California. Dept. of Fish and Game.

California fish and game (Volume 1954-1956) online

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almost entirely to hatchery investigations. Of 120
cases studied, 112 involved fish at hatcheries.

Gill Flukes

Special studies were made of two important trout
diseases. The first disease was caused by a gill fluke
which is particularly serious at the Darrah Springs
Hatchery, and is also important at the Mt. Shasta and
Cr\stal Lake Hatcheries. At the present time it appears
that snails of the genus Goviohasis act as the inter-
mediate hosts for the fluke.

Some strains of rainbow trout are highly susceptible
to this disease and die in considerable numbers; other
strains are relatively immune. However, when the gills
become heavily parasitized the health of the fish is
impaired even though it may not die. An attempt will
be made to break the life cycle of this gill worm at
the Darrah Springs Hatchery by a partial eradication

Department disease laboratory men (Harold Wolf, left, and Bill Schafer) investigate a trout disease threat in a commercial hatcfiery tfiat supplies fish to

private waters connected witf} public fishing wooers.

(Fish and Game Photo)

of the snails and the wild fish in the hatchery water

The second trout disease to receive special attention
during the bienniuni was redmouth, a bacterial disease
of the blood and various tissues of rainbow and eastern
brook trout.

It was found that some commercial trout hatcheries
in other states were seriousl\' affected by this disease.

It was shown in a survey that about 1,000,000 live
trout a year were entering the State and that the num-
ber would increase.

Inspection of Shipments

After this was established, an investigation showed
that there was a danger of introducing diseased fish
into state waters. It was then decided that each ship-
ment of live trout would be inspected for redmouth
as well as other diseases, and only if found to be free
of disease could they be delivered into California. At
the same time all the commercial trout hatcheries and
all the state-owned hatcheries in California were in-
spected for redmouth. The disease was found in seven
commercial hatcheries and one state hatchery.

Treatment of the infected fish with sulfa drugs was
recommended and these lots of fish were quarantined
until inspection showed that they were free of the
disease. It is believed that redmouth will not cause
the State serious trouble as long as infected trout are
prevented from entering California, and as long as

routine inspection of all trout hatcheries, both com-
mercial and state-owned, is continued.


The emphasis of the state-wide warmwater research
program remained on the problem of providing forage
for largemouth bass.

Five species of small fish thought to have potential
value as forage have been planted throughout the
State. The fathead minnow and golden shiner have
become established in several lakes and reservoirs but
have not provided the forage expected of them. The
plains red shiner has been extremely successful in the
Colorado River area, but its value is not clear else-
where. Although the native freshwater smelt found in
the lower reaches of the Sacramento and San Joaquin
Rivers has been introduced into three colder foothill
reservoirs, no evidence of reproduction has been found.


The threadfin shad, imported from the Tennessee
River in 1953, has been very successful and shows
great promise as a forage species.

It was introduced into San Vicente Reservoir, San
Diego County, in June, 1954, and has successfully
reproduced. It is now found throughout the reservoir
and is being utilized by the sport fish. Its effect on the
fishery' in terms of increased angling success has not
had time to become apparent. The fluctuation of the



reservoir has not affected its spawning, and it is utilizing
the open waters not previously used by the other fish.

Two introductions of this fish were made into Lake
Havasu on the Colorado River, one in December, 1954,
and another in March, 1955. By July, 1955, shad were
found throughout the river from below Davis Dam
to Yuma, Arizona, and in the Salton Sea. In April,
1956, an extensive evaluation program was begun. The
results to date show that the shad is being utilized by
the largemouth bass as forage. There is some indica-
tion of an increased growth rate for the bass that
started in the spring of 1955 when the shad were
populating the river at a rapid rate. The relationship
of the shad to the channel catfish is not clear. The
evaluation program is only in its initial phase, however.

Increased angler success at Lake Havasu has been
attributed to the shad.

