498 
Fishery Bulletin 99(3) 
purposes, necessitates a primarily descriptive approach. 
Differences that we observed in fish feeding could relate to 
variable sampling intensity, limited fish sample sizes, gear 
limitations for certain prey taxa, spatial variation in prey, 
or differences in fish depths. Nonetheless, the similarity 
of dietary requirements between YOY pollock and herring 
could induce competition for limited food when these fish 
co-occur during periods or in places of low food availabil- 
ity, particularly late autumn and winter. Stokesbury et 
al. (1999) showed spatial variation in growth of YOY her- 
ring among widespread bays in PWS and surmised that 
density-dependent interspecific competition for food was 
one variable that affected growth rates; likewise, Paul and 
Paul (1999) showed interannual and spatial variations in 
size and energy content of YOY pollock from PWS and 
speculated that prey production and delivery contributed 
to the differences. The densities of planktivorous predators 
may exceed the carrying capacity of bays where walleye 
pollock and Pacific herring are sympatric, adding inter- 
specific competition to the factors limiting growth. More 
studies comparing spatial and temporal patterns of distri- 
bution, abundance, and feeding are needed to clarify the 
extent and frequency of interactions between YOY pollock, 
herring, and other forage species and the impact of chang- 
es in prey and climate on these interactions. 
Acknowledgments 
We thank Lewis Haldorson, Captain Wade Loofborough, 
and the crew of the Alaska Department of Fish and Game’s 
RV Medeia, and Captain Brian Beaver and the crew of 
the chartered trawl vessel FV Caravelle for their dedica- 
tion in collecting samples and oceanographic data. We also 
appreciate the assistance of the biologists and technicians 
from the University of Alaska, Institute of Marine Science 
and Juneau Center for Fisheries and Ocean Science, the 
National Marine Fisheries Service Auke Bay Laboratory, 
and the U.S. Fish and Wildlife Service. We especially thank 
J. Boldt for fieldwork organization, and M. Auburn-Cook, 
R. Bailey, and S. Keegan, who analyzed most of the gut 
contents in the laboratory. We also appreciate the financial 
support of the Exxon Valdez Oil Spill Trustee Council. 
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