
peatlands?) 

Bogs (palustrine scrub- 
shrub wetland), low 
sandy and peaty soil 



20-6 



Table 20-2. (continued) 



Common and taxonornic names 



Family name 



Atlas 
Number 



Habitat 



Ceanothus americanus L. 



New Jersey tea 

Viola brittoniana Pollard 
Violet 

Viola triloba Schwein. 



Violet 



Dirca palustris L. 
Wicopy 

Nvssa sylvat ica Marsh. 
Black gum or sour gum 



Rhamnaceae 



Violaceae 



Violaceae 



Thymelaeaceae 



Cornaceae 



59 Dry open woods, 
gravelly or rocky banks 

60 Sandy or peaty soil 



61 Rich woods, shaded 
ledges (mostly 
calcareous) 

62 Rich deciduous or mixed 
woods 

63 Dry or moist woods 

and palustrine forested 
wetlands 



Lilaeopsis chinensis (L.) Ktze. Apiaceae 

No common name (Umbellif erae) 



64 Brackish estuarine 

emergent wetlands and 
tidal mud 



Clethra alnif olia L. 
Sweet pepperbush 



Clethraceae 



65 Palustine shrub-scrub 

wetlands, damp 
thickets 



Rhododendron viscosum (L.) 
Torr. 
Swamp honeysuckle 

Kalmia lat if olia L. 
Mountain laurel 



Vaccinium caesariense 
Mackenz . 
Highbush blueberry 



Hottonia inf lata Ell. 
Featherfoil 



Primula laurentiana Fern . 
Bird's-eye primrose 

Samolus parvif lorus Raf . 
Water -pimpernel 



Ericaceae 



Ericaceae 



Ericaceae 



Primulaceae 



Primulaceae 



Primulaceae 



67 Palustine shrub-scrub 
wetlands, thickets, 
and damp clearings 

3 

68 Rocky or gravelly 

deciduous woods and 
mixed woods 

69 Palustine scrub-shrub 
wetlands (swamp, 
peaty thickets and 
bogs) 

70 Pools (palustrine 
open water) and 
ditches 

71 Seacliffs, ledges 
near coast (calcareous 
elsewhere) 

2 

72 Shallow brackish 

water, wet, muddy 
soils inland 



20-7 



10-80 



Table 20-2. ' (continued) 



Common and taxonomic names 



Family name 



Atlas 
Number 



Habitat 



Gentiana crinita Froel. 
Fringed gentian 



Bartonia paniculata (Michx.) 
Muhl. 
Screw-stem 

B. Paniculata var . intermedia 
Fern. 



Lomatogonium rotatum (L.) 
Fries 
Marsh-f elwort 

L. rotatum forma americanum 
(Griseb.) Fern. 

Stachys tenuif olia Willd. var. 
platyphylla Fern. 

Gerardia maritima L. 
Gerardia 

Galium obtus um Bigel. 
Bedstraw 

Houstonia lanceolata (Poir.) 
Britt. 
Bluets 

H. longif olia Gaertn. 
Bluets 

Lonicera oblongifolia 
(Goldie) Hook. 
Swamp-fly honeysuckle 



L. sempervirens L. 
Trumpet honeysuckle 

L. dioica L. 
Honeysuckle 



Gentianaceae 



Gent ianaceae 



Gentianaceae 



Gentianceae 



Gentianaceae 



Lamiaceae 
(Labiatae)' 

Scrophulariaceae 



Rubiaceae 

Rubiaceae 

Rubiaceae 
Caprif oliaceae 

Caprifoliaceae 
Caprif oliaceae 



73 Meadows, brooksides, 
wet thickets, low 
woods 

Ik Bogs, wet peat and 

sand (palustrine 
scrub-shrub wetlands) 

75 Bogs, wet peat and 
sand (palustrine 
scrub-shrub wetlands) 

9 

76a" Turfy, sandy seashores 



76b Turfy, sandy seashores 



Low woods, rich fresh 
shores and meadows 

2 
78 Saline estuarine 

emergent wetlands 

7 9 Low woods, wet shores, 

palustrine scrub-shrub 
wetlands (swamps) 

80 Pastures, slopes and 
dry open woods 



81 Rocky or gravelly soil, 
pastures 

2 

82 Bogs, swampy thickets, 

wet woods (palustrine 
scrub-shrub and 
forested wetlands) 

83 Deciduous woods and 
thickets 

84 Rocky banks, dry woods 
and thickets 



20-8 



Table 20-2 (concluded) 



Common and taxonomic names 



Family name 



Atlas 
Number 



Habitat 



Lobelia syphilitica L. 
Great lobelia 



L. icalmii L. 
Lobelia 

Solidago lepida DC. var . 
f allax Fern. 
Goldenrod 

S. lepida var. molina Fern. 

S. alt issima L. 
Tall goldenrod 



Lobeliaceae 



Lobeliaceae 



Asteraceae 



Asteraceae 
Asteraceae 



85 Palustrine emergent 

and scrub-shrub 
wetlands (swamps), 
low ground 

2 
36 Wet ledges, freshwater 

shores, meadows, bogs, 

often calcareous 

(palustrine habitats) 

87a Coastal island (open) 



87b Coastal islands (open) 

88 Pastures, open fields, 

roadsides 



Aster f oliaceus L. 
Aster 



Iva f rutescens L. var. 
oraria (Bartlett) 
Fern. 4 Grisc. 
Marsh-elder 



Achillea borealis Bong . 
Yarrow 



Mikania scandens (L.) 
Willd. 
Climbing hempweed 



Uieracium venosum L. var. 



