Studies on the diversity of flatfishes and the reproductive biology of the dominant species Pseudorhombus pentophthalmus in surrounding water of Gui-San island, northeastern Taiwan

• Main Authors: Wen-Kwen Chen, 陳文魁
• Other Authors: Shyh-Bin Wang
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/85819304742012098136

碩士 === 國立臺灣海洋大學 === 海洋資源管理研究所 === 93 === Species composition and community structure of flatfishes, and reproductive biology of the most dominant species Pseudorhombus pentophthalmus, in surrounding waters of Gui-San Island, northeastern Taiwan were examined based on the samples taken from March 2004 to March 2005. In total, 28 species from 5 families and 18 genera were obtained. The Bothidae is the most dominant genera accounting for 81% of the total catch, while the most dominant species is the P. pentophthalmus. Species richness and diversity were higher between end of fall and spring, but were lower from summer to mid-fall. The multivariate analyses based on the cluster and nonparametric multi-dimensional scaling also identified three groups roughly corresponding to late winter-spring , late spring-summer and fall-winter seasons. The top two dominant species in all groups however, were the same, and were P. pentophthalmus and Cynoglossu kopsii. The rare species seem responsible for differences among clusters identified. The abundance of P. pentophthalmus also was highest during fall-winter season and lower during spring-summer season. The spawning of the species occurs between December and June. And, the size of maturity for female fish is 14.2 cm, but is 13.8 cm for male fish. The hepatosomatic index (HSI), visceral index (VI) and gonadosomatic index (GSI) of P. pentophthalmus all increase during the spawning season, when condition factor (CF) decreased. All indices dropped to the lowest value after spawning. The patterns indicated that P. pentophthalmus reduced feeding activity and used reserved energy in muscle, liver and visceral for spawning. In addition, total catches and by-catch in the surrounding waters of the Island increased in recent years while catches for flatfish decreased. The implications of these changes in relation to the potential change in community structure of demersal species also were discussed.