EPA-R3-73-006
APRIL 1973
Ecological Research Series
Effects of Logging on Growth
of Juvenile Coho Salmon
Office of Research and Monitoring
U.S. Environmental Protection Agency
Washington, D.C. 20460
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Monitoring, Environmental Protection Agency, have
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This report has been assigned to the ECOLOGICAL
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provides the technical basis for setting standards
to minimize undesirable changes in living
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EPA-R3-73-006
April 1973
EFFECTS OF LOGGING ON GROWTH OF
JUVENILE COHO SALMON
Paul M. Iwanaga and James D. Hall
Department of Fisheries and Wildlife
Oregon State University
Corvallis, Oregon 97331
Project 18050 FKT
Project Officer
Walter Preston
Office of Research and Monitoring
Washington^ D.Co 20460
Prepared for
OFFICE OF RESEARCH AND MONITORING
oSo ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20^60
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402
Price 75 cents domestic postpaid or 60 cents GPO Bookstore
-------
EPA Review Notice
This report has been reviewed by the Environmental
Protection Agency and approved for publication.
Approval does not signify that the contents necessarily
reflect the views and policies of the Environmental
Protection Agency, nor does mention of trade names
or commercial products constitute endorsement or
recommendation for use.
ii
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ABSTRACT
The objective of this research was to study the effects of increased
water temperature characteristic of clearcut watersheds of Pacific
coastal streams upon the growth rate of juvenile coho salmon. The
natural temperature fluctuations of the stream were used in the
study of growth of underyearling fish held in aquariums and fed at
various consumption levels.
Juvenile coho experiencing the cooler temperatures of the control
stream demonstrated generally better growth rates than did those
that experienced the warmer temperatures of the clearcut stream.
The reduced maintenance requirements in the control experiment
indicated a reduced basal metabolic demand, which allowed for a
greater portion of the food consumed to be utilized for growth.
This was particularly true at low levels of consumption.
Growth rates of juvenile coho salmon in the wild state were found
to be slightly higher in the clearcut stream as compared to the
unlogged stream. This difference from the experimental results may
have been due to a change in availability and abundance of food.
There was a marked decrease in the cutthroat trout population in the
clearcut stream, which may have reduced competition for the coho
salmon. There was no apparent influence of infestation by "salmon
poisoning" fluke on the condition of the juvenile coho in the
clearcut stream.
This report was submitted in fulfillment of Grant Nos. WP 423-06
(part) and 18050FKT under the sponsorship of the Environmental
Protection Agency.
ill
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CONTENTS
Section
I Introduction 1
II Materials and Methods 5
III Results and Interpretation 11
IV Acknowledgments 31
V References 33
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FIGURES
1 Map of the study watersheds 3
2 Temperature pattern on the days of the annual
maximum recorded on the clearcut and uncut control
watersheds before (1965), during (1966), and after
(1967-1969) logging 9
3 Relationship between growth rate and consumption
rate of coho from the clearcut and control streams 1?
4 Relationship between mean temperature and change
in weight of coho at starvation and 2 and 4
percent rations in the control stream .13
5 Relationship between mean temperature and change
in weight of coho at starvation and 4 and 8
percent rations in the clearcut stream 14
6 Relationship between diel temperature fluctuation
and change in weight of coho at starvation and
2 and 4 percent rations in the control stream 15
7 Relationship between diel temperature fluctuation
and change in weight of coho at starvation and
4 and 8 percent rations in the clearcut stream 16
8 Relationship of consumption rate and growth rate
to mean temperature of coho on repletion rations
in the control stream 18
9 Relationship of consumption rate and growth rate
to mean temperature of coho on repletion rations
in the clearcut stream 19
10 Relation between coefficient of condition and the
number of cysts in juvenile coho salmon from three
coastal streams 26
11 Change in mean length of juvenile coho from
Needle Branch (clearcut) and Flynn Creek (control)
before logging 27
VI
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FIGURES (continued)
12 Change in mean length of juvenile coho from
Needle Branch (clearcut) and Flynn Creek
(control) after logging 28
vii
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TABLES
No.
Stream temperature (°C) experiences of the
juvenile coho from the control and clearcut
watersheds 10
Comparison of growth rate in paired experiments
with similar mean temperatures and/or diel
temperature fluctuations 22
Lengths, weights, and cyst infestation of
juvenile coho salmon 25
VI11
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SECTION I
INTRODUCTION
Lumbering is Oregon's major industry. Because of the extent of its
operation, timber harvest can create serious problems for coho sal-
mon populations utilizing headwater tributaries for spawning and
rearing areas. Besides siltation and stream blockage by debris,
clearcut logging can cause significant increases in water tempera-
ture during the summer, when streamflow is low. Loss of streamside
cover allows direct sunlight to strike the water surface, causing more
radiant energy to be absorbed (Brown, 1970). Temperatures as high as
30 C and diel fluctuations as much as 16 C have been recorded from
small clearcut streams (Brown and Krygier, 1970). The effect of such
temperature variations on fish must be better understood so steps can
be taken to harvest the timber with the minimum amount of damage
to the salmon populations.
The objective of this research was to study the effects of increased
water temperature characteristic of clearcut watersheds upon the growth
rate of juvenile coho salmon. To accomplish this, studies of food
consumption and growth rate similar to those described by Warren and
Davis (1967) were conducted during the critical summer period.
Temperature exerts a significant influence upon the life history of
coho salmon. In addition to affecting food utilization and growth,
stream temperatures also can retard or accelerate the hatching and
emergence of fry, and, in extremes, cause mortality. Temperature
can also influence juvenile coho populations by increasing or
decreasing their food resource and by making conditions more or less
favorable for competing species.
Many animals exhibit a particular range of temperature that is
optimal for growth. Temperature affects metabolism such that increased
cost of maintenance at higher temperature reduces the efficiency at
which an animal utilizes a given amount of food consumed for growth
(Warren and Davis, 1967). Optimum temperature for growth increases
with ration size (Brett, Shelbourn, and Shoop, 1969). This optimum
could be associated with the action of enzymes, which themselves
demonstrate an optimum temperature for activity (Bell, Davidson,
and Scarborough, 1968). There is also a seasonal variation in
metabolism in some fishes, metabolism being usually higher during
winter than summer (Bullock, 1955; Wells, 1935).
