上海淀山湖内河蚬的分布与种群生长的初步研究

Preliminary investigations on the distribution and growth of Corbicula fluminea in the Dianshan Lake of Shanghai

摘要:

2010年6月28日通过取样调查研究了上海市淀山湖沿岸及周边河道内河蚬的分布状况，发现湖内西南方向沿岸区域河蚬分布较多（平均密度62.3 个/m²，生物量62.7 g/m²），而东北方向沿岸区域河蚬分布较少（平均密度13.8 个/m²，生物量12.8 g/m²），位于东南侧的河道内河蚬密度最大，达到318.5 个/m²，生物量225.2 g/m²。2011年1-12月通过按月取样对淀山湖内河蚬群落的生长繁殖特征进行了研究和分析：仔蚬（壳长< 8 mm）在6月份大量出现，指示6月为淀山湖内河蚬的繁殖高峰期，仔蚬在1年后壳长生长至19 mm，2年后壳长生长至27 mm，2年之后仍然存活的个体比例很低。估计淀山湖内河蚬在开始底栖生活之后的生命周期约为2~3年，理论上最大壳长为30 mm, 实际最大壳长为34 mm。 淀山湖河蚬的分布及生长数据将对于此区域河蚬资源保育工作的开展提供重要的依据。

Abstract:

Distribution of Corbicula fluminea in the Dianshan lake was investigated by sediment sampling conducted on 28th June of 2010. Results of distribution survey revealed that C. fluminea in the southeast area (average density 62.3 ind/m²，average biomass 62.7 g/m²) is more abundant than the northwest area (average density 13.8 ind/m²，average biomass 12.8 g/m²), and the highest density was found at a southeast tunnel connected with the lake (average density 318.5 ind/m²，average biomass 225.2 g/m²). Population dynamics of C. fluminea in the Dianshan Lake was investigated by monthly collection of clam specimens from January to December of 2011. Results showed that, large numbers of juvenile C. fluminea (shell length < 8 mm) presented in June, therefore, June can be identified as the peak reproduction season of C. fluminea in the Dianshan Lake. Shell length of C. fluminea increased to 19 mm one year after settlement, and then increased to 27 mm two years after settlement, only very low percentage of individuals can survive more than two years after settlement. The life span of C. fluminea is estimated as 2-3 years after settlement. Theoretically the largest individual is estimated as 30 mm in shell length, whereas practically the largest individual was measured as 34 mm in shell length. Data on the distribution and population dynamics of C. fluminea in the Dianshan Lake can be significantly important to the conservation of this species within this area.