苏北浅滩中部海域春秋季口足目和十足目虾类分布特征

根据2010年5月和9月苏北浅滩如东海域虾类调查资料,研究了苏北浅滩中部海域口足目和十足目虾类种类组成和多样性的时空分布,探讨了主要优势种密度对总优势种密度的影响,并结合该海区地形地貌、水文环境等因素对虾类多样性进行了分析。结果表明,在2次调查中,共鉴定出十足目18种,口足目2种。依据相对重要性指数IRI的计算,得出该海域春季主要优势种为葛氏长臂虾(Palaemon gravieri),秋季为哈氏仿对虾(Parapenaeopsis hardwickii)。尽管春季各站位平均种类数稍高于秋季,但秋季虾类种间分布较均匀,致使该海域虾类重量和尾数多样性指数(H')均值秋季(1.59,1.85)皆高于春季(1.13,1.57)。不同生态类群虾类种类变化形成季节更替,更替率为55%。黄海冷水团和长江冲淡水的季节变化是影响该海域虾类种类生态类群和多样性分布的主要水文因素。

Distribution of Hoplocarida and Decapoda shrimps in spring and winter in the middle area of Subei shoal

Based on the data from two fishery resource surveys in the middle area of Subei shoal in May and September,2010,the paper studied the spatial-temporal distribution of Hoplocarida and Decapoda shrimps(short for shrimp) richness and diversity(H′),discussed the contribution of dominant species to total shrimp density and analyzed shrimp diversity from factors such as geographic and geomorphic conditions and hydrological features.Results showed that 18 Decapoda and 2 Hoplocarida species were identified,of which Palaemon gravieri was the main dominant species in spring and Parapenaeopsis hardwickii in autumn according to index of relative significance(IRI).Although the average number of species in spring was slightly higher than that in autumn,the distribution of shrimps in autumn was more uniform,resulting in that the weight and individual diversity index(H′) in spring(1.13,1.57) was both lower than that in autumn(1.59,1.85).The seasonal species alternation was 55% from spring to autumn.The seasonal variation of Yellow Sea cold water mass and Yangtze River diluted water were indispensible factors that influenced the diversity distribution of shrimps.Judging from value,we draw the conclusion that the variation of the shrimp density was connected to the change of the dominant species density.