Evidence of lake trout (Salvelinus namaycush) natural reproduction in Lake Erie

Native lake trout were extirpated from Lake Erie around 1965 and committed restoration efforts began in 1982. In 2021 and 2022, a total of six lake trout (Salvelinus namaycush) in the free embryo or post-embryo life stage were captured in lake trout embryo traps in Lake Erie offshore of Shorehaven Reef, NY. This represents the first conclusive evidence of successful natural reproduction since extirpation. Trapping locations were identified using the results of a fine-scale positioning acoustic telemetry array, visual observations of adult lake trout exhibiting spawning behavior, and underwater cameras to visually identify possible spawning locations. Lake trout utilized a very specific spawning habitat type-the eastern side of shallow offshore humps in 5-8 m of water. These sites were comprised of habitat typically associated with lake trout spawning with slopes of 5-14 degrees and clean rubble-cobble sized rock with visible interstitial spaces. Genetic barcoding was used to identify the post-embryo stage salmonids to species, and microsatellite genotypes assigned strongly to the Seneca strain which comprises the majority of the adult population. These findings represent a significant milestone for lake trout rehabilitation efforts in Lake Erie, confirming that successful reproduction to the post-embryo stage is possible and supporting continued rehabilitation efforts by Lake Erie management agencies. (C) 2022 International Association for Great Lakes Research. Published by Elsevier B.V. All rights reserved.

Automated summary

Native lake trout were extirpated from Lake Erie around 1965 and restoration efforts began in 1982. The recent capture of six lake trout in the embryo or post-embryo stage provides conclusive evidence of successful natural reproduction in the lake since extirpation. The trapping locations were identified using acoustic telemetry array, visual observations, and underwater cameras to determine possible spawning locations.