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Distribution of genetic variation within and among hatchery strains of lake trout (Salvelinus namaycush)
Strains of five trout species used in the management of U.S. fisheries
HAROLD L. KINCAID’ and CHARLES R. BERRY’ ‘U.S. Fish and Wildlife Service, RD 4, Box 63, Wellsboro, PA 16901 (U.S.A.) ‘Utah Cooperative Fisheries, Utah State University, Logan, UT 84322 (U.S.A.)
ABSTRACT Surveys of trout broodstocks maintained by federal and state fisheries agencies during 1980, 1982, and 1984 identified broodstocks currently used in fishery management programs. Information obtained on each broodstock included broodstock origin, hatchery performance, field performance, disease resistance, management utilization, and breeding practices employed to maintain each broodstock. The number of trout broodstocks maintained in state and federal programs during 1984 were: rainbow trout (75 and 18), brook trout (36 and 4)) brown trout (35 and 6)) cutthroat trout (33 and 5)) and lake trout (16 and 7). Broodstock numbers have declined since 1980 in the rainbow trout ( - 10.5%), brook trout ( -14.6%), brown trout ( -7.0%) and cutthroat trout ( - 7.3% ) but have increased in the lake trout ( + 64.3%). This trend toward fewer broodstocks is partially attributed to an increased awareness by fisheries personnel of strain performance differences which has led to the discontinuance of poorer broodstocks. The impact of this increased “efficiency” on long-term reductions in species genetic diversity is discussed. General breeding practices followed to perpetuate broodstocks were similar in all five species and could be partitioned into three general types: random mating within year classes of a broodstock (33.8%)) random mating between different year classes of a broodstock (37.0%)) and mating according to a specialized selection system (29.2% ) . Traits included in selection programs for individual broodstocks were: body conformation (15)) growth rate (lo), egg quality (lo), color (7), disease resistance ( 6)) spawning time (4)) and longevity (2 ) . Implications of observed trends in management usage and breeding methods are discussed.
Distribution of genetic variation within and among hatchery strains of lake trout (Salvelinus namaycush)
J. ELLEN MARSDEN, CHARLES C. KRUEGER and BERNIE MAY Dept. of Natural Resources, Cornell University, Ithaca, NY 14853 (U.S.A.)
ABSTRACT Lake trout are currently the focus of intensive stocking programs in the Great Lakes and in other smaller inland lakes in North America. These programs propagate lake trout by collecting gametes from either wild populations or hatchery broodstocks. The application of electrophoretic techniques to the study of the processes of genetic change within and among populations has been difficult due to the lack of reported isozyme variability. This study was conducted to (1) examine the electrophoretic expression of enzymes previously undescribed in the literature, (2) identify
372 polymorphic loci potentially useful in future population studies, and (3) describe the distribution of genetic variation within and among hatchery strains. An additional 25 enzymes not previously examined were resolved and data can now be scored from an estimated 100 loci in lake trout. Among these loci 26 were observed to be polymorphic with 18 being useful for population studies among the lake trout strains examined within this study. Polymorphisms in Fum-1 and 2 and Pgm-5 and 6, previously undescribed in salmonids, were resolved. The lake trout strains examined were (omission of the work “lake” indicates a broodstock) : Lake George, Raquette Lake, Clearwater,Lake, Lake Manitou, Killala Lake, Superior, Seneca, Lake Ontario “strain” (1983 and 1984 year classes), and Gull Island Shoal. Clustering of strains based on Nei’s genetic distances matched predictions based on strain lineages. Progress is underway to determine the relative contribution of each of the stocked strains to naturally produced fry in Lake Ontario.
Inheritance of body and tail coloration in two domesticated varieties of the guppy, Poecilia reticulata
V.P.E. PHANG, A.A. FERNANDO and O.K. CHOW Department of Zoology, National University of Singapore, Kent Ridge 0511 (Singapore)
ABSTRACT Several color pattern varieties of Poecilia reticulata, a popular ornamental fish, are cultured in Singapore. The inheritance of body and tail color of the blue tail and red tail varieties of the guppy was studied by reciprocal outcrossing with the wild type straion. Body color was determined by scale melanophore, xanthophore and erythrophore counts. It was demonstrated that body coloration was determined by an autosomal gene, with the wild type dominant over the blue tail and red tail color varieties. The tail colors of the blue tail and red tail varieties were determined by Xlinked, sex-limited genes. Tail coloration was found to be affected by modifier genes.
Stock identification in lake trout using genetic markers
RUTH B. PHILLIPS’ and PETER E. IHSSEN’ ‘Department of Biological Sciences, University of Wisconsin, Milwaukee, WI (U.S.A.) ‘Ontario Ministry of Natural Resources, Maple, Ont. (Canada)
ABSTRACT Data on the frequency of isozyme alleles and chromosome banding polymorphisms were obtained from six different lake trout populations. Chromosome banding polymorphisms scored include quinacrine (Q) band size and intensity variants and nucleolar organizer region (NOR) poly-
HAROLD L. KINCAID’ and CHARLES R. BERRY’ ‘U.S. Fish and Wildlife Service, RD 4, Box 63, Wellsboro, PA 16901 (U.S.A.) ‘Utah Cooperative Fisheries, Utah State University, Logan, UT 84322 (U.S.A.)
