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Gene flow between sympatric life history forms of Oncorhynchus mykiss located above and below migratory barriers.

Van Doornik DM, Berejikian BA, Campbell LA - PLoS ONE (2013)

Bottom Line: We found that the population structure of the O. mykiss in these rivers appears to be influenced more by the presence of a barrier to upstream migration than by life history type.Most (89%) of the resident O. mykiss that produced anadromous offspring were males.Our results add to the growing body of evidence that shows that gene flow does readily occur between sympatric resident and anadromous O. mykiss life history types, and indicates that resident O. mykiss populations may be a potential repository of genes for the anadromous life history type.

View Article: PubMed Central - PubMed

Affiliation: Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Manchester, Washington, United States of America.

ABSTRACT
Oncorhynchus mykiss have a diverse array of life history types, and understanding the relationship among types is important for management of the species. Patterns of gene flow between sympatric freshwater resident O. mykiss, commonly known as rainbow trout, and anadromous O. mykiss, commonly known as steelhead, populations are complex and poorly understood. In this study, we attempt to determine the occurrence and pathways of gene flow and the degree of genetic similarity between sympatric resident and anadromous O. mykiss in three river systems, and investigate whether resident O. mykiss are producing anadromous offspring in these rivers, two of which have complete barriers to upstream migration. We found that the population structure of the O. mykiss in these rivers appears to be influenced more by the presence of a barrier to upstream migration than by life history type. The sex ratio of resident O. mykiss located above a barrier, and smolts captured in screw traps was significantly skewed in favor of females, whereas the reverse was true below the barriers, suggesting that male resident O. mykiss readily migrate downstream over the barrier, and that precocious male maturation may be occurring in the anadromous populations. Through paternity analyses, we also provide direct confirmation that resident O. mykiss can produce offspring that become anadromous. Most (89%) of the resident O. mykiss that produced anadromous offspring were males. Our results add to the growing body of evidence that shows that gene flow does readily occur between sympatric resident and anadromous O. mykiss life history types, and indicates that resident O. mykiss populations may be a potential repository of genes for the anadromous life history type.

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Leave-one-out assignment tests for resident (RES) and anadromous (ANAD) O. mykiss sampled from three rivers.Samples are tested for the percent of correct assignments to population of origin given different population structure configurations depending on sample’s location above or below a barrier to upstream migration, and life history type.
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pone-0079931-g004: Leave-one-out assignment tests for resident (RES) and anadromous (ANAD) O. mykiss sampled from three rivers.Samples are tested for the percent of correct assignments to population of origin given different population structure configurations depending on sample’s location above or below a barrier to upstream migration, and life history type.

Mentions: Results from the leave-one-out tests suggest that for all population structure configurations tested, the number of correct assignments was significantly greater than random expectations (P < 0.001; Figure 4). For the Duckabush and Hamma Hamma rivers, the two populations, above / below configuration had the greatest number of correct assignments, with 84.7% and 90.5% correct, respectively. The only configuration tested for the Skokomish River (two populations, resident O. mykiss / anadromous O. mykiss), had a correct assignment value of only 72.6%.


Gene flow between sympatric life history forms of Oncorhynchus mykiss located above and below migratory barriers.

Van Doornik DM, Berejikian BA, Campbell LA - PLoS ONE (2013)

Leave-one-out assignment tests for resident (RES) and anadromous (ANAD) O. mykiss sampled from three rivers.Samples are tested for the percent of correct assignments to population of origin given different population structure configurations depending on sample’s location above or below a barrier to upstream migration, and life history type.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3818241&req=5

pone-0079931-g004: Leave-one-out assignment tests for resident (RES) and anadromous (ANAD) O. mykiss sampled from three rivers.Samples are tested for the percent of correct assignments to population of origin given different population structure configurations depending on sample’s location above or below a barrier to upstream migration, and life history type.
Mentions: Results from the leave-one-out tests suggest that for all population structure configurations tested, the number of correct assignments was significantly greater than random expectations (P < 0.001; Figure 4). For the Duckabush and Hamma Hamma rivers, the two populations, above / below configuration had the greatest number of correct assignments, with 84.7% and 90.5% correct, respectively. The only configuration tested for the Skokomish River (two populations, resident O. mykiss / anadromous O. mykiss), had a correct assignment value of only 72.6%.

Bottom Line: We found that the population structure of the O. mykiss in these rivers appears to be influenced more by the presence of a barrier to upstream migration than by life history type.Most (89%) of the resident O. mykiss that produced anadromous offspring were males.Our results add to the growing body of evidence that shows that gene flow does readily occur between sympatric resident and anadromous O. mykiss life history types, and indicates that resident O. mykiss populations may be a potential repository of genes for the anadromous life history type.

View Article: PubMed Central - PubMed

Affiliation: Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Manchester, Washington, United States of America.

ABSTRACT
Oncorhynchus mykiss have a diverse array of life history types, and understanding the relationship among types is important for management of the species. Patterns of gene flow between sympatric freshwater resident O. mykiss, commonly known as rainbow trout, and anadromous O. mykiss, commonly known as steelhead, populations are complex and poorly understood. In this study, we attempt to determine the occurrence and pathways of gene flow and the degree of genetic similarity between sympatric resident and anadromous O. mykiss in three river systems, and investigate whether resident O. mykiss are producing anadromous offspring in these rivers, two of which have complete barriers to upstream migration. We found that the population structure of the O. mykiss in these rivers appears to be influenced more by the presence of a barrier to upstream migration than by life history type. The sex ratio of resident O. mykiss located above a barrier, and smolts captured in screw traps was significantly skewed in favor of females, whereas the reverse was true below the barriers, suggesting that male resident O. mykiss readily migrate downstream over the barrier, and that precocious male maturation may be occurring in the anadromous populations. Through paternity analyses, we also provide direct confirmation that resident O. mykiss can produce offspring that become anadromous. Most (89%) of the resident O. mykiss that produced anadromous offspring were males. Our results add to the growing body of evidence that shows that gene flow does readily occur between sympatric resident and anadromous O. mykiss life history types, and indicates that resident O. mykiss populations may be a potential repository of genes for the anadromous life history type.

Show MeSH
Related in: MedlinePlus