2008 Annual Report
Gulf of Maine Research Institute

Spotlight on Science

CAMEO project sheds light on herring's role in ecosystem

Photo by Bill CurtsingerHerring are a key part of the Gulf of Maine ecosystem—they feed on many types of plankton and are an important food source for many different predators, including the highly sought-after bluefin tuna. A collaborative project led by scientists from University of Maine and Gulf of Maine Research Institute is working to understand how changes in environmental conditions and fishing affect both the abundance and condition of herring, and these effects ripple up the food chain to their predators and down to their prey.  The project is funded through the Comparative Analysis of Marine Ecosystem Organization (CAMEO) program, a partnership between National Oceanic and Atmospheric Administration and the National Science Foundation and aims to strengthen the scientific basis for an ecosystem approach to managing fisheries such as herring.

The Gulf of Maine ecosystem has experienced profound changes over the past three decades, which have reached all levels of the food chain and made a deep impact on fisheries. Herring population size has fluctuated and so has the condition of the fish. Years in which their population numbers were up were generally the same years when the herring themselves were thinner.  Years in which populations shrunk were times when individuals were healthier and better fed. These changes were not isolated to herring but rippled both up and down the food chain, impacting the copepods they eat and the tuna that eat them. Herring’s preferred prey is a copepod called Calanus finmarchicus.  Their populations dwindled in the 1990s, likely due to a combination of climate-related changes in the system as well as increased predation from herring. Without enough to eat, herring became thinner and had less energy. Tuna that consumed these lower-energy herring needed to eat more of them in order to get enough energy of their own. These fluctuations in population sizes and condition have led GMRI scientists to examine the trade-offs between food availability and food quality in the Gulf of Maine.

Fisheries are typically managed with an emphasis on abundance—the more fish, the better. GMRI scientists want to know whether we should be giving equal weight to the quality and quantity of fish in the ecosystem, a topic that can only be addressed by taking the whole ecosystem into account. This project looks at the Gulf of Maine as a whole to inform a new ecosystem-based management system that accounts for all of the Gulf’s complex and connected parts. GMRI scientists work on a computer model of the Gulf of Maine simulating conditions in the 1980s, 1990s and 2000s to evaluate the role that changes in ocean conditions have on fish and zooplankton. They also examine the impacts the fishing industry has on the ecosystem. CAMEO is a significant step along the path toward a new ecosystem-based management system, one that accounts for both quantity and quality of zooplankton and fish in the Gulf of Maine.


  • Andrew Pershing, GMRI Ecosystem Modeler and Research Associate Professor at UMaine
  • Jeff Runge, GMRI Biological Oceanographer and Research Professor of Oceanography at UMaine
  • Jason Stockwell, University of Vermont
  • Graham Sherwood, GMRI Demersal Ecologist
  • Jonathan Deroba, NOAA
  • Jon Hare, NOAA
  • David Richardson, NOAA
  • Molly Lutcavage, University of Massachusetts
  • Walter Golet, GMRI and UMaine
  • Rebecca Tien, Ohio State University
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