Full text of "Summary of aquatic studies on Bluewater Creek, Montana"

See other formats

SUMMARY OF AQUATIC STUDIES ON
BLUEWATER CREEK, MONTANA

Patrick E. Marcuson

Fish and Wildlife Biologist

i a r"li . I I :: •■: I <

Fishery Special Publication
Montana Department of Fish and Game
Red Lodge , Montana
February 1979

Federal Aid to Fish Restoration
Project F-20-R
Final Report

MBit DOCUMENTS COLLECTION

sep 1 1 mo

MONTANA STATE LIBRARY

930 E Lyndale Ave.

Helena, Montana 59801

Montana State Library

3 0864 1006 4079 9

TABLE OF CONTENTS

Page

ABSTRACT ' \

INTRODUCTION . ] * ] 1

BACKGROUND ...... 1

STUDY AREA . . . . . 2

METHODS 2

FINDINGS ......... 2

Chemical 2

Thermal 5

Fish composition 5

Aquatic plants 5

Aquatic fauna „ 5

Brown trout diets 9

Fecundity and spawning of brown trout 9

Emergence and survival 12

Population abundance of brown trout 12

Sex ratio 15

Fish harvest 15

Age and growth 16

Sediment study summary ... 16

Instream flow recommendations 19

DISCUSSION . . 20

APPENDIX ......... 24

List of Recognizable Insects Collected from Benthic

and Drift Samples Collected in Bluewater Creek 25

LITERATURE CITED ......... 26

ABSTRACT

Aquatic data collected on Bluewater Creek since 1959 was summarized. Bluewater
Creek was a chemically fertile spring creek with optimum water temperatures for wild
brown trout. Abundant aquatic plants and a diverse benthic fauna maintained stand-
ing crops of benthic organisms of 95 to 310 pounds/acre. Drift organisms moved into
brown trout feeding sites at a rate of 24 to 41 organisms/minute. Brown trout diets
suggest they were opportunists utilizing seasonally available foods. Brown trout
spawning season was from mid-October to the end of November. No Age-I females were
mature, but 82% of the Age-IT. and 100% Age-Ill females were mature. The average egg
complement was 325 eggs/female. Emergences took 60-70 days and February 1 best
describes the birthday of brown trout. Egg mortality was low in clean headwaters
and progressively increased as sediment concentrations increased. Browns were 0.6
inches at emergence.

The average seasonal biomass of brown trout was 261 pounds/acre in the spring
and 264 pounds/acre in the fall. Brown trout larger than 6 inches averaged 159 and
187 pounds/acre in spring and fall, respectively. Catchable-sized brown trout number
16,629 and 3,167 pounds in Bluewater Creek. Densities of catchable-sized fish fluc-
tuated least in the area where the majority of trout were harvested.

Sex ratio of brown trout was 1:1.3 males to females. Males dominated the Age-V+
fish. Total annual harvest of fish 6 inches and larger was 2,500 taken by 500 persons
averaging five fish per trip.

Of 4,292 known-age brown trout from 3-year classes, it was found that the 1973
year class lived 3 years, the 1972 year class lived 4 years and the 1969 year class
lived to their 7th year. Aging by the scale technique was invalid in Bluewater Creek
even though scales appeared typical of brown trout. Growth rates were poor. Fish
averaged 8.5 inches at 30 months of age, while Age-7 fish were only 2.3 inches longer.
Age-0 fish could be separated by length frequencies. Lengths of known-age trout over-
lapped as many as five age groups.

Nine years of stream sediment studies showed reduced carrying capacities with
increased sediment concentrations. Brown trout were most dramatically suppressed at
concentrations over 50 ppm and loads over 40 tons/day. Sediment reductions of 10 to
52% resulted, from three stream improvement projects.

Instream flow requests of 6,878, 18,823 and 14,479 acre-feet were made for three
stream reaches having average annual flow yields of 8,328, 20,502 and 31,974 acre-
feet, respectively.

INTRODUCTION

Bluewater Creek has been a focal point of aquatic study for years because of
accessibility, climate, proximity to two colleges and a university, a self-sustaining
trout fishery, land ownership and use patterns, a substantial spring source and
chemical fertility. Earliest studies centered on the potential of Bluewater Springs
as a water supply for the present Bluewater Springs Trout Hatchery. Specific stream
studies began in 1959. This report summarizes aquatic studies of unpublished data
and portions of research found in job progress reports, theses and publications.

BACKGROUND

An investigation of Bluewater Creek was initiated in 1959 to measure effects of
sediment, discharge and water temperatures on trout populations, bottom fauna and

trout egg incubation. Data from the stream sediment investigation was found in six
federal aid documents, D-J Job Progress Reports F-20-R-5 through F-20-R-15, Job Ill-a,
Marcuson (1966-197^. Bianchi (1963) reported the effects of sedimentation on egg
survival of rainbow and cutthroat trout. Peters (1967) described the influences of
sediment on a trout stream from agricultural practices and later (1971) on the effects
of sediment control on fish populations.

In 1969 Graham and Marcuson started, a study of production of brown trout in Blue-
water Creek. This study failed, statistically, but contributed considerable unpub-
lished detail regarding composition of brown trout. Two additional studies, a quanti-
tative examination of aquatic insects (Zillges, 1971) and a fecundity study (Lockard,
1974) were conducted as supplements to the production study.

Recent investigations include data collected to assist in the selection of ade-
quate instream discharges necessary for the maintenance of the fishery (Montana Fish
and Game Commission, 1976).

STUDY AREA

Bluewater Creek is an 18-mile spring creek meandering through semi-rough prairie
country in south central Montana. It is a tributary to the Clarks Fork of the Yellow-
stone River. Figure 1 shows the location of most of the intensive study sites.
Physical descriptors are presented in Table 1.

