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CAUFQRNIA
FISH- GAME

"CONSERVATION OF WILD LIFE THROUGH EDUCATION"




California Fish and Game is published quarterly by the California Department of
Fish and Game. It is a journal devoted to the conservation and understanding of fish
and wildlife. If its contents are reproduced elsewhere, the authors and the California
Department of Fish and Game would appreciate being acknowledged. f

Subscriptions may be obtained at the rate of $10 per year by placing an order with
the Editor, California Department of Fish and Game, 1416 Ninth Street, Sacramento.
CA 95814. Checks or money orders in U.S. dollars should be made out to: California
Fish and Game. Inquiries regarding paid subscriptions should be directed to the
Editor. Complimentary subscriptions are granted on an exchange basis.

California Department of Fish and Game employees may request complimentary
subscriptions to the journal.



Please direct correspondence to:

Dr. Eric R. Loft, Editor-in-Chief
California Fish and Game
1416 Ninth Street
Sacramento, California 95814



RESOURCES AGENCY

CALIFORNIA



DEPARTMENT




u




VOLUME 79



FALL 1993



NUMBER 4




Published Quarterly by



STATE OF CALIFORNIA

THE RESOURCES AGENCY

DEPARTMENT OF FISH AND GAME

-LDA-



STATE OF CALIFORNIA
PETE WILSON, Governor

THE RESOURCES AGENCY
DOUGLAS P. WHEELER, Secretary for Resources



FISH AND GAME COMMISSION

Benjamin F. Biaggini, President San Francisco

Albert C. Taucher, Member Long Beach

Franl< D. Boren, Member Carpinteria

Gus Owen, Member Dana Point

Robert R. Treanor, Executive Director

DEPARTMENT OF FISH AND GAME

BOYD GIBBONS, Director

John H. Sullivan, Ciiief Deputy Director

A! Petrovich Jr., Deputy Director

Banky E. Curtis, Deputy Director

Perry Herrgesell,Ph.D., Ctiief Bay-Delta Division

Rolf Mall, Ctiief Marine Resources Division

Tim Farley, Ctiief Inland Fisheries Division

Terry Mansfield, Ctiief Wildlife Management Division

John Turner, Ctiief Environmental Services Division

Susan A. Cochrane, Ctiief Natural Heritage Division

DeWayne Johnston, Ctiief Wildlife Protection Division

Richard Elliott, Regional Manager Redding

Ryan Broddrick, Regional Manager Rancho Cordova

Brian F. Hunter, Regional Manager Yountville

George D. Nokes, Regional Manager Fresno

Fred Worthley, Regional Manager Long Beach

CALIFORNIA FISH AND GAME
1993 EDITORIAL STAFF

Eric R. Loft, Editor-in-Ctiief Wildlife Management

Jack Hanson, Betsy C. Bolster, Ralph Carpenter,

Arthur C. Knutson, Jr Inland Fisheries

Dan Yparraguirre, Douglas R Updike Wildlife Management

Steve Crooke, Doyle Hanan, Jerome D. Spratt Marine Resources

Donald E. Stevens Bay-Delta

Peter T. Phillips, Richard L. Callas Environmental Services



CONTENTS

Spawning Season and Microhabitat Use by California Golden
Trout {Oncorhynchus mykiss aguabonita) in the Southern Sierra
Nevada

Jerome A. Stefferud 133



Grazing in the Sierra Nevada: Home Range and Space Use

Patterns of Mule Deer as Influenced by Cattle

Eric R. Loft, John G. Kie, and John W. Menke 145

First Record of the Tripletail {Lobotes surinamensis, Family

LOBOTIDAE) in California Waters

James M. Rounds and Richard F. Feeney 167

Western Gray Squirrels in Baja California

Eric Mellink and Joaquin Contreras 169

Geographical and Size Records of the Electric Stargazer
{Astroscopus zephyreus) Gilbert and Starks, 1896 (PISCES:

URANOSCOPIDAE)

