title: Source-sink estimates of genetic introgression show influence of hatchery strays on wild chum salmon populations in Prince William Sound, Alaska.
abstract: The extent to which stray, hatchery-reared salmon affect wild populations is much debated. Although experiments show that artificial breeding and culture influence the genetics of hatchery salmon, little is known about the interaction between hatchery and wild salmon in a natural setting. Here, we estimated historical and contemporary genetic population structures of chum salmon (Oncorhynchus keta) in Prince William Sound (PWS), Alaska, with 135 single nucleotide polymorphism (SNP) markers. Historical population structure was inferred from the analysis of DNA from fish scales, which had been archived since the late 1960's for several populations in PWS. Parallel analyses with microsatellites and a test based on Hardy-Weinberg proportions showed that about 50% of the fish-scale DNA was cross-contaminated with DNA from other fish. These samples were removed from the analysis. We used a novel application of the classical source-sink model to compare SNP allele frequencies in these archived fish-scales (1964-1982) with frequencies in contemporary samples (2008-2010) and found a temporal shift toward hatchery allele frequencies in some wild populations. Other populations showed markedly less introgression, despite moderate amounts of hatchery straying. The extent of introgression may reflect similarities in spawning time and life-history traits between hatchery and wild fish, or the degree that hybrids return to a natal spawning area. The source-sink model is a powerful means of detecting low levels of introgression over several generations.
authors.affiliation: Commercial Fisheries Division, Alaska Department of Fish and Game, Anchorage, Alaska, United States of America.
authors.forename: James R
authors.initials: JR
authors.lastname: Jasper
authors.affiliation: Commercial Fisheries Division, Alaska Department of Fish and Game, Anchorage, Alaska, United States of America.
authors.forename: Christopher
authors.initials: C
authors.lastname: Habicht
authors.affiliation: Commercial Fisheries Division, Alaska Department of Fish and Game, Cordova, Alaska, United States of America.
authors.forename: Steve
authors.initials: S
authors.lastname: Moffitt
authors.affiliation: Commercial Fisheries Division, Alaska Department of Fish and Game, Cordova, Alaska, United States of America.
authors.forename: Rich
authors.initials: R
authors.lastname: Brenner
authors.affiliation: School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, Alaska, United States of America.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Marsh
authors.affiliation: Commercial Fisheries Division, Alaska Department of Fish and Game, Anchorage, Alaska, United States of America.
authors.forename: Bert
authors.initials: B
authors.lastname: Lewis
authors.affiliation: Commercial Fisheries Division, Alaska Department of Fish and Game, Anchorage, Alaska, United States of America.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Creelman Fox
authors.affiliation: Commercial Fisheries Division, Alaska Department of Fish and Game, Anchorage, Alaska, United States of America.
authors.forename: Zac
authors.initials: Z
authors.lastname: Grauvogel
authors.affiliation: Commercial Fisheries Division, Alaska Department of Fish and Game, Anchorage, Alaska, United States of America.
authors.forename: Serena D
authors.initials: SD
authors.lastname: Rogers Olive
authors.affiliation: Commercial Fisheries Division, Alaska Department of Fish and Game, Anchorage, Alaska, United States of America.
authors.forename: W Stewart
authors.initials: WS
authors.lastname: Grant
mesh_terms: D000413:Alaska; D000818:Animals; D001947:Breeding; D002678:Chimera / Q000235:genetics*; D003247:Conservation of Natural Resources; D005260:Female; D005398:Fisheries; D051456:Gene Flow; D014644:Genetic Variation; D005828:Genetics, Population; D005838:Genotype; D008297:Male; D018895:Microsatellite Repeats; D008957:Models, Genetic; D017685:Oncorhynchus keta / Q000145:classification / Q000235:genetics*; D010641:Phenotype; D010802:Phylogeny; D012474:Salmon / Q000235:genetics*