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 105 , solid line) and dollar values (x 105,

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 106 , solid line) and dollar value (x 106 ,

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 105 , solid line) and dollar values (x 104 ,

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 105 ,
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 10h ,

dotted line) of hloodworms landed in coastal Maine from

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

12-9 Pounds (x lO1* , solid line) and dollar values (x 101* ,

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

PaSs
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 I7-3

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

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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
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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

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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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10

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 Maine5

Species

Principal

spawning

months

Spawning
habitatb

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

0 O

Tautog

JJ

M10W

P

17 -20 C

Northern pipefish

MAMJJA

M

0

o o

Redf ish

MJJA

M

0

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

aBigelow 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.

cEgg 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 0

Atlantic tomcod

JF

ND

E

D

4 0 -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 nF

o o

American shad

MJ

R2,3

D

50 -63nF

O 0

Sea lamprey

MJJA

R3UB

D

50 -68 F

Atlantic salmon

ON

R3UB

D

£ c0

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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11-21

10-80

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lower estuary
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^v>>w^w<

1.0 F=

0.1 =

1969 - 70

0.01

0.001 _

^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

Atlantic
cod

Pollock

Silver
hake

White
hake

Cusk

Red
hake

Haddock

Longfin

hake

Fourbeard

rockling

Ocean
pout

Atlantic cod

"\

••;•&■:■:•:':-:•:■:•:■:-

Pollock

69

Silver hake

59

69

White hake

61

57

56

\

Cusk

27

30

16

23

Red hake

41

47

70

48

38

Haddock

18

15

14

14

19

23

Longfin hake

2

5

2

1

13

7

6

Fourbeard
rockling

18

20

8

6

42

14

25

4

Ocean pout

6

3

3

4

6

11

31

28

4

"\

30
<60

60
<100

0
<30

mmm

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

Factors

of

Abundance

and

J2is.tr ibution

c

o

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4J

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Cfl

4-1

M

1-1

60

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C

CO

■H

,C

3

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cfl

i-l

CC

■i-)

o

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60

CD

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r-4

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4-1

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CO

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•H

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0

X

•H

4.)

cd

03

c

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53

M

"*-^

>

•rl

CO

CO

•H

u

3

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>>

CO

■rl

co

CO

cfl

o

4-1

~-*^

•u

>,

0)

4-1

C

4J

4-1

4J

>

U

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u

4-1

cfl

4-1

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a

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T3

60

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Z a.

Agriculture3

X

X

X

X

X

X

X

X

Forestry

X

X

X

X

X

X

X

Fishing

X

X

X

Power generation"'"

Nuclear

Fossil fuel

Hydroelectric
Transportation0'^

Industrial and

Municipal Waste Disposal
Dredging

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

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 0 . 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 1976a.

Year

Pounds

(1000 lb)

NAb

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 1977a

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

aLewis 1979.

11-39

10-80

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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 Areac

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 bassb
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 salar 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

REFERENCES

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Mountain lakes, Ontario, and resulting fish mortalities. J. Fish. Res.
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Bean, T. H. 1903. Catalogue of fishes of New York. New York State Mus .
Bull. (Zool.) 60(9).

Bell, M. D. 1973. Fisheries Handbook of Engineering Requirements and
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Division, Portland, OR.

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
prey from the region of the Argo Merchant oil spill. Proc. of Univ. of
Rhode Island, Kingston, RI . Symposium, 11-13 Jan 1978. "In the Wake of
the Argo Merchant."

Brown, B. E. 1976. Status of fishery resource assessment in the area off the
coast of the Northeastern United States. Mar. Tech. Soc. J. 10(4):7-18.

Canada Department of the Environment. 1974. Summary of physical, biological,
socioeconomic, and other factors relevant to potential oil spills in the
Passamaquoddy Region of the Bay of Fundy. Fish. Res. Board Can. Tech.
Rep. 428.

Carlander, K. D. 1969. Handbook of Freshwater Fishery Biology, Vol. 1. Iowa
State Univ. Press, Ames, IA.

Central Maine Power Company. 1974 to 1975. Aquatic studies, Upper Penobscot
Bay, for Sears Island Coal Unit No. 1. Augusta, ME.

Chenoweth, S.B. Unpublished Trawl Survey of the Sheepscot-Boothbay-
Damariscotta Region. Raw data. W. Boothbay Harbor, ME.

