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Reproductive potential and fecundity of lake trout strains in southern and eastern waters of Lake Ontario, 1977-1994

Journal of Great Lakes Research

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Abstract

We assessed the reproductive potential of various genetic strains of hatchery lake trout (Salvelinus namaycush) in southern and eastern Lake Ontario from indices of fecundity and indices of male abundance. Indices were constructed from catches of mature lake trout in gill nets during September 1980 to 1994 after correcting for mortality from sea lampreys (Petromyzon marinus) which occurred between September sampling and late fall spawning. Strain and age were assigned to individual lake trout based on clipped fins and maxillary bones or coded wire tags. Fecundity-length relationships for fish of the same age, determined from mature females collected in 1977 to 1981 and 1994, were not different (P > 0.05) among genetic strains. For all strains combined, fecundity-length relationships in 1977 to 1981 were not different among fish of various ages but in 1994, age-5 and -6 fish had fewer eggs (P < 0.003) than age-7 fish, and age-7 fish had fewer eggs (P < 0.003) than fish of age 8, 9, or 10. Annual indices of fecundity varied 19 fold and indices of mature males varied 11 fold; both indices were low in the early 1980s, increased sharply in the mid 1980s, and peaked in 1993. The strain which dominated fecundity and mature male indices shifted during the study from Seneca Lake strain to Lake Superior strain and then back to Seneca Lake strain. However, changes in either reproductive potential or genotypes do not appear responsible for the abrupt appearance of naturally-produced yearling lake trout throughout southern and eastern Lake Ontario in 1994-1995, the first widespread occurrence of juveniles produced by hatchery lake trout in Lake Ontario.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Reproductive potential and fecundity of lake trout strains in southern and eastern waters of Lake Ontario, 1977-1994
Series title:
Journal of Great Lakes Research
Volume
24
Issue:
1
Year Published:
1998
Language:
English
Contributing office(s):
Great Lakes Science Center
Description:
p. 131-144
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Great Lakes Research
First page:
131
Last page:
144
Number of Pages:
13