冬季厄尔尼诺发生期日本海太平洋褶柔鱼耳石外形的生长特征

Growth characteristic of statolith of Todarodes pacificus in the Sea of Japan during the winter of an El-Nino year

太平洋褶柔鱼是西北太平洋海域重要的头足类资源,深入了解其渔业生态学特性是充分开发该资源的基础。耳石是研究头足类年龄与生长、种群结构和生活史的重要材料。根据2018年厄尔尼诺发生期冬季(12月)我国鱿钓船在西北太平洋日本海海域生产调查期间采集的530尾太平洋褶柔鱼样本,首次对厄尔尼诺发生期太平洋褶柔鱼的耳石外形生长特征进行了报道。结果显示,日本海太平洋褶柔鱼的耳石具有较宽大的背区、侧区和翼区,以及较狭长的吻区。主成分分析表明,耳石总长(TSL)、侧区长(LDL)、翼区长(WL)和最大宽度(MW)可以作为描述日本海太平洋褶柔鱼耳石外形生长特征的表征参数。协方差分析表明,耳石各外形表征参数与胴长、体重间的生长关系不存在性别间显著性差异。赤池信息准则表明,TSL、LDL、MW与胴长、体重的生长关系适用幂函数生长模型表示,WL与胴长、体重的生长关系适用线性生长模型表示。研究表明,随着个体的生长,太平洋褶柔鱼耳石整体外形轮廓绝对尺寸的生长逐渐减缓,但耳石整体外部轮廓的相对尺寸基本维持原状。本实验为后续利用耳石研究太平洋褶柔鱼的生活史过程提供了参考,也为研究异常气候事件对头足类硬组织生长的影响提供了科学依据。

Todarodes pacificus is one of the most abundant cephalopod resources in the Northwest Pacific Ocean.Understanding of its fishery ecology is the basis for sufficient exploitation of this resource.Statolith are a vital material for studying the age and growth,population structure and life history of cephalopods.The morphological growth patterns of statoliths of T.pacificus was studied for the first time using samples collected in the Sea of Japan by Chinese squid jigging fishery fleets in December 2018(an El-Nino period).The results indicated that the dorsal dome,lateral dome and wing dome of the statoliths were relatively large and the rostrum dome was relatively small.The result of principal component analysis indicated that the total statolith length(TSL),lat-eral dome length(LDL),wing length(WL)and maximum width(MW)could be used as morphological para-meters to study the morphological growth of statolith.The analysis of covariance(ANCOVA)indicated that there was no significant difference in the relationships between these morphological parameters versus mantle length(ML)and body weight(BW)in different genders.Based on the result of the Akaike’s information cri-terion(AIC),the relationships between ML,BW and TSL,LDL,MW were best described by power functions growth models,but linear function growth models were more effective for WL.The absolute morphological growth of statolith was gradually decreased,while the relative morphological growth of statolith was main-tained steadily with increasing individual growth.This research not only provides reference for study of life history of T.pacificus thorough statolith,but also provides scientific basis for growth pattern of hard tissues of cephalopods under the effect of extreme weather patterns.