Contribution of Hatchery-Reared Fish to Chinook Salmon Populations and Sport Fisheries in Lake Superior

Abstract

Chinook salmon Oncorhynchus tshawytscha stocked in Lake Superior since 1967 to diversify the sport fishery were suspected of reproducing. An abundance of naturalized chinook salmon would reduce the need for hatchery fish but also would decrease our ability to manage chinook populations and their effect on the Lake Superior fish community. Our study objective was to determine the relative contribution of hatchery and wild fish to chinook salmon populations in Lake Superior. All chinook salmon stocked in Lake Superior in 1988, 1989, and 1990 were marked with an agency‐specific fin clip. Contribution of these marked year‐classes were determined from their representation in sampled sport fisheries and spawning runs. Hatchery fish made up 9, 25, 32, and 57% of chinook salmon sampled in Ontario, Michigan, Wisconsin, and Minnesota waters of Lake Superior during 1990–1994. Hatchery chinook salmon stocked by each state or provincial agency were caught in each of the other Lake Superior jurisdictions, and two fish stocked by Michigan were captured in Lake Michigan tributaries. Chinook salmon stocked by Minnesota contributed most hatchery fish to sport fisheries in Michigan, Wisconsin, and Minnesota (10, 15, and 31%), and 1% in Ontario. Chinook salmon stocked by Michigan contributed 8% to Michigan sport fisheries and 5, 6, and 1% to Wisconsin, Minnesota, and Ontario sport fisheries, respectively. Wisconsin hatchery fish contributed 9% to Wisconsin sport fisheries and 5, 13, and 1% to Michigan, Minnesota, and Ontario sport fisheries. Fish stocked by Ontario contributed 5% to Ontario sport fisheries, and 2, 3, and 7% to Michigan, Wisconsin, and Minnesota sport fisheries. Chinook salmon spawning runs were reported in 10 Michigan, 8 Wisconsin, 4 Minnesota, and 19 Ontario tributaries during 1990–1994. In stocked tributaries, most chinook salmon in spawning runs were hatchery fish (70–89%), and in nonstocked tributaries most were wild fish (72–94%). Hatchery‐reared chinook salmon were estimated to make up 25% or less of total chinook salmon populations in Lake Superior. Individual agencies must determine if this contribution is sufficient to justify continued stocking.

Global introductions of salmon and trout in the genus Oncorhynchus: 1870–2007

“…Hundreds of thousands of chinook salmon continued to be released to each of the Great Lakes until approximately 1880 (MacCrimmon 1977;Scott and Crossman 1973). By the early 1880s chinook salmon in the Great Lakes had largely died out, leading both US and Canadian introduction plans to be terminated (Dymond et al 1929;Peck et al 1999). In the 1960s, Michigan stimulated another intensive round of chinook salmon introductions to the Great Lakes by most of the other states and provinces, this time at stocking levels that dwarfed all previous efforts.…”

Hydroacoustic Estimates of Abundance and Spatial Distribution of Pelagic Prey Fishes in Western Lake Superior

“…Such contrasting results across spatial scale may suggest that salmonine growth and foraging is not confined to the Minnesota waters of Lake Superior (Negus 1995), but rather occurs over a much larger spatial arena. For example, pacific salmonines in the Great Lakes show little site affinity during the year (Keller et al 1990, Peck et al 1999) making population estimates and spatial estimates of consumption difficult. Alternatively, pelagic prey fishes may undergo seasonal lake wide movements, periodically enhancing local prey abundance sufficient to support predator demand.…”

Evolution of introduced Chinook salmon (Oncorhynchus tshawytscha) in Lake Huron: emergence of population genetic structure in less than 10 generations

“…In the 1960s, the lower four Laurentian Great Lakes were suffering the consequences of the extirpation of almost all populations of lake trout (Salvelinus namaycush Walbaum) from overharvesting and predation by sea lamprey (Petromyzon marinus Linnaeus) (Coble et al 1990;Eshenroder et al 1992). Since the initiation of the stocking programme, Chinook salmon have established feral populations 1 in Lake Michigan, Lake Superior, Lake Huron, and, to a lesser extent, Lake Ontario (e.g., Peck et al 1999;Weeder et al 2005;Smith et al 2006;Johnson et al 2010). This programme has involved artificial breeding and the release of hatchery-reared juveniles (age 0) into tributaries and along lakeshores.…”

“…In response, fisheries managers initiated a Pacific salmonid stocking programme to control burgeoning alewife (Alosa pseudoharengus Wilson) populations and provide recreational fishing opportunities to coastal communities (Hansen 1999;Crawford 2001). Indeed, largescale mark-recapture studies show that wild Chinook salmon can comprise the majority of the recreational catch in some regions (Peck et al 1999;Johnson et al 2010). Since the initiation of the stocking programme, Chinook salmon have established feral populations 1 in Lake Michigan, Lake Superior, Lake Huron, and, to a lesser extent, Lake Ontario (e.g., Peck et al 1999;Weeder et al 2005;Smith et al 2006;Johnson et al 2010).…”