| 英文摘要 |
The purpose of this research is to estimate the spillover effect of three-nautical-mile prohibiting zone by surveying abundance, species richness, and biomass of demersal resource in waters off Dashi and Miaoli. It’s aimed to result a sustainable management strategy, such as mesh size regulation and establishment of trawling prohibited zone, for bottom trawl fishery. Currently, our data showed: 1) Abundance, species richness, biomass and average weight of demersal fishes in Miaoli have been increased in recent years. However, fishing pressure is still high according to FiSAT analyses. Meanwhile, L50 for economic and dominant fish species are low which may due to small mesh sizes used by trawlers. The demersal fish resources in Dashi did not change in past years during our survey. 2) The amounts of by-catch in the two places are still high (Dashi 93.2% and Miaoli 85.2%). 3) In order to reduce the resource exploitative ratio to 10% (E-10), it is required to change the mesh size to avoid catches of fishes smaller than 14 cm. Moreover, because the compositions of catches in Maioli and Dashi are different, the management strategy for their bottom trawl fisheries should be adaptive to be practical. 4) Our study has generated 83 specimens for genetic Cryobank and more than 90000 records for Trawl Base of Taiwan in 2006 along. |
