Minimization of genetic diversity loss of endangered fish species captive broodstocks by means of minimal kinship selective crossbreeding

The loss of genetic variability in artificially bred seed populations increases the potential risk of reducing the fitness of the hatchery stock as well as that of the wild population when releasing such seed fish to the natural water. With the aid of computer simulation and the minimal kinship (MK) selective crossbreeding model, we have examined how to minimize the loss of genetic variability in future generations, using real data of barfin flounder broodstock management, a rare fish species on the verge of becoming endangered. Two types of selective breeding scenarios were applied: i) selection of parental pairs based on MK by means of mean Ps(proportion of shared alleles) as a similarity measure; and ii) random selection of parental pairs. Gene diversity (expected heterozygosity, He) and allelic diversity (number of alleles, Na) were used as measures of genetic variability. Results showed that the MK selective breeding scenario resulted advantageous in the retention of both gene and allelic diversities.