Vertical distribution of mega-invertebrate and calculation to the stock assessment of commercial species inhibiting shallow hard-bottom in Dokdo, Korea

Abstract

Distribution and stock assessment of mega-benthos living in the shallow hard bottom around Dokdo were studied in July, 2000. Depth and topographical conditions have affected to the densities and biomass of benthic animals. In shallow area, less than 10 m depth, turbo shell, Batillus cornutus, mussel, Mytilus coruscus were dominated and showed distinct patterns in vertical distribution. On the other hand, the area over 10 m depth, it showed diverse pattern depending on topography. Turbo shell, mussel and sea cucumber Stichopus japonicus were dominated in terms of fishery resources, but abalones were rarely sampled. Stock assessment were estimated to be 6.54 M/T, 3.89 M/T and 8.92 M/T, respectively. Some parts of coastal hard bottom around Dokdo, such as the area between Dongdo and Seodo, seemed to play an important role as nursery ground. Therefore, it is necessary to the environmental monitoring for coastal fishery managements aspects.