Biology of Uroteuthis duvauceli in the Southern East China Sea.

Abstract

杜氏鎖管(Uroteuthis duvaceli)是臺灣火誘網漁業常見混獲物種之一。2012年9月至10月間，調查發現南東海之優勢鎖管種已從劍尖槍鎖管和中國槍鎖管轉變成杜氏鎖管，本研究首次研究南東海之杜氏鎖管在年齡、成長、生殖與產卵場等範疇，以究明此改變與杜氏鎖管之生活史，雌與雄性杜氏鎖管最大年齡為99天，是為短生命週期的物種。外套長會隨著年齡而增加，且雌鎖管最適當成長方程式為power model，以及雄性為linear model。此外，本研究也分析三種海域(沿岸、陸棚與海峽海域)共五個杜氏鎖管之族群結構，結果指出海峽海域與陸棚海域分別是產卵場(＞ 72%已交配)與索餌場。同時，研究結果顯示高海水溫度可能是造成杜氏鎖管豐度的激增。Uroteuthis duvauceli is a common bycatch species of torch-light fisheries in Taiwan. We found that the dominant myopsid squid in the southern East China Sea had shifted from U. edulis and U. chinensis to U. duvauceli in a period from September to October 2012. To investigate this change and better understand the life history of this species, the present study collected data including the age, growth, reproduction and spawning grounds of U. duvauceli in the southern East China Sea for the first time. For both male and female U. duvauceli, the observed maximum age was 99 days, indicating a short lifespans. In terms of growth, mantle length with respect to age increase, was best described by a power model for female U. duvauceli and a linear model for males. In addition, we analyzed five population structures of U. duvauceli in three different regions (the inshore water, continental shelf water, and strait water), the results indicated that the strait water and continental shelf are the spawning (＞ 72% mated) and feeding grounds of U. duvauceli, respectively. Additionally, we also observed that high sea temperature may have caused the observed surge in U. duvauceli abundance.