基于海表温度和光合有效辐射的西北太平洋柔鱼冬春生群体栖息地热点预测

柔鱼是大洋洄游性头足类种类,具有重要的生态地位和经济价值,目前是日本、韩国和中国等国家在西北太平洋捕捞的主要对象。柔鱼属于短生命周期生物,其栖息地适宜性受气候和海洋环境变化的显著影响。本文根据中国远洋渔业数据中心提供的2006—2015年9—11月中国鱿钓捕捞数据和海表面温度(SST)以及光合有效辐射(PAR)两个关键环境因子,构建基于捕捞努力量和算术平均算法的柔鱼综合栖息地热点预测模型,并对比分析柔鱼栖息地适宜性在超强厄尔尼诺和强拉尼娜条件下的变动规律及其成因。结果表明:基于SST和PAR的栖息地模型能够有效地预测西北太平洋柔鱼栖息地热点海域;9—11月柔鱼各月适宜的SST和PAR范围具有显著月间变化且逐渐减小;柔鱼产量、捕捞努力量和单位捕捞努力量渔获量(CPUE)随栖息地指数值的增加呈现线性增加趋势。对比2007年强拉尼娜年份和2015年超强厄尔尼诺年份,研究发现,2007年柔鱼CPUE和栖息地适宜性显著高于2015年,其主要原因可能是2007年强拉尼娜现象导致柔鱼渔场内适宜的SST和PAR面积显著增加,而2015年超强厄尔尼诺现象导致两者适宜面积急剧下降,从而导致柔鱼栖息地适宜性变差,柔鱼CPUE降低。

Predicting the habitat hot spots of winter-spring cohort of Ommastrephes bartramii in the northwest Pacific Ocean based on the sea surface temperature and photosynthetically active radiation

The neon flying squid Ommastrephes bartramii from is a migratory ommastrephidae squid species with ecological importance and economic values. At present, O. bartramii is mainly targeted by the squid-jigging fishing vessels from Japan, ROK and China and so on. O. bartramii has only 1-year life span, therefore, its habitat suitability is largely affected by climate variability and environmental conditions. In this study, an integrated habitat suitability index (HSI) model was developed based on the fishing effort and the arithmetic mean method by using the fisheries data from September to November during 2006-2015 obtained from the data centers of Chinese squid-jigging fishery combined with two key environmental variables including sea surface temperature (SST) and photosynthetically active radiation (PAR). This study further evaluated and compared the impacts of very strong El Niño and strong La Niña on habitat suitability of O. bartramii. Results showed that habitat modeling method based on SST and PAR could effectively predict the habitat hot spots of O. bartramii in the Norwest Pacific Ocean. It was clearly found that the suitable ranges of SST and PAR varied monthly, and the ranges decreased from September to November. The catch, fishing effort and catch per unit effort (CPUE)tended to linearly increase with the habitat suitability index. Comparing the 2007 year with strong La Niña and the 2015 year with very strong El Niño, it showed that the CPUE and habitat suitability in 2007 were higher than those in 2015. The difference might be attributed to the high enlargement of suitable area of SST and PAR in 2007due to the strong La Niña, while the very strong El Niño in 2015 led to the sharp decrease of suitable area for both SST and PAR. All of these resulted in the low CPUE.