The study investigates biological ecology, spawning period,and fishing ground of the main economic fishes and crabs in the southwestern waters of Taiwan, and to determine accurately the geographical position of spawning ground by the scientific method, join application of sounding technology at the same time; use to compare trawl net and scientific fish detection with the result of survey synchronously. and then it will be a reference basis in future for the fishery resources estimate, conservation, management and fisheries administration decision-making.