Gulf Apex Predator-Prey Project
Kodiak Seafood and Marine Science Center
University of Alaska Fairbanks • School of Fisheries and Ocean Sciences • Kodiak, Alaska

GAP I: 2001–2003

Project Summary

The precipitous and continued decline of the western stock of Steller sea lions (Eumetopias jubatus) has been well documented. Factors contributing to their decline and preventing recovery remain unclear, although reduced juvenile survival is considered a likely proximate cause. One hypothesis is that the western stock of Steller sea lions is nutritionally stressed and their recovery may be limited by the availability, quality, and/or diversity of their prey. Although evidence from the 1970s and 1980s supports this hypothesis, studies in the 1990s do not, suggesting other factors may now be involved. We currently lack adequate understanding of the dynamic ecological processes affecting Steller sea lions to determine or reduce impediments to their recovery.

The Gulf Apex Predator-Prey Project (GAP) was initiated in 1999 by University of Alaska Fairbanks faculty in Kodiak to address trophic-level questions of immediate biological and economic concern in the western Gulf of Alaska. The project’s goal is to document trophic relationships between Steller sea lions, their prey, competitors, and predators in the Kodiak region. Fundamental to the GAP project is the integration of distinct but related hypothesis-driven research projects. Although focused on sea lion concerns, GAP’s interrelated studies also broadly assess the degree of dietary overlap among Kodiak’s sympatric apex predators while exploring processes that drive populations of their prey within a dynamic marine environment. These studies overlap spatially and temporally, allowing synchronous collection of predator and prey data and synoptic assessment of their seasonal interactions. The Gulf Apex Predator-Prey Project is planned as a multiyear sampling effort that will allow monitoring interannual variability against which effects of human intervention may be compared. GAP investigators strive to facilitate synergistic linkage to related studies and efficiently broaden research beyond the scope of individual projects, and have already fostered collaboration with fisheries and marine mammal researchers within the National Marine Fisheries Service (NMFS) Alaska Fisheries Science Center and Alaska Department of Fish and Game (ADFG).