186 
Fishery Bulletin 108(2) 
and the adult reproductive parameters for July 2003 
and July 2004 (Eq. 7, Table 5) was 39,184 t (CV=0.57) 
and 84,120 t (CV=0.93), respectively, for an area close 
to 200,000 km 2 from 42°N to 48°N off Oregon and 
Washington. 
Discussion 
Dynamics of biomass 
Off the PNW, the seasonal relative abundances of Pacific 
sardine based on the swept area method are nonsta- 
tionary (i.e, not static): high in summer and low in 
spring. Fish residing in the PNW in spring are those 
over-wintering, and in the summer the majority of fish 
>190 mm SL are likely those migrating from Califor- 
nia. The spatial distribution of the Pacific sardine was 
similar between summer and spring: high in the inshore 
area and low in the offshore area, except during March 
2005 when small numbers of sardine were caught in 
the northern offshore area (Fig. 5). This distribution is 
quite different from that off California where the spatial 
distribution varied among years (Lo et al., 2005). The 
PNW biomass estimates, high in July and low in March, 
together with the differential length distributions are 
consistent with the conceptual migration schedule of 
Pacific sardine (a migration route that appears to be 
similar to that of Pacific hake, Merluccius productus), 
namely of movement to the PNW from California before 
Table 5 
Trawl information, estimated female adult parameters, egg production, and spawning biomass (estimated by the daily egg pro- 
duction method (DEPM)) for Pacific sardine ( Sardinops sagax) from July and March surveys conducted from 2003 through 2005 
off Washington and Oregon (Pacific Northwest) and from April surveys conducted from 2003 through 2005 off California and 
in 1994 off California and Mexico. Either the coefficient of variation (CV) or number of positive trawls is in parentheses. na=not 
available. 
Pacific Northwest 
California 
2003 
July 
2004 
March 
2004 
July 
2005 
March 
1994 
April 
2003 
April 
2004 
April 
2005 
April 
No. trawls (positive) 
48(36) 
59(9) 
58(27) 
49(20) 
79(43) 
0 
25(17) 
19(14) 
Ave. surface temperature (°C) 
at sardine locations 
15.4 
10.4 
15.6 
10.4 
14.36 
13.59 
14.18 
Fraction of females by weight 
R 
0.534 
0.568 
0.538 
0.618 
0.469 
Ave. mature female weight 
(g) with ovary 
(g) without ovary 
Average batch fecundity 0 
w f 
W of 
F 
194.36 
189.25 
55,986 
105 
102.7 
193.16 
188.90 
55,883 
102.5 
100.2 
82.53 
79.33 
24,283 
166.99 
156.29 
55,711 
65.34 
63.11 
17,662 
Relative batch fecundity (oocytes/g) 
288 
289 
294 
334 
270 
No. mature females analyzed 
657 
3 
196 
37 
583 
290 
175 
No. active mature females 
374 
1 
81 
11 
327 
290 
148 
Fraction of mature females 6 
spawning per day (CV) 
S 
0.027 
(0.31) 
0 
0.010 
(0.74) 
0 
0.074 
(0.23) 
0.131 
(0.17) 
0.124 
(0.31) 
Fraction of active females 0 
s a 
0.050 
0 
0.025 
0 
0.131 
0.131 
0.155 
spawning per day 
Daily specific fecundity 
RSF 
W 
Po 
4.21 
na 
1.68 
na 
11.7 
27.04 
15.67 
Egg production/0.05 m 2 /day 
(CV) (Eq. 5) 
0.04 d 
(0.51) 
0.037 d 
(0.58) 
0.193 
(0.21) 
1.520 
(0.18) 
0.960 
(0.24) 
1.916 
(0.42) 
Survey area (km 2 ) 
A 
206,037 
190,975 
380,175 
365,906 
320,620 
253,620 
Spawning biomass (t) (CV) 
B s 
39,184 
(0.57) 
na 
84,120 
(0.93) 
na 
127,102 
(0.32) 
485,121 
(0.36) 
281,639 
(0.30) 
621,657 
0.54 
Eggs/min from CUFES sample (CV) 
0.069 
(0.49) 
0.1 
(0.53) 
na 
1.57 
(0.27) 
0.78 
(0.11) 
0.62 
(0.15) 
a Mature females: 1994 estimate was calculated with ^=-10858 + 439.53 W 0/ - (Macewicz et al., 1996), in 2004 with F b = 356.46W o/: (Lo et al., 2005), 
in 2005 with F^-6085 + 376.28 W,^, and for Pacific Northwest in 2003 and 2004 with F h = 295.83 W a ^ 
b Mature females included females that were active and those that were postbreeding (incapable of further spawning during the season). 
c Active mature females were capable of spawning and had oocytes with yolk or postovulatory follicles less than 60 hours old. 
d Calculated by the integral method and corrected for bias (P 0 c ). 