There has been little research on the effects of large natural
fluctuations in diel temperature on the growth or survival of fish.
Almost all work on temperature effects has been conducted at constant
temperature or has involved sudden temperature shock. Mortalities
-------
due to temperature extremes are. a function of both temperature and
exposure time (Brett, 1952). Exposures of fish to different tempera-
tures above their lethal level, without intervals of sublethal
temperature, were found to be cumulative in causing mortality (Fry,
Hart, and Walker, 1946). Fry et^ al. (1946) did demonstrate that
acclimation to higher temperature occurred if the fish were allowed
periodic exposures to sublethal temperatures. Likewise, experiments
with rabbits revealed that a few hours of cooling each day offset
the lethal effects of high temperatures (Ogle and Mills, 1933).
Although increased acclimation temperature resulted in increased
upper temperature tolerances for the opossum shrimp, Neomysis
awatschensis, it also resulted in decreased tolerances to rapid
temperature changes, occurring within a 1-hour period (Hair, 1971) .
Maximum temperatures of 30 C were recorded for short periods during
the days of maximum diel temperature fluctuations in a small Oregon
stream under intensive study following clearcut logging (Brown and
Krygier, 1970). These high temperatures, above the 25 C upper lethal
temperature for juvenile coho (Brett, 1952), may produce mortality,
or cause fish to move to cooler portions of the stream. The cool
night temperatures may have a buffering effect upon the high daytime
temperatures by providing a recovery period and, thus, allow the coho
to survive. The amplitude of the diel temperature fluctuation
gradually increased from early spring to late summer, perhaps allowing
the fish to acclimate to the rapidly changing diel temperatures as well
as the high maximum temperatures. This research was designed to
provide additional information on the fate of salmon in small tributaries
such as those that exhibit such large daily temperature variations as
a result of clearcut logging.
The research was carried out on tributaries of Drift Creek, which
flows into the Alsea Bay near Waldport, Oregon. Work was concentrated
on two streams, Deer Creek and Needle Branch, which drain watersheds
of 304 hectares and 75 hectares, respectively (Figure 1). These
watersheds are subjects of a 15-year study on the effects of logging
practices on water quality and fish resources (Hall and Lantz, 1969).
In 1966, after seven years of pre-logging study, the Needle Branch
watershed was completely clearcut and burned. Deer Creek was
partially clearcut. Three patches involving about 30 percent of the
watershed were cut, and a strip of vegetation was left along the
streambank. The streams have upstream downstream fish traps and
were provided with stations for measurements of such environmental
parameters as temperature, streamflow, and sediment load.
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DEER CREEK
FLYNN CREEK
FISH TRAP
FOREST SERVICE ROAD
LABORATORY
STREAM
STREAM GAGE
LOGGING UNIT
THERMOGRAPH
ALSEA WATERSHED STUDY
mNEWPORT
TOLEDO
Figure 1. Map of the study watersheds
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SECTION II
MATERIALS AND METHODS
Wild underyearling coho salmon of uniform size (50 to 65 mm) were
fed standardized rations during exposure to the high fluctuating
temperatures of the clearcut stream. The resultant food consumption
and growth rates were compared to those of fish fed at similar rates,
but exposed to the cooler and more stable temperatures of the shaded
stream. Water was taken directly from the two streams to utilize
the natural temperature regime.
Fish were held in individual compartments in two types of aquariums.
The first experiment made use of styrofoam cooler boxes that were
divided with plexiglass into four compartments (19 x 19 x 20 cm deep).
Four of these aquariums were used at each stream. Interchange of
water occurred between compartments of each aquarium, but no inter-
change of food was allowed. The remaining experiments were carried
out in plexiglass aquariums which were divided into eight compartments,
Each compartment (15 x 25 x 20 cm deep) had its own water inlet and
outflow, allowing no interchange of water or food. Two of these
aquariums were used on each stream.
Water was piped from a pool above the fish trap and delivered to
each compartment in the aquarium via a system of tygon tubing. The
inlet water was passed through a cloth filter, and the aquarium tops
were screened to keep natural food from reaching the fish. The
temperature in one cell of each aquarium was recorded with a Partlow
thermograph and was also periodically checked with an accurate hand
thermometer.
The rations for the experiment consisted entirely of larvae of the
common house fly (Musca domestica) hatched in gallon jars of
artificial media. The larvae were separated from the media, placed
in aluminum pans, and frozen in water.
Rations used were as follows: 1) starvation, 2) estimated mainten-
ance, 3) twice the estimated maintenance, and 4) repletion. This
design resulted in higher rations being fed to fish in the clearcut
stream, based on an estimate of the increased maintenance ration
that would be required as a result of the higher temperatures there.
The fish in the clearcut stream were fed at 4 (maintenance) and
8 percent of body weight as compared to 2 (maintenance) and 4 percent
in the control stream.
During the first three experiments, rations were fed according to
percentage of initial body weight and were weighed out daily from
the supply of frozen larvae. The procedure was changed for the last
-------
three experiments to reduce weighing error. The 2-week ration for
each" fish was weighed and divided into 14 approximately equal parts,
frozen, and fed to the coho each day. This method also reduced some
of the daily routine of weighing larvae.
Rations of coho fed to repletion were calculated by multiplying the
number of larvae eaten by the average weight of the larvae. Groups
of 25 to 30 larvae of uniform size were weighed to determine average
weight and frozen in an aluminum pan. The pan was numbered and one
pan of larvae used per day for each fish on a repletion ration.
For simplicity, the fish will be referred to in the discussion by
their ration size, estimated on the basis of initial wet weight (i.e.,
2, 4, and 8 percent). However, in the figures, feeding levels are
expressed in terms of the average dry weight equivalents. Because
of growth of the fish during the experiment and the fact that the
food had a lower percent dry weight than did the fish, actual feeding
rates that resulted were approximately 15, 30, and 55 mg/g/day,
respectively.
Juvenile coho were taken from the study streams and held in the
aquariums for 1 week before each experiment was begun. Sixteen fish
out of 28 that began the acclimation period were used at each stream.
