中华绒螯蟹一龄性早熟和二龄成熟家系扣蟹阶段生长和早熟的比较研究

The comparison of the growth and precocity of juvenile Eriocheir sinensis from one-year precocious family and two-year normally mature family during the first year culture stage

河蟹一龄性早熟是扣蟹养殖过程中的一个重要问题,通过构建一龄性早熟和二龄正常性成熟河蟹家系,综合评估了两种家系子一代在扣蟹养殖阶段的生长、早熟率、成活率、产量、早熟蟹和正常扣蟹的平均体质量及其规格分布等参数,结果显示：（1）除215日龄雄体甲壳长外,一龄早熟家系扣蟹在155和215日龄的体质量、甲壳长、甲壳宽、增重率（WGR）和特定生长率（SGR）均显著低于二龄成熟家系（P〈0.05）;（2）整体上两种家系子代的成活率和产量均无显著差异,尽管一龄早熟家系子代雄体的早熟率略高于二龄成熟家系,但是两者的差异不显著,一龄早熟家系子代雌体无一龄早熟现象,二龄成熟家系子代雌体的早熟率是其雄体的两倍;（3）两种家系后代中正常扣蟹各规格比例基本呈正态分布,雌雄体主要集中于3~6 g和6~9 g两个体质量范围,无论雌体还是雄体,二龄成熟家系的大规格扣蟹（体质量〉6 g）比例较高,一龄早熟家系的小规格扣蟹（体质量〈6 g）比例较高。综上,河蟹二龄成熟家系子代在扣蟹阶段的生长性能优于一龄早熟家系子代,两者的一龄性早熟情况也有所不同,需要进一步研究河蟹一龄性早熟的生理机制和性别差异。

The appearance of one-year precocious crabs is a severe problem during the first year culture of Chinese mitten crab（ Eriocheir sinensis）,but it is unclear for the growth and precocious trait of the offspring produced by the one-year precocious crabs. Therefore,this study was conducted to investigate and compare body weight,carapace length,carapace width,weight gain rate（ WGR）,specific growth rate（ SGR）,survival rate,precocious rate,yield,distribution of body weight and final average weight of juvenile Eriocheir sinensis from one-year precocious family and two-year normally mature family during the first year culture stage. The results showed that：（ 1） except for carapace length of male crabs at 215-day-old,despite of males or females,the juveniles from the one-year precocious families had significantly lower（ P〈0. 05） body weight,carapace length,carapace width,WGR and SGR than the juveniles from the two-year normally mature families at 155- and 215-day-old;（ 2） there was no significant difference in survival rate and yield of two types of families. Although the precocious rate of male juveniles from one-year precocious families was slightly higher than that of two-year normally mature families,no female precocious crabs was found in oneyear precocious families. Overall,the precocious rate of two-year normally mature families normal crabs families was about twice that of one-year precocious families;（ 3） the size distribution of body weight was normal for juveniles from the two types of families, and the highest proportions of body weight were concentrated on 3- 6 g and 6- 9g for both males and females despite of families; however,both male and female,two-year normally mature families had the higher proportion of large size crabs（ body weight 6 g）and lower proportion of small size crabs（ body weight 〈6 g） than the one-year precocious families. In conclusion,the growth performance of juveniles from two-year normally mature families was better than that of one-year precocious families during the first year culture,and the precocity rate was different for the two types of families. Therefore,the further study should be conducted to investigate the physiological mechanism and gender differences for the one-year precocity.