Lake Superior Revisited 1984

MacCallum, Wayne R.; Selgeby, James H.

doi:10.1139/f87-306

Cited by 48 publications

(19 citation statements)

References 19 publications

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“…Previous reports of lake trout abundance in the 1970s and 1980s indicated that stocked fish were increasing and wild fish were rare (Lawrie and Rahrer 1973;Lawrie 1978;MacCallum and Selgeby 1987;Hansen et al 1995aHansen et al , 1995b. Our results indicate that wild lake trout were more abundant than stocked lake trout during the 1980s, which was also reported by MacCallum and Selgeby (1987), Peck and Schorfhaar (1994), and Hansen et al (1995a). Our results show that wild lake trout abundance increased slightly or fluctuated without trend in the 1980s and 1990s and that stocked fish became rare over the same period, as also indicated by Peck and Sitar (2000).…”

Section: Relative Abundancesupporting

confidence: 84%

Recruitment Dynamics of the 1971–1991 Year‐Classes of Lake Trout in Michigan Waters of Lake Superior

Richards

Hansen

Bronte

et al. 2004

N American J Fish Manag

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In the 1950s, populations of lake trout Salvelinus namaycush in Lake Superior collapsed because of excessive exploitation and predation by sea lampreys Petromyzon marinus. Restoration began in the 1950s with the stocking of juvenile, hatchery‐reared lake trout and controls on fisheries and sea lampreys. Partial restoration was declared in 1996 because wild fish made up most of the populations in many areas, especially in Michigan waters, so stocking was dramatically curtailed in most areas. We evaluated the production of age‐7 lake trout (recruits) by age‐8 and older wild and stocked parental lake trout (spawners). Using Ricker stock–recruitment models, we also evaluated the effects of large‐mesh (114‐mm stretch measure) gill‐net effort on wild lake trout recruitment in Michigan waters of Lake Superior during 1970–1998. In general, the density of wild lake trout spawners increased, whereas that of stocked lake trout spawners decreased in all management areas investigated. The density of recruits was best described by the combined density of wild and stocked parents, which suggested similar reproductive contributions for both. Recruitment rates declined significantly with increasing spawner density in four of the five management areas and suggested that carrying capacities were reached and exceeded, which may serve as an indicator of population restoration. We conclude that both wild and stocked lake trout have contributed to the recruitment of lake trout in Michigan waters of Lake Superior. Large‐mesh gill‐net fishing effort varied in all Michigan management areas but did not account for the significant variation in wild lake trout recruitment. We conclude that levels of large‐mesh gill‐net fishing effort during 1970–1998 were not having an appreciable effect on wild lake trout recruitment in Michigan waters of Lake Superior.

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Section: Relative Abundancesupporting

confidence: 84%

Recruitment Dynamics of the 1971–1991 Year‐Classes of Lake Trout in Michigan Waters of Lake Superior

Richards

Hansen

Bronte

et al. 2004

N American J Fish Manag

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“…The decline in density of stocked lake trout in every management unit reflected a continuing trend toward wild fish predomination; in contrast, stocks in western Lake Superior before the 1990s consisted of mostly stocked lake trout (Lawrie and Rahrer 1973;Lawrie 1978;MacCallum and Selgeby 1987;Hansen et al 1995aHansen et al , 1995b. By the end of the study period, the percentage of spawners that were wild ranged from 71% in WI-1 to 95% in MN-3.…”

Section: Relative Abundancementioning

confidence: 96%

“…Lake trout stocking rates were consistent in Minnesota during 1980-2003 except for a 1987-1988 decrease caused by an epizootic of epitheliotrophic disease that reduced production of the 1984-1987year-classes (McAllister and Herman 1989Hansen 1996). The total number of lake trout stocked in Minnesota decreased in FIGURE 6.-Geometric mean (695% confidence interval) lake trout catch per effort (fish gill-net km À1 net-night À1 ) for the 1980-2003 year-classes in Minnesota management area 3 of Lake Superior: (a) age-7 natural recruits, (b) wild spawners (age 8 and older), and (c) stocked spawners.…”

