Great Lakes Biology Surveys Aid Commercial, Sport Fisheries Management


Newswise — ITHACA, N.Y. — Cornell University and Buffalo State College will be studying the biology of the Great Lakes in a multi-year research effort that will help fishery managers and policy makers determine fishing seasons, creel limits and other management decisions.

Cornell and Buffalo State researchers have received a five-year, $3.5 million grant from the Environmental Protection Agency’s Great Lakes National Program Office and the Great Lakes Restoration Initiative to survey lower trophic levels – or organisms at the bottom of the food chain – that provide valuable insights into the health of higher species.

Specifically, Cornell researchers are using a 180-foot EPA research vessel to collect phytoplankton, zooplankton and mysid shrimp levels in all of the Great Lakes, while Buffalo State researchers will head up collecting benthos (fauna from the bottom of the lakes) levels. Other researchers are also sampling for such pollutants as mercury, nutrients from farm runoff, viruses and bacteria.

The project continues work by the New York Department of Natural Resources and the Cornell Biological Field Station to assess and research lower trophic levels in Lake Ontario.

“Part of the reason we got this large grant was because of our history of collecting data,” said Lars Rudstam, Cornell professor of natural resources and the grant’s principal investigator. “Without the longer term dataset it is hard to determine changes in the Great Lakes.”

“We provide information to fishery managers that they use to decide how many fish they should stock and how much they should impose or relax fishing limitations,” said James Watkins, a postdoctoral researcher in Rudstam’s lab.

Data of lower trophic levels help researchers predict populations of larger fish, as plankton feed small fry, which in turn feed bigger fish. When levels of plankton drop, repercussions may be seen all the way up the food chain. For example, Pacific salmon were introduced into the Great Lakes in the 1980s, but they crashed in recent years in Lake Huron but not in Lake Ontario, due partly to declining biomass at the base of the food web.

Cornell is also sampling a layer of water called the deep chlorophyll layer, which is located at or below a steep temperature gradient known as the thermocline located around a depth of 15 to 25 meters. A long-term shift of algal primary producers from the surface layer to these depths may lead to vertical redistribution of zooplankton and higher trophic levels.

Two additional grants were funded by the Great Lakes Fisheries Commission and U.S. EPA Region 2, to continue similar sampling in Lake Ontario. These grants, one for $100,000 and another for $50,000, are part of a collaboration that includes the Canadian Department of Fisheries and Oceans, the Ontario Ministry of Natural Resources, the U.S. EPA, USGS, New York DNR and Cornell.

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