1973. Fish larvae of the estuaries and coast of central Maine. U.S.
_ Nat. Mar. Fish. Serv. Fish. Bull. 71:105-113.

1977. Commercial fisheries and Sport Fisheries. In Center for
Natural Areas, A Summary and Analysis of Environmental Information on the
Continental Shelf from the Bay of Fundy to Cape Hatteras (1977). Bureau
of Land Management contract report AA 550-CT6-45 , New York.

Clayton, G. , C. Cole, S. Murawski, and J. Parrish. 1976. Common Marine

Fishes of Coastal Massachusetts. Contribution No. 54 of the

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
groundfish in continental shelf waters, Nova Scotia to Long Island. Nat.
Mar. Fish. Serv. Fish. Bull. 70(3) :637-658 .

, W. G. Smith, A. W. Kendale Jr., P. L. Berrien, and M. P. Fahay.

1979. Principal spawning areas and times of marine fishes, Cape Sable to
Cape Hatteras. Nat. Mar. Fish. Serv. Fish. Bull. 76(4) :911-915 .

Cope, 0. B., E. M. Wood, and G. H. Wallen. 1970. Some chronic effects of
2,4,-D on the bluegill (Lepomis macrochirus) . Trans. Amer. Fish. Soc.
99(1) : 1-12.

Dadswell, M. J. 1975. The biology of the shortnose sturgeon (Acipenser
brevirostrum) in the St. John River estuary, New Brunswick, Canada.
Trans. Amer. Fish. Soc.

Everhart, W. H. 1958. Fishes of Maine. Maine Department of Inland Fisheries
and Wildlife (formerly Maine Department of Inland Fisheries and Game),
Augusta, ME.

Fish, C. J., and M. W. Johnson. 1937. The biology of the zooplankton
population in the Bay of Fundy and Gulf of Maine with special reference
to production and distribution. J. Fish. Res. Board Can. 3(3) : 189-322.

Flagg, L. N. 1976. Alewife Management Plan. Maine Department of Marine
Resources, Hallowell, ME.

. 1979. Development of Anadromous Fish Resources. Research Ref. Doc.

79/5. Maine Department of Marine Resources.

Foye, R. E., C. F. Ritzi and R. P. AuClair. 1969. Fish management in the
Kennebec River. Maine Department of Inland Fisheries and Wildl. Fish.
Res. Bull. 8.

Fried, S. M. , and J. D. McCleave. 1973. Occurrence of the shortnose
sturgeon (Acipenser brevirostrum) , and endangered species, in Montsweag
Bay, Maine. Marine J. Fish. Res. Bd. Canada 30 (1973) :653-564.

Gibbs, K. E. 1977. Bibliography of Environmental Monitoring of Chemical
Control of Spruce Budworm in Maine, 1970-1977. Misc. Rept. 194.
Department of Entomology, University of Maine, Orono, ME.

Graham, J. J., and H. C. Boyar. 1965. Ecology of herring larvae in the
coastal waters of Maine. ICNAF Pub. No. 6; 625-634.

, S. B. Chenoweth, and C. W. Davis. 1972. Abundance, distribution,

movements, and lengths of larval herring along the western coast of the
Gulf of Maine. U.S. Nat. Mar. Fish. Serv. Fish. Bull. 70:307-321.

Greeley, J. R. 1937. Biological Survey of the Lower Hudson Watershed. New
vork State Conservation Department, Albany, NY.

11-52

Hauser, W. J. 1973. Larval Fish Ecology of the Sheepscot River- Montsweag
Bay Estuary, Maine. Ph.D. Dissertation, University of Maine, Orono, ME.
79pp.

. 1975. Occurrence of two Congridae leptocephali in an estuary. U.S.

Nat. Mar. Fish. Serv. Fish. Bull 73(2) : 444-445 .

Jones, J. R. E. 1964. Fish and River Pollution. Butterworth' s , London.

Lagler, K. F., J. E. Bardach, and R. R. Miller. 1962. Ichthyology. Wiley
and Sons, New York.

Langton, R. W. , and R. E. Bowman. 1978. Food Habits and Resource
Partitioning by Northwest Atlantic Gadiform Fishes. National Marine
Fisheries Service, Northern Fisheries Center, Woods Hole, MA.

Leim, A. H. , and W. B. Scott. 1966. Fishes of the Atlantic coast of Canada.
Fish. Res. Board Can. Bull. 155.

