The study measured the excess capacity and the use of inputs piers small trawl in Nha Trang city, Khanh Hoa province based on a mathematical programming approach - data envelopment analysis (DEA). The result from 65 vessels in two areas Vinh Truong and Vinh Luong in 2005 and 2006 showed most of vessels used inputs fully, but excess capacity (calculated by revenue) on average of each vessel was 60.46 percent (2005) and 51.60 percent (2006). This showed that the coastal water resources were over exploited. On the other hand, this study demonstrated that the mdr.ine protected areas (MPAs) were effective in preserving and maintaining the fish species that are at risk of over fishing and contribute to creating abundant resource, that bring high-value in the fishing in some areas in Nha Trang. This showed that the managements should have more policies to maintain and manage effectively the MPAs as well as the fishing from the sea.