论文部分内容阅读
根据2004—2005年大亚湾海域底拖网鱼类调查数据,并结合1980—2007年的历史资料,分析了该海域鱼类的种类组成、区系特征、多样性、优势种和数量变化趋势.结果表明:2004—2005年,大亚湾海域共记录鱼类107种,分属13目50科,以中下层鱼类的种类最多,为48种,其次是中上层和底层种类,分别为37种和21种.大亚湾鱼类区系具热带和亚热带特性,以暖水性种类占绝对优势,为97种,暖温性种类为10种.多样性指数以夏季最高(3.82),其次是冬季(3.37)和秋季(3.00),春季最低(2.40).Pielou均匀度指数的季节变化情况与多样性指数相似.1980—2007年大亚湾海域鱼类群落特征发生了明显的变化:鱼类种类数减少,优势种更替明显.鱼类种类数由1980年的157种减少至1990年的110种,2004—2005年继续减少至107种;鱼类优势种由1980年以带鱼和银鲳等优质鱼为主,更替为以小型和低值的小沙丁鱼、小公鱼和二长棘鲷幼鱼为主.用包含年际变化趋势和季节性周期变化的回归模型模拟1980—2007大亚湾鱼类资源密度的变化,鱼类资源密度在1980—1999年和1990—2007年两个时期均呈下降趋势,但1990—2007年间下降幅度比1980—1999年间大;1980—1999年鱼类资源密度的季节波动幅度较平缓(振幅为0.099),而1990—2007年的季节波动较大(振幅为0.420),说明1990—2007年阶段大亚湾鱼类数量的季节变化更为显著.
According to the survey data of bottom trawl fish in the Daya Bay waters from 2004 to 2005 and the historical data from 1980 to 2007, the species composition, flora characteristics, diversity, dominant species and quantity trends of the fish in this area were analyzed. : From 2004 to 2005, a total of 107 species of fish were recorded in the Daya Bay, belonging to 13 orders and 50 families. There were 48 species of middle and lower strata of fish, followed by 37 and 21 species of middle and upper strata The Dayawan fish zone had tropical and subtropical features, of which 97 were warm water species and 10 were warm and warm species.The diversity index was highest in summer (3.82), followed by winter (3.37) and autumn (3.00), the lowest in spring (2.40) .The seasonal variation of Pielou evenness index was similar to that of diversity index.The fish community characteristics in Daya Bay from 1980 to 2007 changed obviously: the number of fish species decreased and the dominant species changed significantly . The number of fish species decreased from 157 species in 1980 to 110 species in 1990 and continued to decrease to 107 species in 2004-2005. The predominant species of fish were dominated by high-quality fish such as octopus and silver flesh in 1980, Small and low value small sardines, baby male fish and two long spines Juvenile sea bream.The regression analysis of fish resource density in the Daya Bay from 1980 to 2007 was carried out using regression models including interannual variability and seasonal changes. Fish resource density varied from 1980 to 1999 and from 1990 to 2007 However, the declines between 1990 and 2007 were larger than those between 1980 and 1999. The seasonal fluctuation of fish resource density in 1980-1999 was more moderate (amplitude: 0.099), while the season from 1990 to 2007 was more volatile 0.420), indicating that the seasonal variation of fish populations in the Daya Bay during the period 1990-2007 was more pronounced.