长江口中华绒螯蟹繁殖群体的组成与生理特征

Reproductive Population Composition and Physiological Characteristics of Eriocheir sinensis in the Yangtze River Estuary

为探究长江口中华绒螯蟹(Eriocheir sinensis)繁殖群体的组成及交配前后的生理特征变化,于2020年12月在长江口水域进行了调查采样。分析了中华绒螯蟹繁殖群体的规格组成、性别比例、雌蟹繁殖状态以及交配前后的肝胰腺指数(HSI)、性腺指数(GSI)和Fulton条件指数K的变化。结果显示,在长江口中华绒螯蟹繁殖群体中,雌蟹整体规格小于雄蟹,雌雄比例为0.39∶1,雄蟹数量显著大于雌蟹(χ^(2)=101.87,P<0.05)。对生理特征的比较发现,不同繁殖状态雌蟹之间的HSI差异显著(P<0.05),其中,抱卵状态下最高,已交配状态下最低。雌蟹在已交配状态下的GSI和K指数高于未交配状态(P>0.05),抱卵状态下雌蟹的K指数最低(P<0.05)。雄蟹的GSI显著低于雌蟹(P<0.05),而K指数显著高于雌蟹(P<0.05)。雄蟹的HSI、GSI与壳宽之间呈极显著负相关(P<0.01),而雌蟹仅发现HSI与GSI之间呈极显著负相关(P<0.01)。研究结果有助于了解长江口中华绒螯蟹繁殖交配期生理特征,为中华绒螯蟹资源养护及管理提供基础数据。

To investigate the composition of the reproductive population and changes in the physiological characteristics of Eriocheir sinensis before and after mating in the Yangtze River estuary, a survey was conducted in December 2020. The size composition, sex ratio, and reproductive status of female crabs and changes in hepatopancreas index(HSI), gonadosomatic index(GSI), and Fulton’s condition index(K) before and after mating were analyzed. Results showed that in the reproductive population of E. sinensis in the Yangtze River estuary, the overall size of female crabs was smaller than that of male crabs, and the ratio of females to males was 0.39 : 1. The number of male crabs was significantly higher than that of female crabs(χ^(2)=101.87, P<0.05). In the comparison of physiological characteristics, there was a significant difference in the HSI among female crabs of different reproductive statuses(P<0.05), among which the highest was in the egg-bearing status, and the lowest was in the mated status. The GSI and K index of female crabs in the mated status were higher than those in the unmated status(P>0.05), and the K condition index of females in the egg-bearing status was the lowest(P<0.05).The GSI of male crabs was significantly lower than that of females(P<0.05), while the K condition index was significantly higher than that of females(P<0.05). A highly significant negative correlation was found between the HSI, GSI, and carapace width in male crabs(P<0.01), while a highly significant negative correlation was only found between the HSI and GSI in females(P<0.01). These results enrich our understanding of the physiological characteristics of E. sinensis during the reproductive mating period and provide basic data for the conservation and management of E. sinensis resources.