气候变化对冬季东海外海中下层游泳动物群落结构及重要经济种类的影响

以全球气候变暖为主要特征的全球气候变化对海洋生物和海洋生态系统造成的影响已引起国际学者的高度关注。根据中国14家国营渔业公司底拖网渔业生产和渔业资源大面定点调查获得的17种中下层渔业数据,结合1960—2011年东海北部水域海表温度的变化情况,利用Fox模型移除捕捞效应产生的趋势变化后,分析了气候变化对中、下层游泳动物群落结构及几种重要经济种类的影响。通过气候跃变检验分析发现,海表温度在整体变暖的趋势上叠加有年代际波动,研究水域分别在1982/1983年发生了从寒冷期(1960—1982年)向升温期(1983—1998)、经由1998/1999年再到温暖期(1999—2011年)的跃变。群落结构变化特征显示:相比于寒冷期,温暖期间底层类和大型捕食类资源指数降低,中层类和无脊椎类升高;暖水种资源指数升高,暖温种降低;生物多样性指数略有增加。移除捕捞效应后,对不同生态属性种类CPUE与海表温度距平进行相关分析显示:底层类、中层类和无脊椎类残差与海表温度距平均呈正相关关系,其中中层类与海表温度距平显著正相关,而大型捕食类则呈负相关关系;暖水种残差与海表温度距平呈正相关,而暖温种则呈负相关关系。中层类中的黄鲫(Setipinna taty)、银鲳(Pampus argenteus)的CPUE残差均与海表温度距平呈显著正相关关系,近底层类中的带鱼(Trichiurus japonicus)和头足类(Squid)的CPUE残差均与海表温度距平呈正相关关系,而底层类小黄鱼(Larimichthys polyactis)和对虾(Shrimp)则呈负相关关系。在气候变化的大背景下,需加强其对海洋生态系统结构和功能影响的研究,查明渔业资源对气候变化的响应机制和机理,制定科学有效的渔业管理制度,实现渔业资源的可持续发展。

Impact of climate change on nekton community structure and some commercial species in the Offshore Area of the northern East China Sea in winter

Recently, the influence of climate change on marine organisms and ecosystems has attracted attention on a global scale. In an effort to elucidate the impact of climate change on nekton community structure and on some commercial species in the northern East China Sea (NECS) during winter, we summarized the fluctuation of sea surface temperature (SST) in the offshore area of NECS from 1960-2011, and compared this to the catch data of 17 species targeted in bottom trawl fishery and to independent fishery data from the open waters of the NECS. We used Fox models to remove the effect of fishing pressure on changing population trends. Regime shift detection methods were used to identify change points in trends of production and environmental variables. Our results showed that the winter SST from 1960 to 2011 exhibited a long-term warming trend superimposed on interdecadal variability. The NECS experienced a cold period from 1960-1982, followed by a warming period from 1983 to 1998, and then a relatively stable warm period from 1999 to 2011. Changes in the community structure showed that the abundance of demersal and large predatory species was significantly negatively related to SST and the abundance of midwater species and invertebrates was positively related to SST. Abundance of large predatory species was lower in the warm period than in the cold period, while the abundance of midwater species and invertebrates was low in most of the years during 1971-1982, but increased during 1999-2011; catch of warm water species was higher in the warm period than in the cold period, but abundances were generally lower. At the same time, the Shannon diversity index was higher in the warm period than in the cold period. Upon removing the effect of fishing pressure, we found that catch per unit effort (CPUE) residuals for demersal species, midwater species and invertebrates had was positively correlated with SST, particularly the correlation between the CPUE residuals for midwater species and SST anomalies, which was significant. While CPUE residuals for large predatory species were negatively correlated with SST, CPUE residuals of warm water species/warm temperature species presented a positive/negative correlation with SST anomalies, respectively. Correlations between CPUE residuals and SST anomalies differed for commercial species based on habitat. Setipinna taty and Pampus argenteus were significantly and positively correlated with SST anomalies, while the correlation between Trichiurus japonicus, squid, and SST anomalies was positive. Larimichthys polyactis and shrimp were also positively correlated with SST anomalies. Considering the steadily warming climate, research priorities aimed at realizing the sustainable development of fishery resources should include analyzing the impact of warming temperatures on marine community structure and function, identifying variability in fishery resources in East China Sea and the mechanisms behind their responses, and developing scientific fishery management strategies.