利用耳石微结构研究西南大西洋阿根廷滑柔鱼的日龄、生长与种群结构

根据我国鱿钓船2007、2008和2010年在西南大西洋作业期间采集的3 462尾阿根廷滑柔鱼样本(其中2007年308尾、2008年262尾、2010年2 892尾),利用耳石微结构研究了西南大西洋阿根廷滑柔鱼的日龄、生长和种群结构。结果表明,阿根廷滑柔鱼生命周期大约为1年,渔获物主要由冬生群(6—7月)和秋生群(3—5月)组成,不同年份捕捞群体有差异。不同产卵群体、不同性别的阿根廷滑柔鱼胴长和体质量生长均存在显著性差异。冬生群,雌、雄个体胴长的生长方程分别用指数和线性函数来拟合为最适,体质量生长方程则分别用幂函数和指数函数来拟合最适;秋生群,雌、雄个体的胴长生长方程分别用指数和对数函数拟合为最适,体质量生长方程分别用指数和对数函数拟合为最适。随着日龄增加,阿根廷滑柔鱼胴长和体质量相对生长呈现下降趋势,绝对生长率则呈增加趋势,同一日龄段内,雌性个体的胴长与体质量生长率都稍大于雄性个体生长率。

Age, growth and population structure of Illex argentinus based on statolith microstructure in Southwest Atlantic Ocean

Age and growth are two important biological characteristics of cephalopoda. According to the 3462 short-fin squid Illex argentinus samples collected by the Chinese jigging fishing fleet during 2007, 2008 and 2010, the age, growth and population structure of Illex argentinus were studied based on the microstructure of the statolith. The result indicated the life cycle of Illex argentinus is approximately one year, two hatching groups could be identified (austral winter group and austral autumn group), and there was a sexual dimorphism in the mantle length and body weight growth between different groups. The relationship between age and mantle length (ML) was best described by exponential and linear functions for females and males for austral winter group and exponential and logarithm functions for austral autumn group, respectively. The relationship between age and body weight (BW) was best described by exponential and logarithm functions for females and males for both two groups. The instantaneous relative growth rate of Illex argentisnus tended to be high at young stages, and then decreased with the age increasing, however the absolute growth rate tended to be higher with the age increasing, and the growth rate was different between males and females in the same age stage.