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拟锥齿鲨是热带大西洋金枪鱼延绳钓渔业中重要的兼捕物种,对其单位捕捞努力量渔获量(CPUE)与环境关系的研究可为该鱼种的资源保护和管理提供基础资料.根据我国金枪鱼渔业国家观察员2009—2015年在热带大西洋海域(6.38°S—14.92°N,42.03°—18.53°W)调查时采集的1085尾拟锥齿鲨数据及Tweedie类分布理论和特点,建立了GAM-Tweedie模型,对其CPUE的时间变化、空间分布及与环境因子的关系进行了分析.结果表明:时空因子(年、月、经度、纬度)和环境因子对拟锥齿鲨名义CPUE的总偏差解释为40.2%,其中时空因子对其的影响均显著,环境因子中,海表面高度、叶绿素a浓度、作业时天气、海表面盐度、海表面气压对其影响显著,而海况、农历对其影响不显著;不同纬度和不同月份下海平面温度与拟锥齿鲨CPUE呈显著相关.2009—2015年拟锥齿鲨标准化CPUE呈现波动,整体呈上升趋势.
Quasi-cone sharks are important bycatch species in the longline fishery of tropical Atlantic tuna. The study on the relationship between their unit Catch Efforts (CPUE) and environment can provide the basic information for resource conservation and management of this species. Based on the data and Tweedie’s distribution theory and characteristics of 1085 bevel sharks collected by China’s tuna fisheries observers in the tropical Atlantic Ocean (6.38 ° S-14.92 ° N, 42.03 ° -18.53 ° W) from 2009 to 2015, The GAM-Tweedie model was used to analyze the temporal change, spatial distribution and environmental factors of CPUE.The results showed that the spatial and temporal factors (year, month, longitude and latitude) The total deviation was explained as 40.2%, of which the impact of spatio-temporal factors was significant. Among the environmental factors, the sea surface height, chlorophyll-a concentration, operational weather, sea surface salinity and sea surface pressure had significant effects on them. And its influence was not significant. The sea surface temperature at different latitudes and months had a significant correlation with the CPUE of shark sharks. The standardized CPUE of shark sharks fluctuated from 2009 to 2015, showing an overall upward trend.