In Tomales Bay, 5-, 6-, and 7-yr-old herring, Clupea harengus pallasi, composed 75% by number of the 1984-85 season's catch. In San Francisco Bay, 2-, 3-, and 4-yr-old herring composed 82% by number of the roundhaul catch, and 5-, 6-, and 7-yr-old herring composed 68% by number of

the gill net catch.

The percent of 4-yr-old herring increased to a record high level in the San Francisco Bay gill net catch.

Recruitment of 2-yr-old herring into the San Francisco Bay roundhaul fishery was excellent, with 2-yr-old herring composing 41% of the catch.

The growth rate of herring improved in both Tomales and San Francisco Bays, after the period of poor growth during the recent El Nino, when the weight of herring averaged 20% below normal.

(23pp.

Spratt, Jerome D.

English

The 1983-84 Tomales Bay and San Francisco Bay gill net catch was dominated by 5-, 6-, and 7-yr-old herring, Clupea harengus pallasi. The dominant age classes in the San Francisco Bay roundhaul catch were 2- and 3-yr-old herring.

Good recruitment of the 1982 yr class in San

Francisco Bay is indicated by the occurrence of 47% 2-yr olds in the roundhaul catch.

The mean length of herring in the Tomales Bay gill net catch declined to 199 mm BL, while the mean length of the San Francisco Bay gill net catch increased to 205 mm BL. The mean length of the San Francisco Bay roundhaul catch declined to an all time low of 165 mm BL. The mean weight of all age classes in both Tomales and San Francisco Bays was

at least 20% below long-term mean levels. The herring

weight loss in 1983 may have resulted from the poor availability of food caused by the 1982-83 El Nino.  (20pp.

