臺灣近海康氏馬加鰆之年齡成長與季節性分布

Age, growth and seasonal distribution of narrow-barred Spanish mackerel (Scomberomorus commerson) in the water off Taiwan

羅允信(Yun-Sin Lo)

指導教授 ： 蕭仁傑

國立臺灣大學/理學院/海洋研究所/碩士(2018年)

https://doi.org/10.6342/NTU201800630

摘要

康氏馬加鰆，又名土魠魚，是臺灣重要的經濟魚種。根據漁業年報的資料顯示，澎湖的康氏馬加鰆產量已明顯減少，需要強化基礎研究以利漁業管理。本研究以康氏馬加鰆的耳石邊緣明暗帶比例於各月份的消長，驗證耳石輪紋的周期性，再以耳石輪紋估計的年齡和體長資料建立成長曲線和Age-Length Key。結果顯示康氏馬加鰆耳石沉積暗帶的高峰期在12月到隔年3月，而康氏馬加鰆von Bertalanffy growth equation的參數L_∞為117.4公分、K為0.5 year-1、t0為-1.04歲，0到3歲年級群在2016與2017年佔了超過90%。另外以耳石核心至邊緣的氧同位素含量變化，推測康氏馬加鰆的季節性分布。結果顯示康氏馬加鰆的稚魚於春末分布在臺灣西部沿岸以及澎湖到臺灣淺灘一帶，接著分布區域會在臺灣海峽中部分裂後分別繼續往南海及東海移動與擴張，秋季時分布區域又在臺灣海峽中部重合為一連續分布帶，在冬季時分布區域往南移動至南海，在春季時沿臺灣淺灘外側經澎湖水道延伸至臺灣西部沿岸。康氏馬加鰆的季節性分布和溫度23-25℃分布帶的變化有密切關係，推測土魠魚的季節性分布和中國沿岸流與黑潮的鋒面有關。

關鍵字

康氏馬加鰆 ； 年齡成長 ； 耳石穩定性同位素 ； 季節性分布

並列摘要

Narrow-barred Spanish mackerel, Scomberomorus commerson, is a highly valued food fish in Taiwan and is widely distributed from South Africa to Southeast Asia, north to China and Japan and south to southeast Australia. According to the fishery statistics reports, the catch of S. commerson dramatically drop after 2003 and enhancing fishery research and management are imperative. Totally 324 otoliths were examined to validate the period of opaque zone formation, which was the basis for the studies of age, growth and age compositions of S. commerson landed in Taiwan. The generated von Bertalanffy growth equation had L∞ = 117.4 cm, K = -0.5 year-1, t0 = -1.04 years. The age classes of 0-3 years constitute more than 90% of the catch in 2016 and 2017. Otolith stable oxygen isotope, sea sanility and water temperature was also used in estimating the seasonal distribution of S. commerson catched near Penghu island. The results suggested that the juvenile S. commerson were likely to distribute near Taiwan Banks and western coasts of Taiwan in spring, followed by the movement to East China Sea or South China Sea from spring to summer and returned to Taiwan strait in autumn. Then the fish moved into South China Sea again in winter. The fish might return to Taiwan Banks in spring of following year. The seasonal distribution of the juvenile S. commerson was closely associated with the mean water temperature of 23-25℃, which might be influenced by the Kuroshio and China coastal current.

並列關鍵字

narrow-barred Spanish mackerel (Scomberomorus commerson) ； age and growth ； otolith stable oxygen isotope ； seasonal distribution

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