Puddingstone Reservoir, Los Angeles County, was
stocked with shad in March, 1955. They have done
very well here and appear to have favorably influenced
the fishery. The survival of largemouth bass has been


In warmwater impoundments the fishery is sup-
ported by a number of different kinds of fish rather
than just one or two as in trout waters. This compli-
cates management practices as control or heavy use
of one fish often markedly affects the numbers or
success of other fish. Because of the close relationship
between forage fish, sport fish and rough fish, such
as carp, a knowledge of population size and composi-

tion is essential for intelligent management. It may be
possible, for instance, to improve the fishing in a water
by the control or introduction of different fish. An
example of such a manipulation is the introduction of
the threadfin shad into the Colorado River.

This population information is gathered in a number
of ways, some of which are by no means simple. A
short-term, intensive survey method has been devel-
oped and applied in waters throughout the State from
Modoc County to San Diego County.

Included in these surveys were: Big Sage Reservoir,
Modoc County; Lower Susan River, Lassen County;
Millerton Lake in Fresno and Madera Counties; Pardee
Reservoir in Amador and Calaveras Counties; Turlock
Reservoir, Stanislaus County; several San Diego
County reservoirs and Salt Springs Valley Reservoir,
Calaveras County. Much of the information gathered
in these studies is now being applied in the manage-
ment of the waters.


Two pre-impoundment surveys were made. The
American River above the Folsom Dam site was sam-
pled in 1955 and again in 1956, as was Putah Creek
above the Monticello Dam site. The information ob-
tained will be used in the management program for
the completed reservoirs. Evaluation of rough fish
removal prior to the flooding of new reservoir basins
is also in progress.

In 195 3 a largemouth bass tagging study was begun
at Clear Lake, Lake County. The purpose of the study
was to determine the harvest rate for this species.

Boat launching beach at Folsom Lake, one of the State's newest warmwater takes.

(Fish and Game Photo)

Three-year tag returns were received permitting the
calculation of basic mortality figures never before
available for largemouth bass. These were possible
only because a better tag was developed. Similar data
was obtained at Sutherland Reservoir, San Diego

Fish diseases and parasites, normally serious only in
crowded hatcheries, have not been thought to be a
problem in wild warmwater fish populations. In sev-
eral waters where the largemouth bass spawning suc-
cess was very high, serious infestations of heart nema-
todes were discovered. These may be one of the causes
for the great fluctuations in year classes that com-
monly occur in these waters. The effect of the parasite
is not fully known and a control method has yet to
be devised.


In addition to the importation of new forage fish,
several new sport fish were brought into the State.
One of these, the redeye bass, brought in during the
previous biennium, was unsuccessful and none are
now found in the State. The redear sunfish was im-
ported in 1954 and propagated in Southern California
and at Central Valleys Hatchery. It has been planted
into ponds and lakes and is now being observed. The
range of the pumpkinseed sunfish in California was
extended by a series of experimental plants in the
colder ponds of the central coastal region.

White crappie, and the native Sacramento perch
were both tried in new waters. Only the white crappie
has offered improved angling.

The success of the landlocked striped bass in the
east, together with a need for a control on a stunted
panfish population resulted in an introduction of this
species into Millerton Lake in 1956.


Since World War II, the once lowly catfish has
risen rapidly in the esteem of California's anglers. An
indication of its popularity as a game fish is revealed
by the fact that approximately 19 percent of Cali-
fornia's license holders fished for them in 1955. The
total catch that \ear was 7,500,000 catfish, making
California the leading state in the Nation in sport fish-
ing for catfish.

Increasing fishing pressure on the State's catfish pop-
ulations created an urgent demand for statistical data
on the major fisheries, and data on the life histories
of the most important catfish species. Information of
this type was necessary in order to establish a factual
basis for the proper management of the fisheries.

An opportunity to obtain valuable information
about little known catfish was presented in 1951 with
the availability of federal aid funds for sport fish

Angler Phil Douglas displays big channel catfish he took horn the
Colorado River.

(Fish and Game Photo)

A Federal Aid Project was started in 1952, and was
the first freshwater investigation in California sup-
ported with funds derived from excise taxes on fish-
ing equipment. Having accomplished its original ob-
jectives, it was terminated on June 30, 1956.

