利用胃磨鉴定三疣梭子蟹年龄初探

A preliminary study on identification of age of Portunus trituberculatus by gastric mill

三疣梭子蟹(Portunus trituberculatus)是中国重要的经济物种,对其进行年龄鉴定有利于其种群资源的评估和管理。该研究对三疣梭子蟹的胃磨进行制片处理,初步探讨了胃磨鉴龄的可行性。三疣梭子蟹胃磨由5个部分(前幽门骨、外幽门骨、尾贲门骨、轭贲门骨和翼贲门骨)组成,依据前人研究结果选取外幽门骨和尾贲门骨进行切片观察。结果显示,三疣梭子蟹胃磨微结构由4个部分(蜡质层、外角质层、钙化层和膜层)组成,用于年龄鉴定的生长纹主要存在于钙化层中。利用7个生长方程拟合三疣梭子蟹生物学数据与生长纹数目的关系,结合赤池信息量准则(AIC)得出甲长与甲宽呈线性函数关系、甲宽与体质量呈幂函数关系;体质量与胃磨生长纹数目的关系适用于Gompertz模型,甲长、甲宽与胃磨生长纹数目的关系则更适用于v-B生长模型。即胃磨生长纹可以作为甲壳类年龄鉴定的材料,但由于实验样本偏小型化,后续需要延长时间跨度进一步验证。

Portunus trituberculatus is an important economic species in China,and age identification is beneficial to its population resources assessment and management.We discussed the feasibility of gastric mill age identification by gastric mill of P.trituberculatus.The gastric mill was composed of five parts(propyloric ossicle,explyloric ossicle,urocardiac ossicle,zygocardiac ossicle and pterocardiac ossicle).According to the results of previous studies,we selected the explyloric ossicle and urocardiac ossicle for section observation.The results show that the gastric mill microstructure of P.trituberculatus consisted of four parts:wax layer,exocuticle,calcified layer and membranous layer.The growth lines that can be used for research mainly existed in endocuticle.We used seven growth equations to fit the relationship between biological data and the number of growth lines of gastric mill.Combining with AIC method,it is concluded that there are a linear function relation between carapace length and carapace width and a power function relation between carapace width and body mass;the relationship between body mass and the number of growth lines in the gastric mill is applicable to the Gompertz growth model,while that amang carapace length,carapace width and the number of growth lines in the gastric mill is more applicable to the v-B growth model.Thus,the growth lines of gastric mill can be used as the material for Crustacean age identification.However,due to the fact that the samples tend to be miniaturized,the time span needs to be extended for further verification.