Studies of immigratory dynamics and early life histories of larval clupeoids in the coastal waters off Tanshui River Estuary

• Main Authors: Wang, Yu-Tzu, 王友慈
• Other Authors: Tzeng Wann-Nian
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/48216946598254419418

博士 === 國立臺灣大學 === 動物學系 === 85 === Copyright (c) 1990, Microsoft Corp 本研究在1992和1993年間 於淡水河口鄰接海域的鱙漁獲中共計發現了鯡科（Clupeidae）的脂眼 鯡（Etrumeus teres）、圓腹鯡（Dussumieria elopsoides）和未能確定 種類的小砂丁屬（Sardinella spp.）以及鯷科（Engraulidae）的日本鯷 （Engraulisjaponica）、刺公鯷（Encrasicholina punctifer）、異葉 公鯷（E. heteroloba）、島嶼小公魚（Stolephorus insularis）、杜氏 稜鯷（Thryssa dussumieri）和芝蕪稜鯷（T.chefuensis）等9種的鯡類 仔魚。其中數量最多的五種鯷科仔魚，從腹面觀的色素胞分布樣式可以簡 捷的加以區分，並據以建立了一個檢索表。仔魚漁獲量的季內波動很大， 每一次的波動，都代表著不同種類的加入群，且伴隨著水溫的震盪。淡水 河口鄰接海域的鱙漁場屬於河口漁場，各種仔魚的出現時間和漁獲地點 分布，呈現明顯的種類時間演替和空間隔離現象。耳石解析結果，發現刺 公鯷和日本鯷仔魚到達河口域的日齡分別為16-55及18-42天。由日齡逆算 孵化日分布的結果，發現不同月份來游的仔魚之孵化日有明顯區隔，因此 可歸納為不同的來游群。由刺公鯷和日本鯷仔魚的耳石成長輪寬樣式可以 發現不同來游群的成長史有顯著的差異，晚來游的成長率都較低，但日齡 與成長率皆呈反比。 Copyright (c) 1990, Microsoft Corp There were 9 species of clupeoid larvae, 6 species for engraulids,Engraulis japonica, Encrasicholina punctifer, E. heteroloba, Stolephorusinsularis, Thryssa dussumieri, and T. chefuensis, and 3 species for clupeids,Etrumeus teres, Dussumieria elopsoides, and Sardinella spp., to be found inthe fishing ground in the coastal waters off the Tanshui River Estuary, 1992 -1993. Of them, the 5 dominant species of engraulids was discriminated by the ventral-view pigmentation and a quick key for the discrimination of the 5species was proposed. The CPUE of the clupeoid larvae highly fluctuated in thefishing season. Each peak CPUE corresponded to different species of the larvaeand usually occurred at the time when water temperature dramatically changed.The fishing ground of the larvae was estuarine dependent. The larvae exhibiteda distinct temporal succession and spatial segregation in the estuary. Otolithmicrostructure analysis indicated that the ages at immigrate into the estuarywere approximately 16-55 and 18-42 days for the larvae of E. punctifer and E.japonica. The distributions of hatching dates of the larvae which caught fromdifferent months indicated that they were hatched in different months andcould be distinguished in different cohorts. The growth model wassignificantly different among different cohorts. The age at immigration wasinversely related to their growth rate.