阿根廷滑柔鱼年间生长及体征变化

阿根廷滑柔鱼(Illex argentinus)的生长发育及体征变化,可表征其能量积累和生殖投入方面的生活史策略,并随之影响繁殖成效和资源补充量。为此,研究根据2012—2014年在西南大西洋索饵育肥场采集的阿根廷滑柔鱼样本,采用残差指标分析方法和广义线性混合效应模型,分析了阿根廷滑柔鱼个体的体质量-胴长关系和体征变化的差异性。结果显示,阿根廷滑柔鱼样本的总体雌雄比例为1.25﹕1;雌性和雄性个体体型均以2014年的为最大,分别为(271.7±28.3)和(244.7±17.3) mm; 2012年和2013年样本的胴长差异性不显著,前者雌性和雄性胴长分别为(207.9±31.0)和(201.1±28.9) mm,后者雌性和雄性胴长分别为(213.6±18.0)和(203.5±19.0) mm。每个年份雌性和雄性个体的体质量与胴长呈显著的幂函数关系,且每个年份幂函数关系式的b值与匀速生长b=3存在差异。雌性和雄性个体体征的年间差异明显,同年度不同月份之间的体征亦存在显著差异(2012年雌性除外)。雌性和雄性个体的体征与胴长密切相关,胴长×月份作用对不同月份个体体征的影响效应具有一致性,...

THE YEARLY GROWTH AND BODY CONDITION OF ARGENTINEAN SHORTFIN SQUID, ILLEX ARGENTINUS

Argentinean shortfin squid, Illex argentinus is well documented for short life span, fast growth, and semelparity. Hence, the growth and the body condition changes can effectively reflect its life history strategy with respect to energy accumulation and reproductive investment, which subsequently influence the final reproductive efforts and recruitment biomass. This study randomly collected I. argentinus from the feeding ground in the southwest Atlantic during 2012 and 2014 to analyze the body weight—mantle length relationship and the body condition changes by using methodologies of residual index analysis and generalized linear mixed-effects models. The results showed that the overall sex ratio of female to male was 1.25﹕1. The mantle lengths of female and male in 2014 were (271.7±28.3) mm and (244.7±17.3) mm, respectively. There were no significant differences in the mantle length between sampling years of 2012 and 2013. The specimens were (207.9±31.0) mm for females and (201.1±28.9) mm for males in 2012, and there were (213.6±18.0) mm for females and (203.5±19.0) mm for males in 2013. The body weight significantly associated with mantle length for female and male I. argentinus based on power function algorithm, and the coefficient b was different from the isometric growth coefficient b=3 for the specimens from each sampling year. There were significant differences in the body condition among sampling years for both female and male. The body condition was significant difference among each month for each sex except for the female in 2012. Moreover, the interactions between mantle length and month imposed a consistent influence on the body condition, that is, the larger body size with decreased body condition. Cumulatively, these evidence indicate that the growth of I. argentinus is allometric, the body condition is significant different between sampling years and sampling months, and the body condition is negatively related to the mantle length.