Aquatic Commons

CALlFQRNlA DEPT. OF FISH & GAME 
STATE FISHERIES LIBRARY 
LONG BEACH 
State of California 
The Resources Agency 
DEPARTMENT OF FISH AND GAME 
BIOLOGICAL CHARACTERISTICS OF THE CATCH 
FROM 1983-84 PACIFIC HERRING, 
CLUPEA HARENGUS PALLASI, ROE FISHERY IN CALIFORNIA 
by 
Jerome D. Spratt 
MARINE RESOURCES 
Administrative Report No. 84-4. 
JULY 1984 
BIOLOGICAL CHARACTERISTICS OF THE CATCH 
FROM 1983-84 PACIFIC HERRING, 
CLUPEA HARENGUS PALLASI, ROE FISHERY IN CALIFORNIA L/ 
by 
2/ 
.Jerome D. Spratt - 
ABSTRACT 
The 1983-84 Tomales Bay and San Francisco Bay gill 
net catch was dominated by 5-, 6-, and 7-yr-old 
herring, Clupea harengus pallasi. The dominant age 
classes in the San Francisco Bay roundhaul catch 
- 
were 2- and 3-yr-old herring. 
Good recruitment of the 1982 yr class in San 
Francisco Bay is indicated by the occurrence of 47% 
2-yr olds in the roundhaul catch. 
The mean length of herring in the Tomales Bay gill 
net catch declined to 199 rnm BL, while the mean 
length of the San Francisco Bay gill net catch in- 
creased to 205 mm BL. The mean length of the San 
Francisco Bay roundhaul catch declined to an all- 
time low of 165 mm BL. The mean weight of all age 
classes in both Tomales and San Francisco Bays was 
at least 20% below long-term mean levels. The her- 
ring weight loss in 1983 may have resulted from the 
poor availability of food caused by the 1982-83 El 
NiRo. 
1/ Marine Resources Administrative Report. 
- 
2/ Marine Resources Region, Marine Resources 
- 
Laboratory, 2201 Garden Road, Monterey, 
California 93940. 
INTRODUCTION 
The Department began monitoring the age, size, and sex compo- 
sition of the Pacific herring, Clupea harengus pallasi, roe fishery 
catch in Tomales and San Francisco Bays in 1973. 
Spratt (1981, 1982, and 1983) reported on data collected by 
sampling the roe fishery catch from 1973 until 1983. This report 
provides a continuous time series of data through the 1983-84 season. 
METHODS 
Sampling 
In Tomales Bay, herring samples were taken at Marshall, and in 
San Francisco Bay sampling was at Sausalito and San Francisco. Three 
samples were taken per day in each bay during the fishing season when 
herring were available. A sample consisted of 2.3 kg (5 lb) collected 
after the vessel unloaded, 
All samples were processed in a fresh condition. Laboratory pro- 
cedures have remained unchanged since the fishery began in 1973 
(Spratt 1981). Every fish in the sample was weighed to the nearest 
0.1 g, measured in millimeters body length, and sex and maturity were 
determined. Body length was used as the unit of measurement because 
the fleshy caudal peduncle of h e r r i n g  makes the hypural plate diffi- 
cult to locate. Body length was measured from the tip of the snout to 
the end of the silvery part of the body. Otoliths were removed for 
age determination and stored in gelatin capsules. Ages were assigned 
- 2 -  
I 
by the author using previously discussed criteria (Spratt 1981). All I 
otoliths were read twice before final age determinations were made. 
RESULTS 
Tomales Bay 
A total of 14 samples was collected this season and 132 individ- 
ual fish were processed. 
Age Composition 
The Tomales Bay fishery was restricted to gill nets in 1977, and 
since then, the catch has been dominated by 5-, 6-, and 7-yr-old 
herring. 
In the 1983-84 season, gill net landings were dominated by 5- and 
6-yr-old herring, these 2 yr classes comprised 71% of the catch by 
number and 70% by weight (Table 1). The percentage of 8- and 9-yr 
olds in the catch declined to only 5% by number, the lowest level in 
7 yr. 
The percentage of 3- and 4-yr-old herring in the catch has aver- 
aged 11% since the 1979-80 season, but there were no 3-yr-old herring 
in the catch of the past two seasons, and this season 4-yr olds 
accounted for 13% of the catch by number (Table 1). 
Length Composition 
The average length of herring in the Tomales Bay catch during the 
1983-84 season decreased to 199 mm BL (Table 2). This is the smallest 
recorded mean length of the catch since 1977 and represents the second 
consecutive year the average length of herring in the Tomales Bay 
catch has declined. In the past, changes in the average length have 
corresponded to changes in the age composition of the catch. ~uring 
the 1983-84 season, the change in length of the catch was not due to a 
shift in the age composition; the average length of 5-, 6-, and 
7-yr-old herring (Table 3) all declined from the 1982-83 mean lengths 
(Spratt 1983). 
Primary productivity has been very low off the coast of central 
California the past 2 yr due to El NiEo and poor growth is a major 
factor contributing to the decline in mean length during this time. 
Weight Composition 
The mean weight at age of herring has fluctuated within normal 
limits from the 1976-77 until the 1982-83 season. Herring age 5 
through 7 yr, which normally comprise over 80% of the catch, averaged 
145 g in weight during these 7 yr (Table 4). In the 1983-84 season, 
the mean weight of age 5- through 7-yr-old herring was 117 g, an 
average decline of 19% (Table 4) from the 7-yr mean. 
Sex Ratio 
The sex and biomass (weight) ratio of the 1983-84 Tomales Bay 
catch were nearly equal (Table 5). These ratios (60% females) are 
within the range of expected values. 
San Francisco Bay 
A total of 30 samples was collected this season and 345 indi- 
vidual fish were processed. 
Age Composition 
In San Francisco Bay, the roundhaul and gill net fisheries were 
sampled separately. Recruitment has been a major source of variation 
in the age composition of the roundhaul catch over the past two sea- 
sons. Recruitment of the 1981 yr class (2-yr olds) into the 1982-83 