Lewis, R. 1979. An Analysis of Maine Landings. Research Reference Document
79/16. Maine Department of Marine Resources, Hallowell, ME.

Likens, G. E., and F. H. Bormann. 1974. Acid rain: a serious regional
environmental problem. Science 184(4142) : 1176-1179 .

Lyman, H. 1977. The 200-mile limit I: The New England Regional Fishery
Managment Council. Oceanus 20(3): 7-17.

MacKay, A. A., R. Bosien, and B. Wells. 1978. Bay of Fundy Resource
Inventory, 4 vols. Reference NB77, New Brunswick Department of
Fisheries, Fredericton, New Brunwick, Canada.

Maine Department of Inland Fisheries and Wildlife. 1976. Planning for
Maine's Fish and Wildlife Resources, vol. 7: Inland Fisheries. Augusta,
ME.

. MIDAS files on Maine lakes and fisheries, Augusta, ME.

Maine Yankee Atomic Power Company. 1970 to 1976. Environmental Surveillance
Reports and Studies at the Maine Yankee Nuclear Generating System,
Wiscasset, Maine. Maine Yankee Atomic Power Company, Augusta, ME.

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,
(formerly U.S. Fish and Wildlife Service Spec. Sci. Rept. Fish.) No. 398.

, 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
U.S. Fish and Wildlife Service Spec. Sci. Rept. Fish) No. 411.

, 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

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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 .

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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

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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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12-21

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/m2 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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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

REFERENCES

Abbott, R. T. 1974. American Seashells. Van Nostrand Reinhold Company, New
York.

Altobello, M. A., D. A. Storey, and J. M. Conrad. 1976. The Atlantic sea
scallop fishery: A descriptive and econometric analysis. Mass. Agric.
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Anthony, V. C, and S. H. Clark. 1978. A description of the northern shimp
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borealis , in the Gulf of Maine. Maine Department of Sea and Shore
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Atlantic States Marine Fisheries Commission. 1977. Northern Shrimp
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. 1967. The Sea Scallop (Placopecten magellanicus) . Fisheries

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Bass, N. R., and A. E. Brafield. 1972. The life cycle of the polychaete N.
virens. J. Mar. Biol. Assoc. Plymouth, England. 52:701-726.

Bigelow, H. B. , and W. C. Schroeder. 1939. Notes on the fauna above mud
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Boesch, D. F. 1971. Distribution and Structure of Benthic Communities in a
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Bourne, N. 1964. Scallops and the offshore fishery of the Maritimes. Fish.
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Bradley, W. H. , and P. Cooke. 1959. Living and Ancient Populations of the
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Clark, S. H. , and V. C. Anthony. 1977. An assessment of the northern shrimp
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Cobb, S. J. 1976. The American Lobster: The Biology of Homarus americanus .
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, and J. Ewart. 1978. Benthos (commercially important invertebrates).

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12-35

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12-36

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12-37

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12-38

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215.

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12-39

NOAA (National Oceanic and Atmospheric Administration) Tech. Rep. NMFS
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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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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 (lr79)
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

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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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Table 13-6. Principal Food Items (expressed as percentages in parenthesis) of
Marine Mammals in Maine Waters3

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°/0 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 1975a.

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 1976-1977 (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

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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
Capella gallinago
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 pusillus
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 chlororhynchos
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

0

Common eider

0

2

2

2

0

Greater black-backed

gull

2

2

2

2

2

Herring gull

2

2

2

2

2

Razorbill

0

0

2

2

2

Black guillemot

0

1

2

2

0

Leach's storm petrel

0

0

0

1

2

Double-crested cormorant

2

2

2

1

0

Laughing gull

0

2

2

1

0

Common tern

1

2

2

2

0

Roseate tern

0

1

1

1

0

Arctic tern

0

1

2

2

1

Least tern

0

2

2

1

0

Common puffin

0

0

1

1

1

Nonbreeding summer res:

