On-board Breeding Trial of Hilsa (Tenualosa ilisha, Ham. 1822) and Testing of Larval Rearing in Bangladesh

Abstract

The Hilsa shad, Tenualosa ilisha commonly known as Hilsa is one of the most commercially important fish species in South Asian countries. For the conservation of Hilsa it is necessary to establish a standard breeding and culture protocol along with the present Hilsa management activities. The on board breeding trial was conducted during 10 October 2016 to 02 November 2016 which was the peak breeding time of Hilsa for the year 2016. The male and female Hilsa broods were collected from the River Meghna using BFRI experimental net during afternoon and late evening of full moon and new moon time. A total of six breeding trials were conducted in which 13 pairs of selected Hilsa broods were used for the breeding trials. For the breeding trial, both eggs and milt were collected through stripping and then the eggs were mixed with the milt immediately. The fertilized eggs were transferred to a plastic hatching jar for incubation providing mild water circulation, aeration and shade to protect penetration of direct sunlight for controlling temperature i.e., to maintain congenial environment. During the incubation period, the eggs were observed for 24 hrs to study the embryonic and larval development stages of Hilsa. After 4.2-4.5 hrs of fertilization morula stage of embryonic development was identified and after 8-8.5 hrs. of fertilization 18-myotome stage of embryonic development was identified from the sixth breeding trial. After that, no embryonic development of egg was observed up to 12 hrs after fertilization and the fertilized eggs were found to be dead filled with fungus at the end. The water quality parameters were found in good range during the breeding trial though the temperature was found to be fluctuated from the optimum ranges needed for the incubation of fertilized eggs. Although it was not possible to be succeeded completely in artificial breeding of Hilsa, the experience of on board breeding trial in the major breeding ground of River Meghna will give the necessary insight for future works.