AN ATTEMPT TO DOMESTICATE THE WILD THREATENED FISH Cirrhinus reba (HAMILTON-1822) IN CAPTIVITY AND DOSAGE OPTIMIZATION FOR INDUCED BREEDING

Abstract

The reba carp, Cirrhinus reba locally known as Khorkia or Bhagna/Tatkini belongs to the cyprinidae family. Recently the fish is considered as “Near Threatened” categories by IUCN- Bangladesh. By considering its threatened situation and aquaculture potentialities, initiatives were taken to domesticate the wild stock in captivity, and induced breeding through hypophysation. Live C. reba were collected from three rivers of Dinajpur district and reared in two different ponds of Freshwater Sub-station, Bangladesh Fisheries Research Institute (BFRI), Saidpur and in the pond of Hajee Mohammad Danesh Science and Technology University (HSTU) campus. In all the ponds, locally available commercial fish feed having 20% proteins were provided in every pond at 5-6% body weight of fish at 9.00 am and 5.00 pm was provided. Along with the length and weight data, the water quality parameters such as pH, DO, temperature etc. were recorded during domestication of the fish. The growth of C. reba in captivity was compared with the wild stocks through a length-weight relationships analysis by including a total of 120 C. reba individuals, among them 60 were wild and 60 were pond rearing. Subsequently three treatments having different dosages of carp pituitary gland extract, flash and ovatide were used for induced breeding of C. reba. In each breeding trial 12 males and 6 females were used. The result of domestication of C. reba in captive condition showed moderate growth and survival rate. The comparison of length-weight relationship between domesticated and wild stocks of C. reba showed allometirc growth pattern. The ‘b’ value for C. reba also was 3.17 and 2.738 for wild and domesticated fish respectively. The coefficient of determination (R2 ) was 0.96 for wild and 0.91 for wild and domesticated fish respectively. The fish ovulated with the hormonal injection of pituitary gland extracts only and did not respond to flash and ovatide. The ovulation, fertilization and hatching rate were found 78%, 34.22% and 45.12% in the initial study. The results of this study showed the potential of seeds production of this fish through hypophysation. Further details study is highly recommend for producing the seed in large scale. The seed production could be the effective means of revival from the being extinction by restoration as well as incorporation of this species in aquaculture of Bangladesh.