Ldents

Wilson's storm petrel

0

0

0

2

2

Greater shearwater

0

0

1

2

2

Sooty Shearwater

0

0

0

1

2

Manx Shearwater

Fulmar „
w-CommonMurre
Migratory ^effidents

0
0
0

0

0
0

0

0

1

1

1
1

1

1
0

Gannet

0

0

1

2

2

Pomarine jaeger

0

0

0

1

2

Parasitic jaeger

0

0

0

1

2

Skua

0

0

0

0

1

Ring-billed gull

1

2

2

1

0

Black-headed gull

0

0

0

0

0

Bonaparte's gull

1

2

2

2

0

Little gull

0

0

0

0

0

Black tern

1

2

2

0

0

Winter residents

Common loon

2

2

2

1

0

Common eider

0

2

2

2

0

Greater black-backed

gull

2

2

2

2

2

Herring gull

2

2

2

2

2

Razorbill

0

0

2

2

2

Black guillemot

0

2

2

2

0

Red-throated loon

0

0

1

0

0

Red-necked grebe

0

0

1

1

0

(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

0

2

2

2

0

Northern fulmar

0

0

1

2

2

Great cormorant

0

1

2

2

0

Glaucous gull

0

1

1

1

Iceland gull

0

1

1

1

Black-legged kittiwake

0

1

2

2

Common murre

0

0

1

2

Thick-billed murre

0

0

1

2

Dovekie

0

0

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

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a.

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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
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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

aKorschgen 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

0

0

0

0

Red-throated loon

2

0

0

0

0

Red-necked grebe

0

0

2

0

0

Horned grebe

0

0

2

2

0

Pied-billed grebe

0

0

0

2

0

Double-crested cormorant

2

0

1

0

Common eider

0

0

2

0

Glaucous gull

0

0

0

2

Iceland gull

0

0

0

2

Great black-backed gull

0

0

0

2

Herring gull

0

0

0

2

Ring-billed gull

0

0

0

1

Black-headed gull

0

1

0

0

Laughing gull

2

1

0

1

Bonaparte's gull

0

1

0

1

Little gull

2

1

0

0

Common tern

2

0

1

1

1

Roseate tern

2

0

1

1

Least tern

2

0

0

0

0

Black tern

2

0

0

1

0

Onshore-Offshore

Great comorant

2

1

0

1

0

Arctic tern

2

1

0

1

1

Dovekie

1

0

2

1

0

Black guillemot

2

1

2

0

0

Offshore-Pelagic

Northern fulmar

0

0

2

0

2

Greater shearwater

2

2

2

0

0

Sooty shearwater

2

2

2

0

0

Manx shearwater

2

0

0

0

0

Leach's storm petrel

0

1

2

2

0

Wilson's storm petrel

1

2

2

2

0

Gannet

2

2

0

0

0

Pomarine jaeger

2

1

1

1

Parasitic jaeger

2

1

1

1

Skua

0

0

0

1

Black-legged kittiwake

2

2

1

0

Razorbill

2

(Cont

0
inued)

1

0

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

0

1

0

2

1

0

1

0

2

■ 0

0

0

0

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

0
2

0
0

2

2

2

0

0

0

1

0

2

2

2

0

2

2

2

0

0

1

1

0

2

2

2

0

1

1

1

0

2

2

2

0

1

2

2

0

0

1

1

0

2

2

2

0

0

1

1

0

1

0

2

0

1

1

2

0

2

2

2

0

0

1

1

0

2

2

2

0

0

0

0

0

0

1

1

0

1

2

2

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0 = 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

0

Piping plover

0

2

0

0

0

0

American golden plover

1

0

0

1

0

2

Black-bellied plover

2

2

1

0

1

0

Ruddy turnstone

1

2

0

0

2

0

Long-billed curlew

2

2

2

0

0

0

Whimbrel

2

2

2

0

0

2

Spotted sandpiper

1

2

2

2

2

2

Solitary sandpiper

1

1

2

2

0

1

Willet

2

2

2

0

0

1

Greater yellowlegs

2

2

2

2

0

1

Lesser yellowlegs

2

2

2

2

0

0

Red knot

2

2

0

0

0

0

Purple sandpiper

1

2

0

0

2

0

Least sandpiper

2

2

2

2

2

0

White-rumped sandpiper

1

2

0

0

0

1

Dunlin

2

2

1

0

1

0

Pectoral sandpiper

2

1

2

2

0

2

Short-billed dowitcher

2

0

2

1

0

1

Stilt sandpiper

2

0

2

0

0

0

Semipalmated sandpiper

2

1

2

1

0

0

Western sandpiper

2

2

2

0

0

0

Buff-breasted sandpiper

' 0

0

0

0

0

2

Marbled godwit

0

1

2

0

0

0

Hudsonian godwit

0

0

2

0

0

2

Ruff

0

0

1

0

0

1

Sander ling

1

1

0

0

1

0

Wilson's phalarope

1

0

2

0

0

0

Baird's sandpiper

1

1

0

0

0

1

Killdeer

1

0

2

2

0

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. Major fan Migration Periods of the Shorebirds of

Coastal Mainec

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

aModified 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

0

1

2

1

1

1

0

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

0

1

1

1

0

1

0

1

0

1

0

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 19775. ] ,

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

14-43

10-80

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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14-48

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14-50

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14-52

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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.

