Johnson et a I.: Reproductive success of Clupea pallasi after the Exxon Valdez oil spill 
753 
Table 2 
Age, year class, and possible oil exposure for Pacific herring collected in Prince William Sound, Alaska, in 1995. The Exxon Valdez 
oil spill occurred in March 1989. 
Year 
Age class Possible oil exposure 
Year 
Age class Possible oil exposure 
3 1992 no direct oil exposure of any life stage 
4 1991 no direct oil exposure of any life stage 
5 1990 all life stages possibly exposed to 
residual oil 
6 1989 all life stages likely exposed to oil 
7 1988 juveniles at time of spill 
8 1987 juveniles or immature at time of spill 
9+ 1986 mature — reproductive at time of spill 
Table 3 
Fork length (mm) and somatic weight (g) of mature female Pacific herring captured in southeast (SE) and Prince William Sound 
(PWS), Alaska, in spring 1995. Values are mean ( x ) and ± standard error; sample size = n. 
Age (yr) 
3 
4 
5 
6 
7 
8 
9 
10 
11 
Fork length 
SE 
X 
198 
211 
217 
221 
236 
234 
241 
236 
253 
± 
1.9 
2.9 
2.0 
1.2 
1.3 
3.5 
8.4 
3.5 
7.7 
n 
86 
21 
49 
94 
95 
15 
3 
2 
3 
PWS 
X 
196 
219 
225 
236 
242 
260 
259 
259 
260 
± 
1.1 
2.3 
1.1 
1.7 
1.0 
3.2 
1.3 
2.2 
2.9 
n 
81 
18 
65 
25 
149 
10 
16 
7 
13 
Weight 
SE 
X 
65.1 
79.1 
87.2 
91.7 
112.9 
112.7 
117.5 
108.3 
140.4 
± 
1.8 
3.2 
2.1 
1.7 
1.9 
5.1 
4.6 
6.4 
14.7 
n 
81 
21 
49 
93 
94 
15 
3 
2 
3 
PWS 
X 
60.7 
90.3 
95.0 
107.4 
121.0 
149.0 
147.8 
148.9 
151.7 
± 
1.2 
2.2 
1.3 
2.7 
1.5 
8.3 
3.3 
6.8 
5.1 
n 
80 
18 
65 
25 
149 
10 
16 
7 
13 
spinal abnormalities. In PWS, mean responses 
ranged from 78 to 86% for hatching success, 95 to 
96% for live larvae, 92 to 93% for effective swimmers, 
and 4 to 6% for spinal abnormalities. Among all sites, 
reproductive success was consistently best at Sitka 
(e.g. highest hatching success=91% and fewest spi- 
nal abnormalities=l%) and worst at Seymour Canal 
or Ketchikan (e.g. lowest hatching success=63% and 
most spinal abnormalities=7%) (Fig. 2). Of the sites 
in PWS, reproductive success was usually best at St. 
Mathews Bay or Port Chalmers (e.g. highest hatch- 
ing success=86% and fewest spinal abnormali- 
ties=4%) and worst at Fish Bay (e.g. lowest hatching 
success=78% and most spinal abnormalities=6%) 
(Fig. 2). Similarly, when reproductive success was 
estimated for each age class individually, regional 
differences were not significant (P>0.50). This find- 
ing was true for all age comparisons — ages 3 to 9+. 
For example, age-6 (1989 year class) herring in PWS 
did not differ significantly from those in SE (Fig. 3). 
Among all sites where more than four age-6 fish were 
collected (excluding St. Mathews Bay and Sitka), 
hatching success ranged from 66% (Seymour Canal) 
to 91% (Port Chalmers), live larvae from 95% (Fish 
Bay) to 98% (Port Chalmers), effective swimmers 
from 93% (Rocky Bay) to 96% (Port Chalmers), and 
spinal abnormalities from 2% (Port Chalmers) to 6% 
(Fish Bay). 
No significant regional differences were observed 
in progeny of the 1989 year class scored for physical 
condition. Only one larva of 500 had pericardial 
edema. Analyzed with the Kruskal-Wallis test, the 
site with the most yolk-sac edema (Port Chalmers) 
was significantly different from that with the least 
(Ketchikan), but there was no regional trend. Per- 
centages of larvae with yolk-sac edema were low 