- 4 -  
. 
fishery was poor (Spratt 1983) and the catch was dominated by 3-1  4-, 
and 5-yr-old herring. In 1983-84, recruitment improved, and the 1982 
yr class (2-yr olds) composed 47% by number and 35% by weight of the 
1983-84 roundhaul catch (Table 1). The 1982 yr class appears to be 
strong, but the roundhaul fishery in San Francisco Bay was confined to 
the latter part of the spawning season when more younger herring are 
more available; therefore, the 1982 yr class may not be as strong as 
this season's sampling indicates. There were no 9-yr-old herring in_--__. 
the catch samples and 8-yr olds composed less than 1% of the catch; 
this is also typical of a late-season fishery. 
The age composition of the San Francisco Bay gill net catch has 
stabilized the past six seasons and is dominated by 5-, 6-, and 
7-yr-old herring. This season 5-, 6-, and 7-yr-old herring composed 
85% by number and 82% by weight of the gill net catch (Table 1). 
Length Composition 
The mean -length of the San Francisco Bay roundhaul catch declined 
to an all-time low of 165 mrn BL (Table 2) due to the strong 1982 yr 
class and poor growth. All age groups exhibited poor growth during 
1983 (Table 5). A comparison of length at age from the 1983-84 season 
with long-term mean lengths (Table 6) indicates the degree that growth 
was affected. Poor growth is more apparent in younger herring than 
older herring because growth in length slows with age. Two- and 
three-yr-old herring composed 71.5% of the catch (Table 1) and were 
affected far more than older herring. 
The length at age of the gill net catch in San Francisco Bay was 
not affected by the poor growth conditions in 1983. The average 
length at age (Table 7) of herring in the catch and the overall mean 
length were normal (Table 2). 
Weight Composition -
The overall weight composition of the roundhaul and gill net 
catch (Table 1) parallels that of the age composition. The roundhaul 
catch was dominated by 2- and 3-yr-old herring, while the gill net 
catch was composed mainly of 6- and 7-yr-old herring. However, the 
poor growing conditions in 1983 had a much greater effect on the 
weight of individual herring than it did on the length. Samples from 
the roundhaul catch indicate that all age groups were an average of 
23% below normal weight in the 1383-84 season (Table 8). The mean 
weight at age from t h e  gill net fishery, which is selective for large 
herring, declined 18%. The average weight of 6- and 7-yr olds this 
season was less than the normal weight of 5-yr-old herring from past 
seasons. The mesh size restriction for gill nets in San Francisco Ray 
(2 1/4 and 2 1/8 in. minimums for December and later months, respec- 
tively) is believed to have allowed the majority of under-weight 
herring to escape the gill nets and resulted in a catch of only those 
herring that exhibited the best growth during 1983. 
Sex Ratio 
The sex and biomass (weight) ratios in the San Francisco Bay gill 
net catch~re-'~qual, with females composing 67% of the catch (Table 
/-- 
~).<he San Francisco Bay roundhaul catch also included more females 
(55%) than males (45%). 
DISCUSSION 
The overall age composition of the 1983-84 catch from both San 
Francisco Bay and Tomales Bay was normal. The only major change was 
in the San Francisco Bay roundhaul catch which was dominated by 2- and 
3-yr-old -- herring. The age composition of the 1983-84 roundhaul catch , 
---- 
- - - - - - - - 
---- 
--- 
---- 
---- 
---- 
.in San Francisco Bay is similar to the age composition of the 1973-74, 
74-75, and 75-76 seasons (Spratt 1981) when the roundhaul fishery 
occurred late in the spawning season. The decline in numbers of the 
older age groups in the catch in 1983-84 is thought to be an artifact 
of sampling late in the season, but data from Marine Resources Branch 
(Reilly and Moore 1984) indicate there was a decline in older age 
classes. ,I 
d 
2_ 
/----' 
The estimates of the Tomales and San Fancisco Bays herring 
spawning biomass both declined during 1983 (Spratt 1984). The age 
composition of the catch does not reflect this decline. Recruitment 
of the 1982 yr class is good, but sampling late in the season is not 
adequate to estimate relative abundance of older age groups. Mortal- 
ity rates were not calculated, but the abundant 1982 yr class indi- 
cates that total mortality was not excessive in 1983. Two factors, 
poor growth and distribution of the stock, are believed to be the 
major reasons for the declines in biomass. The El NiRo condition of 
1982 and 1983 was severe and had a measurable effect on herring 
growth. Herring growth, in length, in 1983 was 4.6% below normal 
(Table 6). Weight gain during the year normally has a positive influ- 
ence on biomass, but in 1983 herring actually lost weight. The weight 
of individual herring averaged over 20% below normal (Tables 4 and 8). 
Poor growth alone in 1983, accounted for most of the decline in San 
Francisco Bay spawning biomass estimates. The Tomales Bay stock 
------ 
declined far more than San Francisco Bay, but it is unlikely that poor 
environmental conditions affected the survival of Tomales Bay herring 
more than San Francisco Bay herring. The migratory routes of these 
two stocks are unknown after they leave the spawning grounds; however, 
- 7 - 
it is believed that at least part of both stocks normally migrate in 
a southerly direction and spend the summer near Monterey Bay. Unusu- 
ally warm ocean currents from the south this year may have changed the 
distributional pattern of herring. The Tomales Bay stock could have 
been turned north along with part of the San Francisco Bay stock. 