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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) .

15-14

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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 (170/0 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- consumptive 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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10-80

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.

16-2

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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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16-13

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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16-17

10-80

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

0

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. ?

5 0

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

0

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

0

0

0

0

6

57

111

100

57

Mourning dove

4

5

23

27

48

32

77

100

79

Pileated woodpecker

9

3

0

0

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

0

0

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

0

0

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 2970 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

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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 eagles Percentage Mature/Inmaturft

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 0
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 0 2 100 0

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 407o 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
potenfial 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

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16-52

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10-80

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Longfellow, G. 1876. Rogue Island wildlife. Forest and Stream 6:233.

Lyons, 0. P., L. W. Smith, T. G. Libby, G. Roberts, and D. H. Glidden. 1889.
A Brief Historical Sketch of the Town of Vinalhaven. Free Press Office,
Rockland, ME.

MacDonald, E. M. 1962. Bald eagle sighting file. Wildlife Resources,
University of Maine, Orono, ME.

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,
MT.

Mathisen, J. E. 1968. Effects of human disturbance on nesting of bald
eagles. J. Wildl. Manage. 32:1-6.

. 1979. Bald Eagle - Osprey Status Report. Chippewa National Forest.

U.S. Forest Service, Cass Lake, MN.

, D. L. Sorenson, L. D. Frenzel, and T. C. Dunstan. 1977. Management

strategy for bald eagles. Trans. N. Am. Wildl. Nat. Resour. Conf.
42:86-92.

Moorehead, W. K. 1922. A Report on the Archaeology of Maine. Andover Press,
Andover, MA.

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
bird populations. Auk 93:697-708.

Murton, R. K. , and N. J. Westwood. 1974. Some effects of agricultural change
on the avifauna. Br. Birds 67:41-69.

New England River Basins Commission. 1977. 1975 Assessment of Water and
Related Land Resources. Tech. Memo. 4, Boston, MA.

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.
Can. Wildl. Serv. , Fredericton, New Brunswick, Canada.

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
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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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Reitz, R. 1954. Birds meet with disaster at the Brunswick Naval Air Station.
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Robbins, C. S. 1970. Recommendations for an international standard for a
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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,
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, and F. J. Ligas. 1964. The 1963 bald eagle count. Audubon Mag.

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16-56

, W. B. Robertson, Jr., S. Postupalsky, R. J. Hensel, C. E. Knoder and F.

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, H. Crawford, and B. N Burgason. 1979. Songbird responses to

commercial clearcutting in Maine spruce-fir forests. J. Wildl. Manage.
43:602-609.

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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 Order3

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

aSpecies 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 Area3'"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

aNumbers in brackets are percentages of unit totals,
"Adapted from Anderson et al. 1975a.

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(?)

aGodin 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

f> a

1 <

rr i-

< LU

5 g

O
a
<

LU
2

co

Q

LT> —

Z> h-

cr q
i -i
f) O

H
OD

LU

rr
O

LL

W Q
UJ LJ.

O Uj

S £

03

Is

tl LU

O rr
LU o

Q U-

1—

i e

CO

o

LU H

t JS

Z LT
O O

O LL

_l

<

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
O

o
m

-CO

co a

co_j

rr i-

< LU

5g

co

o

Q
<

LU
5

Q

cr o

i -i
coO

p

CO
LU

oc

o

LL
LU "-j

St

co

it

y lu

OCT

LUO

1-

qCO

Is

co

o

LL CO

— LU

zrr

82

_l

<
rr

rx

z
<
m
rx

Z)

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

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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

0

•

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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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

0

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

0

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

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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 8a ' ' 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.
cCounts 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

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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.) 0 1 1 7 37 41 87 82

Otter (2 yr. avg.) 1 11 6 9 18 19 64 55

Coyote (1 yr.) 0 0 1 3 3 12 19 34

aMaine 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

aLavigne 1978b.

Table 17-8. Number of Moose Killed by Causes Other than Legal'Hunting in
Maine, 1969 to 1977a.

