Differences in Reproduction among Hatchery Strains of Lake Trout at Eight Spawning Areas in Lake Ontario: Genetic Evidence from Mixed-Stock Analysis
January 1, 1995
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Author:
David L. Perkins; John D. Fitzsimons; J. Ellen Marsden; Charles C. Krueger; Bernie May
Journal or Book Title: Journal of Great Lakes Research
Keywords: Genetics; DNA analysis; lake trout; behavior; restoration; Great Lakes
Volume/Issue: 21 (Supplement 1)
Page Number(s): 364-374
Year Published: 1995
The restoration of self-sustaining populations of lake trout to the Great Lakes has involved stocking multiple hatchery strains of lake trout. To determine whether reproductive success variedamong strains, embryos and fry from three sites in the eastern basin and four sites in the western basin of Lake Ontario were genetically characterized with allozyme electrophoresis at 18 polymorphic loci. These data and data from previous studies were used to estimate by mixed-stock analysis (MSA) the strain composition of parents that contributed to the embryo and fry mixture samples. In the eastern basin of Lake Ontario, the parental contributor to embryos and fry at three of the four spawning sites was primarily the Seneca strain (73-95%); SuperiorlKillala and Manitou strains contributed to a lesser extent (0-13%) and the Clearwater and Jenny strains were nearly absent from the estimates « 2%). Strain contributions at the fourth eastern spawning area were different: Seneca-10%, SuperioriKillala-43%, Manitou-43%, Clearwater-2%, and Jenny-1%. In the western basin, parental contributors to embryos were similar at three spawning sites; Seneca and SuperiorlKillala each contributed 33-48% with the balance divided among the other three strains. At the fourth western spawning area, the Seneca strain was absent, and contributions from the Clearwater, Manitou, and SuperiorlKillala strains each varied between 15 and 44% depending upon the year. Differences in strain composition among lake trout embryos from spawning sites 10-50 km apart and the temporal consistency of strain compositions at two sites where embryos or fry were collected over 3-7 years indicated that the criterion adult fish used to select spawning sites varied among strains. The SuperiorlKillala strain consistently contributed less than lake-wide stocking rates predicted, but the Seneca strain usually contributed more. Contributions from the Jenny, Manitou, and Clearwater strains were inconclusive because of low expected and observed values. The Seneca strain's greater overall contribution indicates that stocking more of the Seneca strain may increase the potential for natural reproduction. The minimal contribution of the Seneca strain at two of the eight spawning sites, however, suggests that other strains should continue to be stocked to make use of spawning habitat not used by the Seneca strain.
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