Variation in early growth of Neosalanx taihuensis between two populations above and below the Three Gorges Dam, China

Abstract

Otolith microstructure was analyzed to determine the early growth of Neosalanx taihuensis juveniles from Three-Gorges Reservoir (TGR) and Tian-e-zhou Oxbow (TEO, below the dam). The early growth of the N. taihuensis juveniles differed significantly between the two populations. Higher relative condition index and wider otolith increments of the fish in the TGR indicated the faster early growth and larger otolith nucleus radius indicated the larger size of larvae at hatch for the TGR population, which may result in higher early survival rate. We suggest that increased primary production and food availability following the impoundment of the TGR contributed importantly to the increased early growth and survival of the N. taihuensis population. Fishery management and conservation in the TGR should consider the potential impacts to other fish species and the ecosystem of the increasing abundance of N. taihuensis.