厄尔尼诺发生期冬春季西北印度洋鸢乌贼耳石外形生长特性

Growth characteristics of statolith of Sthenoteuthis oualaniensis in the Northwest Indian Ocean in spring and winter in the El Nino year

耳石是头足类重要的硬组织器官之一,是研究头足类年龄与生长、种群结构和生活史等重要材料。根据2019年厄尔尼诺发生期冬春季(2—5月)我国灯光罩网渔船在西北印度洋海域调查生产期间采集的1009尾鸢乌贼(Sthenoteuthis oualaniensis)样本,对厄尔尼诺发生期耳石的外形生长特性进行了研究。结果表明,西北印度洋海域鸢乌贼耳石具有宽大的翼区,较小的背区与吻区。主成分分析表明,耳石总长(TSL)、翼区长(WL)、侧区长(LDL)和最大宽度(MW)可以作为研究鸢乌贼耳石外形生长的特征参数。协方差分析表明,耳石的各特征参数与胴长(ML)、体质量(BW)间的生长关系均存在性别间显著性差异。赤池信息准则(AIC)表明,雄性TSL、WL与ML的生长最适用对数函数表示,LDL、MW与ML的生长最适用线性函数表示,雌性TSL、WL、LDL和MW与ML的生长最适用对数函数表示;雄性TSL、WL与BW的生长最适用对数函数表示,LDL、MW与BW的生长最适用幂函数表示,而雌性TSL、WL、LDL、MW与BW的生长均最适用对数函数表示。随着鸢乌贼个体的增大,其耳石各参数的绝对尺寸逐渐变大,但相对尺寸逐渐减小。本研究结果为后续利用耳石研究鸢乌贼种群鉴定、生活史提供了科学依据,也为研究极端天气变化对头足类硬组织生长的影响提供了参考。

Statolith is one of the most important hard tissues in Cephalopods.It is an important material for studying age,growth,population structure,and life history of Cephalopods.The morphological growth characteristics of statolith in Sthenoteuthis oualaniensis were examined based on samples collected in the Northwest Indian Ocean from February to May of 2019(the period of El Nino occurrence)by the Chinese light falling-net fishery fleets.The results showed that wing dome of the statolith was large,while dorsal dome and rostrum were relatively small.The results of principal component analysis showed that total statolith length(TSL),wing length(WL),lateral dome length(LDL)and maximum width(MW)could be used as morphological indicators for the morphological growth of statolith.The analysis of covariance(ANCOVA)showed significant sex differences in the relationships between these morphological characteristic parameters versus mantle length(ML)and body weight(BW).Based on the results of the Akaike’s information criterion(AIC),logarithm function best described the relationships between ML and TSL or WL,while linear function for the relationships between ML and LDL or MW for males.The relationships between ML and TSL,LDL or MW were best described by logarithm functions for females.The relationships between BW and TSL or WL were best described by logarithm functions but power function for LDL,MW for males.The relationships between BW and TSL,WL,LDL,MW were best described by logarithm functions for females.The absolute growth rate of statolith increased while the relative growth rate decreased with individual growth.Our results provide scientific basis for understanding population structure and life cycle of Sthenoteuthis oualaniensis and the effects of extreme weather on growth characteristics of hard tissues of Cephalopods.