Atlantic cod (Gadus morhua) feeding for ecosystem-based management and sustainability in Newfoundland and Labrador marine ecosystems

Abstract

The purpose of this study is to challenge long-standing assumptions on Atlantic cod (Gadus morhua) feeding around Newfoundland and Labrador, Canada, and provide information that will be useful for the next generation of ecosystem-based models. Using stomach content analysis and published cod stomach data I address two primary questions: Do cod cease feeding during spawning? Does the cod diet reflect changes in prey assemblages in the ecosystem? Spatial and temporal diet variation was additionally analyzed. Regional variation was paramount such that diet diversity, mirroring ecosystem diversity, increased with decreasing latitude. Contrary to current assumptions, feeding continued through spawning. The stomach content contribution of shrimp reflect environmental trends in these prey assemblages over the past 65 years, while crab, a minor part of the cod diet, does not reflect abundance changes. Capelin appeared preferably consumed when encountered. Cod are not complete generalist feeders but select for certain energy rich prey.