Reproductive traits of nine freshwater mussel species (Mollusca: Unionidae) from Poyang Lake, China

摘要

The Yangtze River basin has the highest species richness for freshwater mussels in East Asia, but little is known about the reproductive biology of most species. Here, the reproductive biology of nine freshwater mussel species (Unionidae) found in Poyang Lake, Jiangxi province, China was studied. Sex ratios were not significantly different from 1:1 in eight of the nine species examined. The minimum size and age of sexual maturity (0.2-5.6yr for males and 0.3-5.9yr for females) and of females first becoming gravid (0.6-8.9yr) varied among species. Brooding seasons for glochidia varied among species, but seven of the nine species examined brooded glochidia through the spring and summer. In all species, high frequencies (mean 87.5%) were found to be gravid during their peak brooding period. Fecundity was positively correlated with shell length in the five species in which this was examined. Mean annual fecundity showed wide interspecific variation, ranging from 7,800 to 328,000 propagules/mussel. The findings of this study have implications for the ecology and conservation of unionid species in China and contributes to knowledge of the evolution of reproductive and life history characters of the Unionidae.