Updated 2025-03-24 17:45:49
Lake Huron -> 1.0 Salmonine (Salmon and Trout) -> Lake Trout Wounding Rate
Reporting Interval
2018 - 2022
Area
Ontario waters
Meeting Target?
Does Not Meet
Indicator Trend
Downward trend
Confidence?
High
1.2.7. Sea Lamprey wounding of Lake Trout in Ontario waters
Sea lamprey mortality is considered an impediment to Lake Trout rehabilitation (Ebener 1998), especially in northern areas of Lake Huron where the St. Mary’s River is a major lamprey producing tributary (Criger et al. 2021). The threshold lamprey marking rate is less than 5 wounds per 100 adult Lake Trout. In Ontario waters of Lake Huron, lamprey marking rate is spatially and temporally variable. Marking rates in northern areas and Georgian Bay have declined from earlier in the time series, whereas rates in the southern main basin have been near or below threshold levels in most years (Figure 1). Overall, the lamprey wounding rate is very close to or slightly above the threshold in recent years (Figure 1).
Sea lamprey marking rate per 100 fish examined from OMNR Upper Great Lakes Management Unit sampling and assessments in Ontario waters of Lake Huron. Maintaining Lamprey marking rates at or below 5 per 100 individuals is considered necessary for Lake Trout rehabilitation (Ebener 1998).
Methodology
Data provided by the Upper Great Lakes Management Unit (UGLMU) of the Ontario Ministry of Natural Resources (MNR). Lamprey wounding rates were estimated from Lake Trout sampled from the commercial fishery and from standard index gillnetting. Only A1, A2 and A3 marks were counted as recommended by the Great Lakes Fishery Commission Lamprey wound classification guide. Commercial catch sampling has been conducted annually since 1975. Onboard observations of catches and biological sampling of fish from Lake Huron commercial fishing vessels was conducted by UGLMU fisheries technicians. All gillnetting surveys conducted by the UGLMU are made with monofilament.
Other Resources
Criger, L.A., Barber, J.M., Bravener, G.A., Brenden, T.O. and Neave, F.B., 2021. The evolution of sea lamprey control in the St. Marys River: 1997–2019. Journal of Great Lakes Research, 47, pp. S479-S491.
Ebener, M. P. [ED.]. 1998. A lake trout rehabilitation guide for Lake Huron. Great Lakes Fishery Commission. 48 p.
Contributing Author(s)
- Stephen James & Chris Davis - Ontario Ministry of Natural Resources
- Ji He - Michigan Department of Natural Resources
- Jose Bonilla-Gomez & Scott Koproski - United States Fish and Wildlife Service