Multispecies modeling of Atka mackerel/Pacific cod interactions in the Aleutian Islands

Steller Sea Lions, Pacific cod, and Atka mackerel are part of a complex, interrelated food web in the Aleutian Islands (Fig. 1). The effects of fishing policy changes, therefore, should be evaluated in both single-species and multispecies contexts. In particular, Atka mackerel are a central species in the Aleutian Islands food web, serving as both predator and prey for many species, as well as being the source for a commercially important fishery (Fig. 2). Additionally, Pacific cod play a strong role as a predator within the system, as well as being a food source for marine mammals. In order to evaluate the effects of attempting to direct prey to Steller Sea Lions through fishing reduction or area closure for either species, it’s important to evaluate how these species might interact by using existing multispecies and ecosystem models developed for the Aleutian Islands.