The evaluation of culture performance of the second-year early-maturing and late-maturing strains of the third selevtive generation during the juvenile culture of Chinese mitten crab (Eriocheir sinensis)

Abstract:

The extension of maturing time of second-year Eriocheir sinensis is one of the important breeding goals, and the early-maturing (EM) and late-maturing (LM) of second-year E. sinensis have been mass selected to the third generation (G3), but their juvenile culture performance is not evaluated to date. Therefore, this study was designed to compare the culture performance of EM, LM and non-selective populations (as the control) during the juvenile culture stage of E. sinensis based on the methods of selective breeding, culture experiments and regular sampling. The results showed that: (1) The females of EM had the significantly higher weight gain rate (WGR) and specific growth rate (SGR) than those of LM during the periods of Jul. to Aug. and Sep. to Oct. (P<0.05). Despite of males or females, the WGR of LM was significantly lower than that of control treatment during the period of Jul. to Oct. (P<0.05), and the order of WGR for three populations was control > EM > LM throughout the experiment(P> 0.05). (2) The similar survival was detected between EM and LM juveniles, however, the significantly higher survival was found in LM than the control treatment; The final mean weight of EM was significantly higher than that of LM juveniles, and the final body weight of control treatment was between EM and LM; In harvest, the juvenile production order of the three populations was EM> LM> control. (3) As for the size distribution of juvenile crabs, the body weight of most juveniles were concentrated on the ranges of 0-3 g and 3-6 g, and LM had the highest percentages in those two ranges. In conclusion, EM population showed the faster growth than the other two populations, resulting in the greater final average body weight and higher yield during juvenile crab culture stage, and LM had the significantly higher survival than control treatment; therefore, two selective populations of E. sinensis have their good traits during the juvenile culture stage.