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Using daily growth increments in otoliths to age juvenile fourfinger threadfin (Eleutheronema rhadinum) in waters off western Taiwan
|Authors: ||Lu, Yi-Sin|
|Contributors: ||NTOU:Department of Environmental Biology and Fisheries Science|
Fourfinger threadfin;age and growth;otoliths;daily growth increments
|Issue Date: ||2018-08-08T03:25:22Z
|Abstract: ||本研究以耳石日周輪判讀分析台灣西部沿岸多鱗四指馬鮁幼魚之年齡成長，自2015年1月至2016年12月，在台灣西部雲林箔仔寮漁港、台中松柏漁港、苗栗龍鳳漁港及新北市淡水漁港，採集總計915尾多鱗四指馬鮁生物樣本，樣本尾叉長範圍介於11.5~80.0公分，魚體樣本全重介於29～8100公克，分析量測結果顯示，多鱗四指馬鮁體長體重關係在雌雄間並無顯著差異。研究結果顯示多鱗四指馬鮁耳石輪紋形成具有日週期性，尾叉長範圍50公分以下的多鱗四指馬鮁可判讀耳石日周輪來查定其年齡。本研究重覆判讀三次的結果顯示多鱗四指馬鮁幼魚樣本日齡介於87～326天，平均百分誤差(APE)為2.36%、變異係數(CV)為3.16%。線性函數：尾叉長(FL) = 58.197 × 年齡(t)為多鱗四指馬鮁幼魚套適最佳之成長方程式，多鱗四指馬鮁成長快速，一歲時尾叉長可達50公分以上，個體成長速率具有一致性，本研究建議可以耳石半徑(OR)與日齡(Daily age)關係式：Daily age = 39.258 OR + 16.261，作為簡易推估台灣西部沿岸多鱗四指馬鮁幼魚日齡之方式。|
Daily growth increments in otoliths were used to age juveniles of East Asian fourfinger threadfin, Eleutheronema rhadinum, in waters off western Taiwan. A total of 915 samples with fork length (FL) ranging from 11.5 to 80.0 cm and body weight from 29 to 8100 g were collected at fishing ports in Yunlin, Taichung, Miaoli and New Taipei during January 2015 to December 2016 in this study. There is no significant difference in the relationship of body weight and fork length between sexes. Daily periodicity of microincrement formation in otoliths was further validated based on studies for E. tetradactylum. Results indicated that daily increments could be used as age determination tools for fish smaller than 50 cm in FL. The East Asian fourfinger threadfin were aged from 87 to 326 days in this study, with a reading precision of 2.36% in average percent error (APE) and 3.16% in coefficients of variation (CV). The growth of the East Asian fourfinger threadfin juveniles can be best described using a linear function of length (FL) = 58.097 × Age (t). As a fast growing species, fourfinger threadfin juveniles can reach more than 50 cm in FL, with daily growth rates consistent among individuals. The relationship between daily age and otolith radius (OR): Daily age = 39.258 OR + 16.261 could be considered a convenient approach to age juvenile fourfinger threadfin in waters off western Taiwan as suggested in this study.
|Appears in Collections:||[環境生物與漁業科學學系] 博碩士論文|
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