The compartmentalized aquariums were divided in half to temporarily
hold the 28 fish for acclimation. The coho were weighed, measured,
and fed a ration that they would receive during the experiment. The
fish scheduled to be on starvation during the experiment were fed
the maintenance ration. For the last 3 days of the acclimation
period, all fish were observed closely. Those chosen for the
experiment were the ones that fed readily and ate all their ration.
The fish were first anesthetized in tricaine methane sulfonate
(MS 222) and measured to the nearest 0.5 mm. They were then damp
dried and weighed to the nearest 0.001 gm. At the end of the experi-
ment dry weights were measured after the coho had been in a drying
oven (65 - 70 C) for 3 to 5 days and in a dessicator for another
2 days.
The parameters of consumption rate, growth rate, and gross efficiency
were those used by Warren and Davis (1967) and were based upon dry
weight. The dry weight of food consumed was determined by multiplying
the consumption by the average percentage dry weight of several
samples of larvae. The initial dry weight of the fish was estimated by
multiplying the initial wet weight times the percentage dry weight at
the final weighing.
A small sample of fish was sacrificed at the beginning of several
experiments. Based on a comparison of the percentage dry weight of
these fish and those measured at the end of the experiments, it was
assumed that there was no change in percentage dry weight of the
-------
fed fish, during the feeding experiments. The initial dry weights for
the starved coho were determined by using the average percentage dry
weight of the fish on maintenance rations, since it is known that
starvation affects this parameter. The average of the initial and
final dry weight was then used in the following computations:
Consumption rate * total consumption (mg)/average weight (g)
14 days (length of experiment)
Growth rate = growth (mg)/average weight (g)
14 days
~ ,-,- - total growth (mg)
Gross efficiency = . . 1 s 2- r ^
J total consumption (mg)
The coefficient of condition (K) was used to express the well being
(relative robustness) of the fish in numerical terms. Changes in
K reflect changes in the relationship between length (L) and weight
00 = v Wxl05
K. = ~
The integral mean temperature (referred to as mean temperature) was
calculated for each day and was derived as follows:
1 T vft") dt
Integral mean temperature = = ~/ '
T = 24 hours
t = 2 hours
y = temperature
Temperatures were taken from thermograph charts at 2-hour intervals
for each 24-hour period. The integral mean temperatures were averaged
for each experiment. The arithmetic mean of daily maxima and minima
was used to determine the mean diel fluctuation.
The decision to use naturally fluctuating temperatures in the study
streams caused difficulties in interpretation of the results because
of unusual weather conditions and rapid regrowth of vegetation on
the clearcut stream. The summer of 1968 (experiments 1, 2, and 3)
proved to be unusually cloudy and wet, particularly after August 12.
There was an overall trend of decreasing instead of increasing
water temperatures from July through September. The wet conditions
also increased the turbidity of the water for much of the second and
third experiments. Normal dry weather conditions prevailed during
the summer of 1969 (experiments 4,5, and 6). Stream temperatures
followed the normal increasing trend through August followed by a
decreasing trend in September. Turbidity was not much of a problem,
except during an occasional summer rain.
7
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Needle Branch, underwent a progressive change in streamside vegetation
from 1967 to 1969. The vegetation w.as relatively low during the summer
of 1968, allowing direct exposure of the stream to sunlight for most
of its length.. The following summer th.e alder (Alnus rubra) grew
extensively, resulting in almost complete shading of the entire stream.
This shading considerably moderated the high temperatures that had
been experienced in the previous 2 years (Figure 2). To partially
compensate for this, vegetation was cleared along a short stretch
of stream immediately above the fish trap. This allowed more direct
sunlight to strike the stream and maintain the higher temperatures
more nearly representative of the years immediately following logging,
although they were still substantially lower than those during 1967.
The undisturbed control stream (Flynn Creek) was not regularly
accessible during the summers of 1968 and 1969 because of road con-
struction. Thus the patch-cut stream (Deer Creek) was used as a
control in 1968. Although there was not a significant increase in
the temperature of the main stream (Brown and Krygier, 1970) ,
exposure of the stream water to solar radiation in the pond immed-
iately above the fish trap resulted in a significantly higher
temperature fluctuation than that of Flynn Creek. In 1969, the
control was moved to the laboratory, where a small shaded stream
was used as the water supply, resulting in water temperatures more
closely representative of those in the undisturbed control (Table 1).
-------
- ' ' I I I I I I I ' ' I
80
tr
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uj
o
70
ŁT
UJ
0.
2
UJ
60
50 -
1967
I I96D
y....-- -
Ť ť _ .ť__ _
^rTr^^r^*^**^
CONTROL
1965-1969
I
I
I
I
6 12 18
HOUR (PST)
24
Figure 2. Temperature pattern on the days of the annual maximum
recorded on the clearcut and uncut control watersheds before (1965),
during (1966), and after (1967-1969) logging. (From Brown and
Krygier, 1970)
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TABLE 1. Stream temperature f°C) experiences of the juvenile coho from the control and clearcut
watersheds.
CONTROL
Exp, No.
1
2
3
4
5
6
19
16
11
11
8
5
Date
July-1 Aug. 1968
Aug. -29 Aug.
Sept. -24 Sept
July-24 July
Aug. -21 Aug.
Sept. -18 Sept
1968
. 1968
1969
1969
. 1969
Mean
Temp.
14.5
13.4
11.9
10.8
11.4
10.8
Mean
Diel
Fluct.
4.2
1.4
1.8
2.6
2.3
1.5
Range
9.4-17
10.6-14
9.7-14
8.4-14
8.4-13
8.4-12
.5
.4
.4
.4
.9
.4
Mean
Temp.
17.3
14.6
13.6
15.0
15.4
14.8
CLEARCUT
Mean
Diel
Fluct .
6.8
2.6
3.2
7.6
7.6
9.0
Range
11
11
10
9
10
7
.1-22.5
.6-17.5
.6-18.4
.7-22.2
.0-23.9
.8-25.6
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SECTION III
RESULTS AND INTERPRETATION
Growth Rates of Juvenile Coho Salmon
From Shaded and Unshaded Streams.