..Marcos De Jesus-Roldan, Lloyd Ellis, and Felipe Galvan Magana 171

Index to Volume 79 173



CALIFORNIA FISH AND GAME
Calif. Fish and Game 79(4):133-144 1993

SPAWNING SEASON AND MICROHABITAT USE BY

CALIFORNIA GOLDEN TROUT {ONCORHYNCHUS MYKISS

AGUABONITA) IN THE SOUTHERN SIERRA NEVADA

JEROME A. STEFFERUD

USDA Forest Service, Tonto National Forest

2324 East McDowell Road

Phoenix, Arizona 85012

Spawning of California golden trout {Oncorhynchus mykiss
aguabonita) was observed during May and June 1981, in Cottonwood
and Mulkey creeks in the southern Sierra Nevada, California. Spawning
began when daily water temperatures consistently exceeded 10°C, and
was most intense between 1 300 and 1 600 h when water temperature was
16 to 18°C. Apparent selection of redd site was based on water velocity
and size of substrate, but not on water depth or distance to cover. Water
velocity over redds was between 25 and 77 cm/s (mean 49 cm/s), and
substrate in redds was gravel 2.0 to 19 mm in diameter. Golden trout
constructed redds in water 4 to 24 cm deep. Redds average i 0.22 m^ in
surface area, and were within one-fourth of the stream width from the
stream bank. Distance to cover from a redd often exceeded 15 m.

INTRODUCTION

California golden trout' {Oncorhynchus mykiss aguabonita) is indigenous to
streams in the southern Sierra Nevada, Tulare and Kern counties, California (Moyle
1976, Fisk 1983). Golden trout is the state fish of California and a species of particular
allure to the public. It is a popular sport fish and has been transplanted throughout the
Sierra Nevada and western United States and Canada (Fisk 1983), including a
clandestine (and illegal) transplant to New Mexico (Yeager and Janos 1985). Most of
the transplants outside the Sierra Nevada are hybridized with rainbow (O. mykiss) or
cutthroat trouts {O. clarki) (Behnke 1992a), or have not survived.

Few scientific investigations have examined the natural history of golden trout.
Most accounts described its classification (Gold and Gall 1975, 1981; Gold 1977,
Behnke 1992a), or were popular narratives of its status (Fisk 1983, Gold and Gold
1976). Curtis (1934, 1935) reported on hatching period and age and growth of golden
trout from Cottonwood Lakes. Its growth in two previously fishless lakes in the Sierra

'In this paper, I will use the common and scientific names assigned by Behnke (1992a) to the golden trout
resident in the South Fork Kern River. He reclassified the entity formerly known as the South Fork Kern
golden trout {O. aguabonita aguabonita) and renamed it California golden trout {O. mykiss aguabonita).
The common name is used to distinguish it from the other subspecies of golden trout in California, the Kern
and Little Kern golden trout {O. m. gilberti). The common name may be changed in the near future;
Volcano Creek golden trout is being considered as a replacement (Jack A. Hanson, Assoc. Ed., Calif Fish
and Game, pers. comm.). It is unlikely that any system of classification of western trout will ever receive
universal agreement. Behnke (1992a) advised that workers should avoid taxonomic anxiety, and instead
work towards recognition that the incredible diversity of western trout is a natural resource that needs to
be maintained.

133



1 34 CALIFORNIA FISH AND GAME

Nevada was documented by Needham and Vestal (1938). More recently, growth and
longevity in its native streams were described (Knapp and Dudley 1990). No
investigations have been made to determine timing of spawning in streams, nor
microhabitats used for spawning by golden trout.

Much of its native range is within the Golden Trout Wilderness, established to
preserve the native habitat of the golden trout. Although protected by wilderness
designation, some uses, including recreation and domestic livestock grazing, have
detrimentally altered habitat of golden trout. Efforts by management agencies to
restore populations or habitat often proceeded without the scientific information
necessary to guide the action (Pister 1978, USDA Forest Service 1983). Increased
knowledge of the biology and ecology of golden trout within streams is needed to
assure its survival and vigor.

The purpose of my study was to document timing of spawning and to gather data
on the microhabitats used for spawning by golden trout. This paper summarizes my
data and observations on spawning activity of golden trout in two streams in the
southern Sierra Nevada, Mulkey Creek and Cottonwood Creek.

