湛江湾海域夏季鱼类群落的完整性评价

鱼类群落结构及其完整性是渔业资源有效管理的重要组成部分。根据2008-2012年夏季(8月)湛江湾海域拖网渔业资源调查数据,本文通过单位捕捞努力量渔获量(CPUE)、种类相对重要性指数(IRI)、多样性指数分析了鱼类群落结构;在此基础上应用赋值法构建了鱼类完整性评价指数(F-IBI),以评价该鱼类群落的完整性和受干扰程度。结果表明:该海域共捕获鱼类103种,隶属于17目48科,以鲈形目种类数(58种)最多;质量渔获率、尾数渔获率依次为39.5~75.1 kg/h,1.0×103~1.8×104尾/h;优势种以裘氏小沙丁鱼(Sardinella jussieu)为主。鱼类种类丰富度指数(D)、Shannon-Wiener多样性指数(H')分别为3.34~5.03和2.80~3.28。2008-2012年CPUE均值为(16.11±5.13)kg/(kw·d),整个海湾的年均资源量约为(93.04±26.44)t。鱼类群落完整性分析表明,2008-2012年湛江湾鱼类群落受轻度干扰,鱼类群落完整性较好;2009、2010年湛江湾鱼类群落受干扰程度较重,其余年份较小。此外,2010-2012年鱼类个体平均体质量较2008-2009年降低了53.9%,一定程度上反映了鱼类个体的小型化。

Biotic integrity assessment of summer fish communities in Zhanjiang Bay waters

The fish community structure and its biotic integrity are indispensable for effective fisheries management. The field surveys were conducted in Zhanjiang Bay waters every August from 2008 to 2012 using pair trawls. A total of 103 species were recorded, of which there were 58 species belonging to Perciformes, including 48 families, 17 orders. The catch per hour and numbers per hour ranged from 39.5 kg/h to 75.1 kg/h and from 1.0×10³ ind/h to 1.8×10⁴ ind/h respectively. Following were the community parameters:Sardinella jussieu was the dominant species for five years; the Margalef''s species richness index (D) ranged from 3.34 to 5.03 and the Shannon-Wiener diversity index (H'') ranged from 3.34 to 5.03. The average annual biomass was about 93.04±26.44 t from 2008 to 2012. The values of F-IBI showed that the fish community structure was disturbed more severely in 2009 and 2010 than in other three years, and the biological integrity was slightly disturbed in the whole five years, whereas the 53.9% decrease of average body mass of fish from 2010 to 2012 compared with that from 2008 to 2009 indicated the overall decreasing tendency of fish size.