Accounting for the Role of Big Fish in the Ocean

For some fish species, scientists hypothesize that larger animals may play critical ecological roles within their populations.  This is because as they grow, many species have greater reproductive success and also require less food per pound of fish to support their body size.  This suggests that fish populations with larger individuals  may be less sensitive to outside perturbations, including overfishing and impacts of warming temperatures, and therefore more resilient and able to recover more effectively when populations are depleted.

However, many fisheries disproportionately target large fish. Intensive fishing can therefore lead to changes in the mix of body sizes (known as size structure), which may affect a population’s stability in the face of disturbance. This project will use models to investigate the consequences of removing large fish on individual populations and the broader ecosystem, using North Atlantic cod and Atlantic bluefin tuna as examples.