Juvenile coho salmon experiencing the cooler temperatures of the
control s-tream were generally found to grow more rapidly than did
those that were held in the warmer temperatures of the clearcut
stream (Figure 3). The reduced maintenance requirements of control
fish probably resulted from a reduced basal metabolic demand allowing
a greater portion of the food consumed to be utilized for growth.
This was particularly true at low levels of consumption.
In several experiments, coho at the higher food consumption levels
in the clearcut stream had growth rates approaching or surpassing
those of the control stream. The clearcut stream may have provided
the necessary increased water temperature to complement the higher
rations. An increased optimum temperature for growth with an
increased ration is consistent with results reported by Brett et_ al.
(1969) . However, these results at higher food consumption levels
may not apply to many situations in nature, in light of information
regarding the low feeding levels of wild fish, based on caloric
values as an index to level of nutrition (Warren and Davis, 1967).
Caloric values of wild coho under natural feeding conditions were
similar to those of experimental juvenile coho on low feeding rations
(L. Everson, unpublished data, Department of Fisheries and Wildlife,
Oregon State University). Such evidence for a low feeding rate in
nature would suggest an overall detrimental effect of increased
temperatures upon growth, providing that food availability remained
unchanged.
Effects of Temperature Levels
Within the Streams
The design of the experiment was not well suited for analysis of the
effect on growth rate of the relatively small differences in mean
temperature encountered within a stream. In addition, daily tempera-
ture fluctuations probably had at least as significant an effect on
growth rate as did the small differences in mean temperature among
the experiments (Figures 4, 5, 6, and 7). However, further analysis
of the data may give some additional information that may help us to
understand the effects of increased temperature on growth.
1.1
-------
-10
-20
O CONTROL STREAM
D CLEARCUT STREAM -2Q
-30
-JO
0 20 . 40 60 80 100 120 0 20 40 60 80
Exp. 5
O
-20 I
0 - 20 40 60 80
Exp. 3
O a
-20
30
-20
0 20 40 60 80 0 20 40 60 80 100
CONSUMPTION RATE MG/G/DAY
Figure 3. Relationship between growth rate and consumption rate
of coho from the clearcut and control streams. Curves fitted by
inspection.
12
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Starvation
-10
D
T>
-20
01
\-
CT>
-30
A
A
8
H
2 Percent
10
4 Percent
o
oc
-10
10
O
O
Q_
MEAN
12 13
TEMPERATURE
14
15
Figure 4. Relationship between mean temperature and change in
weight of coho at starvation and 2 and 4 percent rations in the
control stream. Curves fitted by inspection. Symbol and mean
temperature fluctuation (in parenthesis) for each experiment:
O Exp. 1 (4.2 C)
A Exp. 2 (1.4 C)
D Exp. 3 (1.8 C)
Exp. 4 (2.6 C)
Exp. 5 (2.3 C)
Exp. 6 (1.5 C)
1.3
-------
0
-10
Starvation
T)
-20
en
-30
Percent
oc
-10
8 Percent
o
-------
0
-10
Starvation
IP
TJ
TD
O
CC
O
2 Percent
10
0
IO
g
^
2 D
D
A
I
4 Percent
10
Ag
AB u
A H
D
B
4-B ^fi
^
A g
A Q O
A y
o
01 2345
DIEL TEMPERATURE FLUCTUATION °C
Figure 6. Relationship between diel temperature fluctuation and
change in weight of coho at starvation and 2 and 4 percent rations
in the control stream. Curves fitted by inspection. Symbols and
mean temperatures (in parenthesis) for each experiment:
O Exp. 1 (14.5 C)
A Exp. 2 (13.4 C)
D Exp. 3 (11.9 C)
Q Exp. 4 (10.8 C)
A Exp. 5 (11.4 C)
H Exp. 6 (10.8 C)
IS
-------
Starvation
en
en
E
0
-10
-20
-30
LJ
4 Percent
-10
8 Percent
20
5
o
a: 10
o
0
345678
DIEL TEMPERATURE FLUCTUATION °C
Figure 7. Relationship between diel temperature fluctuation and
change in weight of coho at starvation and 4 and 8 percent rations
in the clearcut stream. Curves fitted by inspection. Symbols and
mean temperatures (in parenthesis) for each experiment:
O Exp. 1 (17.3 C)
A Exp. 2 (14.6 C)
D Exp. 3 (13.6 C)
O Exp. 4 (15.0 C)
A Exp. 5 (15.4 C)
U Exp. 6 (14.8 C)
16
-------
The vari.ati.ons in mean temperature experienced in each successive
experiment within a given stream did not consistently influence growth
rates QFigures 4 and 5). In the control experiment, with a mean
temperature range from 10,8 to 14,5 C, there was considerable vari-
ability, but no indication of a relationship between growth rate and
temperature, either at the 2 or the 4 percent feeding levels (Figure
4). In the clearcut stream, with a range in mean temperature from
13.6 to 17.3 C, there was some indication of an optimum temperature
range for growth (Mgu^6 5) . The optimum range was approximately
the same for fish on 4 and 8 percent rations. Since these fish were
fed a fixed ration, any increase in growth, rate within a range of
temperature must have been due to a more efficient utilization of
energy consumed.
The relationship between growth and diel fluctuation was different
between fish from the control and the clearcut streams. The growth of
the coho fry from the control stream remained relatively unchanged
with increasing temperature fluctuations (Figure 6).
The higher temperature fluctuations in the clearcut stream, however,
were associated with a slightly increased growth rate (Figure 7).
At the higher fluctuations (6 - 9C) the starved fish lost an
increasing amount of weight. The higher diel fluctuations may have
increased the efficiency of food utilization in a manner similar to
that of an optimum temperature range for growth. We could speculate
that further increases in temperature fluctuations would ultimately
result in a decreased growth rate. The increased weight loss of the
starved fish may be attributed to an increased drain on body reserves
to meet the increased metabolic demand.
The fish on repletion rations ate different amounts, thus evaluating
growth rates directly without considering consumption levels would
be meaningless. Increasing mean temperatures (10.8 to 14.5 C) in the
control stream resulted in a relatively unchanged growth rate. An
increased consumption rate together with a relatively unchanged
growth rate suggests that efficiency of energy utilization decreases
with increasing mean temperatures (Figure 8).
