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Feasibility of holding wild-caught Lake Whitefish and Sea Lamprey for parasite-host interaction studies
D. Caroffino1, T. Treska2, R. Greil3, G. Fischer4
1 Michigan Department of Natural Resources, 96 Grant Street, Charlevoix, MI 49720
2 U. S. Fish and Wildlife Service, 2661 Scott Tower Drive, New Franken, WI 54229
3 Lake Superior State University, 650 W. Easterday Avenue, Sault Ste. Marie, MI 49783
4 University of Wisconsin-Stevens Point, 36445 State Highway 13, PO Box 165 Bayfield, WI 54814
To assess damages due to sea lamprey (Petromyzon marinus), fisheries managers must be able to calculate lamprey induced mortality. A key parameter to those calculations is the probability that a fish species will survive an attack (P). This parameter has not been examined for whitefish in nearly 50 years, and recently rates of sea lamprey marking on lake whitefish have increased to a point where fishery quotas may be affected as a result of increased lamprey mortality. There are concerns that the P currently used for whitefish may be inaccurate, leading to biased estimates of lamprey-induced mortality. Consequently, there is a need to assess P for whitefish; however, hatchery whitefish are not readily available and it is unknown if wild whitefish can be brought into captivity to accurately assess this parameter. This pilot project sought to determine if transferring wild-caught lake whitefish into captivity was a viable method to support a future assessment of P in a larger-scale project. Whitefish were captured from commercial trap nets and recreational anglers and moved to aquaculture tanks at the University of Wisconsin-Stevens Point Northern Aquaculture Demonstration Facility (NADF) near Bayfield, WI, as well as to floating cages in the power canal near the Lake Superior State University Aquatic Research Laboratory (ARL) adjacent to the St. Marys River in Sault Ste. Marie, MI during 2012 and 2013. Due to various logistical hurdles, only 12 fish could be moved to NADF. Survival of fish caught while hook and line fishing through the ice was poor, but fish caught by trap nets survived 125 days. At the ARL, 101 fish were transferred while water temperatures ranged from 9.3 oC to 19.2 oC and the resulting survival ranged from 0 to 170 days. Parasitic sea lamprey were purchased from a commercial fisher and introduced into whitefish cages at various points during the study. Overall, lamprey attacked 37 whitefish at the ARL, and none of the whitefish survived the attacks. The survival rate observed (0%) indicates that whitefish likely have a low probability of surviving a lamprey attack, but we believe the rate observed here is biased low as many fish held at the ARL showed visible signs of stress, such as fin erosion and fungal growth. We offer recommendations on using wild and hatchery whitefish for lamprey interaction trials to assess the probability of survival.