Ocean temperatures did not cool until the spring of 1984, or after the 
spawning season was over. This would impede the return of herring 
that migrated north because of the warmer ocean temperatures off 
California. The distribution of herring is a plausible explanation 
for the severe decline of the Tomales Bay stock. 
CONCLUSION 
The 1982-83 El NiRo has had a definite impact on the growth rate 
of herring off the California coast. The 1982 yr class, although 
abundant in the catch, may not be as strong as sampling indicated, 
and the strength of the 1983 yr class is unknown at this time. 
These factors, coupled with the possibility of further adverse 
impacts from El NiRo and the fact that both San Francisco and Tomales 
Bays' stocks are declining, are cause for concern. 
The San Francisco Bay fishery is expected to improve in the 
1984-85 season because the growth rate of herring should return to 
/ 
1'- 
normal. &s Bay fishery is in doubt. If migration of her- 
ring out @+he area was the cause for the decline in abundance, the 
/ 
f A m a y  recover quickly. However, the possibility remains that 
the Tomales Bay stock will be depressed for some time. /
- 8 - 
In response to data collected during the 83-84 season, it is 
recommended that the 1984-85 roe fishery quotas be lowered. The 
Tomales Bay quota is recommended to be 260 tons and the San Francisco 
Bay quota is recommended to be 6500 tons, a reduction of 75% and 38%, 
respectively, from the previous season. These recommendations will 
- 
- 
prevent the exploitation rate from exceeding 20% of the available - 
stocks. 
REFERENCES 
Reilly, P.N. and T.O. Moore. 1983. Pacific herring Clupea harengus 
pallasii, studies in San Francisco Bay, Monterey Bay, and the Gulf of 
the Farallones, May 1983 to March 1984. Calif. Dept. Fish and Game, 
Mar. Resources Admin. Rept. 84-3: 1-67. 
Spratt, J. D. 1981. Status of the Pacific herring, Clupea harengus 
pallasii, in California to 1980. California Dept. Fish and Game, 
Fish Bull., (171): 1-104. 
. 1982. Biological characteristics of the catch from the 
1980-81 and 1981-82 Pacific herring, Clupea harengus pallasii, roe 
fishery in California. Calif. Dept. Fish and Game, Mar. Resources 
Admin. Rept. 82-10: 1-16. 
1983. Biological characteristics of the catch from the 1982-83 
Pacific herring, Clupea harengus pallasi, roe fishery in California. 
Calif. Dept. Fish and Gsme, Mar. Resources Admin. Rept. 83-4: 1-11. 
/ 1. 1984. Biomass estimates of the Pacific herring, Clupea 
/harengus pallasi, in California from the 1983-84 spawning-ground 
surveys. Calif. Dept. Fish and Game, Mar. Resources Admin. Rept. 
TABLE 1. Age a n d  W e i g h t  C o m p o s i t i o n  o f  t h e  1983-84 P a c i f i c  H e r r i n g  
Roe F i s h e r y  L a n d i n g s ,  by  Area a n d  G e a r .  
Age 
2 3 4 5 6 7 8 9 
Tomales  Bay 
Gill n e t  
P e r c e n t  by  number - - 13 36 35 11 2 3 
P e r c e n t  by w e i g h t  - - 10 34 36 13 3 4 
S a n  F r a n c i s c o  Bay 
Roundhaul  
P e r c e n t  by  number 47 24.5 8 11 7 2 0.5 - 
P e r c e n t  by w e i g h t  35 24 10 16 11 3 1 - 
San  F r a n c i s c o  Bay I 
G i l l  n e t  
P e r c e n t  by  number - - 0 . 6 1 2  48 25 11 3.4 
P e r c e n t  by w e i g h t  - - 0 . 4 1 0  46 26 13 4.6 
TABLE 2. Mean Length  o f  P a c i f i c  H e r r i n g  f rom Tomales  and  San  F r a n c i s c o  
Bays  Roe F i s h e r i e s ,  1972-73 t h r o u g h  1983-84 S e a s o n s .  
Tomales Bay San F r a n c i s c o  Bay 
G i l l  n e t  G i l l  n e t  Roundhaul 
Mean l e n g t h  S i z e  r a n g e  Mean l e n g t h  S i z e  r a n g e  Mean l e n g t h  S i z e  r a n g e  
1972-73 186 150-234 - - - - 
1976-77 169  140-216 
1977-78* 217 194-248 
1978-79 no  samples  
*Tomales Bay has been  r e s t r i c t e d  Lo g i l l  n e t s  s i n c e  1977. 
- 12 - 
TABLE 3. Length Frequency of Tomales Bay H e r r i n g  C a t c h ,  1983-84 Season. i 
Length Age 
(mm BL) 2 3 4 5 6 7 8 9 
242 1 
240 
238 
236 
234 
232 
230 
228 
226 
224 
222 
220 
218 
216 
214 
212 
210 
208 
206 
204 
202 
200 
198 
196 
194 
192 
190 
188 
186 
184 
182 
180 
178 
176 
174 
N 
Mean 
S tandard  
deviation 
TABLE 4. Comparison of Weight in Grams at Age of the 1983-84 
Tomales Bay Catch with the 7-Yr Mean. 
Age Unweighted 
Season 5 6 7 
7 yr x wt 132 146 156 
99% C.I. 4.4 4.6 4.1 
99% C.I. 4.2 4.4 19.2 
% det.1 ine 20 21 16 3 9 
TABLE 5. Length Frequency of San Francisco Bay'Roundhaul Herring 
Catch, 1983-84 Season. 
Length Age 
(mm BL) 2 3 4 5 6 7 8 9 
Mean 
Standard 
deviation 8.4 6.1 4.8 
TABLE 6. Comparison of Mean Length at Age of the San Francisco Bay 
Roundhaul Catch from the 1383-84 Season with the 10-Yr Mean. 
10-yr mean 
1973-74 - 1982-83 1983-84 season Percent 
Age* Id mmBL N mmBL decline 
These ayc groups compose 96% of samples taken. 
k*  99% confidence interval. 
TABLE 7 .  Length Frequency of San F r a n c i s c o  Bay G i l l  N e t  Herring Catch ,  
1983-84 Season .  
Length 
(mm BL) 2 3 4 5 6 7 8 9 
Age 
232 
230 
1 
228 
1 
226 
1 2 
224 
222 
1 
1 
220 
218 
2 1 
2 
216 6 
214 3 
212 1 
210 2 
208 
Mean - 
Standard 
d e v i a t i o n  - 
TABLE 8. Compar i son  o f  t h e  Mean Weight i n  G r a m s  a t  Age o f  t h e  1983-84 
S a n  F r a n c i s c o  Bay R o u n d h a u l  C a t c h  with t h e  10-Yr Mean. 
Age Unweigh ted  
1983-84 46 58 75 91 103 109 80 
99% C.I. 2.4 3.4 6.0 7.9 11.0 - 
- 
d e c l i n e  25 28 24 20 18 
TABLE 9. Female to Male Sex and Biomass (Weight) Ratios of the Catch 
for the 1983-84 Herring Roe Fisheries. 
Tomales Bay 
Sex ratio 
Biomass ratio 
San Francisco Bay gill net 
Sex ratio 
Biomass ratio 
San Francisco Bay roundhaul 
Sex ratio 
Biomass ratio 