Bluewater Creek valley has a semi-arid climate with an annual average precipita-
tion of 10 inches. The average frost-free season is from May 19 to September 17.
Air temperature extremes are common. Temperatures as high as 108° F and as low as
-35° F were recorded,.

Salix and Betula occidentalis were abundant woody vegetation types along stream
banks in the upper half of the stream. Downstream, considerable woody vegetation had
been removed for intensive agricultural operations.

METHODS

This paper incorporates data collected, as part of several specific studies on
Bluewater Creek. Particular methodologies can be obtained, by examining documents
listed, in the Literature Cited section. Major emphasis involved seasonal collections
of brown trout with a 230-volt d-c powered electrofishing unit. Fish were measured
for total lengths, weighed, marked by various combinations of fin clips and returned
for subsequent recaptures. Permanent marks were applied, to all young-of-the-year
brown trout captured, in the 1969, 1972 and 1973 year classes and for a portion of the
1974 year class. Egg densities, scales and otoliths were collected from sacrificed
brown trout of known age.

Scales were collected in the usual manner and their plastic impressions were
magnified, with a Baush and Lomb projector for interpretation. Otolith interpretation
was attempted, by examination of fresh specimens and by cross sectioning, polishing
and staining preserved otoliths.

FINDINGS

Chemical

Analysis of chemical constituents was performed by technicians at the water
quality laboratory at Montana State University and by field, techniques used in the

- 2 -

1 I

Town of
Fromberg

t- Clarks Fork River
Station 5

Legend

County roads
Bluewater Creek

BLUEWATER CREEK
Carbon County

Station 4

-^-Yellowstone River

\clarks Fork River

Figure 1. Map of Bluewater Creek showing locations of sampling stations.

- 3 -

Table 1. Descriptive parameters for five stations on Bluewater Creek

Stations

'^^0

10.5

27.8

23.7

21.4

41.6

201

263

437

0.8

5.1

18.0

21.1

61.1

8.1

28.1

43.9

46.6

53.2

Mean width (ft.)
Gradient (ft. /mile)
Discharge (cfs)—

Sediment discharge (ppm)^ 71 201 263 437

1/
Sediment discharge (tons/day)—

2
Drainage area (miles )

— Average of 8 years of record.

4 -

various studies. Table 2 lists chemical parameters. As far as is known, Bluewater
Creek is more chemically fertile than any other stream in Montana.

Thermal

Water temperatures for three stations are summarized for 12 years of continuous
records in Table 3. With the exception of small amounts of surface runoff, Bluewater
Creek derives its water from spring flows which hold a constant temperature of 56° F.
Water temperatures change upward or downward depending upon atmospheric conditions
and become more variable as the distance from the spring source increases. Ice
formation does not occur, regardless of the severity and duration of freezing atmos-
pheric conditions, until the water flows at least 10 miles from its spring source.
Water near the mouth undergoes the greatest annual temperature fluctuation.

Fish Composition

Brown trout (Salmo trutta) dominated the fish occupying the upper half of the
creek. Browns have been sampled in low numbers in lower stream reaches; however,
their distribution was such that they are significant in the stream from headwaters
to one-half mile below Station 4.

An occasional rainbow trout (Salmo gairdneri) and on one sampling occasion a few
kokanee (Oncorhynchus nerka) were sampled near Bluewater Springs Trout Hatchery.
These fish were escapees from this rearing station and no natural reproduction was
evident.

People who have lived along the stream 50 or more years remember when cutthroat
trout (Salmo clarki) was the only trout species in Bluewater Creek. Hatchery person-
nel recall catching an occasional cutthroat during the 1930' s. The majority of their
catch was an equal number of brook trout (Salvelinus fontinalis) and brown trout.
No brook trout have been observed since initiation of aquatic research on the creek.

The lower half of the stream contained large numbers of suckers and minnows.
The following include an approximate ranking of abundance of fish other than trout
in Bluewater Creek: longnose dace (Rhinichthys cataractae) , flathead chub (Hybopsis
gracilis) , mountain sucker (Catostomus platyrhynchus) , white sucker (Catostomus
catostomus) , carp (Cyprinus carpio) , mountain whitef ish (Prospium williamsoni) and
shorthead redhorse (Moxo stoma macro lepido turn) .

Aquatic Plants

The upper half of Bluewater Creek had abundant growths of water cress (Rorippa
nasturtium-aquaticum) , Berula erecta and horned pondweed. (Zannichellia) . Nearly all
the undisturbed stream banks had some degree of rooted aquatics. Duckweed. (Spirodela
and Limna) , Chara, Vaucheria, and unidentified moss and. a leafty liverwort were
common. Vegetation existed year-round in the headwaters reaching maximum densities
in early summer. Stream velocities, depths and excellent cover for small trout are
provided by areas of this vegetation. Cladophora was the only common aquatic plant
in the lower portion of stream.

Aquatic Fauna

Seventy-four benthic samples were collected with a Surber sampler along Blue-
water Creek. The average number of organisms per square foot are presented in Table
4. Those forms typical of unpolluted waters were found in the upper stream reaches.

As the collections proceeded downstream, the fauna became less diversified and
was dominated by diptera and aquatic worms. A list of recognizable species is in
the appendix.

Based on total wet weights of 19 of the 74 benthic samples, it was estimated
that the standing crop of bottom fauna ranged from 95 to 310 pounds per acre. Benthic

- 5 -

Table 2. Range and mean chemical values at two stations on Bluewater Creek

Alkalinity (ppm CaC03)
range
mean

Dissolved oxygen (ppm)
range

mean

94. - 220

210

7,8 - 10.8
8.7

101 - 252
212.

