西北印度洋海域鸢乌贼耳石微结构及生长特性

耳石是研究头足类年龄与生长、种群结构和生活史的重要硬组织之一。为研究西北印度洋鸢乌贼耳石微结构及生长特性,根据2019年2—5月我国灯光罩网渔船在西北印度洋调查生产期间采集的1009尾鸢乌贼样本,以耳石总长(TSL)、侧区长(LDL)、翼区长(WL)和最大宽度(MW)作为耳石的外形生长指标,结合日龄数据,对西北印度洋鸢乌贼耳石微结构及其生长特性进行了研究。结果表明: 根据生长纹间宽度,可将耳石微结构分为后核心区、暗区和外围区。协方差分析表明,TSL、LDL、WL和MW与日龄的关系均不存在显著的性别间差异,TSL、WL和MW与日龄的关系最适合用幂函数表示,而LDL与日龄的关系最适合用线性函数表示。总体而言,随着鸢乌贼日龄的增加,TSL、WL、LDL与MW的瞬时相对生长率与绝对生长率基本呈现下降的趋势, 140~180 d可能是西北印度洋鸢乌贼性成熟的日龄段。

Statolith microstructure and growth characteristics of Sthenoeuthis oualaniensis in the northwest Indian Ocean

Statolith is one of the most important hard tissues to study the age, growth, population structure and life history of cephalopods. In order to stuty statolith microstructure and growth characteristics of Sthenoeuthis oualaniensis in the northwest Indian Ocean, 1009 samples were collected by Chinese light falling-net fishery fleets during investigation and production in the northwest Indian Ocean from February to May of 2019. Total statolith length (TSL), lateral dome length (LDL), wing length (WL) and maximum width (MW) were taken as the indicators of morphological feature of the statolith, combined with the age data, the statolith microstructure and growth characteristics of S. oualaniensis were studied. The results showed that the statolith microstructure could be divided into postnuclear zone, dark zone and peripheral zone according to the width of growth increment. The analysis of covariance showed that there was no growth difference of TSL, LDL, WL and MW between different sexes. The relationships between TSL, WL, MW and age were best described by the power functions, while the relationship between LDL and age was best described by the linear function. In general, with the increase of age, the instantaneous relative growth rate and absolute growth rate of TSL, WL, LDL and MW decreased, and 140-180 d may be the age of sexual maturity for this squid.