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

0

216

1971

95

57

41

12

0

205

1972

70

60

50

13

0

193

1973

139

84

27

20

0

270

1974

121

90

41

19

0

271

1975

115

94

33

6

1

249

1976

110

95

38

8

0

2 51

1977

93

130

58

15

1

297

Mean 102 82 41 14 <1 237

lLavigne 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 1977a

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

0

23

5

0

10

4

0

16

5

0

10

3

0

20

6

0

5

1

0

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
0

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

REFERENCES

Ambrose, H. W. III. 1972. Effect of habitat familiarity and toe-clipping on
rate of owl predation in Microtias pennsylvanicus . J. Mammal. 53:909-912.

Anderson, K. H., R. W. Boettger, L. E. Perry, and F. B. Hurley, Jr. 1975a.
Planning for Maine Fish and Wildlife Resources: Big Game. Maine
Department of Inland Fisheries and Wildlife, Augusta, Me. 1.

. 1975b. Planning for Maine Fish and Wildlife Resources: Upland Game.

Maine Department of Inland Fisheries and Wildlife, Augusta, Me. 2.

. 1975c. Planning for Maine Fish and Wildlife Resources: Upland

Furbearers. Maine Department of Inland Fisheries and Wildlife, Augusta,
ME. 4.

. 1975d. Planning for Maine Fish and Wildlife Resources: Aquatic

Furbearers. Maine Department of Inland Fisheries and Wildife, Augusta,
ME. 5.

Banasiak, C. F. , and R. Hugie. 1975. White-tail Deer Management Plan.
Unpublished manuscript. Maine Department of Inland Fisheries and
Wildlife, Augusta, ME.

Barrett, G. W. 1968. The effects of acute insecticide stress on a semi-
enclosed grassland ecosystem. Ecology 49:1019-1035.

Barnett, R. J. 1977. The effect of burial by squirrels on germination and
survival of oak and hickory nuts. Am. Midi. Nat. 98(2) : 319-330.

Buckner, C. H. and R. Sarrazin. 1975. Studies of the environmental impact
of the 1974 spruce budworm control operation in Quebec. Can. For. Serv.
Chem. Control Res. Inst. Rep. CC-X-93.

, B. B. McLeod, and D. G. H. Ray. 1973. The effect of operational

application of various insecticides on small forest birds and mammals.
Can. For. Serv. Chem. Control Res. Inst. Rep. CC-X-91.

, , and P. D. Kingsbury. 1975. Studies of the impact of the

carbamate insecticide Matacil on the components of forest ecosystems.
Can. For. Serv. Chem. Control Res. Inst. Rep. CC-X-91.

, , and T. A. Gochnaner. 1974. The impact of forest spraying on

populations of small forest songbirds, small mammals, and honeybees in
the Menjon Depot area of Quebec, 1973. Can. For. Serv. Chem. Control
Res. Inst. Rep. CC-X-84.

Burgason, B. N. 1977. Bird and Mammal Use of Old Commercial Clearcuts. M.S.
Thesis. University of Maine, Orono, ME.

Caslick, J. W. , and W. G. Smith. 1973. Effects of Dylox on white-footed
mice. Pages 67-75 in Marler, R. L. , Environmental Impact and Efficacy of
Dylox Used for Gypsy Moth Suppression in New York State. School of

17-34

10-80

Environmental Sciences Forestry, State University of New York at Oswego,

Oswego, NY.

Conner, P. F. 1960. A study of small mammals, birds and other wildlife in an
area sprayed with Sevin. N.Y. Fish Game J. 7:26-32.

Coulter, M. W. 1959. Some recent records of marten in Maine. Man and Nature
(formerly Maine Field Nat.) 15:50-53.

Craighead, J. J., and F. C. Craighead, Jr. 1969. Hawks, Owls, and Wildlife.
Dover, New York.

Crowell , K. L. 1973. Experimental zoogeography: Introduction of mice to
small islands. Am. Nat. 107:535-559.

, and S. L. Pimm. 1976. Competition and niche shifts of mice introduced
onto small islands. Oikos 27:251-258.

Day, B. W. , Jr. 1963. Winter Behavior of White-Tailed Deer in North-central
Maine. M.S. Thesis. University of Maine, Orono, ME.

Dimond, J. B., and J. A. Sherburne. 1969. Persistence of DDT in wild
populations of small mammals. Nature 221 (5179) : 486-487 .

