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Causes of declining survival of lake trout stocked in U.S. waters of Lake Superior in 1963-1986

Transactions of the American Fisheries Society

By:
, , , , , , and
DOI: 10.1577/1548-8659(1996)125<0831:CODSOL>2.3.CO;2

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Abstract

Survival of the 1963-1982 year-classes of stocked yearling lake trout Salvelinus namaycush declined significantly over time in Lake Superior. To investigate possible causes of this decline, a Ricker model of stock-recruitment was used to describe the catch per effort (CPE) of age-7 stocked lake trout in the Michigan, Minnesota, and Wisconsin waters of Lake Superior as functions of the numbers of yearlings stocked 6 years earlier (an index of density dependence), the density (CPE) of wild adult lake trout (an index of predation), and large-mesh (a?Y 114-mm stretch-measure) gill-net fishing effort (an index of fishing mortality). Declining CPE of stocked lake trout in Michigan and Wisconsin was significantly associated with increasing large-mesh gillnet fishing effort. Declining CPE of stocked lake trout in Minnesota was significantly associated with increasing density of wild lake trout. Declining survival of stocked lake trout may therefore have been caused by increased mortality in large-mesh gill-net fisheries in Michigan and Wisconsin, and by predation by wild lake trout that recently recolonized the Minnesota area. We recommend that experimental management be pursued to determine the relative importance of large-mesh gillnet fishing effort and of predation by wild lake trout on the survival of stocked lake trout in U.S. waters of Lake Superior.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Causes of declining survival of lake trout stocked in U.S. waters of Lake Superior in 1963-1986
Series title:
Transactions of the American Fisheries Society
DOI:
10.1577/1548-8659(1996)125<0831:CODSOL>2.3.CO;2
Volume
125
Issue:
6
Year Published:
1996
Language:
English
Publisher:
Taylor & Francis
Publisher location:
London, UK
Contributing office(s):
Great Lakes Science Center
Description:
13 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Transactions of the American Fisheries Society
First page:
831
Last page:
843