Great Lakes Fishery Commission

Updated 2021-09-23 15:57:27

Lake Erie -> 3.0 Rehabilitation Species -> Lake Trout

Maintain viable adult lake trout biomass with a goal of documenting evidence of natural reproduction

Lake trout (Salvelinus namaycush) played a historically important ecological role as the primary native coldwater predator in Lake Erie and supported large commercial fisheries. By 1965, over-fishing, excessive nutrients, and exotic species invasions (in particular the parasitic sea lamprey) led to the extirpation of lake trout from Lake Erie. Now supported completely by stocking that has occurred since 1978, the population supports a trophy fishery in the deep, offshore waters of the east basin during the summer months and nearshore areas of the east and central basins in the spring and fall.

Re-establishing a self-sustaining lake trout population continues to be the primary rehabilitation goal in Lake Erie. The current annual stocking goal of 200,000 yearlings has been achieved in 12 of the past 14 years (Figure 1). Finger Lakes (Seneca), Lake Champlain, and Slate Island are the most prevalent strains currently stocked. The population achieved the rehabilitation plan target of at least ten or more different age classes throughout the 2016-2020 reporting period, and older fish (age 10+) continue to increase in abundance. Adult (age 5+) lake trout relative abundance (used as an indicator of adult biomass) achieved the rehabilitation plan target of at least 2.0 fish/net in only two of the five years but exhibited an increasing trend (Figure 2). Average adult relative abundance during the reporting period was 1.9 fish/net. Despite recent positive trends, natural reproduction has not been detected. An acoustic telemetry study that began in 2016 is providing valuable information on movements, spawning locations, and spawning habitat use that will guide future rehabilitation efforts.

Figure 1. Lake trout (in yearling equivalents) stocked by all jurisdictions in Lake Erie, 1980-2020. The current stocking goal is 200,000 yearlings per year.

Figure 2. Relative abundance (number per net, weighted by area) of adult (age-5-and-older) lake trout sampled in standard assessment gill nets in the east basin of Lake Erie, 1992-2020. The adult rehabilitation target is at least 2.0 fish per net.