Distribution and Abundance of Japanese Anchovy Engraulis japonicus and Other Fishes in Asan Bay, Korea, estimated Hydroacoustic Survey

摘要

The distribution and abundance of coastal fish species in Asan Bay, Korea, were estimated from hydroacoustic survey and net catches. Acoustic data were collected with 38 and 200 kHz from July to October of 2012, and converted to the nautical area scattering coefficient (NASC, mVmile^) for 0.25 n-mile along ten transects. Japanese anchovy Engraulis japonicus was the dominant specie in the net catches. The virtual echogram technique was used to distinguish E. japonicus from other species based on the differences in the mean volume backscattering strength (AMYBS) at 38 and 200 kHz. Engraulis japonicus and other fishes are mainly distributed in the center channel and outer part of Asan Bay. E. japonicus tends to move from inner to outer Asan Bay in summer and fall. From NASC data, the target strength and length-weight function of E. japonicus and other fishes were used to estimate the E. japonicus stock at 24A-93.3 tons, and other fish at 40.6-88.4 tons from July to October 2012. The estimated anchovybiomass compared well with the cumulative catch weight from stow net catches. The hydroacoustic method offers an approach to understanding spatial/temporal structure and estimating the biomass of fish aggregations in coastal areas.