A sampling of results and impacts from completed New York Sea Grant-funded research projects, written during the period February 1, 2009 – January 31, 2010

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Mysis in Crisis: Food Web Disruption and the Decline of Mysis relicta in Lake Ontario
R/CE-23, Rudstam /Johannsson / Mills / Loew / Arts / Gal / O'Gorman / Schaner

Mysis relicta is one of the major predators on zooplankton in Lake Ontario and also a major prey for planktivorous fish. Monitoring their abundance is considered important by the agencies around the lake.

This project investigated several aspects of mysid ecology in the lake with special attention to potential mechanisms that can lead to changes in the mysid populations associated with current ecological change in the lake.

Accomplishments from this project are the development of a distribution model using temperature and light gradient, development of an index of mysid growth rates based on RNA content, temperature and mysid weight, and development of mathematical filters to separate mysids and fish contributions to acoustics backscattering obtained during forage fish surveys of Lake Ontario.

The Ontario Ministry of Natural Resources (OMNR) and New York State Department of Environmental Conservation (NYSDEC) are incorporating the acoustics methods as part of their standard assessment in Lake Ontario. The distribution model is providing new understanding of the importance of edges in distributions for food web interactions in Great Lakes. The nucleic acid indices coupled with the fatty acid profiles are providing a new way to assess the nutritional health and growth of mysids. The nutritional health is important not only for the productivity of mysids but as a measure of the fatty acids available to fish. These measures are now included in the fall mysid population assessment carried out by the Canadian Department of Fisheries and Environment Canada.

Analyses using the research team's methods are being conducted in Lakes Michigan and Huron. This should lead to continuous assessment of mysids as part of the long term monitoring of the open water fish populations in these Great Lakes and likely elsewhere as well.