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Éxito Reproductivo en el Medio Natural de Truchas Oncorhynchus mykiss Criadas en Cautiverio: Evaluación de Tres Programas de Criaderos de Peces en el Río Hood
Author(s) -
ARAKI HITOSHI,
ARDREN WILLIAM R.,
OLSEN ERIK,
COOPER BECKY,
BLOUIN MICHAEL S.
Publication year - 2007
Publication title -
conservation biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.2
H-Index - 222
eISSN - 1523-1739
pISSN - 0888-8892
DOI - 10.1111/j.1523-1739.2006.00564.x
Subject(s) - hatchery , biology , fish hatchery , fishery , fish migration , population , brood , rainbow trout , spawn (biology) , trout , captive breeding , endangered species , broodstock , zoology , selective breeding , aquaculture , ecology , fish <actinopterygii> , fish farming , habitat , demography , sociology
Population supplementation programs that release captive‐bred offspring into the wild to boost the size of endangered populations are now in place for many species. The use of hatcheries for supplementing salmonid populations has become particularly popular. Nevertheless, whether such programs actually increase the size of wild populations remains unclear, and predictions that supplementation fish drag down the fitness of wild fish remain untested. To address these issues, we performed DNA‐based parentage analyses on almost complete samples of anadromous steelhead ( Oncorhynchus mykiss ) in the Hood River in Oregon (U.S.A.). Steelhead from a supplementation hatchery (reared in a supplementation hatchery and then allowed to spawn naturally in the wild) had reproductive success indistinguishable from that of wild fish. In contrast, fish from a traditional hatchery (nonlocal origin, multiple generations in hatcheries) breeding in the same river showed significantly lower fitness than wild fish. In addition, crosses between wild fish and supplementation fish were as reproductively successful as those between wild parents. Thus, there was no sign that supplementation fish drag down the fitness of wild fish by breeding with them for a single generation. On the other hand, crosses between hatchery fish of either type (traditional or supplementation) were less fit than expected, suggesting a possible interaction effect. These are the first data to show that a supplementation program with native brood stock can provide a single‐generation boost to the size of a natural steelhead population without obvious short‐term fitness costs. The long‐term effects of population supplementation remain untested.