8.0 - 10.4

range

Total hardness (ppm CaCOo)
range
mean

Conductivity (Umhos)
range
mean

Silica (ppm)
range
mean

Phosphate (P)

Sodium (Na+)

Potassium (K )

Sulfate (S04=)

Nitrogen (N03_N)

Chloride (ppm)

Fluoride (ppm)

7.6 - 8,

280

- 750

451

721

- 938

825

,2 - 12.4

11.2

.01

5.52

1.96

25.8

.312

2.20

1.12

6.6

480 - 1,050

850

812
1

122

2,650

0 -

12.
,4

.02

,87

.42

.8
.409

.45

.19

Table 3. Monthly mean maximum, minimum and mean temperature (F. ) in Bluewater
Creek for 12 years of record at 3 stations

Stations

min.

mean

max.

min.

mean

max.

min.

mean

max.

January

February

March

April

May

June

July

August

September

October

November

December

Table 4. Number of benthic invertebrates per square foot collected at five
stations on Bluewater Creek

Numb

ar Per Square

Foot

Classification

Stations

Amphipoda

Oligochaeta

170

Ephemeroptera

116

Plecoptera

Coleoptera

Tricoptera

175

122

Diptera

136

Mollusca

Others

Totals

339

291

225

247

193

fauna was the lowest during late October and November and highest during March and
April.

Zillges (1971) collected 15 day and 15 night drift samples at Stations 2 and 5.
Over four times more drift occurred at night. May flies, primarily Baetis parvus,
were the major drifting form at Station 5. Station 2 also had large numbers of
drifting May flies (Ephemerella inermis and Baecis) . Stone flies (Isoperla spp.),
Chironomids and Simulium also consistuted major drifting forms in Bluewater Creek;
however, stone flies were a minor item at Station 5.

Table 5 is an abbreviated presentation of Zillges findings on drift forms. My
calculations of Zillges data revealed that the average number of aquatic insects
drifting by Station 2 was 41 per minute compared to 24 per minute at Station 5. The
orders in Table 5 are listed by magnitude for both stations combined; however,
variability between sites was common. The only organism collected in larger numbers
downstream was the caddis fly (Hydropsyche sp.).

Certain aquatic organisms like dragonflies and scuds were readily observed in
upper Bluewater Creek, but rarely captured and quantified. These forms are typical
of aquatic plant communities, undercut banks and debris habitats. In a similar
stream in Minnesota, Waters (1965) found that the scud (Gamma rus limnaeus) was a
primary drift species. Gammarus was commonly observed in Bluewater and in brown
trout stomachs, but was never captured in 30 drift samples and only rarely captured
in benthic collections.

Brown Trout Diets

Stomach contents were examined for numerous brown trout taken during different
seasons. It appears that these fish were opportunists, taking a variety of food
organisms. Their intake paralleled seasonal sources. Trout eggs were common food
for brown trout during spawning season, juvenile trout were consumed during the
emergence period, terrestrial insects dominated during summer and early fall and
aquatic forms were consumed on a regular basis . Food does not appear to be limiting
to fish in Bluewater except possibly for the months of October and November. These
months revealed the lowest numbers of available aquatic forms, terrestrial items were
rare and sexual aggressiveness of brown trout precluded eating or searching out food.
During the spawning season, stomachs often contain burrowing benthic organisms and
trout eggs not commonly observed during other seasons. Those forms dislodged from
the substrate during redd construction were typically small organisms of insignifi-
cant weight. Shrimp (Gammarus) were found in stomach contents, but to a lesser degree
than the more available May flies, stone flies and caddis flies.

Fecundity and Spawning of Brown Trout

Spawning activity became evident by mid-October and most brown trout discharged
sexual products by the end of November. The peak spawning activity occurred the
second week of November. Samples of fish from December through January revealed an
occasional yearling as small as 3.5 inches. This causes speculation that some spawn-
ing occurred later than the end of November. With mean water temperatures of 53 F
in October, 52° F in November, 50° F in December and 51° F in January at Station 1,
it seemed reasonable that the spawning period could be very lengthy. However, no
normal adult females were found with sexual products during December through February
collections. Temperature patterns of the upper two stations during the spawning
season are presented in Figure 2.

In 1974 Lockard compared fecundity of female brown trout with stream fertility
in 17 Montana streams. Fish from Bluewater Creek, the most chemically fertile of
the waters studied, were least fecund. Lockard resolved that chemical fertility of
streams is generally related to age at sexual maturity and fecundity of brown trout
except in fish from Bluewater Creek. His findings were similar to McFadden, Cooper

- 9 -

I-1
o

M
4-1
W

Figure 2,

56 T

55 -■

53 ■-

52 ■■

51 ■■

Spawning

Peak of Spawning
Activity

Spawning
Ends

Station 1

10 15 20
October

30 1

15 20

November

Mean daily temperatures averaged over 5 years of record for the months of October and November at 2
stations on Bluewater Creek.

(

Table 5. Numbers and volumes (cc) of insects from drift samples on Bluewater Creek

Classification

Day Drift
2 5

^tat

ions

Night Drift
2 5

Dominate Species

Ephemeroptera

Unid. pupae
Diptera

Plecoptera

Trichoptera

Coleoptera

Odonata

45.1
(t)

51.5

(t)

121.8 40.3

595.9

(2.7)

384.8
(0.6)

117.9 44.0

34.8

56.6

47.9

63.4

(t)

11.0

1.0

156.6

4.5

(t)

(1.0)

(t)

12.2

9.8

34.9

54.1

(t)

(0.2,

(0.3)

16.7

1.9

44.3

5.1

(t)

1.5

■

(0.2)

241.6

161.1

997.5

555.4

(t)

(3.9)

(1.2)

Baetis parvus
Ephemerella inermis

Chironomidae
Simulium arcticum

Isoperla spp.

Hydropsyche sp,

Optioservus ovalis
Helichus striatus

Ophiogomphus

Totals

- Volumes in parenthesis - t = trace.

11 -

and Anderson (1965) where in Pennsylvania brown trout from infertile waters had a
smaller proportion of mature fish per age class and a smaller weight of eggs than
comparable fish fr^.a fertile waters. Lockard concluded that "Bluewater Creek fish
attained sexual maturity much earlier than fish from less fertile streams; however,
these fish from the chemically most fertile stream had the poorest growth rates of
all the fish studied."