Increasing mean temperatures (13.6 to 17.3 C) in the clearcut stream
also resulted in a relatively unchanged growth rate (Figure 9). The
rate of food consumption increased with increased mean temperature,
also indicating a decrease in food conversion efficiency.
The influence of temperature on growth rate was somewhat different
in the two streams, since there was a greater influence of daily
temperature variations in the clearcut stream than in the control
stream. The reasons for this difference are not immediately apparent,
since the difference in temperature range (3.7 C) was identical in
both streams (10.8 to 14.5 C vs.13.6 to 17.3 C). Aside from the
obviously higher range in the clearcut stream, the average diel
17
-------
90
TJ
en
E 60
LJ
40
30
20
z
o
<-> 10
0
m 25
D
en
Ł 15
UJ
10
O
o:
o
O
10 II 12 13
MEAN TEMPERATURE
14
15
Figure 8. Relationship of consumption rate and growth rate to mean
temperature of coho on repletion rations in the control stream.
Curves fitted by inspection. See Figure 3 for description of symbols
-------
u.100
o
5.90
cn
1^80
LU
< ?0
cc.
z 60
o
t 5Q
j:
cn 40
O
0 30
35
o
-D 30
2
20
10
2 5
D
13 14 15 16 17
MEAN TEMPERATURE °C
18
Figure 9. Relationship of consumption rate and growth rate to mean
temperature of coho on repletion rations in the clearcut stream.
Curves fitted by inspection. See Figure 5 for description of
symbols.
19
-------
fluctuation was significantly greater there. The possible implica-
tions of this difference are considered in a later section.
The possibility of inherent changes in growth rates through the
summer months had been considered as a source of some of the unex-
plained variation. Figures 4 and 5 illustrate the lack of any
detectable seasonal pattern in growth rate in either stream. Brown
(1946) found that the growth rate of 2-year-old brown trout kept at
constant temperatures decreased to a minimum during October and
November, increased to a maximum in February, then decreased
gradually until August, at which time it fell rapidly. Other
experiments with constant temperatures have given evidence for a
decreasing or lower growth rate through the summer (Bullock, 1955;
Wells, 1935). In our case, however, temperature variation may have
masked any seasonal change in growth rate.
Fish Under Starvation
Increasing mean temperatures and diel temperature fluctuations
appear to have affected the starved fish from the control and clear-
cut streams differently. The relatively low diel temperature
fluctuations at low mean temperatures in the control stream had
little effect upon the weight loss of the coho (Figures 4 and 6).
In the clearcut stream, however, with greater temperature fluctua-
tion and higher temperatures, there was a definite relationship
between temperature and weight loss (Figures 5 and 7). The greatest
loss in body weight occurred between 15.0 and 16.0 C (Figure 5),
within the temperature range of optimum growth for the 4 and 8 percent
ration level. The same pattern prevailed for increasing temperature
fluctuation (Figure 7) . In a feeding experiment with brown trout,
the greatest weight loss also occurred at a temperature within the
temperature range for optimum growth (Pentelow, 1939). The optimum
temperature for growth of the trout was from 10.0 to 15.6 C and the
greatest weight loss occurred from 12.8 to 15.6 C. This increase
in loss of body weight most probably occurred in the temperature
range where the metabolic processes of the fish were most active, and
they therefore utilized the greatest amounts of their energy stores.
The validity of including starved fish on growth rate curves may be
questioned, since growth implies the buildup of body tissues.
Starvation results in the breakdown of tissues to produce the energy
required to maintain body activities. Continued starvation creates
a metabolic imbalance resulting in a decrease in the total organic
content and increased percentages of water and ash in the tissues
(Wilkins, 1967). It has also been demonstrated that at higher
temperatures the same physiological activity (increased metabolic
activity in a particular temperature range) resulted in increased
growth rate of fed fish vs. increased weight loss of starved fish.
20
-------
Separating the Effects of Increasing Mean
Temperature and Diel Fluctuation
The design of this experiment resulted in a comparison of growth
rates from two streams that differed in both mean temperature and
diel temperature range. Growth rates could have been affected by
either factor and it is difficult to separate their effects. From
a management point of view it may not be significant which effect
was more important, but further analysis was undertaken in an attempt
to learn more about the mechanisms involved in the change in growth
rate.
Knowledge of the effects of temperature fluctuation on growth of
fish is lacking. However, entomologists have done much work on the
influence of temperature change upon the development of insects.
Increasing diel temperature fluctuation at lower than optimum mean
temperature resulted in faster development of fruit fly eggs than at
the equivalent constant mean temperature (Messenger and Flitters,
1959) . Faster development has been attributed to an increased
metabolic rate during periods of high temperature exposure (Cook,
1927). However, diel temperature fluctuations around the optimum
constant temperature caused no improvement in developmental rate,
and fluctuations above the optimum constant temperature resulted
in a decrease in development rate as well as other adverse effects.
In an attempt to separate out the effects of temperature fluctuation,
the growth rates and temperature experience of specific groups of fish
were compared. Control stream experiments 2 through 6 and clearcut
stream experiments 4, 5, and 6 were included in the comparison.
These groups were chosen for comparison because the mean temperature
or diel temperature fluctuations for these fish showed no more than
an arbitrary 0.5 C difference. In order to facilitate the comparison,
growth rates differing by 1 mg/g/day or less were considered equal.
The following rationale for evaluating the effects of mean tempera-
ture and diel temperature fluctuations on growth rate was used.
Experiments in which the mean temperatures were similar were
compared to estimate the effects of temperature fluctuation on
growth rate while those in which temperature fluctuations were the
same were compared to estimate the effects of mean temperature on
growth rate.
The results of these comparisons, unfortunately, were inconclusive
(Table 2). In this analysis, mean temperature appeared to be the
dominant influence twice as often as did diel temperature fluctuation.
