Identification of Parental Origins of Naturally Produced Lake Trout in Lake Ontario: Application of Mixed-Stock Analysis to a Second Generation
June 1, 1989 - J. Ellen Marsden; Charles C. Krueger; Bernie May
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EmailJournal or Book Title: NORTH AMERICAN JOURNAL OF FISHERIES MANAGEMENT
Volume/Issue: 9/3
Page Number(s): 257-268
Year Published: 1989
Management decisions related to the restoration of a self-perpetuating population of lake trout Salvelinus namaycush in Lake Ontario would be improved with information about differences in the reproductive success of stocked strains. Assessment of differential reproductive success of naturally spawning mixed-stock fish populations requires the use of genetic markers that are transmitted between generations. This paper describes the identification of hatchery lake trout strains that successfully reproduced on a single reef in Lake Ontario in 1986. The analysis used allozyme data from parental stocks and naturally produced young and represents a novel application of the maximum-likelihood method of mixed-stock analysis. Lake trout sac-fry captured in 1986 in Lake Ontario were estimated to have been produced by Seneca x Seneca strain (78%) and Seneca x Superior crosses (20%), although the Seneca x Superior estimate was not significantly different from zero. Eight other strains and strain hybrids were estimated to be absent from this population of young fish. The same analysis was applied to four hatchery year classes of lake trout that were propagated from gametes taken from adult lake trout captured in the eastern basin of Lake Ontario. Results from these analyses also suggest that the Seneca and Superior strains made the highest contribution to populations of young lake trout. However, the proportions of each type of young (hybrids and pure-strain crosses) differed among year classes of the Lake Ontario hatchery strain and between hatchery and wild young. Before these analyses are used to develop future stocking programs, the reproductive success of strains must be assessed over several years and spawning locations. Factors that affect the mixed-stock analysis procedure when it is used for parental origin analysis include the potentially large number of types of young in the F, generation and genetic similarity of types of young that share a common parental stock. The mixed-stock analysis procedure is a viable method for estimating the reproductive success of genetically differentiated strains.
Type of Publication: Journal Article
