756 
Fishery Bulletin 95(4), 1997 
et al. 8 ). Although procedural differences between 
earlier studies and ours may partially account for dif- 
ferences in assessment of reproductive success, the re- 
sponses we observed in 1995 were consistently the best. 
To interpret the effects of the spill on herring in 
PWS, it is necessary to understand the life stage ex- 
posed and the magnitude and duration of exposure. 
Which life stages were impacted, and to what extent, 
however, is largely a matter of conjecture. Adult fish 
may have encountered oil before, during, or after 
spawning, but determining what percentage of the 
population was significantly impacted is impossible. 
Metabolites of aromatic hydrocarbons were detected 
in adult herring (Haynes et al. 13 ), but sample sizes 
were very low. Nematode prevalence 
in adult body cavities differed signifi- 
cantly between contaminated and 
uncontaminated areas (Moles et al., 
1993), also indicating adult exposure. 
The duration and magnitude of oil 
exposure of herring eggs and larvae is 
also unknown. After hatching, herring 
larvae from both contaminated and 
uncontaminated sites may have been 
exposed to oil as they passively tra- 
versed the spill trajectory. For example, 
some of the largest concentrations of 
larvae in June were found in the south- 
west portion of PWS, well within the 
oil trajectory (Norcross et al., 1996). By 
inference, juvenile herring occupying 
the same nearshore habitat used by 
juvenile salmonids may have also been 
exposed to oil: such exposure was docu- 
mented in juvenile pink and chum 
salmon (Carls et al., 1996). 
Response of wild herring to an oil 
spill can be partially inferred from 
laboratory studies. For example, ex- 
posure of mature herring to hydro- 
carbons in the laboratory did not 
cause discernible damage in progeny, 
including fertility, viability, and lar- 
val swimming, physical, and genetic 
abnormalities (Rice et al., 1987; Carls 
et al. 14 ). In contrast, the early life 
13 Haynes, E., T. Rutecki, M. Murphy, and D. 
Urban. 1995. Impacts of the Exxon 
Valdez oil spill on bottomfish and shellfish 
in Prince William Sound, Exxon Valdez oil 
spill state/federal natural resource damage 
assessment final report (fin/shellfish study 
no. 18). Auke Bay Laboratory, National 
Marine Fisheries Service, 11305 Glacier 
Hwy., Juneau, AK 99801. 
14 Carls, M. G., D. M. Fremgen, J. E. Hose, D. 
Love, and R. E. Thomas. 1995. The im- 
pact of exposure of adult pre-spawn herring 
(Clupea harengus pallasi ) on subsequent 
progeny. Chapter 2 in Carls et al., Exxon 
Valdez oil spill report, restoration project 
94166, annual report; the impact of exposure 
of adult pre-spawn herring (Clupea harengus 
pallasi) on subsequent progeny, p. 29- 
49. Auke Bay Laboratory, NMFS, NOAA, 
11305 Glacier Hwy., Juneau, AK 99801. 
PWS 
St. Mathews Bay 
SE AK 
P=0.331 Sitka 
P=0.021 
23456789 10 11 
Age (years) 
Figure 5 
Mean (±SE) percent hatching of larval Pacific herring by female parent age, 
site, and region in Alaska, 1995. Sample size is shown in each bar. Overall P- 
value from ANOVA is listed above each graph. Significant differences were 
Ketchikan, ages 3 and 4 < age 6, 7, and 8 (P<0.015); Port Chalmers, ages 3 
and 4 > age 9+ (P=0.050). 
