Comparison on the summertime ichthyoplankton assemblages along a longitude track line in the Changjiang estuary

• Main Authors: Huang, Yu-Ling, 黃郁玲
• Other Authors: Lee, Ming-An
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/n92h8k

碩士 === 國立臺灣海洋大學 === 環境生物與漁業科學學系 === 104 === This study was tried to investigate summer ichthyoplankton assemblages associated with the hydrologic conditions in Changjiang estuary using the ORI net and CTD hydrological sampling from 2006 to 2014. 　　Sea surface temperature was varied between 17.61℃ and 28.41℃, while sea water surface salinity was ranged from 18.00 to 34.85. In addition, total number of 18729 fish larvae were collected from 27 stations, and 119 taxa contributing to 56 families were identified. The five most dominant species were Gobiidae spp. (42.81%), Engraulis japonicas (35.92), Benthosema pterotum (3.61%), Auxis spp.(2.64%), Cynoglossus spp. (2.1%) and Bregmaceros arabicus (1.80%). Their composition and average abundances of ichthyoplankton in six cruises were significantly different (p<0.05) while the abundances were varied between 1325.5 and 23151.6 ind/1000m3. 　　For the biology diversity including the Richness, Shannon and Evenness, these indices were decreased with the distance away from the coast. And the percentage for the development of larval life in Preflexion larva stage was the highest about 51.5%, proved the Changjiang estuary for a great nursery ground. 　　Four summer communities of fish larvae were recognized by cluster analysis as coastal group, continental shelf group, mixing group and central continental shelf group. The most dominant species in coastal group were Gobiidae spp. (89%), E. japonicas (4.32%). The most dominant species in continental shelf group were E. japonicas (70.93%), Auxis spp. (4.85%), B. pterotum (4.62%) and Gobiidae spp. (4.34%). And the most dominant species in mixing group were E. japonicas (13.16%), Cynoglossus spp. (11.56%), B. arabicus (8.42%), Gobiidae spp. (6.68%), Chaetodontidae spp. (5.56%) and Auxis spp. (5.41%). The Pearson correlation coefficient of dominant species with temperature and salinity indicated that the species of B. arabicus and B. pterotum like to inhabit at the relative high temperature and low salinity, as E. japonicas inhabit at the relative low temperature and salinity and Auxis spp. inhabit at the relative high temperature and salinity. It sugguested that change in hydrologic pattern could give response to the ichthyoplankton communities.