Tagging Studies

Considerable effort during the biennium was directed
toward completion of tagging investigations already
in progress in the Sacramento-San Joaquin Delta,
Clear Lake, and the Colorado River.

The Delta tagging experiments on white catfish
have been remarkably successful. Anglers have re-
turned over 1,300 tags from the 6,966 tagged fish
released since the inception of the project. The results
of these studies have made it possible to calculate the
vital statistics of the Delta catfish population with a
degree of accuracy seldom, if ever, realized before in
any similar studies conducted anywhere in the world.
\^alid measures of annual survival, rate of exploita-
tion, rate of natural deaths, and annual total mortality
have been obtained. Such data will be invaluable in
the conservation of the Delta catfish resource.

The principal factors responsible for the success of
these experiments have been the development of a tag
that will remain on the catfish for three years or more
and the noteworthy cooperation of sportsmen who
voluntarily reported the capture of tagged fish.

Certain sportsmen's groups, such as the Foothill
Sportsmen's Club of Oakland and the Twin Cities
Rod and Gun Club of Yuba City have contributed
greatly by sponsoring prize drawings for anglers who
reported capture of tagged catfish.

Channel Catfish

A tagging study on channel catfish in the Colorado
River, which was begun in 1954, was completed dur-
ing the biennium. Results of the study indicated that
the fishery is being exploited at a safe level and no
drastic changes in regulations are necessary.

Tagging studies at Clear Lake, in which 3,500 white
catfish and brown bullheads were tagged in 1952 and
1954, have demonstrated clearly that the fishery is
greatly underexploited. The annual harvest is only
about 2.5 percent of the catchable population. In other
words, most Clear Lake catfish simply die of old age.
An increased bag limit and liberalization of certain
gear restrictions have been recommended to encourage
better utilization of this resource.

The important channel catfish fishery in the Lower
Sacramento River system and Sutter Bypass was the
subject of a tagging study during 1955 and 1956. Tag
returns after one year indicated that the annual rate
of harvest is approximately 20 percent of the catch-
able population.

Sampling to determine abundance of young striped bass in the Sacra-
menio-San Joaquin delta area.

(Fish and Game Photo)

While fishing lor striped bass in the Sacramento River off Port Chicago,
Catalino Diangson of San Francisco hooked into this 277-pound sturgeon.
Victory over this 8-foof, 5-inch giant required 1 hour and 20 minutes.

(San Francisco News Photo)

Life History Studies

Successful management of a fishery must be based
on a thorough understanding of the biology of the
species concerned. Consequently, a major portion of
the catfish study program was directed toward gain-
ing an understanding of catfish life histories.

Emphasis was placed on study of the biology of
the white catfish in the Delta, since the Delta fishery
is the largest and most important in the State. By the
end of the biennium, data on age and growth, food
habits, size at maturity, reproductive characteristics
and diseases had been obtained.

The age and growth and food habits of channel
catfish in the Colorado River was studied in order to
evaluate the efi^ects of the experimental introduction
of the threadfin shad into that important river. The
catfish project started this work and it is being con-
tinued under the warmwater research program.

\'aluable facts about the food habits and age and
growth of catfish in Clear Lake have also been ob-
tained during the course of project activities.


The 1954-56 biennium coincides with the first two
years this federal aid project has been in operation.
The striped bass fishery is an extremely valuable one,


Trout tagged on under side.

(Fish and Game Photo by E. P. "Phil" Pister)

providing an estimated 2,000,000 days angling and
1,500,000 fish to 150,000 anglers annually.

During the biennium the system of postal card and
party boat catch reports has been maintained and im-
proved. An evaluation of the status of the fishery
based upon these records and data obtained through
special striped bass angler interviews and surveys was
made. It was shown quite conclusively that there has
been a gradual but decided decline in the total catch
and average angler success. Individual angler success
is now only about one-half w hat it was during tiie pre-
war years.

