大治河河口无齿螳臂相手蟹生长和成熟的研究

无齿螳臂相手蟹是长江口潮间带和潮上带的优势种之一,具有重要的生态功能。为探求无齿螳臂相手蟹不同阶段的异速生长和成熟状况,于2009年10月至2010年9月期间采集样本,通过聚类和分段线性回归等分析方法对雌雄蟹头胸甲、螯、腹部等形态数据进行分析,建立区别不同生长阶段的判别函数并用逻辑斯蒂回归估计其50%形态成熟点。结果如下:雌雄蟹50%形态成熟点分别为头胸甲宽18.22mm和16.36mm。雄蟹的螯宽和雌蟹的腹宽均表现出明显的异速生长;根据相对生长率的不同,雄蟹异速生长可分为三个阶段,雌蟹分为2个阶段;不成熟的雄蟹异速生长拐点发生在壳宽11.78mm,不成熟和成熟雌蟹腹部在壳宽13.04～18.64mm范围内重叠。同时研究了50%的生理成熟大小,雌雄成熟大小分别为17.50mm,17.20mm。雄性形态成熟大小小于生理成熟大小,而雌性则相反。

GROWTH AND MATURITY OF CHIROMANTES DEHAANI IN DAZHI RIVER ESTUARY

Chiromantes dehaani,which plays an important role in ecosystems,is one of the most abundant species in intertidal regions of Yangtze estuary.To determine different growth and maturity phase,morphological data collected from October in 2009 to September in 2010,such as carapace,cheliped and abdomen were conducted with cluster and piecewise linear regression analysis.Bivariate discriminant analyses were carried out for classifying any crab as different phases and size at 50% maturity of males and females was estimated by logistic curves.The results are as follows: both the cheliped width in males and abdomen width in females show obviously allometric.The size of 50% morphometric maturity occurred at 16.36mm and 18.22mm carapace width in males and females,respectively.The life history of males shows 3 phases while females only 2 phases according to the different growth rate.A significant change in allometry was detercted in juvenile males with a break point at 11.78mm carapace width;juvenile and adults females overlap in a range of 13.04~18.64mm carapace width.The crabs attain 50% physiological maturity at the size 17.50mm and 17.20mm for females and males respectively.The size of morphological maturity of males is larger than the size of physiological maturity,while the females are just opposite.