Effect of introducing wild paternity on stock performance of hatchery-reared ayu

Iguchi, Kei’ichiro; Mogi, Minoru

doi:10.1111/j.1444-2906.2007.01405.x

Cited by 6 publications

(3 citation statements)

References 19 publications

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“…Free mate choice is preferred to minimize domestication, but if not feasible, protocols must be in place to minimize the impact of artificial selection through multiple randomly-selected pairings (Wedekind 2002;Fraser 2008). New broodstock should also be introduced frequently, preferably every breeding season (Harada et al 1998;Iguchi and Mogi 2007). PTRA plans must set guidelines for an appropriate number of age classes of broodstock and whether to mix pairings between generations.…”

Section: -Brkandalgmentioning

confidence: 99%

Guidelines for Propagation and Translocation for Freshwater Fish Conservation

et al. 2009

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Reestablishment of locally extinct populations and augmentation of declining populations are management activities used with increasing frequency in the conservation of imperiled fishes in the United States. Unfortunately, these options were not always carefully or appropriately used in past cases, partly owing to a lack of guidelines that address scientifically‐based protocols for propagation, translocation, reintroduction, and augmentation (PTRA). PTRA programs are an important management tool for the recovery of imperiled fishes when undertaken with careful planning, including everything from determining that PTRA is necessary to incorporating knowledge of life history and genetics into the PTRA plan. In addition, PTRA programs must also assemble advisory groups, obtain funding and permitting, construct and maintain propagation facilities, and raise community awareness of the program. Because such diverse skills are needed, successful PTRA programs should prepare for long‐term partnerships to achieve the goal of recovery.

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Section: -Brkandalgmentioning

confidence: 99%

Guidelines for Propagation and Translocation for Freshwater Fish Conservation

et al. 2009

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“…In hatcheries, parent fish have been captive-reared for generations, mainly because of difficulties experienced collecting sufficient mature wild fish for synchronous spawning each year (Iguchi & Mogi, 2007). Consequently, genetic diversity of hatchery-born juveniles has decreased over generational (4-31) time (Iguchi, Watanabe & Nishida, 1999;Ikeda, Takagi & Taniguchi, 2005;Tsuboi et al, 2019).…”

Section: Implications For Conservation and Managementmentioning

confidence: 99%

“…Most wild-born juveniles are caught in Shiga Prefecture (the landlocked Ayu collected in Lake Biwa, Figure S2b), and most hatchery fish are produced in Tochigi Prefecture, followed by Miyazaki, Tokushima, Yamaguchi, and Wakayama prefectures. In hatcheries, parent fish have been captive-reared for more than 30 generations, mainly because of difficulties experienced collecting sufficient mature wild fish for synchronous spawning each year (Iguchi & Mogi, 2007). Consequently, genetic diversity of hatchery-born juveniles has decreased over time (4–31 generations) (Iguchi et al, 1999; Ikeda et al, 2005; Tsuboi et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Long-term translocation explains population genetic structure of a recreationally fished iconic species in Japan: Combining current knowledge with reanalysis

Kitada

2021

Preprint

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Ayu (Plecoglossus altivelis altivelis), an important freshwater fisheries resource and popular recreational fishing species, lives for only one year and has a single breeding season. To supplement increased recreational fishing demand, huge numbers of wild-born landlocked juvenile Ayu have been translocated from Lake Biwa into most Japanese rivers for more than 50 generations. Hatchery-born amphidromous fish (including amphidromous and landlocked form hybrids) have also been released for many generations.Hatchery-born fish have low survival and maladapted behaviour in the wild. Landlocked and amphidromous forms of Ayu easily hybridise, but survival of progeny of landlocked forms is very low in seawater. Repeat backcrossing may cause introgression of landlocked forms into amphidromous populations, but this has not been previously identified.Study objectives using genetic data from Ayu from 118 locations throughout the distribution of this species in Japan are to describe contemporary population structure, genetic diversity, and admixture proportions of Ayu forms in populations, and to evaluate how human-induced translocation has affected population genetic structure.The analyses of published genotypes of 12 microsatellite markers provide strong evidence for very high gene flow between populations, but population structure has been retained in several regions, and several populations are nested. Genetic diversity is surprisingly homogeneous. Hybridisation between landlocked and amphidromous forms has occurred in all populations, with a mean hybrid proportion (± standard deviation) of 37 ± 10%, ranging 15%–60%.Results are discussed in relation to the conservation and management of this species. Recommendations are made to reduce translocation and hatchery releases, by establishing rivers and/or areas in every prefecture where translocation does not occur. Release of juveniles is of value for short-term management objectives, but management of spawning escapements, and improving the spawning and nursery habitat are important for this species’ long-term sustainability.

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