nudicaule (michx.) Farw. 
Rattlesnake-weed 



Asteraceae 



Asteraceae 



Asteraceae 



Asteraceae 



Asteraceae 



89- 



90 



91 



92 



93 



Meadows, shores 
thickets, rocky slopes 
(coast islands) 

Saline emergent 
marshes (estuarine) 



Wet rocks, cool 
slopes 

Thickets, swamps, 
banks of streams 
(palustrine scrub- 
shrub and emergent 
wetlands) 

Open woods, clearings 



20-9 



10-80 



This chapter summarizes the distribution of the seven species that were 
previously listed as endangered or threatened in Maine. Geographic ranges, 
preferred habitats, reproductive characteristics, taxonomic status, 
interrelationships with other plant and animal species (i.e., pollinators), 
and the major human-related threats to these species are discussed for each 
taxon. The rare species are discussed as a group. Rare and unusual plant 
communities containing three or more rare plant species are also described. 
Factors affecting abundance and distribution of plants are discussed 
generally, and data gaps and management problems are summarized. The 
approximate locations where endangered, threatened, or rare plants are known 
to occur in coastal Maine are indicated on atlas map 4. Common names of 
species are used except where accepted common names do not exist. Taxonomic 
names of all species mentioned are given in the appendix to chapter 1. 

DATA SOURCES 

Lists of endangered, threatened, and rare plants (table 20-1) were obtained 
from the Federal Register (16 June 1976), the Smithsonian report (Ayensu and 
DeFilipps 1978), the Critical Areas Program of the Maine State Planning Office 
(Eastman 1978a), and the New England Botanical Club (Eastman 1978b). Data on 
the distribution of these species in Maine were gained from the Critical Areas 
Program (planning reports, botanical fact sheets, and unpublished data), 
published literature (Schuyler 1974; Rand and Redfield 1894; Wheary 1938; Wise 
1970; and Fasset 1928) and herbarium specimens (Eastman 1978a; and the Academy 
of Natural Sciences of Phildadelphia) . 

Data on the geographic ranges, preferred habitats, growth habits, and 
longevity of these species were obtained from Fernald (1950) and Gleason and 
Cronquist (1963). Information on reproductive biology, including pollinators, 
came from published literature and personal communications with specialists. 

ENDANGERED AND THREATENED PLANTS 

Of the seven species of endangered or threatened plants in coastal Maine, the 
ram's-head lady' s-slipper ( Cypripedium arietinum ) , auricled twayblade 
( Listeria auriculata ) , pale green orchis ( Habernaria f lava var. herbiola ) , and 
ginseng (Panax quinquefolius) are considered true species by plant 
taxonomists, and further research into their distribution and abundance is 
warranted. The taxonomic status of Orono sedge ( Carex oronensis ) , Long's 
bitter cress ( Cardamine longii ) , and estuary monkey flower is less certain. 
Orono sedge is a member of a genus whose species are difficult to distinguish. 
Long's bitter cress and the estuary monkey flower may be only ecological races 
and not worthy of taxonomic recognition. Available biological information on 
these species in coastal Maine is summarized below. Little information is 
available on most of these taxa . 

The Estuary Monkey Flower 

The estuary monkey flower is a member of the snapdragon family and is 
apparently an ecological variant of the more common M. ringens var. ringens . 
The coastal variety is restricted largely to the upper intertidal zone of 
estuaries in Maine and the St. Lawrence River estuary in Canada. The more 
common variety ( ringens ) is abundant in wet meadows and along the banks of 
streams throughout Maine. At least one specimen of this variety has been 

20-10 



found along each of the following coastal rivers: the Machias River in 
Machias (region 6), Chandler River in Jonesport (region 6), Penobscot River in 
Bangor (region 4), Passagassawakeag River in Belfast (region 4), Kennebec 
River in Topsham (region 2), and at Cape Small Point in Phippsburg (region 2). 
The last collection was made in 1936 along the Chandler River in Jonesport. 
Five specimens were collected between 1896 and 1935. 

The endangered variety ( colpophilus ) is recognized as a true variety in the 
three most recent floras that encompass coastal Maine (Fernald 1950; Gleason 
and Cronquist 1963; and Seymour 1969). However, H. E. Ahles (personal 
communication, University of Massachusetts Herbarium, Amherst, MA; November, 
1979), who is preparing a flora of New England, suggests colpophilus may be an 
extreme form of ringens that he would not recognize as taxonomically distinct. 
Experimental evidence, including reciprocal transplants, and critical analysis 
of key vegetative and reproductive characters would be required to resolve the 
taxonomic status of this variety. 

Reproduction in the estuary monkey flower is primarily sexual, however short 
rhizomes used in asexual reproduction are produced also. The flowers are 
blue, somewhat showy, and asymmetrical in shape. Pollination is done by bees. 
The flowering period is June through August and the fruit matures between 
July and September. The fruit capsule opens passively along horizontal 
sutures. No data are available on seed predation but insects and small 
mammals are the most likely predators. 

Oil spills, tidal power, hydroelectric power, and trampling pose the greatest 
threat to the estuary monkey flower. Plants of the more common variety 
( ringens ) exposed to oil in Connecticut were completely eliminated after one 
growing season (Burk 1977). 

