Kristen Holeck, Chris Hotaling, Lars Rudstam, Jana Lantry (NYSDEC), Brian Weidel (USGS), Zy Biesinger (USFWS) and additional collaborators around Lake Ontario. (Funded by NSYDEC, USGS, USFWS)
Ecosystem-based management is an approach to managing environmental issues that considers how the ecosystem functions as a whole rather than focusing on single species or issues in isolation. In Lake Ontario, managers have used an ecosystem-based approach to managing the productivity and availability of alewife and stocked salmonids since the end of the 1980s. In support of this approach, and with the realization that populations of top predators could not be managed effectively without understanding the production potential of Lake Ontario’s lower trophic levels, the New York State DEC initiated research in 1995 called the Lake Ontario Biomonitoring Program (BMP) to evaluate the condition of lower trophic levels in offshore, nearshore, and embayment areas of the lake. Lower trophic level components (nutrients, phytoplankton, and zooplankton) are indicators of ecosystem health and determine the lake’s ability to support prey fish upon which both wild and stocked salmonids depend. Changes since 1995 have been dramatic with almost an order of magnitude decrease in herbivorous zooplankton, a decrease in summer chlorophyll (an indicator of phytoplankton abundance), and increases in non-native predatory cladocerans (Bythotrephes longimanus and Cercopagis pengoi). Interestingly, Bythotrephes declined in 2013 and 2014 and we observed a change back towards the cyclopoids and small cladocerans abundant in the 1990s. Knowledge of these changes informs management decisions regarding stocking of salmonids in Lake Ontario. The BMP is a collaborative project that, in 2015, included the NYSDEC Cape Vincent Fisheries Research Station and regional NYSDEC staff at Watertown, Cortland, and Avon; the USFWS Lower Great Lakes Fish & Wildlife Conservation Office; the USGS–Lake Ontario Biological Station; and Cornell University.