Purdue University

Lake Sturgeon Research

Effects of Mortality Sources on Population Viability
Lampricide applications in streams containing swim-up larvae and small juvenile lake sturgeon Acipenser fulvescens may negatively impact recruitment, rehabilitation, and sustained viability of this species in the Great Lakes. As a result, a no observable effect (i.e., no mortality) treatment protocol has been implemented in streams supporting lake sturgeon. However, the overall effectiveness of lampricide treatments may be diminished because greater numbers of parasitic-phase sea lampreys Petromyzon marinus may be produced from tributaries through inefficient or failed lampricide treatments. We used a stage-structured, life-history model to examine the impacts of lampricide applications and sea lamprey parasitism on the population viability of lake sturgeon in the Laurentian Great Lakes basin. Population abundance, the number of age-1 recruits, and reproductive potential of lake sturgeon exhibited relative percentage decreases with increasing mortality of age-0 juvenile fish (range, 0 to 100%) as a result of lampricide applications at four-year treatment intervals. When larval sea lamprey mortality (range, 100 to 0%) following lampricide treatments was incrementally decreased, lake sturgeon mortality from increased sea lamprey parasitism for both the low and high mortality simulation scenarios resulted in relative percentage decreases in population abundance, the number of age-1 recruits, and reproductive potential from baseline conditions. Incremental increases in sea lamprey-induced lake sturgeon mortality (range, 0 to 22%) as estimated from wounding rate data resulted in relative percentage decreases in population abundance, the number of age-1 recruits, and reproductive potential from baseline conditions. Based on the results of our model simulations, it appears that mortality agents, such as sea lamprey parasitism, that influence subadult and adult lake sturgeon have a greater impact on the long-term population viability of this species than mortality factors that affect early life stages (i.e., lampricide applications). As a result, we do not recommend that lampricide-application strategies for the control of larval sea lamprey populations in tributaries containing lake sturgeon continue to follow the no effect protocol in order to allow for the long-term rehabilitation and management for this species.

Funding Source: Great Lakes Fishery Commission

Personnel: Trent Sutton and Rebecca Zeiber

Publications:
• Sutton, T. M., R. A. Zeiber, B. L. Johnson, T. D. Bills, and C. S. Kolar. In preparation. Effects of sea lamprey induced mortality sources on lake sturgeon population viability: an ecological modeling approach. Journal of Great Lakes Research.

Collaborators: Barry Johnson, Cynthia Kolar, and Terry Bills


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