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Population recovery and natural recruitment of lake trout at Gull Island Shoal, Lake Superior, 1964-1992

Journal of Great Lakes Research

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Abstract

We documented an increase in the abundance of wild lake trout (Salvelinus namaycush) at Gull Island Shoal in western Lake Superior and examined the relationship between parental-stock size and recruitment of age-0 fish in 1964-1992. Abundance of adult wild female lake trout and densities of age-0 fish both increased during the 28-year period. A significant positive, linear relationship (p = 0.0002) was found between the abundance of wild females on the spawning reef in the fall and density of age-0 lake trout on adjacent nursery grounds in August and September of the following year. The abundance of hatchery-origin females did not explain significant amounts (p = 0.107) of variation in recruitment. We concluded that most recruitment in 1965-1992 was the result of natural reproduction of wild females. After 28 years of recovery the Gull Island Shoal lake trout population appears to have additional capacity to increase because the stock-recruitment relationship is still linear. Therefore, restoration periods on the order of 30 years may be needed for other lake trout populations in the Great Lakes. We recommend that the refuge established to protect this population be maintained to allow further study of the relationship between parental stock and recruitment, and to provide a major source of recruitment to the lake trout population in the surrounding waters.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Population recovery and natural recruitment of lake trout at Gull Island Shoal, Lake Superior, 1964-1992
Series title:
Journal of Great Lakes Research
Volume
21
Year Published:
1995
Language:
English
Contributing office(s):
Great Lakes Science Center
Description:
p. 225-232
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Great Lakes Research
First page:
225
Last page:
232
Number of Pages:
7