農業部-水產試驗所全球資訊網農業部-水產試驗所全球資訊網

本研究利用耳石做為年齡形質，探討東部海域長腰鮪日齡與成長關係，自2006年6月至2007年4月於新港魚市場採集長腰鮪樣本，記錄樣本魚尾叉體長（FL）、體重（W）資料等生物資料，共採得92尾長腰鮪之耳石樣本，體長範圍為30公分至63.6公分，耳石處理過程中碎裂以及研磨失敗，最後可供判讀樣本數為30個。以光學顯微鏡400倍判讀長腰鮪耳石上之日週輪(daily growth increment, DGI)，計數日週輪以估算長腰鮪日齡以及成長之關係，成功判讀之耳石日週輪以及尾叉長關係式為FL=0.086DGI+21.66，並利用非線性迴歸法估算von Bertalanffy成長各項參數，得到成長曲線方程式為Lt=82.149{1-exp(-0.88 (t+0.171))}，推得0.5齡魚尾叉長為36.6公分，1齡魚尾叉長52.8公分，由估算日齡與捕獲日期逆推產卵期為2-7月。

Age and growth of longtail tuna, Thunnus tonggol, in the waters off eastern Taiwan was examined based on daily age estimation with otolith increment of fish ranged from 30 to 63.6 cm in fork length. Size, weight and fish samples were collected during April, 2006 to June, 2007. Parameters for von Bertalanffy growth function were estimated by nonlinear regression method as L∞=82.149 cm, t0=-0.171 year, and K=0.88. Spawned dates were back-calculated from the capture date and number of increment. Distribution of estimated spawned date of fish capture was from February to July.