Biological characteristics of the catch from 1983-84 Pacific herring, Clupea harengus pallasi, roe fishery in California

State of California 
The Resources ' 
DEPARTMENT OF FISH AND GAME 
BIOLOGICAL CHARACTERISTICS OF THE CATCH 
FROM 1984-85 PACIFIC HERRING 
CLUPEA - HARENGUS PALLASI, ROE FISHERY IN CALIFORNIA 
by 
Jerome D. Spratt 
W I N E  RESOURCES 
Administrative Report No. 85-3. 
1985 
BIOLOGICAL CHARACTERISTICS OF THE CATCH 
FROM 1984-85 PACIFIC HERRING, 
1 / CLUPEA HARENGUS PALLASI, ROE FISHERY IN CALIFORNIA - 
21 Jerome D. Spratt  - 
ABSTRACT 
In Tomales Bay, 5-, 6-, and 7-yr-old herring,  Clupea harengus p a l l a s i ,  
composed 75% by number of the  1984-85 season's catch. In  San Francisco 
Bay, 2-, 3-, and 4-yr-old herring composed 82% by number of the  round- 
haul catch, and 5-, 6-, and 7-yr-old herring composed 68X by number of 
the g i l l  net catch. 
The percent of 4-yr-old herring i ~ c r e a s e d  t o  a record high l eve l  i n  
the  San Francisco Bay g i l l  net  catch. 
Recruitment of 2-yr-old herring i n t o  the  San Francisco Bay roundhaul 
f ishery was excel lent ,  with 2-yr-old herring composing 41% of the 
catch. 
The growth r a t e  of herring improved i n  both Tomales and San Francisco 
Bays, a f t e r  the  period of poor growth during the recent E l  Nifio, when 
the weight of herring averaged 20% below normal. 
1/ Marine Resources Administrative Report No. 85-3. 
- 
2/ Marine Resources Region, Marine Resources Laboratory, 
-
2201 Garden Road, Monterey, California 93940. 
ACKNOWLEDGEMENTS 
I wish to thank Davfd Foote, Margaret Graham, Alistair  
Lizaranzu, and Karen Symonds for collecting and processing her- 
ring samples during the season. 
INTRODUCTION 
The Department began monitoring the age, size, and sex' composition of the 
Pacific herring, Clupea harengus pallasi, roe fishery catch in Tomales and San 
Francisco Bays in 1973. Spratt (1981, 1982, 1983, and 1984b) reported on data 
collected by sampling the herring roe fishery from 1973 until 1984. This report 
compliments previous data to provide a continuous seasonal series from 1973 
through the 1984-85 season. 
METHODS 
. Sampling 
In the Tomales Bay area, herring samples were collected at Marshall and 
Bodega Harbors. In San Francisco Bay, herring were collected at Sausalito and I 
San Francisco. This season the sampling level was increased from three per day . 
to four per day in each bay, when herring were available. A sample consisted of 
2.3 kg (5 lb) collected after vessels unloaded. 
All samples were processed in a fresh condition. Laboratory procedures 
have remained unchanged since the fishery began I n  1973 (Spratt 1981). Every 
fish in the sample was weighed to the nearest 0.1 g, measured in millimeters 
- 1  
body length (mm BL), and sex and maturity were determined. Body length was used 
b 
as the unit of measurement because the fleshy caudal peduncle of herring makes 
the hypural plate difficult to locate. Body length was measured from the tip of 
the snout to the end of the silvery part of the body. Otoliths were removed for 
age determination and stored in gelatin capsules. Ages were assigned by the 
author using previously determined criteria (Spratt 1981). All otolfths were 
read twice before final age determinations were made. 
RESULTS 
Tomales Bay 
A t o t a l  of 38 samples was co l l ec ted  t h i s  season and 311 ind iv idua l  f i s h  
were processed. 
Age Composition - 
The Tomales Bay f i s h e r y  was r e s t r i c t e d  to- g i l l  n e t s  i n  1977, and s ince  
then, t h e  catch has been dominated by 5-, 6-, and 7-yr-old herring.  
I n  the  1984-85 season, 5-, 6-, and 7-yr-old herr ing composed 75% of t h e  
catch by number and 77% by weight (Figure l ) ,  about average over the  long run. 
The percent of 8- and 9 y r - o l d  he r r ing  i n  t h e  catch has s t a b i l i z e d  during t h e  
past two seasons a t  5% by number (Figure l ) ,  the  lowest l e v e l  s ince  t h e  f i s h e r y  
was r e s t r i c t e d  t o  g i l l  ne t s  i n  1977. 
The percentage of 4 y r - u l d  he r r ing  i n  t h e  ca tch  (13%) was about average, 
while t h e  percentage of 3-yr-old he r r ing  i n  t h e  ca tch  was a t  i t s  highes t  l e v e l  
(6%) s ince  t h e  1977-78 season, when t h e  f i s h e r y  was r e s t r i c t e d  t o  g i l l  ne ts .  
Length Composition 
The average length of herr ing i n  the  Tomales Bay ca tch  during t h e  1984-85 
/
I season-Sed t o  202 mm BL (Table 1). The average l eng th  of 5-, 6-, and 
L 
7-yr-old herr ing (Table 2) a l l  increased from the  1983-84 season (Sprat t  1984b). 
This increase  is encouraging, but t h e  mean length  of t h e  ca tch  remains 
! depressed. This is  due t o  the  numbers of 3 y r - o l d  he r r ing  i n  the  catch and a 
residual effect of poor growth during 1983, from which the  Tomales Bay he r r ing  