ABSTRACT Surveys of trout broodstocks maintained by federal and state fisheries agencies during 1980, 1982, and 1984 identified broodstocks currently used in fishery management programs. Information obtained on each broodstock included broodstock origin, hatchery performance, field performance, disease resistance, management utilization, and breeding practices employed to maintain each broodstock. The number of trout broodstocks maintained in state and federal programs during 1984 were: rainbow trout (75 and 18), brook trout (36 and 4)) brown trout (35 and 6)) cutthroat trout (33 and 5)) and lake trout (16 and 7). Broodstock numbers have declined since 1980 in the rainbow trout ( - 10.5%), brook trout ( -14.6%), brown trout ( -7.0%) and cutthroat trout ( - 7.3% ) but have increased in the lake trout ( + 64.3%). This trend toward fewer broodstocks is partially attributed to an increased awareness by fisheries personnel of strain performance differences which has led to the discontinuance of poorer broodstocks. The impact of this increased “efficiency” on long-term reductions in species genetic diversity is discussed. General breeding practices followed to perpetuate broodstocks were similar in all five species and could be partitioned into three general types: random mating within year classes of a broodstock (33.8%)) random mating between different year classes of a broodstock (37.0%)) and mating according to a specialized selection system (29.2% ) . Traits included in selection programs for individual broodstocks were: body conformation (15)) growth rate (lo), egg quality (lo), color (7), disease resistance ( 6)) spawning time (4)) and longevity (2 ) . Implications of observed trends in management usage and breeding methods are discussed.
Distribution of genetic variation within and among hatchery strains of lake trout (Salvelinus namaycush)
J. ELLEN MARSDEN, CHARLES C. KRUEGER and BERNIE MAY Dept. of Natural Resources, Cornell University, Ithaca, NY 14853 (U.S.A.)
ABSTRACT Lake trout are currently the focus of intensive stocking programs in the Great Lakes and in other smaller inland lakes in North America. These programs propagate lake trout by collecting gametes from either wild populations or hatchery broodstocks. The application of electrophoretic techniques to the study of the processes of genetic change within and among populations has been difficult due to the lack of reported isozyme variability. This study was conducted to (1) examine the electrophoretic expression of enzymes previously undescribed in the literature, (2) identify
372 polymorphic loci potentially useful in future population studies, and (3) describe the distribution of genetic variation within and among hatchery strains. An additional 25 enzymes not previously examined were resolved and data can now be scored from an estimated 100 loci in lake trout. Among these loci 26 were observed to be polymorphic with 18 being useful for population studies among the lake trout strains examined within this study. Polymorphisms in Fum-1 and 2 and Pgm-5 and 6, previously undescribed in salmonids, were resolved. The lake trout strains examined were (omission of the work “lake” indicates a broodstock) : Lake George, Raquette Lake, Clearwater,Lake, Lake Manitou, Killala Lake, Superior, Seneca, Lake Ontario “strain” (1983 and 1984 year classes), and Gull Island Shoal. Clustering of strains based on Nei’s genetic distances matched predictions based on strain lineages. Progress is underway to determine the relative contribution of each of the stocked strains to naturally produced fry in Lake Ontario.
Inheritance of body and tail coloration in two domesticated varieties of the guppy, Poecilia reticulata
V.P.E. PHANG, A.A. FERNANDO and O.K. CHOW Department of Zoology, National University of Singapore, Kent Ridge 0511 (Singapore)
ABSTRACT Several color pattern varieties of Poecilia reticulata, a popular ornamental fish, are cultured in Singapore. The inheritance of body and tail color of the blue tail and red tail varieties of the guppy was studied by reciprocal outcrossing with the wild type straion. Body color was determined by scale melanophore, xanthophore and erythrophore counts. It was demonstrated that body coloration was determined by an autosomal gene, with the wild type dominant over the blue tail and red tail color varieties. The tail colors of the blue tail and red tail varieties were determined by Xlinked, sex-limited genes. Tail coloration was found to be affected by modifier genes.
Stock identification in lake trout using genetic markers
RUTH B. PHILLIPS’ and PETER E. IHSSEN’ ‘Department of Biological Sciences, University of Wisconsin, Milwaukee, WI (U.S.A.) ‘Ontario Ministry of Natural Resources, Maple, Ont. (Canada)
ABSTRACT Data on the frequency of isozyme alleles and chromosome banding polymorphisms were obtained from six different lake trout populations. Chromosome banding polymorphisms scored include quinacrine (Q) band size and intensity variants and nucleolar organizer region (NOR) poly-