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ABSTRACT Limited approaches exist for studying population connectivity in widely dispersing marine benthic invertebrates. Genetic techniques can provide important insights toward identifying recruitment trajectories. Here, 10 microsatellite loci were used [...]

Dams have contributed to the decline of migratory fishes by blocking access to historical habitat. The active transport (trap and haul) of migratory fish species above existing dams can sometimes support population recovery when the use of fish ladders or dam removal is infeasible. However, little is known about the efficacy of trap and haul conservation strategies. Here we used genetic parentage assignments to evaluate the efficacy of reintroducing adult Chinook salmon (Oncorhynchus tshawytscha) above Cougar Dam on the South Fork McKenzie River, Oregon, USA, from 2008 to 2011. We found that mean reproductive success (RS) declined as adults were released later in the spawning season in 2009 and 2010; however, release location did not affect RS. In 2010 and 2011, we tested for RS differences between hatchery and natural origin (HOR and NOR, respectively) adults. HOR males were consistently less fit than NOR males, but little evidence for fitness differences was apparent between HOR and NOR females. Interestingly, the effect of origin on RS was not significant after accounting for variation explained by body length. Our results indicate that release date and location have inconsistent or no effect on the reproductive success of reintroduced adults when active transport strategies are employed for migratory fishes. Les barrages ont contribue au declin des poissons migrateurs en leur bloquant l'acces a des habitats historiques. Le transport actif (capture et deplacement) d'especes de poissons migrateurs par-dessus des barrages existants peut parfois appuyer le retablissement de populations quand l'utilisation d'echelles a poissons ou le retrait de barrages ne sont pas possibles. Les connaissances sur l'efficacite de strategies de conservation reposant sur la capture et le deplacement sont toutefois limitees. Nous utilisons des affectations de filiation genetique pour evaluer l'efficacite de la reintroduction de saumons quinnats (Oncorhynchus tshawytscha) adultes en amont du barrage Cougar sur la riviere South Fork McKenzie (Oregon, Etats-Unis), de 2008 a 2011. Nous avons constate que le succes de reproduction (SR) moyen etait plus faible quand les adultes etaient relaches plus tard dans la periode du frai en 2009 et 2010; le lieu du lacher n'avait toutefois pas d'incidence sur le SR. En 2010 et 2011, nous avons verifie la presence de differences du SR entre les adultes originaires d'ecloseries et de milieux naturels (HOR et NOR, respectivement). Si l'aptitude des males HOR etait uniformement plus faible que celle des males NOR, rien ne semblait indiquer une telle difference d'aptitude entre les femelles HOR et NOR. Fait interessant, l'effet de l'origine sur le SR n'etait pas significatif une fois prise en compte la variation expliquee par la longueur du corps. Nos resultats indiquent que la date et le lieu du lacher ont une incidence non uniforme ou nulle sur le succes de reproduction des adultes reintroduits quand des strategies de transport actif sont utilisees pour des poissons migrateurs. [Traduit par la Redaction], Introduction Reintroduction programs attempt to reestablish locally extirpated species to their historical habitat (IUCN-SSC 2013) and can serve to restore a species' distribution when access to habitat has simply been [...]

Neutral genetic markers are routinely used to define distinct units within species that warrant discrete management. Human-induced changes to gene flow however may reduce the power of such an approach. We tested the efficiency of adaptive versus neutral genetic markers in differentiating temporally divergent migratory runs of Chinook salmon (Oncorhynchus tshawytscha) amid high gene flow owing to artificial propagation and habitat alteration. We compared seven putative migration timing genes to ten microsatellite loci in delineating three migratory groups of Chinook in the Feather River, CA: offspring of fall-run hatchery broodstock that returned as adults to freshwater in fall (fall run), spring-run offspring that returned in spring (spring run), and fall-run offspring that returned in spring (FRS). We found evidence for significant differentiation between the fall and federally listed threatened spring groups based on divergence at three circadian clock genes (OtsClock1b, OmyFbxw11, and Omy1009UW), but not neutral markers. We thus demonstrate the importance of genetic marker choice in resolving complex life history types. These findings directly impact conservation management strategies and add to previous evidence from Pacific and Atlantic salmon indicating that circadian clock genes influence migration timing. [ABSTRACT FROM AUTHOR]