Impact Assessment of Twenty-Two Days Fishing Ban in the Major Spawning Grounds of Tenualosa ilisha (Hamilton, 1822) on its Spawning Success in Bangladesh

Abstract

This study was conducted to evaluate the impact of twenty-two days fishing ban from October 22-November 02, 2016 on the spawning success of Hilsa in the major spawning grounds of Hilsa. Fishing ban during the spawning season have substantial role in the successful reproduction of Hilsa found from the present study. Among all the Hilsa captured in and around the spawning grounds of Hilsa, male and female were estimated to make up 34% and 64% respectively of the total catch, suggesting a male to female sex ratio of about 1:1.94. In the year 2016 during the major spawning period in the major spawning grounds 43.93% spent Hilsa was found and calculated egg production was 628291 kg and the estimated Jatka production was 39,268 crore which were found to be much higher than the previous years. Increased production of Hilsa eggs and Jatka indicates a positive impact of twenty-two days fishing ban in the spawning season. Percentages of gravid and oozing Hilsa were also found higher compared to previous fishing ban periods. In the spawning grounds, relatively higher amount of spent Hilsa and Jatka were observed whereas fewer spent Hilsa and Jatka were found in the adjacent areas of spawning grounds. Besides Jatka, spawn and fries of other fish species were also found in higher quantity in and around the spawning areas of Hilsa than previous years which indicates fishing ban might have positive impacts on successful breeding and maintenance of biodiversity of other fish species. Overall, twenty-two days fishing ban was found to be very effective for successful spawning of Hilsa.