There were four comparisons where the temperature regimes were the
same, both for mean temperature and the mean fluctuation. Growth
rates in two experiments were the same and in the other two they
21
-------
TABLE 2. Comparison of growth rate in paired experiments
temperature fluctuations
with similar mean temperatures and/or diel
K>
Food Exps .
Level Compared
A B
Growth
mg/g/day
A B
Mean
Temp.0 C
A B
Diel
Fluct.0 C
A B
Influential
temperature
parameter
Remarks
CONTROL
2% 3
4
2
2
3
4% 3
4
2
2
3
5
6
3
6
6
5
6
3
6
6
0.4
0.2
-4.2
-4.2
0.4
0.8
7.8
4.0
4.0
0.8
0.8
-0.3
0.4
-0.3
-0.3
6.2
2.6
0.8
2.6
2.6
11.9
10.8
13.4
13.4
11.9
11.9
10.8
13.4
13.4
11.9
11.4
10.8
11.9
10.8
10.8
11.4
10.8
11.9
10.8
10.8
1
2
1
1
1
1
2
1
1
1
.8
.6
.4
.4
.8
.8
.6
.4
.4
.8
2.3
1.5
1.8
1.5
1.5
2.3
1.5
1.8
1.5
1.5
neither
mean
mean
mean
mean
temp.
temp.
temp.
temp .
Greater fluctuation did not
influence growth rate.
Higher mean temp, resulted in
reduced growth rate .
Higher mean temp, resulted in
reduced growth rate .
Higher mean temp, resulted in
increased growth rate.
neither
diel
mean
mean
mean
f luct .
temp.
temp.
temp.
Higher diel fluct. resulted in
higher growth rates.
Higher mean temp, resulted in
increased growth rate.
Higher mean temp, resulted in
increased growth rate.
Higher mean temp, resulted in
decreased growth rate.
CLEARCUT
4% 4
4
8% 4
4
5
6
5
6
4.4
4.4
10.1
16. 1
3.6
5.3
12.5
12.4
15.0
15.0
15.0
15.0
15.4
14.8
15.4
14.8
7
7
7
7
.6
.6
.6
.6
7.6
9.0
7.6
9.0
neither
diel
f luct .
Higher diel fluct. resulted
in increased growth rate.
neither
diel
f luct .
Higher diel fluct. resulted
in increased growth rate.
-------
were different. These results suggest the possibility that factors
other than temperature and food consumption were affecting growth
rate, as the scatter of points in the previous figures would suggest.
On the few occasions when diel temperature fluctuation appeared to
be the dominant influence, increased growth rates were associated
with increased temperature fluctuation. The lack of a definite
result in this analysis suggests that both mean temperature and diel
temperature fluctuation influenced the growth of juvenile salmon
under conditions of this experiment.
It should be emphasized that in a system of fluctuating temperatures
fish do not actually experience the mean temperature as such. A
mean temperature is employed as a convenient means of expressing the
dynamic temperature changes that occur in natural streams. It would
be more realistic if the temperature experiences could be expressed
with consideration for the continuous and dynamic nature of natural
stream temperatures. A more complete analysis of the problem should
be conducted under controlled laboratory conditions where fish could
be subjected to mean temperatures at several levels combined with
varying levels of diel fluctuation from 0 to 20 C.
Influence of Infestation by Nanophyetus salmincola
Another possible reason for unexplained variation in the experimen-
tal results was suspected to be a variable rate of infestation by
the "salmon poisoning" fluke Nanophyetus salmincola. A heavy infes-
tation of the fluke is known to affect the growth of juvenile coho
salmon. Since the shedding rate of the cercariae from the snail
host is known to be increased by increasing water temperature
(Millemann and Knapp, 1970), it was hypothesized that the incidence
of this fluke in juvenile salmon might increase significantly in the
clearcut stream. With the assistance of Mr. Tom Robinson, an under-
graduate in the Department of Fisheries and Wildlife, a survey of
the problem was conducted.
There was no information available on the pre-logging abundance of
the fluke in the streams, so all that was possible was a comparison
of post-logging infestation in the three streams, clearcut, patch-
cut, and control. A sample of 10 fish was taken from each stream
during August and September of 1969 and processed according to
methods described by Gebhardt et_ al_. (1966).
From the evidence available, it appears that the hypothesis of
increased infestation in the warmer clearcut stream was false. Fish
from both the clearcut and patch-cut streams had a relatively low
incidence of cysts as compared to those in the unlogged stream
23
-------
(Table 3). There was no apparent relationship between the number of
cysts and the condition of the coho fry (Figure 10). Logging may
have created an environment that was unsuitable for a stage in the
life cycle of N_, salmincola, thereby reducing its effectiveness as
a parasite on coho salmon.
Growth of Wild Coho From A
Clearcut and Undisturbed Watershed
To evaluate the results of the experiment, it was desirable to com-
pare the growth of coho in their natural environment to the growth
of fish in the experiment. The mean lengths of juvenile coho
sampled periodically from clearcut and undisturbed watersheds
during pre-logging and post-logging years were compared. Flynn
Creek was used as the control. Carline (1968) concluded that the
technique was valid in that the growth rate of wild fish was
comparable to those of aquarium-held fish that received the same
amount of food as the wild fish.
Growth rates of fry prior to logging were compared during the same
seasonal interval as the experiments (July through September). There
was considerable variation among years, but no clear superiority of
one stream over the other (Figure 11).
There was some evidence of better growth of fry in the clearcut
stream during and shortly after logging, although the evidence was
conflicting (Figure 12). Despite a high growth rate after emergence,
the fry in the clearcut stream decreased in average length from July
to September in 1967, the year of maximum temperature. Several
hundred feet of stream were devoid of fish in the area where temper-
ature was highest (D. Trethewey, unpublished data, Department of
Fisheries and Wildlife, Oregon State University). Despite the
finding by Dean and Coutant (1968) that size of juvenile fall chinook
salmon did not influence their susceptibility to high lethal temper-
ature, our results suggest that some differential mortality may have
occurred. The possibility of sampling error cannot be discounted,
however, as the sample in September was considerably larger than
that in July (314 vs. 118).