Since aging fish in Bluewater Creek by the scale technique was not reliable, I
felt that Lockard may have underestimated the age of some of the small females in
the creek. To test Lockard ' s findings I sacrificed 200 known-age females of the
1974 year class as I's in 1975, II ' s in 1976 and Ill's in 1977. I found no Age-I
females mature, but did note a small number of mature males. Females of Age-II
were 82% mature and all Age III females were found to be mature.

Table 6 presents egg complements of Age-II and III females from known-age brown
trout at two stations. The 187. immature Age-II females were typically smaller fish.

Emergence and Survival

February 1 was considered the birthdate for brown trout in Bluewater Creek.
Based on electrofishing, redd excavation and egg development in plastic vials, it was
found that the earliest emergers escaped the gravels in early January and most were
out by early February at Station 1 r,nd by mid-February at Station 2. The average
water temperature at Station 1 was 52° F during incubation period; however, water
temperatures were 5° F cooler 6 inches within the substrate. It took an average of
60 days to emergence. At Station 2, the average water temperature during incubation
was 48 F and 43° F around the eggs. Average time to emergence was 72 days.

Bianchi (1963) experimented with survival of eggs of rainbow and cutthroat trout
placed in artificial redds at five stations along Bluewater Creek. Egg mortalities
for rainbow trout were 67, 92, 97 , 99 and 997» for Stations 1-5, respectively, and 43,
94, 98, 100 and 877= for cutthroat trout eggs from Stations 1-5. In 1969 sediment
control measures had reduced sediment loads by 32% at Station 2 and 52% at Station 3.
Juvenile brown trout were noted farther downstream than previously observed; however,
egg survival experiments were not repeated. It was assumed that egg survival was
considerably improved at Stations 2 and 3.

Juvenile browns averaged .6 inches at emergence. By mid -March the average length
of both early and late emergers was 2.1 inches.

Population Abundance of Brown Trout

To best describe the population of brown trout in Bluewater Creek, I averaged
28 population estimates collected at three stations over all seasons for 6 years -
1969 to 1975. These average standing crops were further grouped to include fish
above and below 6 inches (Table 7).

Figures for fish less than 6 inches do not include the most prolific size group
of newly emerged juveniles during spring sampling periods. These juveniles are
represented 7 months later in fall samples (Table 7). An accumulation of 2,000
juvenile brown trout are required to increase the biomass by 1 pound. An average
acre of brown trout water in Bluewater Creek contains 76,781 juveniles or 38 pounds.
The above estimate was based on 929 reproducing size fish per acre, 1.3:1 ratio of
females to males, an average egg complement of 325 eggs per female and an egg to
emergence survival rate of 45%.

Not counting the juvenile population each spring, the average spring standing
crop of all brown trout was 223 pounds/acre compared to 264 pounds/acre average for
fall. If 38 pounds/acre was a realistic estimate of juveniles, then the spring and

- 12 -

Table 6. Egg complement of Age II and III females from 119 known-age brown trout
at Station 1 and 2, Bluewater Creek

STATION 1
Age Group

STATION 2
Age Group

III

Mean egg count
Range of eggs counted
Number of females
Mean length of females
Length range of females
Mean weight of females
Weight range of females

218

319

329

436

52-412

72-713

162-534

82-839

7.9

8.2

9.3

6.3-9

5.8-10

7.8-11

6.6-12.2

.17

.22

.31

.32

.09-

.06-.

.16-.

.10-. 68

13 -

Table 7. Brown trout abundance of Bluewater Creek averaged over 6 years, 1969-
1975

Less Than 6 Inches—

6 Inches and Larger

Number/acre (spring).?/
Number/acre (fall)
Pounds/acre (spring).?/
Pounds/acre (fall)
Number/1,000 feet
Pounds/1,000 feet
Yearly number/acre
Yearly pounds/acre
Number/mile

Pounds /mile

3/
Number/ stream-
Pounds /stream

2,298

2,398

603

2,319

3,184

100

39,791

1,254

917
937
159
187
253
48
929
175

1,336

253

16,629

3,167

fish.

Standard deviations were considerably higher than for 6 inch and larger

- Spring numbers do not include juveniles - only yearling and older fish

under 6 inches.

Based on 65,988 feet of brown trout waters,

- 14 -

fall biomasses were about equal. The catchable-sized fish over 6 inches contributed
159 pounds/acre in the spring and 187 pounds/acre average in the fall.

The condition factor (CF = W/LJ x 10 ) of yearling and older brown trout progres-
sively increased downstream from 34.6 to 37.1. The condition of these fish was
slightly higher in the fall (35.7) than in the spring (35.4). Vincent (1977) reported
condition factors in the mid-40 ' s for brown trout in the Madison River.

The number and weight of catchable 6-inch and larger brown trout in Bluewater
Creek was calculated at 16,629 fish and 3,167 pounds (Table 7). Examination of
numbers of 6-inch and larger fish occurring each season at each station divulged a
range of 548 to 1,521 fish per acre.

A comparison of catchable-sized fish/acre at Station 1 disclosed a low population
density of 373 in the spring and 549 in the fall of 1973. Other than this density
change of 176 fish/acre, the population of 6-inch and larger fish remained close to
480 fish/acre.

An electrofishing section between Stations 1 and 2 had a low of 1,020 catchable
fish/acre to a high of 1,521 fish/acre. This 501 density fluctuation was separated
by 4 years and reflected a low spring density and a high fall density. The mean
density of catchable-sized brown trout in this area was 1,176 fish/acre. This sam-
pling area was on private land where no fishing was allowed.