Ram's-Head Lady' s-Slipper 

The ram's-head lady ' s-slipper , a threatened orchid, inhabits mixed forests and 
open white cedar forests. It is found in moist, well-aerated, shady soil. 
This species' range extends from Nova Scotia and northern New England, west 
through Quebec, Ontario, and the Great Lakes. It is rare throughout its 
entire range (Luer 1975). 

The ram's-head lady' s-slipper has been collected in coastal Maine at Cape 
Elizabeth, South Portland, Gardiner, Bucksport, and Orland. It also has been 
collected in the nearby townships of Wayne, Old Town, New Gloucester, and 
Manchester. An estimated 200 to 300 plants were found recently in Wayne 
(Brower 1977). This is the largest number of plants record in Maine thus far. 

Reproduction in this plant is both sexual (by seeds) and asexual (by 
offshoots). The flowers are pollinated by bees which are attracted to the 
flowers by strong odors (no nectar is contained in these flowers). Upon 
landing on a flower the bees may fall into a pouch and are forced to crawl out 
under the reproductive structures where cross-fertilization occurs. 

Lumbering, plant collecting, and trampling pose the greatest threats to the 
ram's-head lady' s-slipper . Insecticides also are a threat because they may be 
toxic to bees which are necessary for fertilization. 



20-11 

10-80 



Auricled Twayblade 

The auricled twayblade, another threatened orchid, is a diminutive herbaceous 
monocot that usually inhabits alder thickets. It is found from northern New 
England to northern Michigan, and northward to the Canadian subarctic. The 
only collections of this plant in coastal Maine were made on Mt. Desert 
Island (region 5) in 1891 and 1927. Its current status is unknown. It has 
been collected at 18 locations in Maine outside the coastal zone, but not in 
recent years. 

Little biological information is available on this species. Other species of 
this genus reproduce both sexually (seeds) and asexually (short rhizomes that 
elongate after flowering) . Flowers of the auricled twayblade bloom in July 
and the fruit capsules mature within a week of fertilization. Twayblades are 
pollinated by mosquitos, small moths, beetles, and ichneumonid wasps (van der 
Pijl and Dobson 1966; and Darwin 1877). The pollen is contained in two simple 
masses called pollinia, which, in Listera , are explosively released at the 
touch of a pollinator. A droplet of a glue-like material from the pollinia 
dries solidly within a few seconds and fixes the pollinia to the pollinator. 
There is no evidence this species forms a close association with a specific 
species of pollinator. Twayblades produce seeds profusely. Seed predators 
probably include insects and small mammals. 

Flooding, peat mining, stream channeling, and logging pose the greatest 
threats to this species. 

Pale Green Orchis 

The pale green orchis is a threatened orchid of which herbiola is the only 
variety found in Maine. This species is also placed in the genus Platanthera 
P. f lava (L.) Lindley var. herbiola (R. Brown) Luer . It grows in low, wet, 
woods, moist thickets, and along marshy banks. It is often found in shallow 
water with a thick layer of decaying leaves (Luer 1975). It's range extends 
from Nova Scotia to Wisconsin, and south to Florida and the Gulf States. The 
northern variety ( herbiola ) is found from Kentucky and western North Carolina 
north. It has been found in four locations in the coastal zone: West Dresden 
in region 2 (1973); Monhegan in region 3 (1964); and Rockport (1935) and 
Frankfort (1916) in region 4. It has been collected in the adjacent townships 
of Clinton (1914 and 1916), Vassalboro (1916), and in 20 other areas in Maine. 
The varieties f lava and herbiola intergrade where their ranges overlap (Luer 
1975). 

Reproduction in the pale green orchis is entirely sexual. It is pollinated by 
small moths and Aedes mosquitos (van der Pijl and Dobson 1966). As with 
Listera, the pollen is borne in two masses; the pollinia, which become 
attached to the insect. The flowering period is between July and early 
August. 

Lumbering, flooding, stream channeling, and plant collecting pose the greatest 
threats to the pale green orchis. 



20-12 



Ginseng 

Ginseng is not rare throughout its entire range but is very rare in the 
coastal zone and is threatened by commercial exploitation. The root of 
ginseng is harvested and exported to the Orient. The root is alleged to be an 
aphrodisiac, to prolong life, to increase mental capacities, and to lessen 
fatigue. An estimated 221,000 lb (100,500 kg) of ginseng root were exported 
from the United States to Hong Kong in 1974. Ginseng was dug commercially in 
Maine during the 1800s and early 1900s and digging ginseng was a common 
practice among woodsmen, guides, and trappers in the Oakland area (adjacent to 
region 2) during the 1920s (Eastman 1976a). No data on annual commercial 
harvest in Maine are available. Ginseng inhabits mature deciduous forests, 
and is usually found in the shade of sugar maple ( Acer saccharum ) , American 
beech ( Fagus grandifolia ) , basswood ( Tilia americana ) , hop hornbeam ( Ostrya 
virginiana), or white ash ( Fraxinus americana ) . It has been collected at 14 
locations in Maine. One of these (Gardiner, region 2) is in the coastal zone 
where a collection was made by A. R. Norton in 1912. Three others are near 
region 2 (Clinton, Oakland, and Fayette). The current status of the Gardiner 
site is unknown because the original collection site was not documented. 

Ginseng reproduction is primarily sexual. Flowers are pollinated by insects. 
Seeds are dispersed by birds, mammals, and gravity. Generally, ginseng occurs 
in colonies formed from seeds falling in the immediate vicinity of parent 
plants. A thick, tuberous root develops after several years. 

