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Oneida Lake Fisheries Survey

The Fishery and Limnology of Oneida Lake 2000-2009

Cornell fisheries scientists, under contract with the Department of Environmental Conservation, regularly sample Oneida Lake to gather information on the lake's fish community. This information is used by NYSDEC to aid in making management decisions to protect and enhance the Oneida Lake fishery. The following is a brief summary of findings of the 2009 sampling efforts. The full Cornell report, which provides a detailed analysis of the data and anticipated changes in Oneida Lake fish community, is available as a PDF titled The Fishery and Limnology of Oneida Lake 2000 - 2009 (PDF) (141 kB).

Researchers at the Cornell Biological Field Station at Oneida Lake completed their annual assessment of the fish community in Oneida Lake. Funded by a Federal Aid to Sportfish Restoration grant, this monitoring project is the longest running warmwater fishery assessment in New York State and continues to provide valuable insight on the complex dynamics associated with warmwater fish populations in large northern lakes.

Ongoing Ecological Changes

In past years Cornell researchers have identified several ongoing ecological changes that are likely to affect the fish community in Oneida Lake. These included climate warming, species invasions, and increased water clarity. The data collected in 2009 are consistent with previous indications that the lake has undergone fundamental changes in physical characteristics and productivity at the lower trophic levels. Water temperatures and ice duration continued to reflect warmer conditions than when studies were first initiated, water clarity remained well above long-term means, and a new invader (Hemimysis anomala) was documented in the lake (Brooking et al. 2010).

Decreased Nutrients

Oneida Lake presently fits the characteristics of a mesotrophic system (moderate nutrients), with reduced nutrient inputs and primary production from early decades of our studies when it was classified as eutrophic (high nutrients). Much of the productivity has shifted from the pelagic (open water) to the littoral (near shore) zones, including dramatic increases in littoral macrophytes (plants), with associated increases in nearshore species. Clearer water conditions appear to have reduced survival of pelagic walleye and yellow perch fry, resulting in lower average year class size and recruitment to subadult stages than was typical of the lake before major ecological changes were observed. Cormorant predation on subadult stages resulted in decreases in recruitment to the fishery, and the establishment of a cormorant management program contributed to increases in adult walleye numbers, but we have not seen anticipated increases in adult yellow perch numbers.

Management Considerations

While the lake supports an excellent fishery for walleye, and should continue to do so under present conditions, Cornell's analyses suggests that recruitment is no longer sufficient given current harvest rates to expect the population to rebuild to levels observed in the 1960s and 1970s. Similarly, yellow perch recruitment has also declined to a new, lower, average level in the last decade, and it is likely that the adult perch population will also stay well below its historic highs. If yellow perch densities are in part limited by productivity, it is also possible that increases in the white perch population may also act as a constraint on the size of the adult yellow perch population.

Smallmouth bass have benefited from changes in the lake, and the population has reached higher levels than were observed in the 1960s and 1970s, and there is no reason to think this will not remain the case. Oneida Lake offers diverse, high quality fishing opportunities, and should continue to do so, but all indications are that the fish community has changed as a result of larger ecological events, and it does not appear practical to use benchmarks established in the 1960s and 1970s as gauges of what is realistic today.