The 6-year mean number of 6-inch aud larger fish at Station 2 was 1,129 fish/
acre. The density of these fish ranged from 584 to 1,285 fish. The low 584 fish/
acre occurred in the fall of 1970. The next lowest population estimate of 6-inch plus
fish per acre was 788 in the spring of 1975. The typical fluctuation of catchable-
sized fish, disregarding the two extremes above, was within 150 fish of the 1,129 fish/
acre mean. This portion of the brown trout fishery received the majority of the
angling pressure on Bluewater Creek.

Sex Ratio

Yearling and older brown trout are easily sexed by the curvature of the anal fin
method described by Gruchy and Vladykov (1968). The method was found valid in Blue-
water Creek. Sexes of 8,600 fish collected at Stations 1 and 2 kindled a ratio of
1.3 females per male. Sex ratio of 819 known-age brown trout was dominated, by females
through Age Group IV. Among fish V and older, males surpassed females 3 to 1.

Fish Harvest

Creel census designed to produce total harvest estimates was never conducted on
Bluewater Creek. Total harvest of fish was estimated by combining results of random
creel checks, observations of fishermen by hatchery and management personnel and
discussions with landowners. The vast majority of the fishing pressure occurred on
state owned land near the hatchery. No fishermen were ever observed or reported by
landowners along lower reaches of Bluewater. Several areas under private ownership
were essentially closed, to fishing.

Bluewater Creek was open year-long and received fishermen mostly from the Bridger-
Fromberg area. Most fishing occurred during the spring and fall. The area had a
reputation for abundant rattlesnakes which discouraged fishing during the hottest
season. The majority of the fishermen were retired persons.

The Bluewater area averaged one car per day with a 1.5 fisherman per car average.
They caught an average of five fish per trip over 6 inches in length. Considerably
more fish less than 6 inches were captured, but were returned voluntarily for larger
fish. Total annual harvest was estimated at 2,500 fish over 6 inches in length.

- 15 -

With the exception of a few hatchery reared rainbow trout, the anglers harvested wild
brown trout.

Age and Growth

Aging brown trout by the scale method was performed by Peters (1971) for Blue-
water fish. He found, no significant differences of growth rates between stations
which were subjected to increased degrees of sediment loads. Peters assigned overall
lengths to the last annulus as follows: Age I - 3.9 inches, II - 6.6, III - 9.7;
older fish scales were not readable.

Graham and I also reviewed scales from brown trout in Bluewater Creek and
arrived at growth interpretations (unpublished), but both of us agreed, that we were
influenced by length frequency and that scale interpretation was not self-evident.
As a part of an attempted production study, we permanently marked juveniles of the
1969, 1972 and. 1973 year classes and recorded progress of these fish at each recap-
ture until none remained in the population. Data collected from three mark and.
recapture sections has been combined with three year classes (Figures 3 and 4).

A total of 4,292 juveniles of the 1969, 1972 and 1973 year classes were marked
in early September. Emerging fish were not marked until 7 months of age to lessen
chances of mortality and for ease of handling and better recruitment to electrofish-
ing gear for population estimates. An unexplained decline in both length and weight
occurred between Age II fish captured in the fall and Age III fish captured the
following spring. A similar decline occurred between Age IV and Age V fish. It was
obvious that such declines were impossible for specific individuals, but the possi-
bility of sampling smaller individuals within a population could be real. This
exemplified the disadvantage of using marks other than those identifying individuals.

The last individuals of the 1969 year class were captured in mid-September 1975
as VI' s. Only three marked fish of the 197 2 year class were captured in October of
1976 as Age Group IV and of 1,294 juveniles ol the 1973 year class only 22 were recap-
tured beyond Age II; the last three were captured, at 44 months of age. No explain-
able reasons were evident to account for the loss of the 1972 and 1973 year classes.

Examination of Figures 3 and 4 show not only poor growth of fish, but a large
degree of overlap of sizes among age groups. For example, the smallest Age IV fish
falls within the size ranges of every age group to Age I. Only Age 0 fish separated,
from the others in a length-frequency distribution.

Growth of known-age fish in the fall was Age 0-3.6 inches, I - 7.0, II - 8.5,
III - 8.5, IV - 9.3, V - no fall fish and IV - 10.8 inches and Age 0 - .03 pounds,
I - .14, II - .22, III - .24, IV - .32, V - no fall fish and VI - .52 pounds. Except
for the first 30 months of age, the brown trout living 6 years only grew 2.3 inches
and .30 pounds. Fall to spring sampling revealed little overwinter growth despite
water temperatures in the low 50 's for most of the trout producing water. Following
spawning season, fish in Bluewater Creek tend to become snakey in appearance and
remain so until early spring. I'm sure a production study would reveal negative
values during a portion of this period.

When scales were examined from fish of known-age, I was able to achieve the
following interpretation of readable scales: 100% - Age 0, 63% - I, 59% - II, 36% -
III, 10% - IV and 0% on all older fish. Otoliths from numerous known-age fish were
examined as fresh, stained, cut and polished specimens without meaningful results.
The only reliable aging technique for brown trout in Bluewater Creek appears to be
known-age measurements of individually identifiable fish.

Sediment Study Summary

The first 6 /~=»rs (1961-1966) of the stream sediment investigation involved

- 16 -

^1
I

o
a

00
C

Age III Age IV
{— — l

24 30 36 42 48 54 60
Age in Months and Age Group

Age V Age VI
66 72 78 84

Figure 3. Age and growth in length of known-age brown trout of three year classes averaged for three sections,
Bluewater Creek,

CO'

1.10 T

1.00 ■■

Age III Age IV
„{ — .—~_^— ^_ ■!_.. -}_ _ ^_

36 42 48 54 60

Age V

Age In Months and Age Group

Figure 4. Age and growth in weight of known-age brown trout of three year classes for three sections, Bluewater
Creek.

