Experimental design in studying the community structure of mega-crustaceans collected by the deep-sea fishing boats in Dasi and the dynamic of the mega-crustacean community structure in the fishing ground there

• Main Authors: Che-Wei Huang, 黃哲葦
• Other Authors: Tin-Yam Chan
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/76766010604948499909

碩士 === 國立臺灣海洋大學 === 海洋生物研究所 === 100 === The present study used the catches of mega-crustaceans from the commercial fishing boats in the deep-sea fishing port Dasi to investigate the appropriate experimental design needed to understand the community structure of a high deep-sea biodiversity area. Extensive collections were conducted in three time periods with hot and cold seasons. Altogether 100 collecting events were conducted, with each collecting event last from 1:30pm to 4:00 pm and not interrupted for more than three working days of the fishing boats there. A total of 55 families, 150 genera and 285 species mega-crustaceans have been collected. Representative sampling was only achieved after 40 times of collecting events in hot season and 26 times was needed in cold season. Moreover, there are significant differences in the species compositions between the cold and hot seasons. Comparison with the data from previous studies in the catches of Dasi fishing boats backed to 1981 showed that altogether 74 families, 216 genera and 443 species of mega-crustaceans are known from there. Furthermore, catches during summer are most important in understanding the species composition there. ANOSIM, CLUSTER and nMDS analyses all suggested that the community structure can be divided into two main groups by the year 2000. Trajectory graph revealed that the mega-crustacean community structure is changing with fishing pressure, and marked difference in dominant species were observed before and after the year 2000 from SIMPER analysis. Analysis of taxonomic distinctness showed that the number of species increased with time but with the complexity in community structure becoming more simple. The present results demonstrated again that rare species play a key factor in the understanding of the community structure in areas with high biodiversity.