. population has not completely recovered. 
The timing of the fishery also influenced the size and age composition of 
the catch this season. Most of our samples were taken late in the spawning 
season when the older age classes are less abundant. 
Weight Composition 
The mean weight at age of Tomales Bay herring declined dramatically in the 
1983-84 season, when weight at age of all exploited year classes was below' 
normal (Table 3). In the 1984-85 season, the mean weight of all age classes 
increased, but the average weight of the dominant age classes 5- through 7-yr 
olds remains below the 7-yr mean (Figure 2), and still exhibits the effect of 
poor growth in 1983. 
Sex Ratio 
The female to male number and biomass (weight) ratios of the 1984-85 
Tomales Bay catch were equal (Table 4). These ratios (60% females) are within 
the range of expected values, 
San Francisco Bay 
A total of 55 samples was collected this season and 531 individual fish 
were processed. 
Age Composition 
In San Francisco Bay, boih roundhaul and gill net fisheries were sampled. 
Recruitment, which can be quite variable, has stabilized the past two seasons, 
Recruitment of the 1983 yr class (2-yr olds) into the 1984-84 fishery was ex- 
cellent (Spratt 1984b) when the 1983 yr class composed 47% of the 1983-84 
season's roundhaul catch. In 1984-85, recruitment was again very good and the 
1983 yr class (2-yr olds) composed 41X by number and 31% by weight of the 1984- 
85 roundhaul catch (Figure 1). The 1983 yr class appears to be strong, but the 
roundhaul f i she ry  i n  San Francisco Bay was again confined t o  the  latter p a r t  of 
the  spawning season when young herr ing a r e  more ava i l ab le  t o  t h e  f i she ry .  There 
I 
were no 8- o r  9-yr-old herr ing i n  the  ca tch  samples, but i n  7 ou t  of 12 seasons, 
8- and 9-yr-old herr ing have composed 1% o r  less of t h e  roundhaul catch. 
The San Francisco Bay g i l l  ne t  ca tch  i s  normally.dominated by 5-, 6-, and 
7-yr-old herring.  This season 5-, 6-, and 7-yr-old herr ing composed 68%,by 
number and 71% by weight of the  g i l l  ne t  ca tch  (Figure 1). P r i o r  t o  t h i s  sea- 
son, 2 114 i n .  mesh was the  minimum mesh s i z e  allowed i n  the  December g i l l  ne t  
f i shery .  In  the  1984-85 season, t h e  minimum mesh r e s t r i c t i o n  was lowered t o  2 
118 i n .  This had an impact on the  o v e r a l l  age composition of the  g i l l  ne t  f i sh -  
ery. The percent of 4-yr-old herr ing i n  t h e  g i l l  ne t  ca tch  increased t o  21% by 
number, and the three  predominant age c l a s s e s  t h i s  season were a c t u a l l y  4-, 5-, 
and 6-yr o lds  (Figure 1). Three-year-old he r r ing  a l s o  were present  i n  unusually 
high numbers i n  the  g i l l  ne t  catch. 
Length Composition 
The mean length of the  San Francisco Bay roundhaul ca tch  declined t o  an 
all-time low of 165 mm BL i n  the  1983-84 season due t o  t h e  s t rong  1982 y r  c l a s s  
r- 
and poor growth during 1983 (Sprat t  1984b). The growth r a t e  improved i n  1984 
and t h e  mean length of t h e  1984-85 roundhaul ca tch  increased t o  176 ~ I U  BL 
(Table 1). 
Herring age 2 through 6 normally comprise about 90% of t h e  roundhaul ca tch  
and these five year classes have recovered from t h e  e f f e c t s  of poor environ- 
mental conditions i n  1983 (Figure 3), and t h e  mean length  of a l l  age groups 
sampled returned t o  normal (Table 5). 
The mean length of the g i l l  net catch i n  San Francisco Bay dropped below 
200 mm BL f o r  the f i r s t  time (Table 1). The average length a t  age (Table 6) of 
herring i n  the g i l l  net catch was normal, but the  change i n  mesh s i z e  from 2 1/4 
in.  t o  2 1/8 in .  caused an increase i n  the numbers of 3- and 4-yr-old herring 
resu l t ing  i n  the decline i n  overa l l  mean length of the catch. 
Weight Composition 
The overal l  weight composition of the  San Francisco Bay roundhaul and 
g i l l  net  catches (Figure 1) pa ra l l e l s  tha t  of the  age composition. The round- 
haul catch was dominated by 2- and 3 y r - o l d  herring,  while the  g i l l  net  catch 
was composed mainly of 5- and 6-yr-old herring.  The poor growth i n  1983 had 
much amre of an e f f ec t  on the  weight of individual herring than i t  did on the 
length. Samples from the roundhaul catch i n  the 1983-84 season indicated tha t  
a l l  age c lasses  were below normal weight (Table 7). In the  1984-85 season, San 
Francisco Bay herring exhibited a complete recovery from the period of poor 
growth i n  1983 (Table 7 and Figure 3). Poor growth and the subsequent improve- 
ment was not evident i n  the g i l l  net catch because g i l l  ne t s  a r e  s e l ec t i ve  f o r  
large herring. However, the g i l l  net catch was very poor i n  the 1983-84 season, 
indicat ing tha t  there were not many large herring avai lable  during the  season. 
