Abstract
Anguilla marmorata Quoy & Gaimard 1824 is widespread in the fresh waters of the islands and the coast of the Indo-Pacific ocean. The research regarding this subject is really sparse. Therefore, the collection of migratory Anguilla marmorata eel elvers at Hsiukuluan River in Eastern coast of Taiwan started in June 2000 to May 2001 in order to analyze the migration rhythm of eels, and the relation between the migration rhythm and environment factors.It was found that eel migration reaches a peak during the summer time, whereas eels hardly migrate upstream around November to the following May. The pigmentation stage of elvers in October is much more matured; approach the later stage, than in July or in August. This might be caused by that the elvers stay six to seven days more in the estuary. Elvers primarily migrate upstream by the surface and the bank area of the river. In addition, elvers are incapable to resist the velocity of water flow faster than 40 cm/sec.Based on the data of the peak migration of the elvers in the year 2000, the peak time is 20 to 24 days later than year 1997. Employ Fourier Transform to process the analysis, the effect factors of the different years are discovered to be identical. Tidal stage was considered as the most important environment factor in determining the magnitude of elver migration.中文摘要 …………………………………………………………………Ⅰ英文摘要 …………………………………………………………………Ⅱ目錄 ………………………………………………………………………Ⅲ謝誌 ………………………………………………………………………Ⅴ壹、前言 ………………………………………………………………… 1 一、淡水鰻魚的種類與分佈 ……………………………………… 1 二、淡水鰻魚的生活史 …………………………………………… 1 三、淡水鰻魚溯河研究 …………………………………………… 2 四、實驗魚種 ……………………………………………………… 3 五、研究動機與目的 ……………………………………………… 4貳、材料和方法 ………………………………………………………… 5 一、採集地點 ……………………………………………………… 5 二、時間與方法 …………………………………………………… 5 三、外部形質測量 ………………………………………………… 7 四、色素發育頻度分析 …………………………………………… 7 五、離散傅利葉轉換 ……………………………………………… 7參、結果 ………………………………………………………………… 9 一、鰻苗溯河數量調查 …………………………………………… 9 A.出海口鱸鰻鰻苗上溯數量調查結果 …………………… 9 B.河內鱸鰻鰻苗上溯數量調查結果 ……………………… 9 C.氣候與水文資料 ………………………………………… 9 二、溯河鰻苗週期性觀察 ………………………………………… 10 A.鰻苗上溯日週期 ………………………………………… 10 B.鰻苗上溯月週期 ………………………………………… 10 三、形質測量 ……………………………………………………… 11 A.鰻苗全長組成 …………………………………………… 11 B.鰻苗色素發育階段 ……………………………………… 11 C.色素發育頻度分析 ……………………………………… 11 四、鰻苗溯河與流速之關係 ……………………………………… 12 A.河川流速分佈情形 ……………………………………… 12 B.鰻苗溯河行為 …………………………………………… 12 C.鰻苗上溯利用之流速 …………………………………… 12 五、不同年度來游週期分析 ……………………………………… 13 A.不同年度來游週期之比較 ……………………………… 13 B.以傅利葉轉換分析不同年度來游週期之相關性 ……… 14 六、鰻苗上溯週期與環境因子之關係 …………………………… 14肆、討論 ………………………………………………………………… 16 一、鰻苗溯河日週期分析 ………………………………………… 16 二、冬季河內鰻苗極少上溯可能之原因 ………………………… 16 三、不同月份溯河鰻苗色素頻度變動可能之原因 ……………… 16 四、鰻苗上溯速度之評估 ………………………………………… 18 五、鰻苗上溯最適流速與其應用 ………………………………… 18 六、造成鰻苗來游時間延後之原因 ……………………………… 19 七、傅利葉轉換在生物週期分析之應用 ………………………… 21 八、環境因子對鰻苗上溯之影響 ………………………………… 22伍、結論 ………………………………………………………………… 24陸、引用文獻 …………………………………………………………… 25圖與表 …………………………………………………………………… 30附錄 ……………………………………………………………………… 48