Commercial and private plant collecting and lumbering pose the greatest 
threats to this species. 

Orono Sedge 

Orono sedge, an endemic sedge found only in the Penobscot River valley, is 
another threatened species. Carex is a large genus of morphologically similar 
species which are grouped into sections. The Orono sedge is a member of the 
section Ovales, of which there are 19 species in Maine. The Orono sedge may 
be of hybrid origin (Gleason and Cronquist 1963) which would prevent its being 
listed as a threatened species. 

The current distribution of this plant in coastal Maine is unknown. It is 
probably overlooked by most botanists, who tend to avoid collecting sedges. 
It was collected in Old Town, Orono, Bangor, Dedham, Frankfort, and 
Mattawamkeg between 1890 and 1916, and again (1978) in Old Town (personal 
communication from L. M. Eastman, botanist, Old Orchard Beach, ME.; August, 
1978). 

The Orono sedge is a wind-pollinated, tufted, perennial that grows in wet and 
dry fields, meadows, and clearings. It is often found in gravelly substrates. 
Over-grazing, mowing, and construction are the chief threats to this plant. 

Long's Bitter Cress 

Long's bitter cress is a small biennial or short-lived perennial mustard. 
According to herbarium specimens, Long's bitter cress grows only on muddy 
banks of tidal and nontidal estuaries and streams. It is most frequently 
reported in the freshwater area of tidal estuaries and not along the borders 

20-13 

10-80 



of salt marshes as stated by Gleason and Cronquist (1963). Four collections 
of this plant have been made in coastal Maine: two along the Cathance River 
in Bowdoinham (region 2), one in Ocean Point, Lincoln County (region 2), and 
one in Hancock County (regions 4 and 5; Crovello 1978). Unverified specimens 
of Long's bitter cress were collected at Pine Point in Phippsburg (region 2), 
and on Mt. Desert Island (region 5). It also has been collected in New 
Hampshire, Massachusetts (where it was introduced), Connecticut, New Jersey, 
Virginia, and the Carolinas (Crovello 1978). 

Long's bitter cress, C. longii , looks very much like extreme forms of C. 
pensylvanica var. brittoniana Farw. , which is not as rare in Maine. Whether 
C. Longii is a species has been questioned (personal communications from: H. 
E. Ahles, University of Massachusetts Herbarium, Amherst, MA., February, 1978; 
T. J. Crovello, University of Notre Dame, Notre Dame, IN., February, 1978; and 
L. M. Eastman, botanist, Old Orchard Beach, ME., February, 1978). It may be a 
form of C. pensylvanica , whose compound lower leaves drop off prematurely 
leaving only the simple cauline leaves found on all the collected specimens. 
Transplant experiments of C. longii and C. pensylvanica, followed by analysis 
of the critical characters of their fruits, pedicels, and flowers, would help 
evaluate the taxonomic status of this plant. 

Eastman (1976b), Ahles (in preparation ) , and Crovello (1978) reviewed the 
distributional status of Long's bitter cress in Maine, New England, and North 
America, respectively. Fernald (1917 and 1941) and Fassett (1928) commented 
on its restricted distribution in Maine in the past. One station (occurrence) 
of the species was found in Maine in 1972, which was located again by Eastman 
and Delaney in 1976 (Eastman 1976b). This station is located along the 
Cathance River near the River Bend Camps in Bowdoinham (region 2), and has 
been designated a critical area by the Critical Areas Program of the Maine 
State Planning Office. Another station was located upriver in Topsham in 1979 
by biologists from the Critical Areas Program. 

The species was first described by Fernald (Eastman 1976b; and Crovello 1978) 
based on collections made at the River Bend Camps in 1916. Fasset collected 
the species from the Cathance River area in 1920, and from Centers Point, 
Bowdoinham, in 1921. litis and Patman, in 1959, and Crovello, in 1975 
(Crovello 1978), changed a specimen labelled Cardamine pensylvanica Muhl . 
(which was originally collected from a small brook in Ocean Point, Lincoln 
County, and identified by Fasset in 1925) to Cardamine longii . A second 
specimen labelled Cardamine hirsuta L., which was collected in Hancock County, 
by E. L. Rand in 1890, was similarly changed to C^ longii by Crovello (1978). 

Little biological information on C. longii is available. Reproduction is 
sexual and the apetalous flowers are probably self-pollinated since mustard 
pollen is heavy and is not easily transported by wind. Seeds are borne in 
elastically dehiscing capsules (siliques). This method of dehiscence is found 
only in this genus (personal communication from H. E. Ahles, University of 
Massachusetts, Amherst, MA; November, 1979). 

Stream channeling, hydroelectric dams, plant collecting, and competition from 
introduced weeds, are the major threats to this species. 



20-14 



RARE PLANTS 

To date, 84 species of vascular plants in the coastal zone are considered rare 
in Maine (table 20-2; Eastman 1978a and b) . Six of these are trees, 15 are 
shrubs, 58 are herbaceous dicots, 17 are herbaceous monocots, and 6 are lower 
vascular plants (ferns and club mosses). Six species are annuals, 3 are 
biennials, and 75 are perennials. 

Of the 84 rare species, 28 are located near the southern edge of their ranges, 
42 are located near the northern edge, and 14 are located near the center 
portion of their range. Many of the northern species are relict populations 
from the last glacial period ( 12,000 years ago ), and many of the southern 
species are relict populations from the hypsithermal period (a warm period), 
which ended about 2500 years ago. 

