Resource Investigation And Domestication Of Semilabeo Obscurus In Beipanjiang River

The age structure and growth characteristics of fish can reflect the resources status and growth rules to a certain extent,and we can formulate fishery policy which is beneficial to the survival and development of fish on this basis.In this study,through resource investigation,age structure characteristic analysis and growth characteristic study of the Dusky Labiaet-barbel(Semilabeo obscures)distributed in Beipanjiang,we found out the status of resources,and carried out their artificial domestication and breeding research.From October 2017 to October 2018,we investigated the Dusky Labiaet-barbel distributed in Beipanjiang,including the measurement,identification and data fitting of the body length,weight,age characteristics and growth characteristics.Meanwhile,the study on the artificial domestication of Dusky Labiaet-barbel was carried out.The main results are as follows.A total of 56 samples were obtained in this survey,with body length ranging from 8.90 mm to 416.3 mm and body weight from 27.8 g to 1397.48 g.Comprehensive comparative analysis showed that the scale is the best age identification material among scale,spine and gill operculum.The results using scales as the age identification material showed that the age composition of 56 samples ranged from 1 to 6 years old,and 53.57% of them were 1year old and there were few elderly samples.The results of data analysis and fitting showed that the power function formula of body length-weight is w = 0.01643L3.0689(n = 56,R2 = 0.9924),which belongs to the type of uniform growth;the relationship between scale length(R)and body length(L)is: L=0.6089+63.857 R.The Von bertalanffy's growth equations of body length and body weight were: Lt=673.71(1-e-0.1509(t+ 0.1632)),Wt = 6275.51(1-e-0.1509(t + 0.1632))3.0689.The growth inflection point of Dusky Labiaet-barbel was 7.26 years old,which the body length was 454.19 mm and the body weight was 1871.34 g.The results showed that the miniaturization of Dusky Labiaet-barbel was very serious,and the amount of its resources has decreased sharply.In 2018,a total of 2100 Dusky Labiaet-barbel were introduced for domestication and breeding.The number of domesticated Dusky Labiaet-barbel was 1800 in the base of Zhujiang Source Company.The feeding activity was high and the mortality rate was low(after 3 months of domestication,only 16 Dusky Labiaet-barbel died in total).In Huishui base of Huizhong Company,300 Dusky Labiaet-barbel were domesticated in the sturgeon pool,and no dead individuals were found.Due to the deep water in the pond,it is difficult to observe the feeding activities of these Dusky Labiaet-barbel.