Site Selection and Time of Spawning by Two Groups of Kokanee in Odell Lake, Oregon

Averett, Robert C.; Espinosa, F. A.

doi:10.2307/3798238

Cited by 10 publications

(8 citation statements)

References 2 publications

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Section: Discussionsupporting

confidence: 89%

“…Phenotypic trait comparisons revealed variation both among and within ecotypes. Length, age at maturity, fecundity, and egg size differed among spawning groups, similar to the findings of other studies (Killick and Clemens 1963;Woodey 1965;Averett and Espinosa 1968;Burger et al 1997); however, variation in reproductive characteristics was largely due to differences in length distributions. Spatial separation, the absence of genetic structure, and differences in length and age composition among groups suggest that the spawning distribution of kokanee in Lake Pend Oreille is more likely structured by assortive mating than by natal homing.…”

Section: Discussionsupporting

confidence: 89%

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Using Genetic and Phenotypic Comparisons to Evaluate Apparent Segregation among Kokanee Spawning Groups

et al. 2018

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Genetic and phenotypic traits of spatially and temporally segregated kokanee Oncorhynchus nerka spawning groups in Lake Pend Oreille, Idaho, were compared to test for evidence of divergence on the basis of ecotype (stream spawners versus shoreline spawners) and spawn timing and to describe morphological, life history, and reproductive variation within and among groups. Early and late spawning runs were found to be reproductively isolated; however, there was no clear evidence of genetic differentiation between ecotypes. Spawning groups within the same ecotype differed in length, age distribution, mean length at age, fecundity, and egg size. Variation in reproductive attributes was due primarily to differences in length distributions. Larger‐bodied shore‐spawning kokanee were located in areas where egg survival is known to be enhanced by downwelling, suggesting that the distribution of shore‐spawning kokanee may be partly structured by competition for spawning habitats with groundwater influence. This study contributes to other research indicating that introduced kokanee populations are unlikely to undergo adaptive divergence if they have a history of population fluctuations and are supplemented regularly.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 89%

Using Genetic and Phenotypic Comparisons to Evaluate Apparent Segregation among Kokanee Spawning Groups

et al. 2018

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“…Third, residuals turn olive green at maturity, in contrast to the red of their anadromous counterparts (Ricker 1938;Krogius 1981). However, kokanee introduced to the same lakes containing residuals (Ricker 1940(Ricker , 1959 as well as other lakes (Averett and Espinosa 1968) turn red. Further, sockeye that become landlocked upon introduction to other systems also turn olive green to dusky reddish green at maturity (Ricker 1959;Scott 1984;Quinn et al 1998).…”

mentioning

confidence: 99%

Countergradient Variation and Secondary Sexual Color: Phenotypic Convergence Promotes Genetic Divergence in Carotenoid Use Between Sympatric Anadromous and Nonanadromous Morphs of Sockeye Salmon (Oncorhynchus Nerka)

2001

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Abstract. Genetically distinct anadromous (sockeye) and nonanadromous (kokanee) morphs of the Pacific salmon, Oncorhynchus nerka, develop identical, brilliant red color at maturity during sympatric breeding in freshwater streams. The marine and lacustrine environments they occupy prior to maturity, however, appear to differ in the availability of dietary carotenoid pigments necessary to produce red coloration. We tested the hypothesis that kokanee, which occupy carotenoid-poor lakes, are more efficient at using the dietary pigments than are sockeye, which occupy the more productive North Pacific Ocean. In a 2-year controlled breeding study, flesh and skin color of mature and immature crosses fed a low-carotenoid diet were quantified with both a chromameter and by chemical extraction of carotenoid pigments. Results revealed striking countergradient variation in carotenoid use, with kokanee approximately three times more efficient at sequestering the pigments to the flesh musculature than similar age sockeye. This difference translated into virtually nonoverlapping differences between pure crosses in secondary sexual color at maturity, when the pigments are mobilized and transported to the skin. Kokanee crosses turned pinkish red over most of their body, whereas sockeye turned olive green. The olive green was similar to the breeding color of residuals in the wild, the progeny of anadromous sockeye that remain in fresh water and are believed to have given rise to kokanee on numerous independent occasions. Reciprocal hybrids were similar to each other and intermediate to the pure crosses, indicating additive genetic inheritance. Mate choice trials with sockeye males in the wild showed the ancestral morph strongly preferred red over green models. These results suggest a preference for red mates maintained in nonanadromous breeding populations drove the reevolution of the red phenotype in kokanee via more efficient use of dietary carotenoid pigments. This is a novel, yet hidden, mechanism by which sexual selection promotes the genetic differentiation of these sympatric populations.

