Data Synthesis to Assess Anchovy and Sardine Consumption By Seabirds, Fish and Mammals in the California Current

Forage fish populations in the California Current fluctuate in an ecosystem with >160 species of marine predators of forage species. Understanding just how much forage predators consume in ecosystems with large numbers of wide-ranging species has many challenges. These include synthesizing diet data when >60 species can eat one forage fish species (e.g., anchovy), compiling predator population and diet data across large ecosystems and international boundaries, and providing realistic consumption estimates that account for variability in predator and prey data. Our solutions highlight an EBFM approach by compiling diet data for >120 predators, including explicit spatio-temporal assessments of diet, using bioenergetic models and Monte Carlo simulations to characterize predator consumption in biomass units for comparison with fisheries stock assessments, and collaboration with other EBFM researchers to standardize model inputs and share the burden of data synthesis. To provide a snapshot of predator consumption of anchovy and sardine in the California Current, we selected 35 predatory fish, seabirds, and mammals that are abundant and consume anchovy and/or sardine. We used diet records at regional scales to account for spatial variation in predator-prey interactions, with a focus on summer, when diet data were robust.