The habitats, or plant communities, where rare plants are found include: 
mature forest; sphagnum bogs, fens, and Atlantic or northern white cedar 
forested wetlands; wet meadows and alluvial thickets; estuarine emergent 
wetlands and estuarine shorelines; outer coastal headlands and islands; ledges 
and open ground; and non-sphagnous palustrine wetlands. Many of these plant 
communities are unique or rare. Associations of three or more rare plants 
occur in coastal plateau bogs, on outer headlands and islands, and in 
freshwater and brackish tidal marshes. 

Locations where rare plants have been known to occur in coastal Maine are 
plotted on atlas map 4. Most locations are based on herbarium specimens which 
usually identify only the general location (i.e., a particular bog) and not 
the exact place of growth (i.e., location within the bog). The Critical Areas 
Program has additional data on the exact locations of species for which they 
have prepared critical area reports or botanical fact sheets, and species for 
which they are currently conducting inventories (see table 20-2). 

UNIQUE OR RESTRICTED PLANT COMMUNITIES 

There are several plant communities found along the Maine coast that have 
restricted distributions in Maine or the United States, or that support 
several rare plant species. These include coastal plateau bogs and shrub 
slope peatlands, some outer headland and coastal island plant communities, 
freshwater and brackish water intertidal emergent wetland communities, a 
forested wetland community dominated by Atlantic white cedar, and several sand 
beach and dune communities (sand beach and dune communities are discussed in 
chapter 4, "The Marine System"). 

Plant communities are composed of groups of species whose range of ecological 
requirements overlap. Individual species or groups of species are not 
restricted to particular plant species associations, rather each species is 
distributed along environmental gradients almost without regard to the 
occurrence of others. The more important ecological gradients influencing 
plant distribution in the coastal zone are atmospheric moisture (rainfall, 
runoff, and fog), soil and air temperature, evapotranspiration rate, substrate 
type (mineral vs. organic), nutrient availability, salinity (including salt 
spray), tidal regime, drainage, and others. These factors may act 
independently or interact to influence plant species distribution. 

20-15 



10-80 



a 




'■it-: -sji 



Till or bedrock 



Inland Domed Bog 



-33^ 



f 4 ,»-*:<■ 




V*'i9"F «? 



Till or bedrock 



Coastal Plateau Bog 



jW-W&S 




bedrock 



Shrub Slope Bog 



Figure 20-1 Comparison of the Three Types of Raised Bogs Found Along the Maine 
Coast (adapted from Damman 1979). 



20-16 



Coastal Plateau Bogs and Shrub Slope Peatlands 

Coastal plateau bogs, or plateau peatlands, are a type of raised bog found 
primarily in eastern coastal Maine, usually within 6 miles (10 km) of open 
ocean. They differ from inland domed bogs, the more common type of raised bog 
found in coastal Maine, in surface topography and plant species composition. 
Plateau bogs have a pronounced slope which rises from a well-developed bog 
moat, or lagg, to an almost flat central bog plain (figure 20-1; Damman 1977). 
Inland domed bogs, such as the Great Heath in Cherryfield (region 5), are 
clearly domed with a gentle or gradual slope in all directions from the 
center, and the moat or lagg is usually lacking (figure 20-1). Plateau bogs 
and domed bogs correspond to Types 3 and 4, respectively, of Cameron's (1975) 
classification which is discussed and illustrated (figure 8-4) in chapter 8, 
"The Palustrine System." 

A unique plant community dominated by black crowberry ( Empetrum nigrum ) , 
Scirpus cespitosus , and baked apple berry ( Rubus chamaemorus ) , is found on the 
flat central bog plain of plateau bogs. This community is very rare or absent 
from inland domed bogs but may occur on the tops of higher inland mountains. 
Several rare plant species occur in association with this plant community 
including baked apple berry, dragon's mouth (Arethusa bulbosa ) , a sedge ( Carex 
rariflora) , northern comandra ( Geocaulon lividum ) , and possibly purple 
crowberry ( Empetrum atropurpureum ) . 

Coastal plateau bogs are found only along the Atlantic coast from eastern 
Maine to Labrador. These areas are characterized by a maritime climate with 
frequent summer fogs, cool temperatures (2.5 to 4°C; 4.5 to 7 F; less than 
nearby inland domed bogs; Damman 1977), high rainfall, high moisture input 
from fog drip (Davis 1966) , and reduced evapotranspiration which results in a 
surplus of moisture during the growing season. The larger coastal plateau bogs 
are plotted on atlas map 4. 

Shrub slope peatlands have been described only recently (Worley 1980b). They 
generally are associated with plateau peatlands, but are more restricted in 
distribution, being found only within a few km of open ocean (principally in 
region 6). Shrub slope peatlands have a dense cover of ericaceous shrubs, 
such as sheep laurel (Kalmia angustifolia ) and leather leaf ( Chamaedaphne 
calyculata ) . Black crowberry, baked apple berry, and Sphagnum spp. are also 
present. The dense vegetation covers a layer of peat some 4 to 16 inches (10 
to 40 cm) thick that lies over undulating bedrock with slopes of at least 13 
(figure 20-1; Worley 1980b). Shrub slope peatlands occupy terrain with "the 
most exposed, rainy, foggy, cool, temperate, maritime climate on the Maine 
coast" (Worley 1980b:31). The best examples are found on the southern end of 
Great Wass Island. 