Sex Ratio 8 
There was an unexpected change i n  the  sex and biomass (weight) r a t i o s  i n  
the San Francisco Bay f i shery  t h i s  season. Normally, females compose about 2/3 
of the  g i l l  net  catch and a l s o  compose about half of the  roundhaul catch. This 
season the percentage of males i n  the  g i l l  net  catch was 53% (Table 4) and the  
percentage of females in the roundhaul catch was 65% (Table 4). This is a com- 
plete reversal from previous seasons and no explanation is apparent at this 
, 
time . 
DISCUSSION 
Both the Tomales Bay and San Francisco Bay herring stocks were affected 
severely by the 1982-84 El ~i&, The herring Siomass in both bays declined in 
the 1983-84 season (Spratt 1984a) and the growth rate of individual herring was 
also depressed (Spratt 1984b). Oceanic conditions improved in 1984 and both 
populations responded favorably. The San Francisco Bay herring population in- 
creased 15% during 1984 and the Tomales Bay population recovered to a near 
normal level (Spratt 1985). 
The overall age composition of the Tomales Bay herring catch changed very 
little from 1983 to 1985. Even when the biomass was at its lowest level in 
1984, the age composition of the catch was composed of 5-, 6-, and 7-yr-old her- 
ring. The effect of the poor environmental conditions on Tomales Bay herring 
was uniform across all exploited age classes, causing poor growth, increased 
natural mortality exhibited by the decline in abundance from the recent peak in 
1983, and movement of the stock away from its traditional spawning ground. This 
is substantiated by the return of herring in the 1984-85 season and the improve- 
ment in the growth characterstics of the stock. 
The 1984 yr class could be weak, due to the low spawning escapement in 
1984, but the 1984 yr class will not be recruited into the gill net fishery un- 
til the 1987-88 or 1988-89 season. We have no data on the strength of the 1982 
or 1983 yr classes, but these two year classes exhibited good recruitment in San 
Francisco Bay, suggesting that recruitment may have been good in Tomales Bay 
also. 
* The age composition of the San Francisco Bay roundhaul herring catch has 
also changed little during the past 12 yr (Figure 4). In the 1983-84 and 1984- 
85 seasons, the late-season roundhaul fishery resulted in catch samples heavily 
weighted toward young herring. Nevertheless, the abundance of 2-yr-old herring 
both seasons indicated that the 1982 and 1983 yr classes' are strong. Good 
recruitment occurred during the decline in overall biomass from the peak of 
100 000 tons in the 1981-82 season, and follows the weak 1981 yr class. Pre- 
liminary data on the strength of the 1984 yr class in San Francisco Bay is 
encouraging. The 1984 yr class will be recruited as 2-yr-old herring next sea- 
son. Therefore, three consecutive years of good recruitment are expected. I 
believe that this accurately reflects the recruitment pattern of the San 
Francisco Bay herring population, and that there are relatively fewer older her- 
ring in the population now than in recent years. The reduction in spawning 
biomass from 1982 occurred during a time when recruitment was relatively good, 
resulting in a population age structure that is heavily weighted toward newly 
recruited year classes. This age structure is expected to continue for at least 
one more season or until the 1982, 1983, and 1984 yr 
gill net fishery as 5-yr olds in the 1986-87 season. 
I 
classes begin to enter the 
CONCLUSION 
The 1982-84 El NGO is the most severe environmental phenomenon of this 
century, and its lingering effects are still noticeable along California's 
coastline in 1985. Considering that California marks the southern limit of 
major herring concentrations, it is surprising that our stocks were not affected 
t o  a g r e a t e r  degree. Both Tomales and Sari Francisco Bays' he r r ing  populations 
a r e  now w e l l  below recent  peak l e v e l s ,  but remain above recent  low l e v e l s  of 
abundance. They have a l s o  exhibi ted  a dramatic improvement i n  growth rates i n  
1984 and excel lent  recruitment during the pas t  2 yr .  Ca l i fo rn ia ' s  herr ing 
stocks have responded t o  the  decrease i n  abundance, s ince  1982, wi th  an  increase  
i n  productivi ty and growth. This is an ind ica t ion  t h a t  these  s tocks  a r e  i n  a 
healthy condit ion even though biomass l eve l s  nay be depressed. 
The Tomales Bay herr ing population is expected t o  e x h i b i t  normal v a r i a t i o n  
next year and f l u c t u a t e  within the  range of  previous season es t imates .  The San 
Francisco Bay herr ing biomass is  expected t o  continue t o  inc rease  i n  1985 due t o  
good recruitment i n  recent  years  and improved environmental condi t ions  which are 
expected t o  r e s u l t  i n  b e t t e r  growth r a t &  and normal n a t u r a l  mor ta l i ty  during 
