太平洋褶柔鱼秋生群产卵场环境变化及对资源丰度的影响

摘要

根据日本渔业机构提供的2002-2011年太平洋褶柔鱼(Todarodes pacificus)秋生群的生产统计数据,结合产卵场环境数据以及厄尔尼诺指数(Ni(n)o 3.4区海表温度距平值,NI)和太平洋年代际涛动指数(PDOI),利用交相关函数分析NI和PDOI与太平洋褶柔鱼秋生群资源丰度(CPUE)、产卵场海表温度(SST)、叶绿素a(Chl-a)浓度以及适宜产卵场面积(Ps)之间的关系,检验不同气候条件下太平洋褶柔鱼产卵场环境变化.结果表明,NI与CPUE和Ps均显著正相关,与产卵场SST显著负相关,但与Chl-a浓度相关性不显著;PDOI与CPUE显著正相关,与SST显著负相关,与产卵场Ps和Chl-a浓度相关性均不显著.PDO位于正位相或发生厄尔尼诺事件时,太平洋褶柔鱼秋生群的产卵场SST偏低,Chl-a浓度偏高,Ps增大,提供了有利的资源量补充条件,太平洋褶柔鱼秋生群资源丰度增加;而PDO位于负位相或发生拉尼娜事件时,产卵场SST上升,Chl-a浓度降低,Ps减小,不利于资源量的补充,其资源丰度相应降低.研究表明,PDO模态转换以及厄尔尼诺和拉尼娜事件对太平洋褶柔鱼秋生群产卵场环境和资源丰度具有显著影响.%Based on fishery statistical data of T.pacificus autumn cohort during 2002-2011 obtained from Japanese fisheries institutions,as well as environmental data of the spawning grounds,and the Ni(n)o index (NI,which was indicated by the sea surface temperature anomaly (SSTA) in Ni(n)o 3.4 region) and Pacific Decadal Oscillation index (PDOI),we evaluated the relationships of NI and PDO with the squid abundance (CPUE),sea surface temperature (SST),chlorophyll-a concentration (Chl-a) and suitable spawning area (Ps) of the spawning grounds,respectively,based on the cross correlation function.The environmental variability of the spawning grounds of T.pacificus was further explored under different climate modes.The results showed that there were significantly positive relationships between NI with CPUE and Ps,and significant decreasing trend through SST,however,no relationship was observed between NI and Chl-a.Meanwhile,the PDOI showed significantly positive relationship with CPUE and negative relationship with SST,but no relationship was observed between PDOI with Ps and Chl-a.When the PDO mode was in positive phase or El Ni(n)o events occurred,the SST decreased,the Chl-a increased,and the Ps would enlarge in the spawning grounds,which would result in favorable recruitment conditions,the abundance index of T.pacificus autumn cohort would be high.However,when the PDO mode shifted to negative phase or the La Ni(n)a events occurred,the SST increased,the Chl-a decreased,and the Ps would shrink,which was unfavorable for the squid recruitment,the abundance index of T.pacificus autumn cohort would be low.Our findings suggested that shifts in PDO modes and the ENSO events had significant impacts on the squid abundance of T.pacificus autumn cohorts and environmental conditions of the spawning grounds.