The coefficient of condition provided an additional index to the
well being of the coho fry in a clearcut watershed. During the hot
summer of 1967 the fry grew rapidly in early summer, but showed a
drop in condition in late summer. This loss of weight indicated
extreme physical stress and the lack of food to maintain the initial
nutritional level of the fry. The extreme temperatures character-
istic of the summer of 1967 proved to be unfavorable for coho fry
(D. Trethewey, unpublished data).
24
-------
TABLE 3. Lengths
salmon.
Date Sampled
9/5/69
9/15/69
8/26/69
9/9/69
8/29/69
9/2/69
9/3/69
9/12/69
, weights, and cyst infestation of juvenile coho
Length (mm) Weight (g)
DEER CREEK
61.0
70.0
66.0
71.0
60.5
68.5
63.0
63.0
60.5
58.5
FLYNN CREEK
59.0
74.0
57.0
63.0
71.0
67.5
68.5
64.0
68.0
67.0
NEEDLE BRANCH
63.0
61.5
71.5
67.0
66.0
68.0
57.5
67.0
67.5
67.0
2.38
4.23
2.97
3.94
2.31
3.27
2.49
2.51
2.27
2.09
2.18
4.45
1.87
2.67
3.52
3.45
3.59
2.71
3.21
3.34
2.63
2.45
3.77
3.10
3.11
3.34
2.00
3.17
3.49
3.21
Number of Cysts
34
105
59
167
291
178
84
31
101
68
414
646
440
1080
346
392
639
644
921
496
827
176
72
703
68
84
94
75
112
81
25
-------
1100
1000
900
800
700
CO
1
$2 600
O
fe 500
JUMBER
^
o
o
300
200
100
0
A
A
D
n
A A A
A
A A A
A
O
on o
n 0 p n n C
0 § o H D n n
0 0
.98
1.00 1.02 U34 1.06 1X18. 1.10
COEFFICIENT OF CONDITION
U2
L24
Figure 10. Relation between coefficient of condition and the
number of cysts in juvenile coho salmon from three coastal streams
A
O
D
Flynn Creek (Unlogged watershed)
Deer Creek (Patchcut watershed)
Needle Branch (Clearcut watershed)
-------
70
CO
60
50
LU
40
30
MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC
Figure 11. Change in mean length of juvenile coho from Needle Branch (clearcut) and Flynn Creek
(control) before logging. Data from Chapman C1965).
-------
90
DO
80
in
i-
cu
+-
-------
The difference in growth rates between the clearcut and control
stream prior to logging was likely due to natural variations in
environmental conditions. Those instances of higher growth rates in
the clearcut stream after logging could be attributed to a number of
interacting factors. One possible influence could have been an in-
creased food production to offset the increase in metabolism the
fish would have experienced under higher temperature, but there was
no information on changes in food production following logging. The
fact that most of the data available for growth comparisons relate
to growth in length must be kept in mind. In the few cases where
comparisons are available on a weight basis, the evidence for
improved growth following logging is less clear.
Clearcutting resulted in less favorable conditions for cutthroat
trout, bringing about a greater than 50 percent reduction in their
numbers (Hall and Lantz, 1969). Cutthroat trout are known to
interact with juvenile coho salmon, the presence of one species
affecting the growth and survival of the other (Mclntyre, 1970).
Thus the reduced trout population may account in part for the
apparent success of the coho population in the face of a severely
altered environment.
Another factor that should be considered in evaluating the results
is the possibility that the ration fed to the aquarium fish (fly
larvae) was not an adequate diet nutritionally. The adequacy of the
diet could have been different at different temperatures, possibly
leading to poorer growth of aquarium fish at high temperatures.
Further work should be done on this question.
The constant level of rations in the experiment makes somewhat
difficult the comparison with a natural stream situation, where
there are most likely periodic fluctuations in food availability.
Slight increases in water temperatures have caused caddis flies to
emerge as much as 2 weeks earlier than normal (Coutant, 1968). The
higher temperatures of the clearcut stream might have altered the
pattern of insect emergence and thus, subsequently reduced insect
availability.
An analysis of the effects of increased temperature on fish popula-
tions should clearly focus on a broader spectrum than simply the
metabolic changes that occur in the fish. The original design of
this study included an analysis of food habits of fish from the
control and clearcut streams. However, a delay in funding prevented
accomplishment of that work, which would have provided additional
insight into the changes occurring following logging.
It is evident that an evaluation of the effect of clearcut logging
on the fisheries resource must consider many factors. The present
research concerned itself mainly with growth of coho fry and
indicated a reduced growth rate when food consumption levels were
29
-------
unchanged. There was some evidence of slightly increased growth
rates in the natural stream situation, due possibly to increased
production and availability of food. The apparent increase in food
may have been due to reduced competition from cutthroat trout. The
recovery capabilities of a watershed must also be considered, since
temperatures extreme as those of the summer of 1967 were adverse for
the coho. Many watersheds would not recover as rapidly as did Needle
Braneh. In keeping with the total outlook, the significant reduction
of cutthroat trout must also receive consideration as an important
factor in judging the effects of clearcut logging on the fisheries
resource. Evaluation of other impacts of logging in this stream
system are discussed by Hall and Lantz (1969) .
30
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SECTION IV
ACKNOWLEDGMENTS
We are grateful to Drs. Donald Buhler and David Au for their
advice and review of the manuscript. The use of unpublished data
provided by Larry Everson, Don Trethewey, and Tom Robinson is much
appreciated.
The support of the Water Quality Office, Environmental
Protection Agency, through Grant Nos. WP 423-06 and 18050FKT, is
acknowledged with thanks.
31
-------
SECTION V
REFERENCES
Bell, G. H., J. N. Davidson, and H. Scarborough. 1968. Factors
influencing enzyme activity, p. 118-119. In_ Physiology and
biochemistry. The Williams and Wilkins Company, Baltimore.
Brett, J. R. 1952. Temperature tolerance of young Pacific salmon.
J. Fish. Res. Bd. Canada 9:265-323.
Brett, J. R., J. E. Shelbourn, and C. T. Shoop. 1969. Growth rate
and body composition of fingerling sockeye salmon, Oncorhyn-
chus nerka, in relation to temperature and ration size. J.
Fish. Res. Bd. Canada 26:2363-2394.
