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Sea Lamprey Parasitism work at UWSP NADF

Quantifying the Effects of Sea Lamprey Parasitism

FUNDED BY: THE GREAT LAKES FISHERY COMMISSION

BACKGROUND

The presence of parasitic sea lamprey in the Great Lakes is an ongoing challenge that costs the Canadian and United States governments millions of dollars in sea lamprey monitoring and control every year. The principal damage metric used in these calculations is estimated mortality of lake trout from sea lamprey attacks. Although sea lamprey are non-specialist feeders, damage to the lake trout population is a primary concern due to the economic value of this species in the Great Lakes.

PREVIOUS RESEARCH DONE AT UWSP NADF DEMONSTRATED LAKE TROUT THAT SURVIVE A LAMPREY ATTACK EXPERIENCE LONG TERM IMPAIRMENTS TO GROWTH AND REPRODUCTION…

Although parasitism can lead to direct mortality, up to 75% of lake trout may survive a parasitism event and recent research done at UWSP NADF demonstrated that survivors experience long-term growth and reproductive impairments, including skipped spawning. While the mechanisms underpinning these effects are unknown, this work highlights that sublethal responses to a sea lamprey attack can reduce host fitness. This begs the question whether damage estimates could be improved by including a more fulsome assessment of host health.

Currently, the only source of biological information used to understand host-parasite encounters in the Great Lakes is the wound or scar (collectively called “marks”) left behind after the parasite detaches from its host.

Wounding data collected from host fish is an integral part of sea lamprey (SL) monitoring efforts and helps inform management decisions. However, wound assessment is subjective and error prone. An objective and quantitative index of SL parasitism could improve damage estimates derived from wound assessments. Previous research has found that the abundances of several blood clotting proteins were altered in host blood after SL parasitism.

HYPOTHESIS

SL parasites induce predictable and quantifiable changes to hemostatic regulation in host fish.

APPROACH

Rainbow trout (Oncorhynchus mykiss) are a known host of SL parasites. They are easily reared, widely available, and offer a trove of physiologic and genomic data that will enhance results interpretation. A comprehensive investigation of hemostatic regulation in rainbow trout during a controlled parasitism trial will be followed by a targeted validation study in lake trout.

ANTICIPATED RESULTS

These experiments will yield a deeper insight into the sublethal effects of SL parasitism on host fish and may help establish quantitative relationships between parasitism and host fitness. Importantly, this study will provide the necessary foundation for developing hemostatic endpoints into field-ready tools for enhancing the accuracy and interpretation of wound assessment data.

PARTNERS