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“…Typically, sockeye salmon and kokanee spawn in streams tributary to juvenile nursery lakes after maturing in the sea or lakes, respectively (Burgner 1991). There are, however, a few lake systems where O. nerka populations also spawn on lakeshore gravel beaches (Averett & Espinosa 1968;Blair et al 1993;Burger et al 1995). In such systems, 'beach-' and 'stream-spawning' sockeye salmon and kokanee appear to share the same pelagic feeding habitats, but their reproductive ecology is markedly different.…”

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confidence: 99%

Postglacial genetic differentiation of reproductive ecotypes of kokanee Oncorhynchus nerka in Okanagan Lake, British Columbia

Taylor

Harvey

Pollard³

et al. 1997

Molecular Ecology

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Okanagan Lake, south-central interior of BC, contains two reproductive ecotypes of kokanee Oncorhynchus nerka; individuals spawn in tributary streams ('stream-spawners') as well as on shoreline gravel areas ('beach-spawners'). We tested the hypothesis that these sympatric ecotypes comprise a single panmictic population by assaying variation in morphological traits and at allozyme, mitochondrial and minisatellite DNA loci in fish collected from three stream-spawning and two beach-spawning sites. No morphological traits consistently distinguished the reproductive ecotypes with the exception of the number of anal fin rays which was greater in stream-spawning kokanee. Four of 18 allozyme loci screened were polymorphic, but no significant allele frequency differences were detected among populations within ecotypes or between ecotypes. Similarly, allele frequencies at two minisatellite DNA loci were not significantly different among populations or between ecotypes. By contrast, significant differences in the frequencies of mitochondrial DNA restriction fragment length polymorphism (mtDNA RFLP) haplo-types were detected between stream- and beach-spawners, but not among populations within ecotypes. Further, two RFLPs that distinguished stream- and beach-spawning adults were found in juvenile kokanee sampled from the limnetic zone of Okanagan Lake. The two mtDNA RFLPs and a d-loop sequence variant appear to be unique to Okanagan Lake Kokanee because we did not observe these haplotypes in sockeye salmon and kokanee sampled outside of Okanagan Lake. Our data suggest that: (i) there is restricted female-mediated gene flow between stream- and beach-spawning kokanee in Okanagan Lake, (ii) the forms have diverged within the lake basin since the retreat of the Wisconsinian glaciers (< approximately equal to 11 000 years ago), and (iii) distinct reproductive niches may promote divergence in north temperate freshwater fish faunas.

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Site Selection and Time of Spawning by Two Groups of Kokanee in Odell Lake, Oregon

Cited by 10 publications

References 2 publications

Using Genetic and Phenotypic Comparisons to Evaluate Apparent Segregation among Kokanee Spawning Groups

Using Genetic and Phenotypic Comparisons to Evaluate Apparent Segregation among Kokanee Spawning Groups

Countergradient Variation and Secondary Sexual Color: Phenotypic Convergence Promotes Genetic Divergence in Carotenoid Use Between Sympatric Anadromous and Nonanadromous Morphs of Sockeye Salmon (Oncorhynchus Nerka)

Postglacial genetic differentiation of reproductive ecotypes of kokanee Oncorhynchus nerka in Okanagan Lake, British Columbia

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