Section: Relative Abundancementioning

confidence: 96%

Recruitment Dynamics of Lake Trout in Western Lake Superior during 1988–1995

Corradin

Hansen

Schreiner

et al. 2008

N American J Fish Manag

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Stocks of lake trout Salvelinus namaycush in Lake Superior are recovering from historical collapse. Stocking, control of sea lampreys Petromyzon marinus, and harvest restrictions have aided lake trout recovery, but the contribution of stocked lake trout to contemporary recruitment has not been quantified in western Lake Superior. Using variants of the Ricker stock-recruit model, we evaluated the production of age-7 lake trout (recruits) by examining age-8 and older wild and stocked parental lake trout (spawners). We found that density of wild lake trout spawners and recruits increased during 1980-2003, whereas the density of stocked spawners decreased in all management areas. Two competing models best described recruit density of the 1988-2003 year-classes: (1) wild and stocked parents each contributed to recruitment but stocked parents contributed negatively and (2) only wild parents contributed to recruitment. Recruitment rates declined significantly with increasing spawner density in four of five management areas, which suggests that recruitment is density dependent in much of western Lake Superior. We conclude that stocked lake trout did not contribute significantly to lake trout rehabilitation in western Lake Superior during 1980-1995.

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“…At its peak the commercial fishery in Black Bay harvested more than 125 Mg (metric tons) of walleye annually, which accounted for .90% of all walleye harvested in Lake Superior (Furlong et al 2006). Historical overexploitation and habitat loss have both been recognized as important contributing factors to this collapse (Colby and Nepszy 1981, MacCallum and Selgeby 1987, Furlong et al 2006. Historical overexploitation and habitat loss have both been recognized as important contributing factors to this collapse (Colby and Nepszy 1981, MacCallum and Selgeby 1987, Furlong et al 2006.…”

Section: Introductionmentioning

confidence: 99%

Genetic and ecological assessment of population rehabilitation: walleye in Lake Superior

Garner

Bobrowicz

Wilson

2013

Ecological Applications

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Sustainable management of exploited species is an ongoing challenge, particularly where populations have collapsed or been depleted by overharvest and habitat alteration. The walleye (Sander vitreus) population in Lake Superior's Black Bay historically supported more than 90% of the commercial walleye harvest from the entire lake, but collapsed in 1968 and has still not recovered despite long-term closure of the fishery. In an effort to rehabilitate this population, hatchery-origin walleye from exogenous sources were released into Black Bay between 2003 and 2005. We used individual-based analysis of genetic data collected between 2007 and 2010 to examine the contributions of different wild sources and hatchery stocking events to the contemporary walleye population in Black Bay. We found that 75% of the walleye in Black Bay originated from above- and below-barrier native populations in the Black Sturgeon River. The hatchery stocking events differed considerably in their effectiveness: the 2003 release of fry had no measurable contribution, whereas the 2004 and 2005 releases of fingerlings contributed 71% and 45% of the fish in their respective age classes. Hatchery and wild fish were similar in size, but hatchery fish rarely utilized the river habitat where Black Bay walleye historically spawned, and there was little genetic evidence of interbreeding or natural recruitment of stocked fish. Overall, our results suggest that restoring habitat connectivity to facilitate wild recruitment has greater potential than further exogenous stocking to contribute to the recovery of walleye in this system.

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Lake Superior Revisited 1984

Cited by 48 publications

References 19 publications

Recruitment Dynamics of the 1971–1991 Year‐Classes of Lake Trout in Michigan Waters of Lake Superior

Recruitment Dynamics of the 1971–1991 Year‐Classes of Lake Trout in Michigan Waters of Lake Superior

Recruitment Dynamics of Lake Trout in Western Lake Superior during 1988–1995

Genetic and ecological assessment of population rehabilitation: walleye in Lake Superior

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