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CALIFORNIA
FISH-GAME




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

Subscriptions may be obtained at the rate of $10 per year by placing an order
with the California Department of Fish and Game, 1416 Ninth Street,
Sacramento, CA 95814. Money orders and checks should be made out to
California Department of Fish and Game. Inquiries regarding paid subscriptions
should be directed to the Editor.



Complimentary subscriptions are granted on an exchange basis.



Please direct correspondence to:

Perry L Herrgesell, Ph.D., Editor
California Fish and Game
1416 Ninth Street
Sacramento, CA 95814



u






D



V



VOLUME 72



JANUARY 1986



NUMBER 1




Published Quarterly by

STATE OF CALIFORNIA

THE RESOURCES AGENCY

DEPARTMENT OF FISH AND GAME

—IDA—



STATE OF CALIFORNIA
GEORGE DEUKMEJIAN, Governor



THE RESOURCES AGENCY
GORDON VAN VLECK, Secretary for Resources



FISH AND GAME COMMISSION

BRIAN J. KAHN, President
Santa Rosa
ABEL C. GALLETTI. Vice President WILLIAM A. BURKE, Ed.D, Member

Los Angeles Brentwood

ROBERT BRYANT, Member ALBERT C. TAUCHER, Member

Yuba City Long Beach

HAROLD C. CRIBBS
Executive Secretary



DEPARTMENT OF FISH AND GAME

JACK C. PARNELL, Director

1416 9th Street
Sacramento 95814



CALIFORNIA FISH AND GAME

Editorial Staff

Editorial staff for this issue consisted of the following:

Wildlife William E. Grenfell, Jr.

Anadromous Fish Kenneth A. Hashagen, Jr.

Marine Resources Robert N. Lea, Ph.D.

Striped Bass Donald E. Stevens

Editor-in-Chief Perry L. Herrgesell, Ph.D.



CONTENTS



Page



Population Characteristics of Pacific Herring, Clupea harengus

pallasi, in Humboldt Bay, California Douglas J. Rabin

and Roger A. Bamhart 4

The Striped Bass Sport Fishery in the Sacramento-San Joaquin

Estuary, 1969-1979 James R. White 17

Food of Juvenile Chinook, Oncorhynchus tshawytscha,
and Coho, O. kisutch, Salmon off the Northern Oregon
and Southern Washington Coasts, May-September 1980

Robert L. Emmett,

David R. Miller and Theodore H. Blahn 38

Line-Transect Censuses of Fallow and Black-Tailed Deer on

the Point Reyes Peninsula Peter J. P. Gogan,

Steven C. Thompson and Reginald H. Barrett 47

Notes

Utilization by Salt Marsh Harvest Mice,

Reithrodontomys raviventris halicoetes, of a

Non-Pickleweed Marsh Fred Botti,

Dee Warenycia and Dennis Becker 62
A Method for the Efficient Removal of Juvenile Saimonid

Otoliths Brian D. Winter 63



4 CALIFORNIA FISH AND GAME

Calif. Fish and Came 72(1 ): 4-16 1986

POPULATION CHARACTERISTICS OF PACIFIC HERRING,
CLUPEA HARENGUS PALLASl, IN HUMBOLDT BAY,

CALIFORNIA 1

DOUGLAS J. RABIN 2 AND ROGER A. BARNHART

California Cooperative Fishery Research Unit

Humboldt State University

Areata, California 95521

Population characteristics of Pacific herring, Clupea harengus pallasi, were
determined for spawning stocks in Humboldt Bay. Fecundity was estimated to be
220 ±35 eggs per gram. Biomass of hearring was estimated to be 372 tons (237mt)
in 1974-75 and 232 tons (210mt) in 1975-76. Spawning occurred from early December
to early March both years, primarily in north Humboldt Bay. Two- and three-year-old
herring accounted for about 46% and 57% by number respectively for the 1974-75
and 75-76 spawning stocks.

INTRODUCTION

In 1972, Japan removed its import quota on herring roe which stimulated the
market for herring and encouraged development of herring fisheries from
California to Alaska. The present study was designed to obtain information
needed for management of the Humboldt Bay herring fishery.

