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Long-term studies of Oneida Lake

Randy Jackson, Tom Brooking, Tony VanDeValk, Lars Rudstam, Kristen Holeck, Chris Hotaling, John Forney (Funded by NYS DEC with contributions from the Brown Endowment)

Our studies of the fisheries and limnology of Oneida Lake were initiated in the mid-1950s as an assessment of the status of the lake’s important walleye and yellow perch fisheries. The program has enjoyed continuous funding from the New York State Department of Environmental Conservation (NYSDEC), and for over 60 years and has included annual monitoring of multiple trophic levels and physical conditions, representing a true ecosystem approach to understanding the dynamics of the lake’s fish community and fisheries. Ongoing studies on Oneida Lake include detailed studies of walleye and yellow perch from larval to adult life stages, assessment of offshore and inshore fish community composition and monitoring of nutrients, primary and secondary production, as well as annual creel surveys. While maintaining the continuous data set started by John Forney, we have increased the scope of our studies, which now include intensive sampling of the lake’s nearshore fish community and annual creel surveys. Oneida Lake is the State’s third most heavily fished lake, and data collected by Field Station staff provide timely information to DEC managers to ensure sustainable fishing opportunities, particularly for walleye, yellow perch and smallmouth bass. The data series has also allowed important insights into the response of lake ecosystem to perturbations such as exotic species and climate change. We have already documented fundamental shifts in fish community composition resulting from increases in water clarity associated with zebra mussels, and are currently assessing the impacts of displacement of zebra mussels by quagga mussels. The double-crested cormorant had profound impacts on walleye and yellow perch, and our studies of these impacts have informed cormorant management throughout their range. Analyses of the response of walleye and yellow perch to cormorant management are shedding light on the relative importance of that management and concurrent restrictions of walleye harvest. Warming water temperatures may be contributing to increased production of largemouth and smallmouth bass, gizzard shad and other species near the northern extent of their range. Sampling in 2014 revealed that the round goby had finally become established in the lake, although densities were low. By late summer of 2015, gobies were the most abundant species in our trawl samples and gobies continued to be abundant in 2016. There is evidence that there was a die off of round goby during the winter of 2016-17, but enough remained to reproduce successfully. Gobies remained at depressed numbers in 2018, but recovered in 2019 to the highest densities observed since 2016.  Gobies appeared in the diets of most of our more common fish species and were also foraged upon by cormorants. We observed marked declines in angler success in 2016, which is most likely related to the abundant new prey resource represented by gobies, but angler catches improved in 2017 and 2018 when goby densities were reduced. Despite increasing goby numbers, angler catch rates of walleye in 2019 were the highest observed since 2004.  We will have an excellent opportunity to continue assessing the impacts of this new invasive on the lake’s fish and fisheries in the upcoming years. CBFS research specialist Kristen Holeck discovered Bythotrephes longimanus, the spiny water flea, in Oneida Lake in the fall of 2019 during sampling with Cornell’s Field Biology class.  Subsequent sampling revealed localized high densities of this new invasive and use of this new food source by juvenile yellow perch.  Our long-term data set will position us well to understand what impacts this new invasive species may have on the lake.  Walleye continue to be the most popular sport fish in Oneida Lake. Bass are also a popular fishery, and typically account for 25-30% of the anglers interviewed during our June/July creel survey, another sign of change from the days when walleye anglers comprised most of the lake users. A walleye mark-recapture population estimate in 2019 produced an estimated adult walleye population of just over 1,000,000 fish, the first time this mark has been achieved since 1986.  Management responses to sharp walleye population declines in the 1990s  (resulting in a record low population size of 200,000 fish in 2000), including harvest restrictions and cormorant management, appear to be paying off.  The lake sturgeon restoration program in Oneida Lake received a lot of attention in 2019 when our sampling produced a 139-pound fish, by far the biggest we have seen so far.  As Oneida Lake has changed, so too has the fish community and the fishery, and our studies continue to expand our efforts to understand the dynamics of this economically important resource.