Surface Seawater Temperature as a Potential Cause of Delayed Arrival of the Japanese Eel Anguilla japonica Elvers on the Coast of Taiwan

海水表層溫度是導致日本鰻鰻線延遲到達台灣沿岸之可能原因

曾萬年(Wann-Nian Tzeng)

《臺灣水產學會刊》 33卷2期 (2006/06) Pp. 115-126

https://doi.org/10.29822/JFST.200606.0003

摘要

日本鰻為台灣最重要的食用魚類之一。為了養殖的目的，漁民於河口域捕獲即將溯河的野生鰻線族群。本研究根據1980年以來，台灣東北部雙溪河口的每日漁獲量資料，分析鰻線入添的時機與海水表層溫度之關係。結果發現鰻線於每年的十二月至隔年的一月大量入添至河口域，漁獲量呈現月週期的律動現象。1986-87、1990-91及1995-96三個漁期，鰻線的漁獲量高峰出現在三月，較正常年延遲約二個月。鰻線的延遲入添，發生在低水溫的年度，表示冬季台灣沿岸陸棚區的低水溫可能是影響河口域鰻線之入添時期的主要原因。

關鍵字

日本鰻 ； 鰻線 ； 漁獲量 ； 水溫 ； 耳石

並列摘要

The Japanese eel Anguilla japonica is one of the most important food fish in Taiwan. For cultivation, elvers of the eel are caught from the wild population in estuaries during their upstream migration. The relationship between recruitment timing of elvers and surface seawater temperature was analyzed based on the daily catch data of elvers in an estuary of northeastern Taiwan since 1980. It was found that most elvers recruited to the estuary during the period from December to January, with a rhythmic activity that follows the lunar cycle. However, the peak recruitment period in the years of 1986-87, 1990-91 and 1995-96 occurred in March, delayed approximately two months. This delay coincided with low temperature years. The low surface seawater temperature, in winter, in the continental shelf area of Taiwan may influence the recruitment period of the elvers in estuaries.

並列關鍵字

Japanese eel ； Elver ； Catch ； Water temperature ； Otolith