Outer Headlands and Outer Island Communities 

Plant communities occupying exposed outer headlands and outer islands support 
rare plant species with northern affinities. These communities occupy the 
area between the exposed shoreline and the coastal spruce-fir stands, and are 
characterized by a dense shrub and herbaceous ground cover. Plant species 
that commonly occur in these communities are sheep laurel, ground juniper 
( Juniperus horizontalis ) , mountain cranberry ( Vaccinium vitis-idae ) , black 

20-17 

10-80 



crowberry, three-tooth edcinquefoil ( Potentilla tridentata ) , seaside plantain 
( Plantago juncoides ) , and various grasses. 

The rare plant species found in this community are able to survive because of 
the cooler temperatures found along the coast. Many also are found inland at 
higher elevations (above 500 to 800 m) where temperatures are comparable to 
those along the immediate coast. Examples of some of the rare species found 
in these communities are beachhead iris (Iris hookeri) , blinks ( Montia 
lamposperma ) , mountain sandwort ( Arenaria groenlandica ) , roseroot ( Seduro 
rosea ) , purple crowberry, bird's-eye primrose ( Primula laurentiana ) , marsh 
felwort ( Lomatogonium rotatum ) , goldenrod ( Solidago lepida ) , and yarrow 
( Achillea borealis ) . Iris, sandwort, roseroot, and primrose are often found 
together on the exposed ledges of coastal headlands in regions 5 and 6, and on 
outer islands in regions 3 through 6. The Great Wass Island archipelago in 
region 6, Little Moose Island near Schoodic penninsula in region 5, Isle au 
Haut in region 4, and Matinicus Isle and Matinicus Rock in region 3 support 
important associations of the above rare species. 

A plant community dominated by jack pine ( Pinus banksiana ) is found in several 
areas on Mt. Desert Island, and the Schoodic and Corea peninsulas in region 5, 
and on Great Wass Island (region 6). 

Freshwater Intertidal Emergent Wetlands 

Freshwater intertidal emergent wetlands are relatively uncommon along the east 
coast of the United States. Large expanses of undisturbed freshwater 
intertidal emergent wetlands occur in Merrymeeting Bay in region 2, and lesser 
amounts occur in the Penobscot River estuary (region 4). Several rare plant 
species and named ecotypic varieties of more widely distributed species occupy 
these habitats, including Long's bitter cress, estuary monkey flower, and 
pipewort ( Eriocaulon parkerii ) . This association is most abundant along the 
Cathance River in Topsham and Bowdoinham (region 2) and other localities in 
Merrymeeting Bay, and in the Reed Brook estuary (a tributary of the Penobscot 
River, region 4) . 

Brackish Intertidal Emergent Wetlands 

An association of rare plant species is found locally in brackish intertidal 
emergent wetlands dominated by cordgrass ( Spartina patens ) . These species are 
generally found in the upper portions of estuaries, especially the Sheepscot 
River, Sasonoa River, and Back River in region 2, and the Marsh River in 
region 4. Important rare plants occupying these habitats include a bulrush 
( Scirpus cylindricus ) , horned pondweed ( Zannichellia palustris ) , water 
pimpernel (Samolus parvif lorus ) , spike-rush (Eleocharis rostellata ) , and 
pipewort ( Lilaeopsis chinensis) . 

Atlantic White Cedar Forested Wetlands 

There is one forested wetland in the characterization area dominated by 
Atlantic white cedar (as opposed to northern white cedar which is very 
common). It is located in the town of Northport (region 4) and is registered 
as a critical area. This wetland is also dominated by sphagnum mosses. This 
community is the northernmost Atlantic white cedar wetland in Maine, although 
there are several others found in Maine south of the characterization area, 

20-18 



and they are abundant in the coastal plain of the southeastern United States. 
In addition to Atlantic white cedar, dragon's mouth is the other rare plant 
species associated with this community. 

FACTORS OF ABUNDANCE 

The distribution and abundance of plant species are the result of natural and 
human-related factors. Long-term changes in climate and land forms (i.e., 
glaciation and mountain emergence) have resulted in the development of new 
species (speciation) , the loss of species (extinction) , and changes in 
distribution of species. Speciation and extinction are usually long, slow 
processes. People accelerated the extinction process in the last century by 
altering the earth's surface with advanced technology (Ayensu and DeFilipps 
1978). 

Some plant species are naturally rare, and have evolved adaptations to permit 
existence under conditions of low abundance. Many orchids, for example, have 
highly specific and "faithful" pollinators that allow them to exist in 
scattered populations. In addition, each plant produces large numbers of 
small seeds, a practice beneficial to less dense populations. Among species 
less-specialized than orchids, rarity is the result of a species' inability to 
adapt to change in habitat, climate, predator pressure, or competition. 

Biotic factors affecting the distribution and abundance of plants include 
competition with newly-evolved or formerly allopatric (species whose ranges do 
not overlap) species, disease, damage from overgrazing by animals, insect 
damage, loss of pollinators, destruction of seeds and fruit, and changes in 
the soil-water regime (i.e., changes in drainage patterns, water table level, 
and waterholding capacity of the soil). 

Plant populations have been reduced severely by human activities such as real 
estate developing, impounding water, and lowering the water table by wells, 
drainage, and peat mining. Populations of ginseng have been eradicated by 
commercial plant collectors along with mountain laurel and rhododendron. 
Orchids, and other aesthetically attractive plants, are subject to private 
plant collecting. 