(

comparisons of fish species abundance and distribution with suspended sediment con-
centrations, discharge and water temperature. Sediment loads which are a measure
of sediment concentrations and discharge averaged 0.7 tons per day in the headwaters
and progressively increased to a mean of 75.8 tons per day near the mouth. As a
result of irrigation withdrawals and warmed return flows, lower reaches of Bluewater
Creek underwent wide ranges of temperature fluctuations. Brown trout numbers
decreased progressively downstream as the aquatic environment deteriorated. The
first 6 years of study documented the detrimental effects of sediment on trout.

The nature of the study was then altered to evaluate major factors causing sedi-
mentation in Bluewater Creek and take corrective steps to reduce this silt load.
Three improvement projects were undertaken in the spring of 1966. A pipeline was
installed to control erosion from a waste water ditch. Several hundred feet of
eroded stream bank were lined with rock and as a part of the fishing access program,
approximately 100 acres involving % mile of stream were fenced to restrict access by
cattle.

Continued evaluation of the silt content in Bluewater Creek suggested that the
improvements were effective in reducing silt loads. The average sediment load
figured on 48 months of data collected prior to improvements was 6 tons per day at
the sampling station immediately downstream from the improvements (Station 2). The
average load at this station was reduced to 4.1 tons per day based on 28 months of
record after improvements. This represents a 3270 reduction of sediment load. At
Station 3, a 52% reduction occurred and at Station 4, suspended sediments were
reduced 44% - calculated, over the 28 months of record.

Response of the fishery to the improved water quality was obvious to the inves-
tigator, but did, not statistically show a significant response. Lack of statistical
response might be explainable when one considers natural fluctuations of various
year classes. Apparently many years and many year classes are needed to accurately
assess responses of a population to subtle changes in the environment (see discussion,
also Hunt, 1966 and Chapman, 1965). This investigator noted that following reduc-
tions of sediment loads, there were juvenile brown trout farther downstream than
previously observed, and that large brown trout were more abundant at Station 4 than
previously noted (Marcuson, 1967).

A positive response of brown trout to sediment reductions was with the percent-
age ratio of total weight of trout to rough fish of 39:61 before (1963) compared to
78:22 after (1968) stream improvements. Six miles farther downstream (Station 4)
the trout: rough fish ratio was 12:88 before compared to 51:49 after improvements.

The stream sediment investigation was completed in 1970. Observations and subse-
quent measurements indicated additional discharge of approximately 6 cfs after 1970.
This additional flow was due to additional flows collected for hatchery operation.
Sediment loads responded upward with these flow increases and from intensified agri-
cultural operations upstream. Increased loads, however, do not appear to be anywhere
near the magnitude common prior to the improvement projects.

Stream sediment problems can be effectively reduced; however, land use changes
often diminish or negate the results over time. Earlier discussion on sediment find-
ings alluded to the precent reduction based on 28 months after stream improvements.
Suspended sediment monitoring was discontinued in 1970, 52 months after improvements.
By this time, Station 2 had a 20% suspended sediment reduction, Station 3 had a 107»
reduction and Station 4 had a 14% reduction compared to reductions of 32, 52 and 44%

C after 28 months at Stations 2, 3 and 4, respectively.

Instream Flow Recommendations

Due to irrigation practices and type of agriculture along Bluewater Creek, three

- 19 -

reaches were picked to best characterize flow regimes. These three reaches (upper,
middle and lower Bluewater) are described in unpublished form (Marcuson, 1976) on
file at the State 'c Montana, Department of Fish and Game office in Billings.

The 9-year mean monthly discharge was 11 cfs, 28 cfs and 44 cfs for the upper,
middle and lower sections, respectively. Discharge at the middle section averaged
34 cfs at the time this report was compiled, due to additional discharge from Blue-
water Springs Trout Hatchery. Historic flow measurements were measured, over the
9-year period at the five sediment stations and reflected existing agricultural use.

Bluewater Creek has special need for flow maintenance in that it is one of the
few rich prairie spring creeks. It is also a focal point of activity for wildlife,
livestock, recreation and human occupation in this semiarid area. The recommended
flows presented in Table 8 are considered necessary for maintenance of the fishery
and allows for additional water for future agricultural expansion.

Major consideration was for adequate flows in the upper and middle trout produc-
ing sections. The upper section has little opportunities for intensifying agricul-
tural operations. The request of 9.5 cfs is 1.5 cfs less than mean flows. The
middle section requires 26 cfs to minimize sediment deposition and. is 8 cfs less
than the new (since 1970) mean discharge. The mean monthly flow in lower Bluewater
for 9 years of record was 44 cfs, thus 24 cfs or 55% of the annual discharge is
available for future agricultural expansion in the area where enlarging the agricul-
tural base is most feasible.

DISCUSSION

A good trout fishery is the result of a combination of many ecological features.
Adequate water precedes all needs, thus instream flow requests are essential to Blue- ^
water's fishery. Secondly, trout need water of good quality. The chemical fertility
of Bluewater Creek was well established; its major deterent to quality water was
silt pollution from agricultural practices. The sediment study fortified knowledge
of the detrimental effects of sediment to trout and. also established, that suspended
sediments could be effectively reduced even in highly erodable country. It was also
learned that an improved stream will need continued surveillance to retain a new
improved status. With Bluewater Creek, improved water quality opened, the door for
new agricultural developments and subsequently new sediment sources. The possibility
of new contamination is always a threat and will have to be contended with on a case-
by-case basis. Besides treating sources of sediment, I feel the most effective means
of maintaining quality water is through good land management techniques, efficient
water use and. maintaining good stream bank vegetative cover. Stream bank cover
provides an effective sediment filter, trapping rich silts where vegetative matter
quickly establishes.

Numerous researchers documented, reduced carrying capacity of trout in lotic
waters because of high sediment concentrations (Sanders and Smith, 1965; Herbert, et
al., 1961; Condone and Kelly, 1961; Doudoroff, 1957; Hynes, 1960 and Wallen, 1957).
Unfortunately, the quantity of sediment capable of harming an environment has never
been firmly established for various fish species. The contention of this author is
that sediment acted as the agent responsible for the demise of cutthroat trout and
indirectly for the brook trout in Bluewater Creek.