Bass Size Limit

In an attempt to improve the present quality of
angling a 16-inch minimum size limit and three fish
bag limit was recommended. These recommendations
were based on the biology of the striped bass and
angler catch records.

The annual striped bass fry surveys, which indicate
spawning success and the distribution and abundance
of frv on the nursery grounds, w as continued. Spawn-
ing success in 1955 and 1956 appeared to be very poor
in comparison with 1953 and 1954. The distribution
of fry and fingerling bass is an important consideration
in relation to the large water diversions in the Delta
and in industrial pollution.

Commercia/ Gill Netters

During the biennium, project personnel investigated
the commercial salmon and shad gill netters in the
Delta to obtain estimates of the number of game fish
destroyed during normal commercial operations. The
study was conducted during the 1954 and 1956 shad
seasons and the 1955 salmon season.

The investigations have shown that a greater num-
ber of bass are caught in the channel areas than in the
shallow flats of Honker and Grizzly Bays. However,
in the flats the percentage of striped bass in the catch
is almost twice that of the channels and the percentage
of mortality is also much greater. It is apparent that
the flats gill netters inflict the greatest relative amount
of damage in terms of fish destroyed per number or
poundage of marketable fish.

Salmon catch figures have been computed for the
last 10 years. Since the loss of the San Joaquin spring
salmon run, the August 10th to September 26th

commercial season provides about 97 percent of the
total annual river salmon catch. Gill netting for the
few salmon caught throughout the rest of the year
does not seem to justify the losses of bass caught in
gill nets.

On the basis of the data brought out by these in-
vestigations the department is recommending addi-
tional measures to protect the sport fishes.

In 1954 the taking of sturgeon on sporting tackle
was legalized for the first time in 37 years. The de-
partment felt that they were once again abundant
enough to support a hook and line fishery.

Sturgeon Size Limit

A sturgeon investigation was initiated to provide the
necessar\- data for the proper management of these
fish. A total of 1,003 white sturgeon were tagged in
San Pablo Bay. Tag returns indicate they are not
being overharvested by the anglers, although a con-
siderable number are caught by commercial gill net-
ters. The pattern of migrations has not yet been
\\ orked out in detail but there appears to be a general
tendencN' for them to move upstream in the late fall
and w inter. Two returns of San Pablo Bay were re-
corded from near the Columbia River in Oregon.

A method of determining the age of sturgeon was
developed and an age and growth formula has been
computed. This study showed that the San Pablo Bay
population was principally composed of 6- and 16-
year-old fish. The fishery is apparently dependent
upon a few successful year classes. It was shown that
a size limit of 50 inches offers greater protection for
the fishery than 40 inches. Sturgeon do not mature
until the\- are 15 to 20 years old and should be given
protection at least to that size.

Pollution Investigation

Project personnel ran a series of bioassays on the
waste effluent from an industrial plant near Antioch
and found it to be quite toxic to fish life. Another
series of tests is being run on the effluent, using striped
bass as the test fish. As a result of these tests improved
standards were required by the Pollution Control
Board and plant waste discharges are noticeably


Nearh- all of the department's basic trout research
is now performed under the auspices of a single Din-
gell-Johnson (Federal Aid) project, which was en-
larged during the biennium to include work on
catchable trout evaluation.

During the period, project activities were devoted
primarily to: (1) basic trout disease studies; (2) de-
veloping methods for the evaluation and improvement
of trout planting; (3) comparing difi^erent species and
strains of trout to determine which are the most suit-
able for the various types of California trout waters.





) Dots Ih. -o-t -tu tofcw

X Plot* IbfflfH in relation 10 land'

brM««> coodi bain, otc






Board designed by department to encourage tag returns.

(Fish and Game Photo)

Since the hatchery and planting program takes up
the largest portion of the department's fisheries
budget, a major effort was put forth in exploring and
developing methods to assure that the public will re-
ceive maximum value from the planted fish.