STUDY AREAS

Mulkey Creek is a headwater tributary to the South Fork Kern River, a Pacific
Ocean drainage. Cottonwood Creek flows eastward to the Owens River drainage
within the Great Basin (Fig. 1 ). Both streams have their headwaters along the crest of
the Sierra Nevada. Upper Mulkey Creek in Mulkey Meadows and upper Cottonwood
Creek were originally Ashless, but around 1872, golden trout from Golden Trout
Creek were carried to upper Mulkey Creek (Pister 1991, Behnke 1992b), and from
there to Cottonwood Creek in 1876 (Evermann 1906). Golden trout now occupy the
entire length of Mulkey Creek (ca. 15 km), and the headwater lakes and upper 13 km
of Cottonwood Creek.

Mulkey Creek meanders through broad meadows, with occasional short, steep
descents through rocky gorges. Its width to depth ratio was 28.6, and the pool to riffle
ratio was 0.12. Vegetation covered 55% of the stream banks (Knapp and Dudley
1990). The channel was saucer-shaped in profile with an average channel width of 4.7
m. The wetted width was 2.2 m, and depth was 0.1 m. Maximum summer water
temperatures of 25°C were recorded, with diel fluctuations of 15°C. Study site
elevation at Mulkey Creek was 2,840 m. Slope gradient was less than 0.5%. Flow was
about 3.4 mVmin, and was continuous throughout the stream length. Season-long
livestock grazing caused unstable and eroding banks along most of the stream's length
(Inyo National Forest, Bishop, California, unpubl. data). Mulkey Creek supported a
population of golden trout (age l-i-) of more than 3,000 fish/stream km (Darrell Wong,
Calif. Dept. Fish and Game, pers. comm.). At the time of the study, Mulkey Creek was
considered within the native range of golden trout.

Cottonwood Creek is a boulder-dominated, cascading stream with short, flat
reaches through meadows. Through the meadows, both channel and wetted width



SPAWNING AND HABITAT USE BY GOLDEN TROUT



135



were about 4 m, water depth was 0.3 m or greater, and the channel profile was
rectangular or parabolic in cross section. In these reaches the pool to riffle ratio was
close to unity, cascades with small pools predominated in the remainder of the stream.
Stream banks were stable and densely vegetated and no livestock grazing occurred in
the watershed (Inyo National Forest, Bishop, California, unpubl.). Study site elevation
at Cottonwood Creek was 3,050 m. Cottonwood Creek had modal flows between 12
and 15 mVmin (Pister 1984), and an estimated trout (age 1+) population of between
250 and 1,800 fish/stream km (Pister 1978, 1984).

In both streams, golden trout were isolated from other fishes by natural waterfall
barriers, and remoteness of the streams discouraged introduction of other salmonids.




Figure 1. Map of California showing study sites and place names used in text. Location of study sites
indicated by dotted lines.



1 36 CALIFORNIA FISH AND GAME



Upper Cottonwood Creek has been managed as a wild trout stream since 1972, and
its headwater lakes annually provided CDFG with 750,000 eggs of golden trout.
Natural reproduction sustains both populations, and angling pressure is light in these
streams (Pister 1978, 1984).

METHODS

Study streams, and reaches within each stream, were chosen based on likelihood
of spawning activity, and reasonable access for observations. To begin the study, I
looked for reaches within each stream that appeared suitable to support spawning, that
is, rapidly-flowing water over expanses of substrates composed of small gravel. Once
spawning began, presence or absence of redds dictated the extent of observations.