Timber removal, particularly clearcutting, directly alters plant habitats. 
Clearcutting results in changes in the light regime of the understory, the 
shrub and herbaceous layers, mechanical damage to the residual vegetation, 
changes in evapotranspiration rates, and increased erosion and nutrient 
depletion of the soil. The site preparation procedures most commonly used in 
coastal Maine are bulldozing, burning, and herbicidal application, which 
destroy the residual vegetation. Timber removal is likely to affect rare 
forest-dwelling species. 

Introduced vascular plants sometimes reproduce prolifically and compete more 
successfully for light and space than native species. Introduced species are 
usually free of native diseases and pests, which, if present, keep them in 
biological balance. Many introduced species are vigorous, aggressive weeds. 
Approximately 24% of Maine's flora is composed of naturalized exotics and 
garden escapees. The degree of competition between introduced plants and 
rare species in coastal Maine is unknown. 

20-19 

10-80 



The direct and indirect ways in which plants and plant habitats in the United 
States are threatened by human activities are summarized by Ayensu and 
DeFilipps (1978). The following apply to coastal Maine: 

Forestry practices : clearcutting; herbicides; replacing native trees 

with exotic timber trees. 
Biocide spraying : insecticides; herbicides. 
Mining : peat mining; subsurface mining. 
Real estate development and construction : roads; housing tracts; 

landclearing; power plants; shopping centers; golf courses; 

landscaping. 
Over grazing : by domesticated or feral goats, sheep, cattle, deer, pigs, 

rabbits, with associated trampling; (this is the greatest potential 

problem on coastal islands). 
Introduction of competitive weeds : chokers of native vegetation. 
Fire : destructive fires; preventing natural fires. 
Agriculture : fields cleared of vegetation for monoculture crops. 
Water management : flooding; stream channeling; tidal power; 

hydroelectric dams; drainage of swamps. 
Illegal removal of rare plants: from Federal, State and private land. 
Commercial exploitation : potential for most rare plants. 
Collecting by private individuals : for transplanting to gardens. 
Trampling of vegetation by people: inviting accelerated soil erosion, 

and destruction of fragile ecosystems, such as bogs and fens. 

PROTECTION OF ENDANGERED, THREATENED, AND RARE PLANT SPECIES 

The Endangered Species Act of 1973 places legal restrictions on the 
exploitation, propagation, use, and destruction of endangered and threatened 
species (or parts derived from them) or their habitats. For example, 
interstate and international commerce of threatened and endangered plants is 
illegal. Federal permits are required to propagate or enhance the survival of 
these species and for their use in scientific study. Plans for developments 
requiring Federal approval (e.g., highways, dams, stream alteration) must 
include consideration of endangered and threatened species. 

The Endangered Species Act also mandates the responsibility of maintaining 
lists of plants and animals throughout the world judged by the Secretary of 
the Interior to be in danger of extinction or likely to become so. Once a 
plant species, subspecies, or variety is determined by the FWS to be 
endangered or threatened its name is placed on an official list published in 
the Federal Register . The estuary monkey flower is the only coastal Maine 
variety whose name has appeared on this list. After a plant has been listed, 
habitats critical to its survival must be identified and public hearings may 
be held for discussion of its status. Critical habitats must be named within 
one year of listing or the plant will be removed from the list. On 10 
November 1979 all plants listed as endangered or threatened in coastal Maine 
were removed from the official list because critical habitats were not named. 
Any species can be relisted at any time. FWS biologists give priority to 
complete species (rather than subspecies) and species whose taxonomic status 
is generally agreed upon by taonomists. 

Rare plant species do not receive protection under the Endangered Species Act. 
The locations where rare plants are found may be designated critical areas by 

20-20 



the Critical Areas Program. Through the efforts of the Critical Areas Program 
some rare plant stations have been protected through the cooperation of the 
landowner (Tyler and Gowler 1980). The Critical Areas Program, working 
closely with the Nature Conservency and Maine Coast Heritage Trust, has helped 
acquire (i.e., Great Wass Island in region 6), or gain conservation easements 
on (i.e., Seawall Beach in region 2), several rare plant locations or unusual 
rare plant communities. 

MANAGEMENT 

The management of endangered plant species is regulated by the Department of 
the Interior. Currently no plant species in the coastal zone are under 
Federal protection because critical habitat was not described within the one 
year following listing. However, species on the original list ( Mimulus 
ringens var. colpophilus ) , species listed in the Smithsonian report, and most 
species on the Maine rare plant list are in need of protection. 

The Smithsonian report (Ayensu and DeFilipps 1978) summarized the key elements 
of endangered species management: 

1. Prevention of the destruction of populations and their habitats. 

2. Monitoring and research on population levels and viability. 

3. Prevention of collection and commercial exploitation. 

This report states that the preservation and protection of habitats upon which 
the plants depend for growth and reproduction are the foremost needs in rare 
plant management. It further states that in situ perpetuation of sufficient 
populations of endangered and threatened plants is required to ensure their 
survival . 

Various methods of protection and preserving habitats and populations include 
landmark designations, conservation easements, tax breaks for landowners, 
acquisition, and penalty procedures. Priority should be given to habitats 
supporting more than one species. 

