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Dynamics of individual growth in a recovering population of lake trout (Salvelinus namaycush)

Canadian Journal of Fisheries and Aquatic Sciences

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Abstract

In 1976, the Wisconsin Department of Natural Resources established a refuge for a nearly depleted population of lake trout (Salvelinus namaycush) at Gull Island Shoal, Lake Superior. The refuge was intended to reduce fishing mortality by protecting adult lake trout. We examined the growth dynamics of these lake trout during the period of recovery by comparing estimates of ndividual growth before and after the refuge was established. Our estimates are based on an annual mark-recapture survey conducted at the spawning area since 1969. We developed a model that allowed mean growth rates to differ among individuals of different sizes and that accommodated variation in growth rates of individuals of the same size. Likelihood ratio tests were used to determine if the mean growth increments of lake trout changed ater the refuge was established. Our results suggest that growth of mature lake trout (particularly wild fish) decreased significantly in the postrefuge period. This decreased growth may have been associated with a reduction in food availability. We also observed reductions in growth as wild fish grew older and larger, which suggests that the growth of these fish may be adequately approximated by a von Bertalanffy growth model if it becomes possible to obtain accurate ages.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Dynamics of individual growth in a recovering population of lake trout (Salvelinus namaycush)
Series title:
Canadian Journal of Fisheries and Aquatic Sciences
Volume
58
Issue:
2
Year Published:
2001
Language:
English
Contributing office(s):
Great Lakes Science Center
Description:
p. 262-272
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Canadian Journal of Fisheries and Aquatic Sciences
First page:
262
Last page:
272
Number of Pages:
10