Mulkey Creek and Cottonwood Creek were visited weekly from 1 May to 20 June
1981. Water temperatures (beginning 10 May and extending until after spawning
ended) were continuously recorded at each study site with submersible thermographs.
Study protocol involved walking upstream beginning at the lower end of the site,
examining recently constructed redds, and noting fish behavior at each redd. A redd
was defined as the total area excavated by fish during spawning, and redds recently
completed were distinguished from the surrounding substrate by their cleaner, silt-
and debris-free appearance and characteristic structure (Bjomn and Reiser 1991).
Spawning activity was defined as courtship behavior, digging by female fish, and the
presence of more than one fish at a redd (Breder and Rosen 1966). One hundred redds
in Mulkey Creek were examined on 1 6 and 23 May 1981, and 99 redds in Cottonwood
Creek on 30 May, 6 and 12 June 1981. No attempt was made to count total redds at
each study site or estimate active versus inactive redds during the observation period.
No measurements were taken in areas of the stream undisturbed by spawning activity.

Water velocity (nearest 1 .0 cm/sec) at each redd was measured with a pygmy
current meter placed 4.5 cm above the substrate over undisturbed gravel at the
upstream edge of the redd. Water depth (nearest 1 .0 cm) was taken at the same
location. That point was chosen because it most closely approximated conditions
before redd construction and reflected the depth and velocity selected by the fish for
spawning (Bjomn and Reiser 1991). Water depth in the deepest part (pit) of the redd
(nearest 1 .0 cm), total length and width (nearest 5.0 cm), and distance (nearest 0.5 m)
from the center of the redd to the nearest stream bank were also measured.

A 13-cm diameter cylinder was used to sample substrate in ten newly constructed
redds in Mulkey Creek on 23 May, and ten in Cottonwood Creek on 6 June. The
cylinder was inserted 3 to 6 cm into the tailspill of the redd and all material removed
and placed in bags for later analysis. Samples were air dried and sorted with standard
Tyler sieves into classes defined as coarse gravel (particles >19.0 mm diameter),
medium gravel (9.5 to 19.0 mm), fine gravel (4.8 to 9.4 mm), coarse sand (2.0 to 4.7
mm), medium sand ( 1 .2 to 1 .9 mm), and fine sand (< 1 .2 mm). The amount caught by
each sieve was dried and weighed (nearest 1.0 g), and expressed as a percentage of
total sample weight.

A two-sample analysis procedure was used to estimate and test the means and



SPAWNING AND HABITAT USE BY GOLDEN TROUT 137

variances of the data sets gathered from each creek. The difference between the means
of two independent samples was determined by a t-test, which was based on the pooled
estimate of the standard deviations. Statistical significance was assumed atP< 0.01
for all tests. All analyses were performed with STATGRAPHICS, a statistical
program for personal computers (Statistical Graphics Corporation 1991).

RESULTS
Initiation and Duration of Spawning

Neither spawning activity nor redds were seen in 3 km of Mulkey Creek on May
1 (Figure 2). Between 1 and 1 5 May, maximum daily water temperatures in Mulkey
Creek varied between 15 and 18°C. When the stream was visited again on 16 May,
the presence of completed redds showed that spawning had occurred during the
preceding days. Spawning activity increased during the day as water temperatures
rose from 10 to 16°C between 1 100 and 1600 h. After varying between 12 and 16°C
during 1 6 to 2 1 May, maximum daily water temperatures declined to 8°C on 23 May.

On 23 May, many fish maintained position over redd sites, but no spawning
activity was seen. A few new redds were found, but most were several days old with
dull tailings, and sand, debris, and algae in the pits. From 24 to 30 May, maximum
water temperatures in Mulkey Creek steadily rose to 18°C.

Spawning was again observed when the stream was next visited on 30 May. Many
redds were recendy constructed, and spawning activity was occurring. Spawning
activity increased as the water temperature rose in the afternoon, but never reached
the level seen on 16 May. Fish that exhibited spawning behavior were noticeably
smaller than individuals spawning earlier in the season. During 1 to 5 June, maximum
water temperatures rose to 22°C. On 6 June, few fish occupied redds, and most were
feeding and not exhibiting spawning behavior.

Maximum daily water temperatures in Cottonwood Creek did not exceed 10°C
between 16 and 23 May. The first spawning activity in Cottonwood Creek was noted
on 23 May as the water temperature approached 6°C at 1710 hr. Some digging had
taken place and individual fish were maintaining position over spawning sites, but no
completed redds were seen. Maximum water temperature reached 13°C on 30 May,
and spawning activity on that day was high.