The biology of Pacific herring, Clupea harengus pallasi, has been extensively
studied for more than half a century (Rounsefell 1930, Taylor 1964,
Blankenbeckler 1978, Spratt 1981). Pacific herring spawning grounds extend
from southern California along the North Pacific rim to Japan. Spawning occurs
in inshore waters, bays, and estuaries, beginning in the late fall in California and
lasting up to four months.

When herring schools move into shallow inshore waters, they become highly
vulnerable to commercial fisheries. Fishery managers must know when
spawning occurs and where spawning schools are located to regulate the fishery.
The objectives of the present study were (i) record the time and distribution of
herring spawning in Humboldt Bay for two seasons, (ii) estimate biomass of the
spawning population and of the spawning substrate, and (iii) determine age
structure, maturity, and sex ratio of adult herring in Humboldt Bay. A concurrent
studv determined the fecundity of Humboldt Bay herring (Rabin and Barnhart
1977).

DESCRIPTION OF STUDY AREA
The 22.4 km-long Humboldt Bay is about 144 km south of the
California-Oregon border (Figure 1). It is a marine embayment having small
localizaed habitats with true estuarine characteristics (U.S. Army Corps of
Engineers 1976). Skeesick (1963) presented an extensive description of the
physical and chemical characteristics of Humboldt Bay.



1 Part of a thesis submitted by the senior author to Humboldt State University in partial fulfillment of a Master of

Science degree.

2 Mr. Rabin's present address is: P.O. Box 342, Kirkland, Washington 98033. Accepted for publication March

1985.



POPULATION CHARACTERISTICS OF PACIFIC HERRING



ARCATA



PAC I F I C

OCEAN




MAP LOCATION



FIGURE 1. Map of Humboldt Bay, California



Large beds of eelgrass, Zostera marina, grow from mud flats that characterize
north and south Humboldt Bay (Figures 2 and 3). Harding, Butler, and Heft
(1975) estimated that the north and south bays had 4.35 X 10 6 m 2 and 8.86 X
1 6 m 2 of eegrass, respectively. Mud flats and eelgrass beds are exposed at most
minus tides and are divided by a network of narrow channels. Distribution of
eelgrass is limited primarily to shallow mud flat areas due to high water turbidity
and tidal scouring along channel edges. Eelgrass is the primary herring spawning
substrate in Humboldt Bay.



CALIFORNIA FISH AND CAME



PAC I F I C
OCEAN




|.Vv. : :-' - | EELGRASS

A- I SPAWNING LOCATIONS



%



ARCATA



%



%i



°"> i



MUD




MUD



METERS



_i



1000



2000



NORTH HUMBOLDT BAY



FIGURE 2. Map of north Humboldt Bay at 0-tide. Stippled areas indicate eelgrass distribution for
winters 1974-75 and 1975-76.

HISTORY OF FISHERY

The Bay has supported a relatively small bait and commercial herring fishery
for over 50 years. A total of about 630 1 of herring were harvested from 1 926-76;
the largest annual catch, 63 t was taken in 1943. There were no commercial
landings of herring in 1965-72. In 1975 and 1976, 1 and 11 t respectively, were
caught under temporary state legislation allowing a winter harvest of 20 t. The
state increased the harvest quota to 50 t in 1977 and the quota was approached
each year from 1979 through 1981 and exceeded in 1982 (Table 1 ). The quota
was increased to 60 t in 1983.

METHODS AND MATERIALS

Fish Sampling
Herring were caught in 1974-75 with a variable mesh sinking nylon gill net,
38.1 by 1.8 m with equal lengths of 1.3, 1.9, 2.5, 3.2 and 3.8 cm bar mesh. The
net was allowed to soak no more than 10 min per set in areas where birds and



POPULATION CHARACTERISTICS OF PACIFIC HERRING



seals were actively feeding. During 1975-76 a 60.9 by 6.1 m beach seine was
used for sampling and a recording fathometer used to locate the fish.

The following data were recorded for each fish sampled; standard length in
mm, weight to the nearest 0.1 g, sex, and maturity. Scales were removed for age
determination. Fish caught in the 1974-75 season were categorized as being
either immature, having undeveloped gonads, or mature, with gonads filling the
body cavity (Bagenal and Braum 1971 ). In the 1975-76 season mature fish were
further categorized as having opaque (ripening) or translucent (ripe) eggs.