Brown trout in Bluewater Creek were found in far fewer numbers where sediment
sustained high concentration levels. Like most fish these brown trout tolerated
extremely high sediment discharge for short periods of time without noticeable harm.
Populations of brown trout in Bluewater Creek were greatly diminished at concentra-
tions over 50 ppm and loads over 40 tons per day.

- 20 -

( C1

Table 8. Recommended flows for three sections of Bluewater Creek

___»««___«»___. 2/
Sept. Oct. Nov. Dec, Total-

Upper cfs 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5

AF 584 528 584 565 584 565 584 584 565 584 565 584 6,878

( 8,328)

Middle-'cfs 26 26 26 26 26 26 26 26 26 26 26 26

AF 1,599 1,444 1,599 1,547 1,599 1,547 1,599 1,599 1,547 1,599 1,547 1,599 18,823

(20,502)
i
S3 Lower cfs 20 20 20 20 20 20 20 20 20 20 20 20

AF 1,230 1,111 1,230 1,190 1,230 1,190 1,230 1,230 1,190 1,230 1,190 1,230 14,479

(31,974)

- Does not include additional 6 cfs since 1970.

- Number in parentheses is the 9-year average annual yield,

It was the feeling of researchers on Bluewater Creek that the amount of sediment
settling on the streambed. over time was closely related to numbers, age structure,
species composition and biomass of fish populations. For sediment standards, it
would be beneficial to quantify sediment loads with deposition rates. Meaningful
standards would consider silt deposition during incubation periods of trout eggs.

Fishermen using Bluewater Creek seem satisfied with fishing. Brown trout have
been harvested at a rate of 2,500 fish by 500 anglers since 1970. Most of this
harvest was from a stretch of accessible stream less than 1 mile in length (Station
2) out of 12.5 miles of brown trout water. This particular site maintained the
highest number of catchable sized fish, the largest mean sized fish and the most
stable density of fish 6 inches and longer among the sampling sites. Densities of
6-inch and larger brown trout fluctuated more from the 6-year mean density in areas
where little or no angling occurred. Regulations of ten fish daily and a season
open 365 days per year were generous and with low fishing pressure appeared to be
grossly underutilizing this resource.

It is my opinion that a spring stream as rich as Bluewater Creek and with opti-
mum water temperatures for trout growth, should yield considerably more large fish.
An acre of trout water produced an average 929 fish over 6 inches in length (175
pounds) per acre, but the mean length of brown trout only reached 10.8 inches, .52
pounds as 6-year-old fish, 9.2 inches, .30 pounds as 5-year olds and smaller. The
creek produced some large individuals (largest trout was 22.1 inches, 3,75 pounds),
but some year classes died before they reached 9 inches and .25 pounds. The loss of
2 year classes^' eliminated 4 and 5-year old brown trout from Bluewater Creek in 1975.
This loss occurred in areas of no fishing as well as areas with fishing.

I do not know whether losses of year classes are common phenomenons in wild
fisheries or an unusual event; however, fluctuations in population density are com-
monly reported. McFadden (1961, 1967) and Hunt (1966) reported numerical variations
and differing biomass contributions of numerous year classes in the same stream
sections. It seems reasonable that these fluctuations in density are expected and
that management interpretations based on short-term population changes should be
carefully scrutinized.

Aquatic organisms in Bluewater Creek were more diversified than that found in
brown trout diets. Besides diversity of food organisms, large numbers of aquatic
organisms commonly utilized as brown trout food were readily available. Drifting
foods also appeared readily available. Waters (1965) noted that quantitative
relationships between drift rates and population density on the stream bottom have
not been determined. He noted, that drift forms may originate 50-60 meters upstream
and. that physical nature of the stream, upstream from the drift site, influenced
drift composition and density.

In Bluewater Creek the major aquatic foods consumed by brown trout were organ-
isms typical of the drift community. For the most productive trout water, there
were 40 organisms per minute entering the feeding stations downstream from riffles.
It appeared that aquatic food was more than adequate to feed, fish in Bluewater Creek
not counting allochthonous foods available from spring to fall.

Where water chemistry, temperature, habitat, food, etc. appeared ideal for
trout production, the trout population was high, fish harvest was low yet growth was

- All permanently marked members of the 1972 and 1973 year classes from three
sampling sections were no longer sampled nor were their unmarked cohorts recognized.

- 22 -

^gy

poor. It appears that a spatial problem might well exist. Chapman (1962) suggested
that spatial limitations act as density regulators in coho, forcing less aggressive
fish to emigrate. He also found that feeding of coho in excess did not alter hold-
ing capacity of st'°aij aquaria. Since it appeared that food was not limiting, I
felt that crowding of fish in Bluewater Creek had lessened growth potential.

Manipulating seasons and catches at low fishing intensities will not allow ade-
quate population reductions to see if there would be a positive growth response.
Assuming that harvest rate remained nearly constant, then additional population
reductions by more controllable means would best test the growth/density hypothesis.
In the event more research be undertaken on Bluewater Creek, I would urge manipulat-
ing population size of brown trout and if positive responses are not realized, then
I would attempt manipulation of the genetic pool by introducing new stocks of brown
trout.

APPENDIX

List of Recognizable Insects Collected from Benthic
and Drift Samples Collected in Bluewater Creek

Coleoptera

Agabus sp.
Bidessus af finis
Deronectes griseostriatus
Dineutus sp.
Elmidae
Enochrus sp.
Gyrinus bifarius
Haliplus strigatus
Haliplus borealis
Helichus striatus
Hydroporus sp.
Laceophilus maculosus
Optioservus ovalis
Peltodytes callosus
Tropisternus sp.

