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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

A study was carried out to assess the ecological aspects of Balla beel ecosystem in Moulavibazar district and the affectivity of the ongoing biodiversity restoration program from July 2011 to June 2012. Seventy-four fish species belonging to 21 families were identified during the study period. About nine types of fishing methods and one type of fish aggregating device were identified in the surveyed beel. Increasing pressure of illegal current jal (gill net), ber jal (seine net) and FAD (Fish Aggregating Device) was detected as the reduction of almost all type of species. About 24 aquatic weeds were found in the Balla beel, among them both emergent and spreading were 29%, followed by floating 21%, 13% were rooted plants with floating leaves and 8% were submerged. The dissolved oxygen content 5.22±1.60 mg/l inside and 5.70±1.38 mg/l outside of the Balla beel sanctuary were found to be congenial for aquatic life. pH of the beel water both inside and outside of the sanctuary were slightly acidic to moderately alkaline (7.0±0.68 inside and 6.88±0.43 outside the sanctuary). Lower values of alkalinity and hardness indicating beel water to be less nutrient enriched. The contribution of phytoplankton (79%) was larger than zooplankton (21%). The diversity of phytoplankton both inside and outside of the sanctuary was dominated by three group Chlorophyceae, Myxophyceae and Bacillariophyceae.Asian J. Med. Biol. Res. June 2015, 1(2): 198-208

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