PACIFIC OCEAN





SPAWNING LOCATIONS,
EELGRASS



SOUTH HUMBOLDT BAY



METERS
i



2000



FIGURE 3. Map of south Humboldt Bay at 0-tide. Stippled areas indicate eelgrass distribution for
winters 1974-75 and 1975-76.

Scales used for age determination were taken from the area below and anteri-
or to the dorsal fin, then mounted between two glass plates and aged without
reference to fish length. An annulus at the outer edge of the scale was assumed
on scales of herring caught during the spawning season. For example, a herring
hatched in January 1974 and caught in January 1976 was considered a 2-year-
old, although showing only one annulus inside the scale margin.



8 CALIFORNIA FISH AND CAME

TABLE 1. Pacific Herring Landings, Humboldt Bay, California. 1974-1983.

* Landings Quota

Year Tons Pounds (tons)

1974 0.2 500 20

1975 1.0 2,000 20

1976 11.6 23,134 20

1977 21.5 42,949 50

1978 11.7 23,417 50

1979 49.4 98,831 50

1980 49.5 98,981 50

1981 43.0 85,920 50

1982 51.6 103,280 50

1983 9.5 18,980 60

• Ron Warner, California Department of Fish and Came Eureka, Ca. (pers. comm.).

Spawn Surveying

Time, distribution, and density of spawns were determined for the winters of
1974-75 and 1975-76. From late November to late March, daily surveys of
eelgrass beds were conducted, alternating days between north and south Hum-
boldt Bay. Surveying was done from a 5 m flat bottom boat. Two garden rakes,
wired back to back and attached to the boat with a 10 m rope, were used to
uproot eelgrass and examine it for attached eggs. The rake was used to outline
spawning areas with the aid of buoys, duck blinds, and other landmarks as
reference points. We installed 5 m wood poles as additional channel markers
to facilitate surveying at higher tides.

The modified rake was randomly cast from a boat in a spwaning area to obtain
3-16 samples of 100-400 g of eelgrass on which eggs had been deposited in
order to calculate mean number of eggs per kg of eelgrass. The size of the
spawning area and density of egg deposition determined the number of samples
collected. After roots were removed, each sample was placed in a plastic bag,
brought to the laboratory, rinsed clean of sediment, and allowed to drain. Leaves
were weighed to the nearest 0.1 g and preserved in 10% formalin. Eggs in each
sample were hand counted and mean number of eggs per kg of eelgrass was
estimated for each spawning area.

Fish sometimes spawned two or more times in areas that already contained
unhatched eggs. Even though the first spawn had already been measured and
sampled it was difficult to determine the extent of overlap and relative density
of the more recent egg deposition. In such instances water temperature and egg
development were monitored and hatching time for the first spawn was predict-
ed according to Alderdice and Velson (1971 ) and Taylor (1971 ). After the first
eggs hatched, the more recently deposited eggs were measured and sampled as
a single unit. The estimates were calculated and reported as separate spawns.

Mean weight/m 2 of eelgrass was obtained by sampling eelgrass during day-
time minus tides in February and March. A 0.15 m 2 hoop was cast randomly in
areas where spawning occurred. Eelgrass rooted within the hoop was cut to
exclude the roots and bagged. Samples were brought to the laboratory, rinsed
clean of sediment, drained, and weighed to the nearest 0.1 g. Mean weight/m 2
values were derived each winter for areas having light and medium eelgrass
growth, as classified by Harding (1973).



POPULATION CHARACTERISTICS OF PACIFIC HERRING 9

Number of kilograms of eelgrass on which eggs were laid was determined by
multiplying the spawning area in m 2 by mean weight of eelgrass per m 2 within
the same area. We used a polar planimeter and Coast and Geodetic Survey chart
of Humboldt Bay to measure the previously outlined spawning area.

Fecundity
The mean number of eggs per gram of fish was derived from a concurrent
fecundity study of Humboldt Bay herring (Rabin and Barnhart 1977). We deter-
mined the mean number of eggs per gram of female herring to be 220 ± 35
(95% CI) for ages 2-9.

Biomass Estimation
Biomass of herring in each spawning school was determined by the following
equation:

B C



D



where:



A = grams of fish spawning

B = kilograms eelgrass on which eggs were deposited

C = mean number of eggs per kilogram of eelgrass

D =mean number of eggs per gram of spawning adults (sexes combined)
Confidence limits of final biomass estimates were calculated from the com-
bined variance for eggs/kg eelgrass of all samples taken for the respective
season.

