Updated 2024-11-22 14:29:27
Lake Superior -> 3.0 Lake Trout -> Lake Trout Spring Catch Rate
Reporting Interval
2017 - 2021
Area
US Waters
Meeting Target?
Meets
Indicator Trend
Upward trend
Confidence?
High
3.1.1 Geometric mean lean lake trout catch rates>8.7 fish/km
Relative abundance of lean lake trout in US waters of Lake Superior has steadily increased since the mid-1980s and achieved rehabilitation state starting in 2010. The recent decline in abundance between 2017 and 2021 was similar to the decline observed between 2006-2010 and is not cause for concern. The variations in abundance (up to 40%) were due to multiple factors such as density-dependent declines in recruitment, sampling variability, and changes in mortality rates. Overall, lake trout populations are stable and abundant in Lake Superior and continue to be sustained by natural reproduction.
Figure 1. Lake Superior lean lake trout catch rates (geomean CPUE) weighted by habitat area (<80m) in US waters from agency spring assessment gillnets. The reference period (1929-1943) lean lake trout catch rates (geomean CPUE) weighted by habitat area (<80m) in US waters was derived from Michigan commercial catches.
Methodology
Contemporary data are based on Lake Superior Technical Committee standardized agency spring (lean) lake trout surveys conducted in nearshore US waters of Lake Superior in 30-80 m using 11.4 cm mesh, multifilament, benthic gill nets fished for 1-3 nights based on a fixed-station sampling design (Sitar et al., 2024). Historic fishery catch rate data were based on commercial fishery CPUE based on similar benthic gill nets as contemporary survey (Wilberg et al. 2003), though the populations were fished intensively causing uncertainty in relative abundance estimates.
Other Resources
Sitar, S.P., M.J. Seider, M.P Ebener, S.C. Chong, C.A. Goldsworthy, I. Harding, S.B. Michaels, S.A. Moore, T. Pratt, and B.A. Ray. 2024. Synthesis of recent research and attributes of recovered lean Lake Trout populations in Lake Superior, 1993-2022. North American Journal of Fisheries Management.
Wilberg, M.J., M.J. Hansen, and C.R. Bronte. 2003. Historic and modern abundance of wild lean lake trout in Michigan waters of Lake Superior: Implications for restoration goals. North American Journal of Fisheries Management 23:100-108.
Contributing Author(s)
- Lake Superior Technical Committee -