The importance of genetic diversity in commercial fsh species and a simple detection of decline

Abstract

Overfishing has produced declines in the population sizes of fish species. Population genetics theoretical predictions indicate that declines in population sizes will produce genetic diversity loss by the effect of the genetic drift (i.e. random sampling of the gametes). As genetic diversity is the raw material of natural selection, which allows species to adapt to new environmental conditions, its loss will decrease the species’ adaptive potentials. The objective of our study is to create an early detection tool to evaluate the conservation status of commercial fish according to their levels of nucleotide diversity in COI mitochondrial gene. The level of nucleotide diversity in the COI mitochondrial gene can be used as a proxy of the species’ conservation status because it shows significant differences between threatened species and nonthreatened species assessed by IUCN based on population census (n = 1260 species). Therefore, we sampled different fish species in the Fujian region, China by trawling and evaluate the COI genetic diversity and show that genetic diversity in just one gene to be a good indicator of fish population exploitations levels. We suggest incorporating genetic diversity estimates into fisheries population management as a tool and a predictor of population decline.