Study to Explore the Big Roles of Herring and Other Small Fish in the Sea

Contact: Andrew Pershing, UMaine and GMRI Research Scientist, 207-228-1656;
Blaine Grimes, GMRI, 207-228-1655;
Ron Lisnet, UMaine, 207-581-3779

The role played by herring and other small pelagic fish in the Gulf of Maine, including the nutrients they supply to larger animals like tuna and whales and their effect on zooplankton, is the focus of a more than $346,000 research project led by oceanographer Andrew Pershing of the University of Maine (UMaine) and Gulf of Maine Research Institute (GMRI).

The project was one of eight funded this year by the Comparative Analysis of Marine Ecosystem Organization (CAMEO), a program of the National Oceanic and Atmospheric Administration (NOAA) and the National Science Foundation. In addition to Pershing, the research team includes two scientists from UMaine, two from GMRI, three from NOAA, the one each from the University of Massachusetts and Ohio State University.

The scientists will compare the physical changes in the Gulf of Maine over three decades, beginning in the 1980s when herring stocks were low. The goal is to evaluate the role of bottom-up changes in physical conditions, such as temperature, and productivity in relation to top-down forces such as fishing in shaping large-scale ecosystem changes.

According to Pershing, previous studies detailed a series of changes in the Gulf that occurred in the 1990s. They included a dramatic increase in herring and a decrease in their primary prey — large zooplankton. The decline in large zooplankton, especially the copepod Calanus finmarchicus led to leaner herring and the births of fewer right whale calves. The leaner herring then led to bluefin tuna of lesser value.

The researchers hope to better understand how these trade-offs between fish abundance and fish weight are linked in fishery ecosystems.

“We’ll be using a variety of data sources as well as building models to try to understand these changes,” Pershing says. “In addition to helping uncover the mechanisms driving big changes in systems like the Gulf of Maine, our work will help improve forecasts of fisheries in the Gulf.”