A special tag was developed from vinyl plastic. It
is placed under the thin skin covering the ventral sur-
face of the trout, but does not affect growth or be-
havior of the fish. It has enabled the research workers
to follow particular groups of planted fish and to
determine, through the return of these tags, many
things. These include total catch of the planted fish,
migration from the area of plant, growth of the trout,
and overwinter survival— in essence, the value of the
planted trout to the angler.

Special tagging studies were carried out on various
types of waters receiving large plants of catchables.

Some of the waters on which the department made
test evaluations are: South Fork of the American
River, El Dorado County; South Fork of the Yuba
River; Lake Pillsbury, Lake County; Big Bear Lake,
San Bernardino County, and the Kern River in Kern

Tag Returns Encouraged

A great deal of publicity was given to the studies
at the latter two waters in order to encourage tag
returns. An added incentive for tag return was the

donation of money and awards by sportsmen and local
businessmen at public drawings.

Other waters of the State will be studied to deter-
mine whether they fall within the observations made
to date. Ultimately, through the methods used here,
fisheries managers in the regions will be able to deter-
mine more effectively the value of catchable trout in
their particular areas. Adjustments will be made from
w ater to water to utilize more effectively the hatchery
product. Total planting of catchables on some waters
will be increased and others decreased to the general
good of the fishing public.

The comparison of different species and strains of
trout in various types of California waters mainly in-
volved the planting of different lots of marked hatch-
ery fish and the checking back of returns to the
angler through intensive creel census studies. Other
work performed in conjunction with this phase of the
project consisted of comparing survival of trout
planted by air with others planted by truck or pack-
stock. These studies were conducted at Castle Lake
in Siskiyou County, Rush Creek in Mono County,
and at several lakes in the Lakes Basin Recreation
Area of Sierra and Plumas Counties.

Castle Lake Study

The results of the eastern brook trout phase of the
Castle Lake study were published in April, 1956, issue
of California Fish and Game. Some of the more im-
portant points brought out by this study are the fol-

\. After the removal of the predatory brown and
lake trout in 1946, the survival to the angler of eastern
brook fingerlings jumped from 1.9 percent to 35 per-
cent of those planted.

2. Although 1,503 pounds of yearling brook trout
were planted in 1947, only 978 pounds of fish from
this plant were eventually caught by the anglers. In
marked contrast, 100 pounds of brook fingerlings
planted in 1948 yielded 923 pounds to the anglers.

3. If predatory fish are not present, brook trout
fingerlings when planted will yield a high return to
the angler, and many will remain in the lake to spawn
and establish a large self-propagating population.

4. In Castle Lake at least, the brook trout is rarely
cannibalistic, so if too many are planted or if too
many are propagated naturally the food supply of
the lake will not be sufficient, and thin, stunted trout
will result.

5. The average catch of brook trout by the anglers
was about 10 pounds per acre per year.

Tmto Important Studies

Some of the facts gathered in the Lakes Basin
Recreation Area and at Rush Creek which could



'7ft^^w Ttea/^ ;





JULY 1, 1954, AND JUNE

30, 1956




Name of water





None noted


Folsom Reservoir. _

Placer, El



U. S. Corps of Engi-

Nimbus Reservoir

(Lake Natoma)-.

Sacramento . .


D. S. Bureau of Re-

Sly Park Reservoir.

El Dorado


U. S. Bureau of Re-


Kent Lake



Marin Municipal Water

Chesbro Reservoir.

Santa Clara ..


South Santa Clara
Water Conservation


Avocado Lake



U. S. Corps of Engi-

Pine Flat Reservoir



U. S. Corps of Engi-

Isabella Reservoir



U. S. Corps of Engi-

Los Banos Ponds..



Wildlife Conservation

Hume Lake*



Wildlife Conservation

Vermillion Reser-




Southern California
Edison Co.


Santa Felicia Res-




United Water Conser-

vation District of

Ventura County

* Repair and rehabilitation.

have considerable influence on the department's trout
management program are:

1. The "Splake," a hybrid fish resulting from the
cross of eastern brook trout and lake trout, was found

1 2 3 4 5 7 9 10 11 12 13 14 15 16

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