Impact of fifteen days fishing ban in the major spawning grounds of hilsa (Tenualosa ilisha Hamilton 1822) on its spawning success

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

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

“…Similar findings were observed by Rahman, et al [3]. Higher percentage of Hilsa with length group greater than 35 cm was observed in the downstream areas of Monpura and Hatia which is supported by Rahman, et al [4]. Almost all the larger Hilsa found in the downstream areas were matured gravid Hilsa.…”

“…Most of the Hilsa were found at MS IV, MS V &MS VI where MS V means before spawning and MS VI means oozing Hilsa from which eggs or milt runs out at catch with higher length group (Figure 8, Table 6). The percent of Hilsa was 81.76% at MS V with length group 46 cm-50 cm indicates that most of the larger Hilsa were gravid in the major spawning ground which is very similar to Rahman, et al [9]. Due to the imposition of fishing ban the increased availability of matured gravid Hilsa were found in the spawning ground.…”

Impact of fifteen days fishing ban in the major spawning grounds of hilsa (Tenualosa ilisha Hamilton 1822) on its spawning success

“…The potbellied, reddish and bigger anus also identified the fishes as female. As such, the percent composition of gravid and oozing hilsa was determined (Rahman et al, 2013). The spent fishes were identified by observing their very lean and thin and elongated body and health condition and shrunken belly.…”

Gill Net Selectivity of Hilsa (Tenualosa ilisha) in Meghna River Estuary of Bangladesh

“…The length rage found from the present study was 314.69 mm to 342.02 mm is within the range of above mentioned length range. Moreover fish at 30 cm to 35 cm length range are being caught enormously by the fisherman in Bangladesh [6,[17][18][19][20][21]. On the other hand Hilsa above 35 cm length size are found in lesser amount day by day in the commercial catches.…”

“…Increasing population, protein demand, temptation of huge income makes an overfishing of Jatka and adults in the gill net fishery [4][5][6].…”