Tropical hilsa shad, which is an anadromous fish migrating from the sea to spawn in freshwater river, constitutes an important fishery in some Asian and Middle East countries, particularly in Bangladesh. But, historical information on hilsa biology and ecology has confronted the scientists and policymakers with research and management challenges. We have reviewed both the old and recent findings on hilsa fishery to document the status of knowledge and potential gaps, necessary to comprehend for formulating a more effective fishery management plan. Thus, there has been a decline in hilsa catches in the riverine system associated with shift in fish migration routes, indiscriminate harvesting of brood and juvenile fish, and degradation of habitat. Specifically, the riverine hilsa catches peaked in the 1960s, declining thereafter, and became relatively abundant in marine waters since 1990s. Biological data indicated that hilsa goes through multiple reproductive cycles; therefore, a comprehensive understanding of reproductive biology, recruitment by various cohorts, stock abundance and habitats across the life cycle are necessary to accurately impose fishery regulatory measures, such as fishing ban in spawning season in Bangladesh. Moreover, domestication initiative is important for artificial seed production and mariculture development of hilsa that can not only offer economic return to small‐scale farmers but also reduce the growing pressure on capture fishery. Importantly, the arrangement of co‐management is found ideal as fishermen, scientists and managers can work jointly to improve the regulatory processes and to sustain the hilsa fishery over time.

not available DOI: http://dx.doi.org/10.3329/jbs.v21i0.22528 J. bio-sci. 21: 141-144, 2013

The predators of hilsa shad (Tenualosa ilisha) in the marine and riverine ecosystems of Bangladesh were identified. Data on the availability of hilsa shad in the stomach contents of top carnivore fishes were collected from 324 individuals with diversified occupations and hilsa-dominated geographical locations. Data analysis revealed that 15 predatory fishes preyed on hilsa, of which tuna, mackerel, shark, Indian threadfin, red snapper and fourfinger threadfin are dominant predators of adult hilsa in the Bay of Bengal, while freshwater shark, giant catfish, river catfish, humped featherback, stripped snakehead and giant snakehead are the main predators of juvenile hilsa in the Padma-Meghna river systems of Bangladesh. Further research leading to predation observations in controlled experiments can provide novel and robust information on predator-prey interactions in the context of ecosystem-based fisheries management and conservation initiatives.

Context: Alpha-tocopherol has significant effect on the growth performance and fillet proximate composition of Striped Catfish (Pangasius hypophthalmus). Objectives:To study the effect of DL-alpha tocopheryl acetate on the fillet proximate composition (moisture, crude protein, crude lipid, ash and alpha-tocopherol), survival rate and growth performance (SGR, weight gain, PWG) of P. hypophthalmus. Materials and methods:Striped Catfish were fed with three trial diets (diet-1, diet-2 and diet-3) were prepared by adding different amounts of alpha-tocopheryl acetate (ATA, 0, 90 and 300 mgKg -1 diet), over a period of 122 days. In each pond, 10% of the total fish were randomly selected and individually weighed once every fortnight and growth parameters were determined after each weighing. Moisture, dry matter, crude protein, lipid, ash and alpha-tocopherol of the experimental diets and fish fillet were determined by Conventional procedure, standard test method, micro-kjeldahl method, Bligh and Dyer method, standard methods and chromatographic method, respectively. Results:Fish that were fed 90 mg kg-1 and 300 mg kg -1 ATA supplemented diets had significantly higher growth performance than fish that were fed only farm processed diet (P<0.05). The fillet protein, lipid content and alpha tocopherol level of the fish flesh were increased due to ATA supplementation in diets. The vitamin-E levels in fish fillet reflected dietary ATA levels. These results showed that fish on Diets 2 (supplemented with 90 mgKg -1 ATA) and Diet 3(supplemented with 300 mg kg -1 ATA) had significantly better production and resulted better flesh quality of fish than those on Diet 1 (without ATA supplementation). Conclusion:Scanty information is available on the fillet proximate composition and growth performance of P. hypophthalmus fed with diets containing different amounts of alpha-tocopherol. The present study provides baseline information for establishing improved and profitable cultured system of the fish in impounds water of Bangladesh.