Evaluation on culture performance of the first generation 

of odd year “Changdang Lake 1” Eriocheir sinensis

during the adult culture stage

Abstract: High survival rate and large size are the main breeding standards for strain A and strain B of “Changdang Lake 1” Chinese mitten crab (Eriocheir sinensis). In order to explore the culture performance of the first generation of “Changdang Lake 1” Eriocheir sinensis in odd year population, juveniles were reared to adult in 9 similar ponds close to production conditions in Changdang Lake area from March to November 2020. The average body weight, weight growth rate, specific growth rate, genital molting rate, gonadal development, survival rate, yield, feed coefficient ratio and final body mass distribution were evaluated among strain A, strain B and the control group (unselected population). The results showed as follows: 1) The average body weight of strain B was significantly higher than that of other groups from June to October (P<0.05), and the average body weight of strain A was slightly higher than that of the control group, but there was no significant difference (P＞0.05); moreover, a clear difference began to emerge in the average body weight of male and female in June; 2) At early stages of culture (AprilJune), the weight growth rate (WGR) of three groups was more than 200%, and the WGR of strain B was significantly higher than that of strain A and the control group (P<0.05); from August to October, the weight growth rates of male were less than 60%, and that of female were generally less than 30%; 3) The changes of specific growth rates were similar to weight growth rates of the three groups; after August, the daily increase rate of body weight of male was less than 0.8%, and that of female was less than 0.5%; 4) There was no significant difference in genital molting rate among three groups (P<0.05); the genital molting rate of male and female crabs increased gradually from July, and the genital molting rate of female was about 20% higher than that of male in the same period from August to September; by September 20th, the genital molting rates among three groups were nearly 100%; 5) The gonadosomatic index gradually increased from September to November among all groups, but there was no significant difference (P<0.05); from October to November, the gonadosomatic index of female in three groups was higher than that of male; 6) The hepatosomatic index of female decreased from September to November in the three groups, while the change of hepatosomatic index of male was different among three groups; the hepatosomatic index of male in two selected strains slightly increased at the beginning, and then decreased from September to November, while the hepatosomatic index of the control group decreased month by month, but there was no significant difference among all groups (P＞0.05); 7) In terms of male crabs, the distribution proportion of large size (≥250g) in strain B was significantly higher than that in strain A and the control group (P<0.05), while the proportion of small size (< 125 g) in strain A was significantly higher than that in the other two groups (P<0.05); in terms of female crabs, the distribution proportion of large size (≥150 g) in strain B was significantly higher than that in the other two groups (P＞0.05). Although the distribution proportion between 125200 g in strain A was higher than that in the control group, there was no significant difference (P＞0.05); 8) In terms of survival rate, the total survival rates of two selected strains were significantly higher than that of the control group (P<0.05), and the total survival rate of strain A was significantly higher than that of strain B (P<0.05), among which the female survival rate of strain A was as high as 76.93%; 9) The yield of the two selected strains were significantly higher than that of control group (P<0.05), and there was no significant difference between strain A and strain B (P＞0.05); 10) In terms of feed conversion rate, strain B was the lowest and the control group was the highest, but there was no significant difference among three groups (P＞0.05). In conclusion, the survival rate of “Changdang Lake 1” strain A was significantly higher than that of the other two groups, the average body mass of “Changdang Lake 1” strain B was higher than that of the other two groups, and the yield and feed conversion rate of two selected strains were higher than those of the unselected population. The results provide a detailed practical reference for the breeding of new Eriocheir sinensis strains, and provide data for the continuous breeding and promotion of “Changdang Lake 1” Eriocheir sinensis.  

Keywords: Eriocheir sinensis; Changdang Lake 1; complete set line breeding; culture performance; gonadal development