Between 1 and 1 2 June, maximum water temperatures in Cottonwood Creek were
between 12 and 18°C. Spawning activity was intense on 6 June, and continued until
12 June. The surface of many riffles was completely disturbed and new redds were
constructed on top of older redds. By 20 June, when maximum water temperature
reached 18°C, spawning activity diminished, and few new redds were seen. As in
Mulkey Creek, the fish observed digging redds during the latter part of the season were
smaller than spawning fish seen earlier in the season.

Spawning Habitat

Substrate composition in redds was mostly medium-size gravel and finer material



138



CALIFORNIA FISH AND GAME



o

CD
Q.

E
o

\-



O

9^
0)

Z)

■Jo

(D
Q.

E




Increasing
activity



Intense
activity



Intense
activity



Decreasing
activity



30



25



20



15



10



5-



MaxTemp
Min Temp



Cottonwood Creek




0-1— r
10



~1 — \ — I — I — 1 — I — I — I — 1 — 1 — I — I — I I r-



~i I I I r~



20



25



30



May



June



Figure 2. Daily maximum and minimum water temperatures in Mulkey and Cottonwood creeks during 1 1
May to 19 June 1981. Apparent intensity of spawning activity by golden trout in each creek noted.



(Table 1). Differences in composition of material in redds between the two streams
were not significant. Through visual observation it was possible to discern an obvious
difference in gravel composition and sand embeddedness between substrates and
riffles chosen for redd construction and those not used for spawning. Riffles used for
spawning had less surface sand then those not used. However, this distinction was not
apparent towards the end of the spawning season when many smaller fish began to



SPAWNING AND HABITAT USE BY GOLDEN TROUT 1 39



Table 1. Mean and standard deviation (SD) of habitat parameters in redds of golden trout in
Mulkey and Cottonwood Creeks, California, 1981. Substrate values are percentages of total
sample weight.





Mulkey Creek


Cottonwood (
n Mean


Zreek


Parameter


n


Mean


SD


SD


Substrate


10






10






Coarse gravel (>19.0 mm)




14.6


9.8




26.0


17.7


Medium gravel (9.5-19.0 mm)




42.4


6.0




36.5


11.0


Fine gravel (4.8-9.4 mm)




17.8


5.0




18.0


6.1


Coarse sand (2.0-4.7 mm)




12.7


7.0




9.5


3.9


Medium sand (1.2-1.9 mm)




4.1


2.6




3.2


1.8


Fine sand (<1.2 mm)




8.4


4.1




6.8


5.3


Velocity (cm/s)


100


50.0


10.1


99


48.2


11.2


Water depth














Upper edge of redd (cm)


100


7.8*


2.0


99


13.7


4.4


Pit of redd (cm)


50


12.5*


2.5


99


16.4


3.5


Redd dimensions














Width (cm)


50


34.1*


8.5


99


29.6


8.0


Length (cm)


50


89.3*


25.0


99


62.5


19.1


Area (m-)


50


0.3*


0.1


99


0.2


0.1


Distance to stream bank (cm)


50


63.6*


21.6


99


96.0


43.9


*Values significantly different (P <


0.01) between creeks.









exhibit spawning behavior, and selected sites over substrates with more sand or finer
material evident.

Water velocities over redds averaged 49 cm/s (32 to 77 cm/s in Mulkey Creek, 25
to 77 cm/s in Cottonwood Creek) and were not significantly different between
streams. In Mulkey Creek depths used for spawning were between 5 and 12 cm, and
in Cottonwood Creek, 6 and 24 cm, and were significantly different between creeks.

Redds were large in surface area, but shallow. Significant differences in redd
length, width, and depth existed between creeks. Surface areas of redds in Mulkey
Creek averaged 0.31 m^ and were excavated to a depth of 4.6 cm, whereas in
Cottonwood Creek redds averaged 0.19 m^ in surface area and were 2.8 cm deep.