Endangered, threatened, and rare plants should be recognized as basic elements 
in land-use plans and inventories in which the Federal Government is involved 
either in a direct capacity or in the role of a guiding or advisory party. 
Federal agencies involved in land management, including the Bureau of Land 
Management, Fish and Wildlife Service, Department of Energy, Army Corps of 
Engineers, National Park Service, Forest Service, Energy Research and 
Development Administration, Department of Defense, Soil Conservation Service, 
and U.S. Geological Survey, should recognize endangered, threatened, and rare 
species as natural resources and consider their distribution in natural 
resource surveys and inventories. 

RESEARCH NEEDS 

Little is known about the current population status of endangered, threatened, 
and rare plant species in the coastal zone. More information is needed to 
evaluate potential threats from human activities and to help guide protective 
and management procedures. 



20-21 

10-80 



The taxonomic validity or invalidity of Carex oronensis , Cardamine longii , and 
Mimulus ringens var. colpophilus needs to be established so protective 
measures may be implemented on the valid species or varieties. 

Information on important 'life history' characteristics of endangered and 
threatened species would help guide management decisions affecting these 
species . 



20-22 



REFERENCES 

Ahles, H. E. A Flora of New England. University of Massachusetts Herbarium, 
Amherst, Mass. In preparation . 

Ayensu, E. S., and R. A. DeFilipps. 1978. Endangered and Threatened Plants 
of the United States. Smithsonian Institution and the World Wildlife 
Fund, Inc. Washington, DC. 

Brower, A. E. 1977. Ram's-Head Lady' s-Slipper , Cypripedium arietinum R. Br. 
in Maine and Its Relevance to the Critical Areas Program. Report No. 25 
prepared for the Maine Critical Areas Program, Maine State Planning 
Office, Augusta, ME. 

Burk, J. D. 1977. A four-year analysis of vegetation following an oil spill 
in a freshwater marsh. J. Appl. Ecol. 14:515-522. 

Cameron, C. 1975. Some peat deposits in southeastern Aroostook and 
Washington Counties, Maine. U.S.G.S. Bull. 1317-C. 

Crovello, T. J. 1978. The mustard data bank. Computer printout of all label 
data on 54 specimens of Cardamine longii borrowed by Crovello from 75 
museums and herbaria. Available from T. J. Crovello, Department of 
Biology, University of Notre Dame, Notre Dame, Indiana. 

Damman, A. W. H. 1979. Geographic patterns in peatland development in 
eastern North Amerian. Proc. Intern. Sym. on Class, of Peat and 
Peatlands. Hyytiala, Finland. Intern. Peat Soc. Pp. 42-57. 

. 1977. Geographic changes in the vegetation pattern of raised bogs in 

the Bay of Fundy Region of Maine and New Brunswick. Vegetatio 35:137- 
151. 

Darwin, C. R. 1877. The Fertilization of Orchids by Insects. 2nd ed. D. 
Appleton, NY. 

Davis, R. B. 1966. Spruce-fir forests of the coast of Maine. Ecol. Mono. 
36:79-94. 

Eastman, L. M. 1976a. Ginseng ( Panax quinquefolius L.) in Maine and Its 
Relevance to the Critical Areas Program. Report No. 16 prepared for the 
Maine Critical Areas Program, Maine State Planning Office, Augusta, ME. 
19 pp. 

. 1976c. Long's Bitter Cress ( Cardamine longii Fern.) in Maine and Its 

Relevance to the Critical Areas Program. Report No. 17 prepared for the 
Maine Critical Areas Program, Maine State Planning Office, Augusta, ME. 

. 1977. Auricled Twayblade (Listera auriculata W.) in Maine and Its 

Relevance to the Critical Areas Program, Maine State Planning Office, 
Augusta, ME. 15 pp. 



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10-80 



. 1978a. Rare Vascular Maine Plants: A Compilation of Herbarium and 

Literature citations. Planning report prepared for the Maine Critical 
Areas Program, Maine State Planning Office, Augusta, ME. 

. 1978b. Rare and Endangered Vascular Plant Species in Maine. The New 

England Botanical Club in cooperation with the U.S. Fish and Wildlife 
Service, Newton Corner, MA. 

Fassett, N. C. 1928. The vegetation of the estuaries of northeastern North 
America. Proc. Boston Soc. Nat. Hist. 39(3) : 73-130. 

Federal Register. 1976. Endangered and threatened species of plants. 
41(117) :24, 524-24, 572 (Wednesday, 16 June 1976). Department of the 
Interior. U.S. Fish and Wildlife Service. 

Fernald, M. L. 1917. A new Cardamine from southern Maine. Rhodora 19:91-92. 

. 1941. Flora of Virginia. Rhodora 44:346-347, 400. 

. 1950. Gray's Manual of Botany, 8th ed. D. Van Nostrand Co., New York. 

1632 pp. 

Gleason, H. A., and A. Cronquist. 1963. Manual of Vascular Plants of the 
Northeastern United States and Adjacent Canada. D. Van Nostrand Co., 
Princeton, N. J. 810 pp. 

Luer, C. A. 1975. The Native Orchids of the United States and Canada. New 
York Botanical Garden, New York. 

Rand, E. L., and J. H. Redfield. 1894. Flora of Mount Desert Island, Maine. 
Univ. Press, Cambridge, MA. 

Schuyler, A. E. 1974. Scirpus cylindricus : an ecologically restricted 
Eastern North American tuberous bulrush. Bartonia 43:29-37. 

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1980b . Shrub slope peatlands of Great Wass Island, Maine. In 
preparation . 



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