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​Effects of Sea Lamprey Sub-lethal Parasitism on Lake Trout

9 year old Lake Trout Broodstock sized.jpg

Historically, lake trout have been an important species in the great lakes for commercial, subsistance and sport fisheries, not to mention a top predator in Lake Superior. Although, many non-native species have entered the Great Lakes over the years, the parasitic sea lamprey is showing to be one of the most harmful, especially for lake trout populations. At their parasitic stage, sea lamprey attach to their fish host, extracting blood and tissue fluids with their specialized mouth parts (photo at right).Sea Lamprey  mouth part.jpg

It is estimated that 45-75% of lake trout survive a sea lamprey parasitism event.  The sub-lethal physiological effects of sea lamprey parasitism on their hosts are likely to have significant population and management implications.  Yet we currently know little about how fish respond to sub-lethal parasitism events or how these events alter growth, body condition or reproduction.  Because of this gap in knowledge, it is likely that we are underestimating the damage caused by sea lamprey parasitism on lake trout populations.

In collaboration with UWSP NADF, Tyler Firkus, (doctoral candidate) and Dr. Cheryl Murphy of Michigan State University, Dr. Rick Goetz of NOAA, and Shawn Sitar of MI DNR, will assess the effects of sub-lethal sea lamprey parasitism on two different lake trout morphotypes. Funding for this project is provided by the Great Lakes Fishery Commission. 

Using siscowet and lean lake trout reared at the UWSP-NADF in a common environment for 11 years, project partners will assess how lake trout physiology is altered long-term after a parasitism event.  Additionally, this information will be used to refine current physiological and bioenergetics models to better predict how sub-lethal Sea Lamprey parasitism affects growth, reproduction, and population structure.

The data from this project will be most important for understanding and preserving  lake trout populations in the Great Lakes.


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