1985. 
The improved condit ion of bath s tocks  j u s t i f i e s  a quota inc rease  f o r  the  
1985-86 season, but the exp lo i t a t ion  r a t e  must be kept i n  t h e  15% t o  16% range 
i n  order t o  promote f u r t h e r  recovery of the  stocks.  
REFERENCES 
Spra t t ,  J. D. 1981. Sta tus  of the  Pac i f i c  he r r ing  Clupea harengus 
p a l l a s i ,  i n  Cal i fornia  t o  1980. Cal i f .  F isb  and Game, Fish Bull. 
171: 1-104. 
. 1982. Biological  c h a r a c t e r i s t i c s  of t h e  ca tch  from the  1980-81 
and 1981-82 Pac i f i c  he r r ing ,  Clupea harengus p a l l a s i ,  roe f i s h e r y  
i n  California.  Cal i f .  Fish and Game. Mar. Resources Admin. R e p t .  
. 1983. Biological  c h a r a c t e r i s t i c s  of t h e  ca tch  from t h e  1982-83 
P a c i f i c  herr ing,  Clupea harengus p a l l a s i ,  roe  f i s h e r y  i n  
Cal i fornia .  Cal i f .  Fish and Game, Mar. Resources Admin. Rept. 
83-4: 1-11. 
- 
. 1984a. Biomass es t imates  of Pac i f i c  he r r ing ,  Clupea harengus 
p a l l a s i ,  i n  Cal i fornia  from t h e  1983-84 spawning-ground surveys. 
Cal i f .  Dept. Fish and Game, Mar. Resources Admin. Rept. 84-2: 
1-29. 
. 1984b. Biological  c h a r a c t e r i s t i c s  of t h e  ca tch  from t h e  1983- 
84 P a c i f i c  herr ing,  Clupea harengus p a l l a s i ,  roe f i s h e r y  i n  
Cal i fornia .  Cal i f .  F ish  and Game, Mar. Resources Admin. Rept. 
84-4: 1-18. 
. 1985. Biomass es t imates  of P a c i f i c  he r r ing ,  Clupea harengus 
p a l l a s i ,  i n  Cal i fornia  from t h e  1984-85 spawning-ground surveys. 
Cal i f .  Dept. Fish and Game, Mar. Resources Admin. Rept. 85-2: 
TABLE 1 .  Mean Length of P a c i f i c  Herring from Tomales Bay and 
San Francisco Bay Roe F i sher ies ,  1972-73 through 
1984-85 Seasons, 
Tomales Bay San Francisco Bay 
G i l l  ne t  G i l l  net  Roundhaul 
Mean Mean Mean 
length  Size length  Size length  Size 
Season mm BL range mm BL range mm BL range 
186 150-234 
190 146-248 
189 142-236 
184 150-230 
169 140-216 
217 194-248 
No Samples 
214 196-236 
Note: Tomales Bay has been r e s t r i c t e d  t o  g i l l  n e t s  only s ince  
1977,  and i n  San Francisco Bay the  g i l l  ne t  mesh s i z e  was 
lowered from 2 1 / 4  i n .  t o  2 1 / 8  i n .  for  t h e  December 
f i s h e r y  i n  the  1984-85 season. 
TABLE 2. Length Frequency of the Tomales Bay G i l l  Net 
Catch i n  the 1984-85 Season. 
226 1 
224 2 
222 1 2 1 
220 1 5  
218 1 1 4  1 
216 3 6 3 
214 4 7 
212 1 5 7 2 
210 1 1 1 8 6 1 
208 1 2 12 2 
206 1 1 2 20 3 
204 4 13 1 
202 7 20 2 
200 1 .  6 9 
198 1 13 2 
196 1 3 ' 20 4 
194 1 6 14 1 
192 1 6 10 
190 12 4 
188 1 4 
186 3 
184 1 2 3 
182 2 
180 5 
178 2 
176 
174 
172 1 ,  
170 
168 
166 
164 1 
N 2 19 41 85 104 46 13 1 
Mean 174 187 191 197 205 213 220 221 
14 11 5 5 5 6 7 - St. 
dev . 
TABLE 3. Mean Weight i n  Grants at  Age of Herring i n  the 
Tomales Bay G i l l  Net Catch by Season. 
Season 2 3 4 5 6 7 8 9 
1977-78 - - 142 139 155 157 165 184 
1978-79 No Samples 
TABLE 4. Female to Male Sex and Biomass 
(Weight Ratios of the Catch for 
the 1984-85 Season by ~rea.' 
Tomales Bay 
Sex ratio 1:0.7 
Biomass ratio 1:0.7 
San Francisco Bay Gill Net 
Sex ratio 
Biomass ratio , 
San Francisco Bay Roundhaul 
Sex ratio 1 : 0.5 
Biomass ratio 1:0.5 
TABLE 5 .  Length Frequency of  the San Francisco Bay 
Roundhaul Catch i n  the 1984-85 Season. 
/ dev . 
TABLE 6. Length Frequency of the San Francisco Bay G i l l  
N e t  Catch i n  the 1984-85 Season. 
Mean 157 1'78 186 194 201 207 213 229 
St .  2 3 4 4 3 6 13 
dev . 
TABLE 7. Mean Weight i n  Grams at Age of Herring i n  the 
San Francisco Bay Roundhaul Catch by Season. 
Season 2 3 4 5 6 7 , 8  9 
. TOMfXES BAY 
.... .-.-.............-......-....--.-..- .... " 
2 
LJ 
U 
k! 
.............. ..........-..... I..... 
SRN F M I S C O  M Y  G T U  NET 
- fiGE COMPOSITION WEIGHT CCUWOSLTrOH 
m ffiE COFPOSITT ON WEIGHT COMPOSITION 
FIGURE 1. Age and weight composition of the 1984-85 Pacific 
herring roe fishery landings by area. 
f3GE 
m 7-YR WEW 1983-84 MEAN 
0 1984-85 m N  
FIGURE 2. Comparison of 7-yr mean weight at age for the dominant 
age classes o f  herring in Tomales Bay with data from 
the 1983-84 and 1984-85 seasons. 
lB-YR MEhN 1983-84 MEAN . 
0 1984-85 WEEIN 
Figure 3. Comparison o f  10-yr mean weight and length a t  age for 
the dominant age classes o f  herring i n  the  San Francisco 
Bay roundhaul f ishery  wi th  data from the 1983-84 and 
1984 seasons. 



Biological characteristics of the catch from 1984-85 Pacific herring, Clupea harengus pallasi, roe fishery in California

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Biological characteristics of the catch from 1984-85 Pacific herring, Clupea harengus pallasi, roe fishery in California

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