Long-Term Trends in Burbot Abundance in Oneida Lake, New York: Life at the Southern Edge of the Range in an Era of Climate Change
James R. Jackson, Anthony J. VanDeValk, John L. Forney, Brian F. Lantry, Thomas E. Brooking, and Lars G. Rudstam
Abstract.—The burbot Lota lota is a cold-stenothermal species with a circumpolar distribution that rarely extends below latitude 40°N. Oneida Lake, New York, is a large (20,670 ha), shallow (mean depth 6.8 m) lake and its position at latitude 43°N places it near the southern border of the burbot’s range. Although abundant enough to be considered detrimental to more desirable species during the early 1900s, previous research indicated that burbot abundance was limited by sea lamprey Petromyzon marinus predation and marginal thermal conditions during the summer in Oneida Lake. However, a lamprey control program initiated in 1985 did not result in significant increases in burbot catches. Oneida Lake’s morphology results in homothermal conditions throughout much of the summer, reducing the availability of coldwater refuges. High occurrence of empty stomachs and reduction in energy density of livers during the summer months suggest that high summer water temperatures may limit burbot in Oneida Lake. Long-term trends in catches of burbot in bottom trawls, gill nets, and trap nets since the 1960s have exhibited significant declines. During the same period, summer water temperatures have increased significantly. Bioenergetics models suggest that water temperatures greater than 21°C will result in weight loss in burbot, and the average duration of this period of high summer stress has increased to almost 2 months in recent years. Declines in burbot catches were significantly correlated with increases in summer temperatures and the number of days when weight loss was predicted by energetics models. Continued warming of Oneida Lake may result in extirpation of this burbot population.