The sex ratio of adult herring in both years did not differ significantly from 1:1,
therefore, the value (D) used for fish biomass computations was 220/2 or 110
eggs per gram of herring for both sexes.

RESULTS

Age and Growth Relationships

During January and early February 1975, herring were caputured near spawn-
ing areas Ui>ing a variable-mesh gill net. In 1976 a beach seine was used to
capture herring. Adult herring, 2 to 1 1 years old, were found in the spawning
populations in both years. For 1974-75 and 1975-76, respective mean lengths
ranged from 157 to 230 mm and 166 to 223 mm, and mean weights from 63 to
195 g and 79 to 178 g (Table 2). Two-years-olds from the 1975-76 catch were
markedly longer and heavier than 2-year-olds from the 1974-75 catch. Length
overlapped considerably among all adjacent age groups (Figure 4). Two- and
three-year-old herring far outnumbered all other age groups (Figure 5) but were
not distinguishable by length alone (Figure 6).

Ages 2 and 3, combined, accounted for 57.1% by number and 43.8% by
weight offish spawning in 1975-76 (Table 2). No young of the year or yearlings
were taken in either season.

Maturity

Of 408 adult herring examined in 1974-75, 96% were mature. All herring
caught in 1975-76 were mature; most (99%) were in ripe or running ripe
condition.



10



CALIFORNIA FISH AND CAME



TABLE 2. Year Class Statistics for

1974-75 and 1975-76.

Season

and age Year

group class

1974-75

2 1973

3 1972

4 1971

5 1970

6 1969

7 1968

8 1967

9 1966

10 1965

11 1964

1975-76

2 1974

3 1973

4 1972

5 1971

6 1970

7 1969

8 1968

9 1967

10 1966

11 1965

1 From gill net catches.

2 From seine catches.

2^0



230
220



Humboldt Bay, Pacific Herring Caught During Winters



210



200



c

01



\~190



10 «-«

% 180
u



170
160
150

1U0



T



T



T
I
I
T



I 1



1









Mean


Mean




Percent


Percent


standard


weight


mber


number


weight


length (mm)


<g>


75


29.6'


15.3


157


63


42


16.6


14.0


179


103


41


16.2


16.2


190


122


19


7.5


9.4


205


153


11


4.3


6.5


212


181


19


7.5


10.7


212


173


30


11.9


18.0


218


185


11


4.4


7.0


224


195


3


1.2


1.7


217


173


2


0.8


1.2


230


191


97


33.6 2


22.9


166


79


68


23.5


20.9


183


102


33


11.4


12.3


197


123


28


9.7


12.1


204


142


14


4.8


6.8


212


159


10


3.5


5.1


217


168


25


8.7


13.0


219


170


10


3.5


4.9


218


160


3


1.0


1.6


221


178


1


0.3


0.4


223


153



„ T



T



t T



1



H 1 1

I

1



t
I
1



*



III



11 l 1



I



. 1974-75 winter range and •
" 1975-76 winter range and o



FIGURE 4.



1 2 3 ^ 5 6 7 8 9 10 II

Age ( Yeors)
Age and length relationships for Humboldt Bay herring caught during winters 1974-75
and 1975-76.



POPULATION CHARACTERISTICS OF PACIFIC HERRING



11



kO



30



20



c

V

u

L.
0>

0.



10



l 23^56789 10 11

Age (yr)
FIGURE 5. Age composition of 289 Humboldt Bay herring, January 1976.



}k



c
a>
u

L.

a>



12

10

8

6



1M).5 150.5 160.5 170.5 180.5 190.5 200.5 210.5 220.5 230.5 2U0.5

Standard Length (mm)

FIGURE 6. Length groups for 289 Humboldt Bay herring, January 1976.



1 2 CALIFORNIA FISH AND CAME

Eelgrass Biomass Estimates

Eelgrass biomass estimates for areas where spawning occurred were derived
from 50 samples taken in 1974-75 and 71 samples in 1975-76 (Tables 3, 4).

