鄱阳湖子湖“堑秋湖”渔业资源结构特征分析

"堑秋湖"是广泛存在于鄱阳湖湖区且与鄱阳湖水文节律特征相顺应的一种渔业方式。为了解"堑秋湖"渔获物组成特征及其产量与水位之间的关系,于2011~2013年"堑秋湖"期间对江西鄱阳湖国家级自然保护区的子湖大湖池和沙湖进行了连续3年的渔业调查。2011年,大湖池和沙湖与修河分别相通23d和10d,鄱阳湖属旱涝急转气候;2012年鄱阳湖水势较大,大湖池和沙湖与修河分别相通124d和108d。2013年鄱阳湖再现旱情,大湖池和沙湖均未能与修河连通。2011年渔业调查开展7次,2012年调查9次,2013年调查5次。3a调查累计获得鱼类59种隶属于6目12科43属。3年研究结果表明渔获物以鲤科鱼类为主,在种类上变化不大但优势物种有所改变且渔获物产量呈下降趋势,无度量多维排序结果(MSD)显示鱼类群落在不同年度和子湖间分离明显。经济鱼类的单位捕捞努力量(CPUE)与水位变化的线性回归分析结果表明,2011年经济鱼类产量与当日水位呈正相关性,但2012年和2013年两者的相关性却不明显。

STURCTURE AND FEATURES OF FISHERY RESOURCES OF SUB-LAKES IN POYANG LAKE,JIANGXI, CHINA

Autumn fishery by enclosing plate-shaped sub-lake is an extensive fishing method around the Poyang Lake,which is influenced by the hydrological changes and has a certain negative impact on fishery resources.In order to research the composition and characteristic dynamics of fish community in the sublake,and observe the correlation between the catch and water level changes,an investigation was carried out for three times in Dahuchi and Shahu located in Poyang Lake National Nature Reserve,Jiangxi province,China,from 2011 to 2013.The study was conducted in aspects of catch species diversity and the relation between its yield of commercial fishes and water level changes to describe the true situation and its change features and probable problems.The connection time of Dahuchi and Shahu with Xiu River in 2011 were 23 days and 10 days respectively,and a phenomenon of drought-flood abrupt alternation occurred in Poyang Lake.Poyang Lake had a flood year in 2012,and the connection time of Dahuchi and Shahu with Xiu River were 124 days and 108 days respectively.While Poyang Lake suffered a drought year again in 2013,and both lakes did not connected with the river.7 times inquiries were implemented in two lakes in 2011,9 times in 2012 and 5 times in 2013.In this study,totally 59 fish species were collected,belonging to 6 orders,12 families and 43 genera.In 2011,totally 41 fish species were collected,belonging to 6 orders,10 families and 34 genera,and 38 species in Dahuchi,belonging to 6 orders,10 families and 31 genera,and 32 species in Shahu,belonging to 6 orders,7 families and 27 genera,six of them were commercial fishes.In 2012,totally 49 fish species were collected,belonging to 6 orders,10 families,35 genera,and 44 species in Dahuchi,belonging to 6 orders,10 families,32 genera,and 36 species in Shahu,belonging to 6 orders,8 families,27 genera,8 of them were commercial fishes.In 2013,totally 38 fish species were collected in Dahuchi,belonging to 6 orders,10 families,32 genera,7 of them were commercial fishes,and there was no fisheries production in Shahu because of the low water level.The results of the investigation study showed that the largest group was from Cypriniformes,and had the similar fish species in different years,but the dominant species were changed and the yield of catch had a downward trend.The analysis of non-metrimultidimensional scaling (MDS) showed that community diversity varied among years and sub-lakes.The correlation analysis indicated that there was a positive correlation between CPUE a day and the water level in the year of 2011,while such correlation declined in the year of 2012 and 2013.