Redds were located within about one-fourth of the total stream width from either
stream bank in Cottonwood Creek. In Mulkey Creek, they were much closer to the
stream bank, usually within one-eighth of the total stream width. In Mulkey Creek
where deep pools, overhanging stream banks and vegetation, or other forms of trout
cover were scarce, spawning fish frequently darted 15 m or more from a redd to a
hiding place.

DISCUSSION

Spawning of golden trout occurred in the spring as maximum daily water
temperatures rose above 10°C. In Mulkey Creek spawning began in mid-May and



140



CALIFORNIA FISH AND GAME



Table 2.Water temperature, velocity, substrate size, and depth used for spawning by several
species of western trout.





Temp.


Velocity


Substrate size


Depth




Species


(°C)


(cm/s)


(mm)


(cm)


Source


Cutthroat trout


6-17


11-72


6-52


>6


Reiser and Bjomn 1990


Rainbow trout


2-20


48-91


6-102


>18


Reiser and Bjomn 1990


Gila trout


>8


5-42


2-38


6-15


Rinne 1980


Apache trout


>8


8-17


8-32


19-28


Harper 1970


Golden trout


7-15








Curtis 1935


Golden trout


10-16


25-77


2-19


4-24


This study



extended into early June, whereas in Cottonwood Creek the spawning season began
two weeks later. Temperatures at onset of spawning in these streams were warmer than
those reported for golden trout in Cottonwood Lakes (Curtis 1934), Gila trout (O.
gilae) (Rinne 1 980), and Apache trout {O. apache) (Harper 1 978), but within the range
of temperatures reported for rainbow trout and cutthroat trout (Bjomn and Reiser
1991) (Table 2).

Whereas other factors, such as photoperiod, hydrologic regime, and genetic
heritage probably influenced maturity and spawning readiness of the fish, spawning
activity seemed correlated with increasing water temperature. This is substantiated by
the two-week difference in onset of spawning activity between Mulkey Creek and
Cottonwood Creek, where initiation of spawning closely followed the pattern of
maximum daily water temperatures in both streams. Spawning activity in Mulkey
Creek was temporarily interrupted by reduced water temperatures. Finally, spawning
in both streams was most intense between 1300 and 1600 h, when daily water
temperatures were highest.

Spawning of golden trout continued while maximum daily water temperature was
between 16 and 18°C, near the maximum reported for spawning by rainbow and
cutthroat trouts (Bjomn and Reiser 1991). How long spawning might be delayed
during a cool spring, or accelerated during a warm spring is unknown.

The narrow range of water velocities used for spawning by golden trout, and the
similarity in velocities selected in Mulkey and Cottonwood creeks (32 to 77, 25 to 72
cm/sec, respectively) suggest that velocity was critical in the selection of redd sites.
Composition of substrate material in redds also was similar between creeks, but since
substrate size largely is determined by water velocity (Shirvell and Dungey 1983), it
is unclear which was more important in site selection. Both velocity and substrate
composition are important determinants in reproductive success (embryo survival and
alevin emergence) among salmonids. Bjomn and Reiser (1991) noted when an adult
fish selects a spawning site, it is also selecting the incubation environment. Shirvell
and Dungey (1983) commented that salmonids can probably discern velocity better
than substrate quality, and the selection of "correct" water velocities for spawning
may have evolved as a surrogate for the proper substrate.



SPAWNING AND HABITAT USE BY GOLDEN TROUT 141

The average water velocity at redds of golden trout was similar to velocities
reported for rainbow trout, but 1.5 to 3 times greater than velocities reported for
cutthroat trout (Bjomn and Reiser 1991), Gila trout (Rinne 1980), and Apache trout
(Harper 1978). The size of the substrate material in golden trout redds was similar to
substrates used by Apache trout (Harper 1978) and Gila trout (Rinne 1980), species
of similar size to golden trout in their native habitats (Rinne 1982, 1990).

The suitability of substrate for spawning depends mostly on fish size, with small
fish using finer substrates than large fish (Bjomn and Reiser 1991). In their native
waters, golden trout mature sexually at total lengths of between 10 and 13 cm (Pister
1978), and seldom exceed 18 cm standard length (Knapp and Dudley 1990). The


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