Eelgrass density was variable from year to year. In 1975-76 eelgrass biomass
in north Humboldt Bay was 25% less than in 1 974-75. However, areas classified
by Harding (1973) as having light eelgrass growth (Figure 2, areas A-D) had
more eelgrass biomass each year than did Harding's areas of medium growth
(Figure 2, areas E-l).

Eelgrass biomass per unit of area is typically higher in south Humboldt Bay
than in north Humboldt Bay (Harding 1973). Spawning biomass estimates for
south Humboldt Bay are conservative because due to time constraints we used
north bay eelgrass density values in our calculations.

Herring Biomass Estimation

Random samples of eggs on eelgrass were collected nine times in 1 974-75 and
eight times in 1975-76. The number of spawns each winter was greater than the
number of sampling dates, judging by the occurrence of intermittent overlapping
spawning. These intermittent spawnings were observed in January and February
of both seasons.

Spawning began in mid-December and ended in early March; about 99%
occurred between December 14 and February 14. More than 99% of the total
egg deposition was in north Humboldt Bay — 80% in the eelgrass beds southeast
of Bracut channel (Figure 2, Area A).

Estimated Humboldt Bay Pacific herring spawning biomass was 372 ±8 t in
1974-75 and 232 ±6 t (95% CI) in 1975-76. In addition 1 t (0.9mt) of adult
herring was taken commercially in 1974-75 and 11 t (10mt) were caught in
1975-76 in Humboldt Bay (Tables 3, 4).

DISCUSSION

Most herring spawning took place in Humboldt Bay during December through
March, the same months in which spawning occurred in San Francisco and
Tomales Bays, California (Spratt 1976, 1981 ). Eighty percent of all spawning in
Humboldt Bay occurred in the North Bay eelgrass beds nearest the creeks
flowing into the bay. South Humboldt Bay receives comparatively little fresh
water and was practically unused by herring — even though South Bay has more
than twice the eelgrass biomass of North Bay. Outram (1951 ) found that low
salinity water stimulated herring to spawn while in captivity. Taylor (1971)
reported that hatching success decreases with increasing salinity. The location
of fresh water inflow apparently influenced the location of herring spawning in
Humboldt Bay.

Seasonal catches of Humboldt Bay herring did not exceed 12 t (10,980 kg)
from 1959 through 1976. From 1979 through 1982 landings approximated 50 t
annually. We believe that the population characteristics during our data collec-
tion period resemble those of an unexploited resource.

Our sampling data show full recruitment of herring into the spawning stock
at age 2. Spratt ( 1 981 ) , from his work on San Francisco and Tomales Bay herring
populations, states that California herring enter the spawning population at 2
years of age and by age 3 all herring are mature. Recruitment of British Columbia



POPULATION CHARACTERISTICS OF PACIFIC HERRING



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POPULATION CHARACTERISTICS OF PACIFIC HERRING 15

herring occurs primarily at ages 3 and 4 (Outram and Hymphreys 1974). The
infrequency of spawning checks or false annuli on the scales we examined
indicated that the herring spawning season in Humboldt Bay does not overlap
significantly with the resumption of growth in late winter and spring.

Since seasonal abundance of eelgrass in north Humboldt Bay can be substan-
tially influenced by water quality (Harding 1973), bird feeding rates (Yocum and
Keller 1961 ), and oyster culture (Waddell 1964), the annual change in eelgrass
density we observed was not unusual. Our eelgrass biomass values represent
only the wet weight of eelgrass leaves since the rhizome is an inaccessible
substrate for herring eggs.

Field observations indicate that herring eggs do not adhere well to eelgrass
coated with sediment or decaying epiphytes. Our herring biomass estimates are
conservative due to the detachment of eggs between sampling periods, which
Hart and Tester (1934) attribute to wave action.

Although bird predation of herring eggs can account for high removal rates
of eggs before hatching (Cleaver and Frannett 1946, Outram 1958, Steinfeld
1972, Spratt 1981 ), we believe that predation was not a significant factor in the
calculation of Humboldt Bay herring biomass estimates. Few to no bird aggrega-
tions were observed at Humboldt Bay spawning sites, regardless of tidal height.
Spawning intensity was relatively light, which according to Spratt (1976) makes
bird predation on eggs difficult.

Our 1974-75 and 1975-76 spawning biomass estimates of 372 t (337mt) and


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