Lo et al. Biomass and reproductive status of Sardinops sagax off the Pacific coast. 
183 
Table 3 
Estimated Pacific sardine (Sardinops sagax ) egg densities, egg production ( P 0 c , Eq. 5) with coefficient of variation (CV) in paren- 
theses, and number of collections with positive collections in parentheses from California Cooperative Oceanic Fisheries Inves- 
tigation vertical egg tow net (CalVET) and continuous underway fish egg sampler (CUFES) samples in two strata with dividing 
latitude of 125°W and the entire survey area for the July 2003 and July 2004 surveys. Dashes indicate where statistics were not 
computed because of small or zero catches. 
Stratum 1 
Stratum 2 
Entire survey area 
July 2003 
CalVET 
Egg density (eggs/0.05 m 2 )(CV) 
0.388(0.51) 
0 
0.073(0.51) 
P 0 c (Egg production /0.05 m 2 /day)(CV) 
— 
— 
0.04(0.51) 
No. of CalVET tows (positive) 
18(4) 
36(0) 
54(4) 
CUFES 
Eggs/min (CV) 
0.148(0.61) 
0.05(0.74) 
0.069(0.49) 
No of CUFES samples (positive) 
316(102) 
166(15) 
482(117) 
Survey area (km 2 )(%) 
40,043(19) 
166,334(81) 
206,377(100) 
July 2004 
CalVET 
Egg density (eggs/0.05 m 2 )(CV) 
0.0(— ) 
0.088(0.56) 
0.070(0.56) 
P 0 c (Egg production /0.05 m 2 /day)(CV) 
— 
— 
0.037(0.58) 
No. of CalVET tows (positive) 
14(0) 
34(3) 
48(3) 
CUFES 
Eggs/min (CV) 
0.11(0.42) 
0.097(0.67) 
0.1(0.53) 
No of CUFES samples (positive) 
197(65) 
450(64) 
647(129) 
Survey area (km 2 )(%) 
40,043(21) 
150,932(79) 
190,975(100) 
Table 4 
Percentage and average size in each maturity class of Pacific sardine ( Sardinops sagax ) females in the random samples from 
trawls conducted during four research surveys in 2003-05 off Oregon and Washington. Maturity was based on histological 
analysis of ovaries. 
Survey dates 
(n females) 
Maturity class 
Percentage 
of females 
Mean standard 
length (mm) 
Mean whole 
body weight (g) 
6-25 July 2003 
Immature 
0.7 
204 
124 
(690) 
Mature 
98.3 
238 
194 
29 Feburary-19 March 2004 
Immature 
97.2 
108 
14 
(108) 
Mature 
2.8 
207 
105 
6-25 July 2004 
Immature 
62.2 
147 
43 
(410) 
Mature 
37.8 
240 
200 
2-21March 2005 
Immature 
89.2 
161 
51 
(241) 
Mature 
10.8 
195 
87 
female maturity and reproductive state (Macewicz et 
al., 1996; Lo et al., 2005). 
Sufficient numbers of immature and mature females 
in the random 50-fish subsample of a positive trawl 
for estimation of the length at which 50% were ma- 
ture were collected during July 2004 and March 2005 
(Table=4). Females were grouped into 10-mm length 
classes and the length at which 50% were mature was 
estimated by logistic regression: y=l/(l + e~ <a+bL) ), where 
y = the proportion of mature female sardine and L = the 
standard length in mm. The length-specific maturation 
relationships were compared to those off California in 
April 1994, 2004, and 2005 (Macewicz et al., 1996; Lo 
et al., 2005). 
Because the spawning season occurs in early summer, 
we used the two sets of July survey data to estimate 
the following adult reproductive parameters, which were 
used in the spawning biomass computation based on 
the daily egg production method (Lasker, 1985; Parker, 
1985; Lo et al., 2005): the daily spawning fraction (S) 
