Bronze croaker (Otolithoides biauritus) is one of the amphidromous fish belongs to family Sciaenidae. The fish commonly distributes in large estuarine areas along Vietnam coastline, especially in Bach Dang, Van Uc, Thai Binh, Lach Truong and Lam Rivers. Before 1990 fish yields were from 72,7 - 132 tons/year, however after 1990 the fish product was decreased sharply to 0.11 tons/year. The surveys in 2006 and 2007 showed the distribution of the species were spatially sparse point and at very low density in Thai Binh and Van Uc Rivers. Indeed. Bronze croaker populations have been declined dramatically, this is able to lead disappearance of this species along Vietnam coast in near future. The reasons blamed were over fishing due to extremely high value of the fish's swimming ladder in recent
losing or narrowing the habitat such as mangroves
environmental pollution derived from industrial areas along the coast and hydro-power dams constnlction callsed the changes of hydrodynamics of the rivers could affect the fish migratory routes. Therefore, it is high time to undertake study on the proper solutions to protect the resource and preserve the fish habitats.