Developing Ecosystem Based Management Metrics for Forage Fish using Jellyfish

Scientists are increasingly concerned that overfishing of forage fish may exacerbate naturally occurring jellyfish blooms. Because jellyfish may compete with forage fish for plankton in some ecosystems, removing too many forage fish could allow jellyfish populations to increase to the point of shifting the ecosystem into a jellyfish dominated state. Yet most fisheries stock assessment models have not included jellyfish when they predict how species will respond to different fishing levels.

This project explores ways fisheries managers can account for jellyfish and forage fish interactions, focusing on five marine ecosystems: the Gulf of Mexico, the Northern California Current, the Bering Sea, the Peruvian Upwelling, and the Sea of Japan. Using existing datasets from these regions, the researchers are examining the relationships between jellyfish and forage fish to identify the conditions under which an ecosystem moves to a jellyfish dominated system. Fishery managers may use the resulting metrics (e.g. ratio of jellyfish to forage fish) to help them set fishing levels that reduce the risk of reaching these tipping points.