东海太平洋褶柔鱼生殖群体的空间分布及其与环境因子的关系

Spatial distribution of mature stock of Pacific squid,Todarodes pacificus and its relation to environmental factors in the East China Sea

依据1997-2000年在东海(26°00′-33°00′N、120°30′-128°00′E)进行的4个季节的底拖网调查资料,分析了该海区太平洋褶柔鱼生殖群体的时空分布特征,同时结合广义相加模型(GAM),量化分析了各环境因子对于其种群成熟度指数(PMI)空间分布的影响机制。结果表明:太平洋褶柔鱼生殖群体春、夏、秋、冬4个季节在东海均有分布;秋季PMI值最高,春季最低;4个季节太平洋褶柔鱼生殖群体的分布范围均较广,主要集中在东海外海受台湾暖流和黑潮控制的水域。太平洋褶柔鱼生殖群体的环境适应性存在明显的季节差异:其分布的底温范围为:春季14.70-18.30℃、夏季13.18-20.91℃、秋季13.96-24.67℃、冬季14.33-19.75℃。底盐范围为:春季29.52-34.63、夏季31.57-34.27、秋季32.26-34.72、冬季34.25-34.70。水深范围为:春季55-179m,夏季43-176m、秋季40-184m、冬季79-152m。综上所述,东海太平洋褶柔鱼生殖群体的时空分布具有广范围、多季度的特点,这种分布特征可有效降低其幼体间的种间竞争,为确保其种群繁衍提供有利保障。

Based on data collected from four bottom trawl surveys conducted in the East China Sea（26°00＇-33°00＇N、120°30＇-128°00＇E）during autumn 1997,spring 1998,summer 1999 and winter 2000,the temporal-spatial distribution of mature stock of T.pacificus was analyzed,and the relationships between the population maturity index（PMI）and environmental factors were examined by using a generalized additive model（GAM）.The results indicated that the mature stock of T.pacificus was found in all seasons,with the highest value of PMI in autumn and the lowest in spring.The mature stock was mainly distributed in offshore of the East China Sea,where environmental conditions are influenced by both the Kuroshio Current and the Taiwai Warm Current.The environmental adaptation of mature stock of T.pacificus showed significant seasonal variations.The seasonal distribution patterns of temperature,salinity and water depth were 14.70-18.30 ℃ in spring,13.18-20.91 ℃ in summer,13.96-24.67 ℃ in autumn,and 14.33-19.75 ℃ in winter;29.52-34.63 in spring,31.57-34.27 in summer,32.26-34.72 in autumn,and 34.25-34.70 in winter;and 55-179 m in spring,43-176 m in summer,40-184 m in autumn,and 79-152 m in winter,respectively.In summary,the temporal-spatial distribution of mature stock of T.pacificus was characterized by a wide range of areas and multiple seasons.These distribution patters can reduce the competition among individual juveniles of T.pacificus and enhance the mature stock for reproduction.