Diptera

Cecidomyiidae
Chironomidae
Dicranota sp.
Dixa sp.
Empididae
Euparyphus sp.
Fannia sp.
Heme rod romiinae
Hexatoma sp.
Lispoides aequifrons
Pericoma sp.
Phaenicia sericata
Simulium arcticum
Sphaerophoria sp.
Tetanocera sp.
Tipula sp.

Ephemeroptera

Bertis parvus
Choroterpes albiannulata
Ephemerella inermis
Heptagenia elegantula
Tricorythodes minutus

Odonata

Ophiogomphus sp.

Plecoptera

Acroneuria sp.
Isogenus sp.
Isoperla spp.
Kathroperla sp.
Nemoura sp.

Trichoptera

Brachycentrus sp.
Hydropsyche sp.
Ochrotrichia sp.
Rhyacophila acropedes

LITERATURE CITED

Bianchi, D. R. 1963. The effects of sedimentation on egg survival of rainbow
trout and cutthroat trout. MS thesis. Mont. State Univ., Bozeman, Mont.
28 pp.

Chapman, D. W. 1965. Net production of juvenile coho salmon in three Oregon
streams. Trans. Amer. Fish. Soc. 94(1): 40-52.

1962. Agressive behavior in juvenile coho salmon as a cause of

emigration. J. Fish Res. Bd. Canada 19: 1, 047- 1,080.

Condone, A. J. and D. W. Kelley. 1961. The influences of inorganic sediment on
the aquatic lift of streams. Calif. Fish and Game, 47(2): 189-228.

Doudoroff, P. 1957. Water quality requirements of fishes and the effects of toxic
substances, pp. 403-430* In the Physiology of Fishes. Vol. II (Ed. M. E.
Brown) Academic Press., N. Y. 526 pp.

Gruchys C. G. and V. D. Vladykov. 1968. Sexual dimorphism in anal fin of brown
trout, Salmo trutta, and close relatives. J. Fish Res. Bd. Canada 25(4)-
813-815.

Herbert, D. W. M. , J. S. Alabaster, M. C. Dart, and R. Lloyd. 1961. The effect of
china clay wastes on trout streams. Int. J. Air Wat. Poll., 5(1): 56-74.

Hunt, R. L. 1966. Production and angler harvest of wild brook trout in Lawrence
Creek, Wisconsin. Wisconsin Conservation Dept. Technical Bulletin, No. 35.
52 pp.

Hynes, H. B. N. 1960. The biology of polluted water. The Univ. Press, Liverpool.
366 pp.

Lockard, L. L. 1974. Some environmental influences on egg production in brown
trout (Salmo trutta) from Montana streams. MS thesis. Mont. State Univ.,
Bozeman, Mont. 28 pp.

Marcuson, P. E. 1966. Stream sediment investigation. Mont. Dept. of Fish and
Game, Job Progress Rpt. F-20-R-10, Job H-a, mult. 6 pp.

1966. Stream sediment investigation,, Mont. Dept. of Fish and Game,

Job Progress Rpt. F-20-R-11, Job Il-a, mult. 7 pp.

1967. Stream sediment investigation. Mont. Dept. of Fish and Game.

Job Progress Rpt. F-20-R-12, Job Il-a, mult. 9 pp.

1968. Stream sediment investigation. Mont. Dept. of Fish and Game,

Job Progress Rpt. F-20-R-13s Job n-a, mult. 10 pp.

1969. Stream sediment investigation. Mont. Dept. of Fish and Game,

Job Progress Rpt. F-20-R-14, Job Il-a, mult. 8 pp.

1970. Stream sediment investigation. Mont. Dept. of Fish and Game,

Job Progress Rpt. F-20-R-15, Job n-a, mult. 7 pp.

- 26

McFadden, J. T. 1961. A population study of the brook trout, Salvelinus fontinalis.
Wildl. Monogr., No. 7.

McFadden, J. T., F I. Cooper and J. K. Anderson. 1965. Some effects of environ-
ment on egg production in brown trout (Salmo trutta) . Limn, and Ocean. 10(1):
88-95.

1967. Numerical changes and population regulation in brook trout,

Salvelinus fontinalis. J. Fish. Res. Bd. Canada 24(7): 1,425-1,459.

Mont. Fish and Game Commission. 1976. Application for reservation of water in the
Yellowstone River basin. Helena, Mont. 300 pp.

Peters, J. C. 1967. Effects on a trout stream of sediment from agricultural
practices. J. Wildl. Mgmt. 31(4): 805-812.

1971. Effects of sediment control on fish populations. Ph. D thesis

Colo. State Univ., Fort Collins, Colo. 86 pp.

Sanders, J. W. , and M. W. Smith. 1965. Changes in a stream population of trout
associated with increased silt. J. Fish Res. Bd. Canada 22(2): 395-404.

Vincent, E. R. 1977. Madison River temperature study. Mont. Dept. of Fish and Game,
Job Progress Rpt. F-9-R-25, Job H-a, mult. 10 pp.

Wallen, I. E. 1951. The direct effect of turbidity on fishes. Bull. Oklahoma Agric.
Mech. College, Stillwater. Oklahoma Arts and Science Studies. Biol. Ser. 2,
48(2): 1-27.

Waters, T. F. 1965. Interpretation of invertebrate drift in streams. Ecology
46(3): 327-333.

Zillges, G. F. Jr. 1971. The aquatic insects of Bluewater Creek, Montana, above
and below an area of intensive agriculture. MS thesis. Mont. State Univ.,
Bozeman, Mont. 29 pp.

- 27

„

o
o

u
0

d
o

■mmI

Internet Archive Audio

Featured

Top

Images

Featured

Top

Software

Featured

Top

Books

Featured

Top

Video

Featured

Top

Mobile Apps

Browser Extensions

Archive-It Subscription

Save Page Now

Full text of "Summary of aquatic studies on Bluewater Creek, Montana"

See other formats