Dunn, F. , C. F. Banasiak, and R. Hugie. 1975. Moose Management Plan.
Unpublished manuscript. Maine Department of Inland Fisheries and
Wildlife, Augusta, ME.

Errington, P. F. 1963. Muskrat Populations. Iowa State University Press,
Ames, IA.

Ferguson, R. H. , and N. P. Kingsley. 1972. The timber resources of Maine.
U. S. For. Serv. Res. Bull. NE-26.

Ferris, C. R. 1977. The Effects of Interstate 95 on Songbirds and White-
tailed Deer in Northern Maine. Ph.D. Thesis. University of Maine,
Orono, ME.

Gilbert, F. F. 1974. Paraelaphostrongylus tenuis in Maine, II: Prevalence
in moose. J. Wildl. Manage. 38:42-46.

Gill, D. , and P. A. Bonnet. 1973. Nature in the Urban Landscape: A Study of
City Ecosystems. York Press, Baltimore, MD.

Gill, J. D. 1957. Review of deer yard management, 1956. Game Div. Bull. 5.
Maine Department of Inland Fisheries and Wildlife, Augusta, ME.

Glasgow, L. L. 1949. A Winter Habitat Study of Deer in Maine. M.S. Thesis.
University of Maine, Orono, ME.

Godin. A. J. 1977. Wild Mammals of New England. John Hopkins University
Press, Baltimore and London.

17-35

Hugie, R., and C. F. Banasiak. 1975. Black Bear Management Plan.
Unpublished manuscript. Maine Department of Inland Fisheries and
Wildlife, Augusta, ME.

Hunt, J. H. 1975. Fox management plan in Anderson et al. Planning for
Maine's fish and wildlife resources. Vol. IV. Upland furbearers. Maine
Department of Inland Fisheries and Wildlife, Augusta, ME.

Keith, L. B. 1974. Some features of population dynamics in mammals. Proc.
Int. Cong. Game Biol. 11:17-58.

Lavigne, G. 1978a. Summary of 1977 Moose Mortalities. Unpublished
manuscript. Maine Department of Inland Fisheries and Wildlife, Augusta,
ME.

. 1978b. Mortalities Other Than Legal Kill. W-67-R-9. Maine

Department of Inland Fisheries and Wildlife, Augusta, ME.

Leedy, D. L., R. M. Maestro, and T. M. Franklin. 1978. Planning for Wildlife
in Cities and Suburbs. Biol. Serv. Prog. U. S. Fish Wildl. Serv., Dept .
of the Interior, Washington, DC.

Maine Department of Inland Fisheries and Wildife (MDIFW) . 1979. Big Game
Research Files. Located at University of Maine, Orono, ME.

Manville, R. H. 1942. Notes on the mammals of Mt. Desert Island, Maine. J.
Mammal. 23:391-398.

. 1960. Recent changes in the mammal fauna of Mt . Desert Island, Maine.

J. Mammal. 41:15-416.

. 1964. The vertebrate fauna of Isle au Haut, Maine. Am. Midi. Nat.

72:396-407.

Mech, L. D. 1966. The wolves of Isle Royale. U.S. Natl. Park Serv. Fauna
Natl, parks. U. S. Fauna Ser. 7.

Michael, E. D. 1975. Effects of Highways on Wildlife. Rep. WVD0H42 . West
Virginia Department of Highways, Charleston, WV.

Monthey, R. W. 1978. Relative Abundance of Mammals in Commercially Harvested
Forests in Maine. Ph.D. Thesis. University of Maine, Orono, ME.

Morse, D. H. 1966. Hog Island and its breeding vertebrate fauna. Man and
Nature (formerly Maine Field Nat.) 22:127-133.

Murie, A. 1944. The wolves of Mount McKinley. U.S. Natl. Park Serv. Fauna
Natl, parks. U.S. Fauna Ser. 5.

Oxley, D. J., M. B. Fenton, and G. R. Carmody. 1974. The effects of roads on
populations of small mammals. J. Appl. Ecol . 11:51-59.

17-36

10-80

Palman, D. S. 1977. Ecological Impact of Interstate 95 on Small and Medium-
sized Mammals in Northern Maine. M.S. Thesis. University of Maine,
Orono, ME.

Palmer, R. S. 1956. Gray fox on the northeast. Man and Nature (formerly
Maine Field Nat.) 12(3):62-70.

Pearson, 0. 1964. Carnivore-mouse predation: an example of its intensity
and bio-energetics. J. Mammals. 45:177-188.