Brown, G. W. 1970. Predicting the effect of clearcutting on
stream temperature. J. Soil Water Conserv. 25:11-13.
Brown, G. W., and J. T. Krygier. 1970. Effects of clearcutting
on stream temperature. Water Resources Res. 6:1133-1139.
Brown, M. E. 1946. The growth of brown trout (Salmo trutta Linn.)
II. The growth of two-year-old trout at a constant temperature
of 11.5°C. J. Exp. Biol. 22:130-144.
Bullock, T. H. 1955. Compensation for temperature in the metabo-
lism and activity of poikilotherms. Biol. Rev. 30:311-342.
Carline, R. F. 1968. Laboratory studies on the food consumption,
growth, and activity of juvenile coho salmon. M. S. Thesis.
Oregon State University. 75p.
Chapman, D. W. 1965. Net production of juvenile coho salmon in
three Oregon streams. Trans. Am. Fish. Soc. 94:40-52.
Cook, W. C. 1927. Some effects of alternating temperatures on the
growth and metabolism of cutworm larvae. J. Econ. Ent.
20:769-782.
Coutant, C. C. 1968. Effect of temperature on the development
rate of bottom organisms, p. 9.12-9.14. I_n_ Pacific Northwest
Laboratory Annual Report for 1967. Vol. 1. Biological
Sciences. Battelle Northwest, Richland, Washington.
33
-------
Dean, J. M., and C. C. Coutant. 1968. Lethal temperature relations
of juvenile Columbia -River chinook salmon, p. 9.5-9.10. In
Pacific Northwest Laboratory Annual Report for 1967. Vol. 1.
Biological Sciences. Battelle Northwest, Richland, Washington.
Fry, F. E. J., J. S. Hart, and K. F. Walker. 1946. Lethal
temperature relations for a sample of young speckled trout,
Salvelinus fontinalis. Pub. Ont. Fish. Res. Lab. No. 54.
Univ. of Toronto Press. 35 p.
Gebhardt, G. A., R. E. Millemann, S. E. Knapp, and P. A. Nyberg.
1966. "Salmon poisoning" disease. II. Second intermediate
host susceptibility studies. J. Parasitol. 52:54-59.
Hair, J. R. 1971. Upper lethal temperature and thermal shock
tolerances of the opossum shrimp, Neomysis awatschensis, from
the Sacramento - San Joaquin estuary, California. California
Fish and Game 57': 17-27.
Hall, J. D., and R. L. Lantz. 1969. Effects of logging on the
habitat of coho salmon and cutthroat trout in coastal streams,
p. 355-375. In_ T. G. Northcote (ed) Symposium on Salmon and
Trout in Streams, H. R. MacMillan Lectures in Fisheries,
University of British Columbia, Vancouver.
Mclntyre, J. D. 1970. Production and behavioral interaction of
salmonids in an experimental stream. Ph.D. thesis. Oregon
State Univ. 58 p.
Messenger, P. S., and N. E. Flitters. 1959. Effect of variable
temperature environments on egg development of three species
of fruit flies. Ann. Ent. Soc. Am. 52:191-204.
Millemann, R. E., and S. E. Knapp. 1970. Biology of Nanophyetus
salmincola and "salmon poisoning" disease, p. 1-141. In_
Advances in Parasitology, Vol. 8, Academic Press, London" and
New York.
Ogle, C., and C. A. Mills. 1933. Animal adaptation to environ-
mental temperature conditions. Amer. J. Physiol. 103:
606-612.
Pentelow, F. T. K. 1939. The relation between growth and food
consumption in the brown trout (Salmo trutta). J. Exp. Biol.
16:446-473.
34
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Warren, C. E., and G. E. Davis. 1967. Laboratory studies on the
feeding, bioenergetics, and growth of fish, p. 175-214. In
S. D. Gerking (ed) The biological basis of freshwater fish
production. Blackwell Scientific Publications, Oxford and
Edinburgh.
Wells, N. A. 1935. Variations in the respiratory metabolism of
the Pacific killifish, Fundulus parvipiniiis, due to size,
season, and continued constant temperature. Physiol. Zool.
8:316-336.
Wilkins, N. P. 1967. Starvation of the herring Clupea haregus L.
survival and some gross biochemical changes. Comp. Biochem.
Physiol. 23:503-518.
35
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SELECTED WATER
RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
4. Title EFFECTS OF LOGGING ON GROWTH OF
JUVENILE COHO SALMON,
7. Autboi(s)
Iwanaga, P. M., and Hall, J. D.
9. Organization
Department of Fisheries and Wildlife
Oregon State University
Corvallis, Oregon 97331
10. Project No.
11. Contract/Grant No.
18050FKT
15. Supplementary Notes
Environmental Protection Agency Report Number EPA-R3-73-006, April 1973
16. Abstract The objective of this research was to study the effects of increased water temperature
characteristic of clearcut watersheds of Pacific coastal streams upon the growth rate of juvenile
coho salmon. The natural temperature fluctuations of the stream were used in the study of growth of
underyearling fish held in aquariums and fed at various consumption levels.
Juvenile coho fed in the control stream grew somewhat faster than did those that experienced
the wattner temperatures of the clearcut stream. This was particularly true at low levels of
consumption. Growth rates of juvenile coho salmon in the wild state were found to be slightly higher
in the clearcut stream as compared to the unlogged stream. This difference from the experimental
results may have been due to a change in availability and abundance of food. There was a marked
decrease in the cutthroat trout population in the clearcut stream, which may have reduced competition
for food. There was no apparent influence of infestation by salmon poisoning fluke on the condition
of the juvenile coho in the clearcut stream.
This report was submitted in fulfillment of Grant Nos. WP423-06 (Part) and 18050FKT
under the sponsorship of the Environmental Protection Agency.
T7a. Descriptors
Uescrtptors
*Salmon, *Growth rates, * Thermal stress, Lumbering, Clear-cutting,
Fish parasites, Oregon, Water temperature, Pacific Northwest U.S.
Fish,
Ub. Identifiers
17c. CO WRR Field & Group 05C
18. Availability
Send To:
WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON, D. C. 20240
Institution
WPOIf
913.26f
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