Oregon Sea Grant

Marine systems undergo changes in community composition over time as a result of a variety of environmental and anthropogenic factors. The overall objective of this study was to investigate the potential impact environmental variables may have in structuring the Gulf of Alaska (GOA) ecosystem by using statistical analyses of diets and an ecosystem modeling framework. We focused on three commercially and ecologically important groundfish predators: Pacific cod (Gadus macrocephalus), Pacific halibut (Hippoglossus stenolepis), and sablefish (Anoplopoma fimbria). We also focused on a key prey species, walleye pollock (Gadus chalcogrammus), and used environmental data collected during trawl surveys and Pacific Decadal Oscillation data generated for the entire North Pacific region. Results indicate the potential importance of environmental context when collecting diet data to be used in ecosystem models designed to provide fishery management recommendations​. As ecosystem models are used more commonly, taking the time to investigate the factors that structure diets, and how predation changes due to environment, can yield more representative—​and potentially more accurate—biomas​s projections and recommendations for the GOA and likely many other managed marine ecosystems.