Early male maturity explains a negative correlation in reproductive success between hatchery‐spawned salmon and their naturally spawning progeny

Ford, Michael J.; Murdoch, Andrew R.; Howard, S. M.

doi:10.1111/j.1755-263x.2012.00261.x

Cited by 60 publications

(83 citation statements)

References 42 publications

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“…Our results support other studies that have shown that HOR steelhead and salmon are less fit in the wild than NOR steelhead or salmon (Christie and others, 2014;Sard and others, 2015). Although many hypotheses are still being tested regarding the causal mechanisms for this relationship (Hankin and others, 1993;Theriault and others, 2011;Ford and others;2012;Milot and others, 2013), our data suggest that behavioral differences play a role.…”

Section: Discussionmentioning

confidence: 57%

Behavior patterns and fates of adult steelhead, Chinook salmon, and coho salmon released into the upper Cowlitz River Basin, 2005–09 and 2012, Washington

Kock¹,

Ekstrom²,

Liedtke³

et al. 2016

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Section: Discussionmentioning

confidence: 57%

Behavior patterns and fates of adult steelhead, Chinook salmon, and coho salmon released into the upper Cowlitz River Basin, 2005–09 and 2012, Washington

Kock¹,

Ekstrom²,

Liedtke³

et al. 2016

Open-File Report

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“…Salmonid domestication has both environmental and genetic components [24] and the reduced reproductive success of captive individuals in the wild environment may persist past the first generation of natural spawning [25]. Realistic accounting for reduced fitness of captive salmon in the wild environment in salmonid population viability analysis indicated that the release of captively-bred individuals into rebuilding wild populations after four to six generations of captivity was as likely to prevent as to facilitate wild population recovery [13].…”

Section: Introductionmentioning

confidence: 99%

Maintenance of Genetic Diversity in Natural Spawning of Captively-Reared Endangered Sockeye Salmon, Oncorhynchus nerka

et al. 2014

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Captive propagation of Pacific salmon is routine, but few captive breeding programs have been conducted to successfully re-establish extirpated wild populations. A captive breeding program for endangered Sakinaw Lake sockeye salmon was established from 84 adults between 2002 and 2005, just prior to extirpation of the wild population. After several years of absence, sockeye salmon released from captivity returned to spawn in Sakinaw Lake in 2010 and in all years thereafter. Freshwater survival rates of released hatchery fry and naturally produced progeny of reintroduced sockeye salmon have not limited abundance of the reintroduced population. In contrast, marine survival rates for Sakinaw sockeye salmon have been <1%, a level that precludes population restoration in the absence of supplementation. Genetic diversity commensurate with the number of parental founders has been maintained in captivity. The 517 adult second-generation captive fish that spawned in Sakinaw Lake in 2011 produced a smolt emigration of almost 28,000 juvenile fish with an effective population size of 132. Allelic richness and gene diversity levels in the smolts were similar to those observed in captivity. This indicates genetic contributions from all or most founding parents have been retained both in captivity and in the nascent reintroduced natural population.

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“…) and spring Chinook Salmon O. tshawytscha (Ford et al. ) have been found to interbreed with natural‐origin fish, presenting a potential genetic risk to native stocks as well.…”

Section: Discussionmentioning

confidence: 99%

Age at Release, Size, and Maturation Status Influence Residualism in Hatchery Steelhead

Tatara

Larsen

Cooper

et al. 2019

N American J Fish Manag

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Steelhead Oncorhynchus mykiss that fail to emigrate seaward after release from hatcheries, commonly referred to as “residuals,” can have negative impacts on natural populations ranging from competition and predation to interbreeding with returning anadromous adults. We investigated how age at release, size, and maturation status influenced the rate of residual production in hatchery summer‐run steelhead released from the Winthrop National Fish Hatchery (Methow River, Washington) between 2010 and 2015. Migration data from 21,598 individuals implanted with PIT tags identified 1,783 residual steelhead expressing two distinct phenotypes: immature male and female parr; and precociously mature males. We found that age at release significantly affected the predominant residual phenotype. Age‐1 steelhead residuals (S1 rearing strategy) were dominated by smaller parr of both sexes (fish < 146 mm FL), while age‐2 residuals (S2 rearing strategy) were dominated by mature males, although both phenotypes were present in both S1 and S2 residual groups. Collections of residual steelhead in the Methow River indicated that parr phenotype residuals grew as well as natural‐origin juvenile O. mykiss, suggesting potential competition for food resources and habitat. Detections of PIT tags within the Methow River basin indicated that precocious male residuals may overlap both spatially and temporally with previously documented spawning anadromous adults, posing a potential genetic management risk. Both residual phenotypes had poor overwinter survival, and only 1 of the 1,783 residual fish eventually returned to the Methow River as an anadromous adult. We conclude that the ecological and genetic consequences of residual steelhead far outweigh their potential contribution to anadromous production, and measures should be taken to reduce their production by changing hatchery rearing practices.

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Early male maturity explains a negative correlation in reproductive success between hatchery‐spawned salmon and their naturally spawning progeny

Cited by 60 publications

References 42 publications

Behavior patterns and fates of adult steelhead, Chinook salmon, and coho salmon released into the upper Cowlitz River Basin, 2005–09 and 2012, Washington

Behavior patterns and fates of adult steelhead, Chinook salmon, and coho salmon released into the upper Cowlitz River Basin, 2005–09 and 2012, Washington

Maintenance of Genetic Diversity in Natural Spawning of Captively-Reared Endangered Sockeye Salmon, Oncorhynchus nerka

Age at Release, Size, and Maturation Status Influence Residualism in Hatchery Steelhead

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