利用2014年11月17日～12月2日我国拖网渔船在中东大西洋部分区域(塞内加尔共和国专属经济区)作业时获取的FURUNO FCV-292型船载探鱼仪声学映像资料,结合渔业声学原理与水文环境数据,分析了该海域小型中上层鱼类的集群分布特征.结果显示:调查期间该海域底拖网渔船捕获主要小型中上层渔业资源为北梭鱼(Albula vulpes)、斑鳍圆鰺(Decapterus rhonchus)与黑斑十指马鲅(Galeoides decadactylus)等鱼类,分别占总渔获量的11.23％、11.34％,5.78％,其它捕捞种基本为底栖鱼类;将鱼群集群类型分为散点状、短带状、散带状、块状与带状等5种集群类型,统计了每种集群类型出现的站位地理信息,5种集群类型占比依次为22.4％、15.3％、27.6％、22.4％与12.2％;在水平尺度上,鱼群集中分布于海表温度为27℃与28℃等温线之间的水域,且集中现象明显,两个集中区域分别位于近岸海域中部与南部;鱼群主要栖息水层深度为10 ～30 m,占整个水层的90％以上;受水温垂直梯度变化影响较小,对盐度的垂直变化有一定的应激行为;鱼群的形态在夜间分散日间聚集,夜间多表现为散点状集群,日间多表现为短带状、块状与带状等聚集程度高的集群类型;集群数量表现出明显的日间多夜间低的变化趋势.结合历史研究讨论了该海域主要中上层鱼类资源情况;分析了鱼群集群类型与生物量的内在关系,发现在生物量上表现出较高水平的集群类型为散带状与带状,此结论可在一定程度上指导渔船的瞄准捕捞.%Based on the echogram pictures collected from the commercial echo-sounder FURUNO FCV-292 equipped on the F/V "SUN-51 ",which was operating in the eastern central Atlantic (Senegal Exclusive Economic Zone) in winter (17th Nov.to 2nd Dec.,2014),the spatiotemporal distribution patterns of the small pelagic fish aggregation were analyzed in this paper by utilizing fishery acoustic together with hydrology data set.Albula vulpes,Decapterus rhonchus and Galeoides decadactylus were considered to be predominant pelagic species in this area catched by a bottom-trawl vessel,accounting for 11.23％,11.34％ and 5.78％ respectively in total net catch,while the others were bottom fish.The echos were coded into five different types named scattered,short belted,scattered belted,patched and belted according to the echogram pictures,and 22.4％,15.3％,27.6％,22.4％ and 12.2％ were the percentage of five types respectively in all data set.Then the analysis of habitat's characteristics showed that the small pelagic fish aggregations were concentrated between the sea surface temperature isotherm at 27 ℃ and 28 ℃ horizontally,near the central and the southern parts of the operation area.The optimal habitat depth for the small pelagic fish was 10-30 m,and the rate was more than 90％ to all depth.Neither obvious thermocline nor halocline was found in this area due to the strong mix of water masses.However the schooling behaviour appeared to be more correlated to vertical salinity gradient than temperature.The difference of school morphology between day and night was determined by fractal dimension,as different echo types showed in echogram pictures.More dense schools as scattered belted,patched and belted types were found at day time while more scattered types at night.Finally,by discussing the resource condition and the correlation between aggregation type and the biomass,we found that the pelagic fish school behaviour appeared to be more dense in scattered belted and belted types,and this was very useful for commercial operation.
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