【摘要】 根据2012—2013年在北部湾口和南沙群岛西南部海域进行的春、秋季2个航次底拖网调查数据,分析了2个海区的渔获种类组成、主要经济鱼类生物学特征和生物量密度。结果表明,北部湾口海域有竹荚鱼(Trachurus japonicus)、发光鲷(Acropoma japonicum)和蓝圆鲹(Decapterus maruadsi)3种优势种和8种主要种。南沙群岛西南部海域有锯棘尖牙鲈(Synagrops serratospinosus)1种优势种和14种主要种。与历史调查数据对比分析发现,两水域的优势种组成变动显著,发光鲷和尖牙鲈等小型鱼类渔获比例增加,同时经济鱼类如竹荚鱼、蓝圆鲹、短尾大眼鲷(Priacanthus macracanthus)和深水金线鱼(Nemipterus bathybius)个体尺寸有所减小,呈现经济鱼类被小型非经济鱼类取代的趋势。北部湾口和南沙群岛西南部海域的平均生物量密度分别为1 587.8kg/km~2和2 289.2kg/km~2,呈现西南部高北部低、秋季高于春季的特点。更多还原

【Abstract】 Fishery surveys using bottom trawl were conducted in the mouth of Beibu Bay and the southwestern waters of Nansha Islands in the autumn of 2012 and the spring of 2013.Spatial distribution of fishery catches and biology of main commercial fish in the surveyed waters were analyzed.Results showed that there were three dominant species(Trachurus japonicus,Acropoma japonicum and Decapterus maruadsi,IRI>500)and 8main species(500>IRI>100)in the mouth of Beibu Bay,in comparison with one dominant species(Synagrops serratospinosus)and 14 main species,respectively,in the southwestern waters of the Nansha Islands.Compared to the survey data in the corresponding areas conducted in the 1990 s,the current dominant species changed significantly.Traditional commercial fishery species such as Lutjanus sanguineus and Gerres filamentosus were hardly found in the present surveys,while T.japonicus and D.maruadsi had a relatively high catch with large seasonal variation.Furthemore,the catch proportion of A.japonicum and S.serratospinosus had reached 7.8% and42.7%.The individual size and biomass of commercial specie including T.japonicus,D.maruadsi,Priacanthus macracanthus and Nemipterus bathybius became smaller in the past decades.These populations,as the dominant or main species,tended to be replaced by small non-commercial exploited fish in the present surveys.The biomass density of the benthic nekton averaged 1 587.8kg/km~2(1.5~7 521.2kg/km~2)and 2 289.2kg/km~2(28.6~33 745.1kg/km~2)in the mouth of Beibu Bay and the southwestern waters of Nansha Islands,respectively.At present,the commercial fishery species both in the North and South had declined seriously while the fishery resources in the local sea had not been significantly reduced due to the large number of non-commercial fish population that increased.更多还原