Schemnitz, S. D. 1975. Marine island-mainland movements of white-tailed
deer. J. Mammal. 56:535-537.

Scholander, P. F., V. Walters, R. Hock, and L. Irving. 1950. Body insulation
of some artic and tropical mammals and birds. Biol. Bull. (Woods Hole)
99:225-236.

Schoultz, J. D. 1978. Habitat Use of Commercially Harvested Forests by Moose
in North Central Maine. M.S. Thesis. University of Maine, Orono, ME.

Schreiber, R. K. , and J. H. Graves. 1977. Powerline corridors as possible
barriers to the movements of small mammals. Am. Midi. Nat. 97:504-508.

Sherburne, J. A., and J. B. Dimond. 1969. DDT persistence in wild hares and
mink. J. Wildl. Manage. 33:944-948.

Soutiere, E. C. 1978. Effects of Timber Harvesting Upon the Marten. Ph.D.
Thesis. University of Maine, Orono, ME.

Stanton, D. C. 1960. Two recent occurrences of the gray fox. Man and Nature
(formerly Maine Field Nat.). 16:52-53.

Stehn, R. , and J. Stone. 1975. Impact on small mammals. Pages 123-171 in
Lake Ontario Environmental Laboratory, Environmental Impact Study of
Aerially Applied Orthene on a Forest and Aquatic Ecosystem. State
University of New York at Oswego, Oswego, NY.

Stone, T. L. 1977. Production and Utilization by Deer and Moose of Woody and
Herbaceous Vegetation on Areas Commercially Clearcut in Northern Maine.
M.S. Thesis. University of Maine, Orono, ME.

Tierson, W. C, E. F. Patric, and D. F. Behrend. 1966. Influence of white-
tailed deer on the logged northern hardwood forest. J. Forestry.
64:801-805.

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

aIncludes 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

Pa

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

aP=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
hern
k oa
ican
ican
pery

e

aple

pie

ir ch

rch

rch

ch

hornbeam

h ickor y

beech
h
h
h
t

liophornbeam
oplac

a spen
aspin
er ry
k

red oak
k
bast" wood
e lm
e In.

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Ju n i£er u s virg^iniana L.

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Li££§ abies (L.) Karst

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Ex ££§iH2§i Ait.

Ex liaili mil.

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Ex £XlX££££i£ (!•)

E§£li^2i£li3.§. 5i££zie£ii (fiirb.) Franco

Thuja Occident a lis L.

l£££a canadensis 1 •

Abies balsamea (L.) Mill.

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Lm. £acchar inum L-

Lm. £^ccharum Marsh.

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Ex £a.£I£i£££a Harsh.

Ex £2££i.i£2ii2 Harsh,

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£i£i£ £vata (Mill.) K. Koch

I^.3.H£ 2£and i f_olia Ehrh.

Fr a x__i n us americana L.

Ix £A2£a. Harsli.

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J.£2.I§££ cine re a L •

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E2££i££ £a±sam i f e r a L •

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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 Areac

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.

aAdapted 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.

Management 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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Figure 19-2.

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(curves corrected to breast-height age of 50) (Frothingham
1914).

19-20

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19-21

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 1979a

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 Maine1

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

n2

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 obtusum 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.

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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

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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.

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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 .

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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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. 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.

Seymour, F. C. 1969. The Flora of New England. Charles E. Tuttle Co.,
Rutland, VT.

Tyler, H. R. , and S. C. Gowler. 1980. The botanical aspects of Maine's
critical areas Program. Rhodora 82:207-225.

van der Pijl, L. , and C. H. Dobson. 1966. Orchid Flowers, Their Pollination
and Evolution. Univ. of Miami Press, Coral Gables, FL.

Wheary, E. T. 1928. Wildflowers of Mount Desert Island, Maine. Garden Club
of Mount Desert, Bar Harbor, ME.

Wise, D. A. 1970. The flora of Isle au Haut, Maine. Rhodora 72:505-532.

Worley, I. A. 1980a. Botanical and ecological aspects of coastal raised
peatlands in Maine and their relevance to the critical areas program of
the State Planning Office. Planning Report No. 69 (draft). Maine State
Planning Office, Augusta, ME.

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1980b . Shrub slope peatlands of Great Wass Island, Maine. In
preparation.

& U. S. GOVERNMENT PRINTING OFFICE: 1980 — 60 1-47 7--229

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