Impacts of hatchery release on genetic structure of rock carp Procypris rabaudi in the upper Yangtze River, China

Abstract

Rock carp Procypris rabaudi is a vulnerable endemic fish in the upper Yangtze River. Hatchery release has been carried out as a major stock enhancement strategy for this species. Ten microsatellite loci were chosen to compare genetic variation between one wild population and two hatchery groups to evaluate the potential impacts of hatchery release on the genetic structure of the wild population. Two different models indicated strong evidence of recent bottlenecks in all groups. The hatchery groups were lower in the mean number of alleles per locus, allelic richness, and allelic diversity compared with the wild population. The 80% membership coefficient indicated that 14% of the wild fish could be assigned as hybrids of wild and hatchery fish. Our results suggested that hatchery release will further reduce the natural genetic diversity in the wild population, change the genetic structure of the rock carp population, and may not benefit restoration of this vulnerable fish species.

Genetic Diversity and Structure Analysis of Percocypris pingi (Cypriniformes: Cyprinidae): Implications for Conservation and Hatchery Release in the Yalong River

“…Releasing hatchery-reared fish with reduced genetic variability to natural areas may possibly reduce genetic diversity of wild populations, the consequences of which can reduce productivity and fitness [19]. Such deleterious genetic impacts of captive breeding and hatchery release on wild population restoration have been observed in hatchery release activities for several species [20,21,22]. Additionally, when hatchery populations are genetically divergent from wild populations, severe reductions in fitness and changes in genetic structure of the wild populations may occur [23], as in the case of salmonids and largemouth bass [24,25].…”

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“…Some previous studies have reported some adverse genetic effects caused by releasing hatchery-produced individuals in restocking programs (Cheng et al, 2011;Li et al, 2016). Here, despite the high level of heterozygosity, the wild populations of R. kutum showed lower level of allelic diversity and a sign of genetic bottleneck.…”

Life history traits and implications for conservation of rock carp Procypris rabaudi Tchang, an endemic fish in the upper Yangtze River, China

“…The previous study indicated that the genetic diversities of the rock carp's populations were very low and would be in further decline. It has been reported that 14 % of the wild fish are probably hybrids of wild and hatchery specimens, leading the authors to suggest the hatchery releases as one of the major causes for the declining genetic diversity [35]. Additionally, many hatcheries are using rock carp males and Cyprinus carpio females to breed hybrids, which are often released into the wild, competing with the native populations for resources [20].…”

“…To date, genetic diversity [31][32][33][34][35][36], artificial propagation [37][38][39], and conservation [21,[25][26][27] of the rock carp have been extensively studied. However, the understanding of its life history is still incomplete.…”