Abstract
The present study was conducted to assess the impact of fifteen days fishing ban on breeding success of hilsa shad in the major spawning grounds of hilsa in the month of September and October, 2015. The study showed that fishing ban during spawning seasons have significant role in the successful reproduction of hilsa. In and around the spawning grounds among all the captured hilsa, male: female ratio was found 1: 1.86 and percent composition was 35% and 65% respectively. In 2015, percent composition of spent hilsa during major breeding period in the spawning grounds was found 36.60%. The eggs production of hilsa was calculated, in the year 2010, 2011, 2012, 2013, 2014 and 2015 about 336199Kg, 385500Kg, 380400Kg, 447100Kg, 417765Kg and 494365Kg respectively, hilsa eggs could have been produced indicating a positive impact of 15 days fishing ban in the spawning season. Comparatively higher percentages of gravid hilsa were found which were not available in the similar quantity and condition in the fishing ban period in other than spawning areas of hilsa. During the present investigation, fairly higher amount of spent hilsa and juveniles were observed in the spawning grounds. On the other hand, fewer juveniles and spent hilsa were observed in the adjacent areas of the spawning grounds indicating that in comparison to the recent reports there might have little or no changes of the spawning grounds of hilsa occurred. Along with the jatka fry, spawn and fries of other fishes were also found in higher quantity than the previous years and thus it is assumed that 15 days fishing ban also might have positive impact on the successful breeding of other fishes. Overall, the fishing ban was found effective for successful breeding of hilsa.Res. Agric., Livest. Fish.2(3): 491-497, December 2015
Highlights
The hilsa shad, commonly known as Hilsa (Tenualosa ilisha, Hamilton 1822) referred in the literature as an anadromous Clupeid of the Bay of Bengal and Indian Ocean, established as a diadromous ascends in the rivers flowing into the Bay of Bengal, Arabian Sea and Persian Gulf
Sex and percent composition of berried hilsa During the river cruise gradually larger sized hilsa were found from Chandpur to the downstream
Most of the hilsa found were below 35 cm, whereas, more than 85% hilsa were above 35 cm in the downstream areas
Summary
The hilsa shad, commonly known as Hilsa (Tenualosa ilisha, Hamilton 1822) referred in the literature as an anadromous (earlier) Clupeid of the Bay of Bengal and Indian Ocean, established as a diadromous ascends in the rivers flowing into the Bay of Bengal, Arabian Sea and Persian Gulf. Tenualosa ilisha (Fisher and Bianchi, 1984) is the most widespread tropical shads found from north Sumatra in the east to Kuwait in the west and is the basis of important fisheries in Bangladesh, India, Burma, Pakistan and Kuwait (Al-baz and Grove, 1995; Whitehead, 1985; Blaber, 2000) It is the national fish of Bangladesh and the largest single species fishery contributing 75% of total catch in this region (Raja, 1985) that accounts nearly half of the total marine catch and about 12-13% of total fish production of the country (Haldar, 2008)
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