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The present study was conducted in the southwest part of Bangladesh from 2008 to 2009 in order to assess of mud crab fattening practice and its production performance between two different seasons. Generally two crab fattening seasons are observed in Bangladesh, one is the dry or peak season (October to May) and another one is lean season or wet season (June to September). Significant variation in stocking density was observed between two seasons during the study period. Comparatively higher stocking density and higher production was found in dry season in comparison to wet season. The reasons behind higher production and production rate were; the availability of the crabs and high market price for the crabs during dry season. On the other hand, rain fall, occurrence of diseases and natural disaster might be the cause of lower production of crab during wet season. Crab farming and fishery could play a sustainable alternative employment opportunity for the development of coastal people. So government should take some necessary steps for the development of this fishery.Res. Agric., Livest. Fish.2(1): 135-141, April 2015

Ichthyofauna diversity acts as a bio-indicator and is playing a significant role in the sustainability of an aquatic environment. The present study explores the ichthyofauna assemblage in one of the largest wetlands of Bangladesh known as Asura beel located in Dinajpur district. Fortnightly fish samplings were done from November 2017 to October 2018 considering three seasons as winter,summer, and rainy. Fish biodiversity was assessed with their threatened status and analyzed seasonal abundance with the diversity indices. Findings revealed a total of 35 identified species of fish belonging to 7 orders, 17 families, and 26 genera. According to IUCN- Bangladesh 2015, the current research recorded 6 fish species as vulnerable (17%). While only 1 species is data deficient (3%), 6 species are endangered (17%), and the other 22 species are not threatened (63%). Among the fish species, Amblypharyngodon mola of Cypriniformes order contributed the highest abundance (12%). On the contrary, Ostreobrama cotio and Macrognathus armatus both represented the lowest abundance by contributing 0.35%. The survey also reported that the seasonal diversity indices and richness values did not vary significantly according to seasons although the number of catches was found higher in the winter season followedby summer and rainy seasons.

The study was conducted to assess the cost and return from tilapia farming. Fifty homestead aquaculture ponds practicing monoculture and polyculture of tilapia (25 farmers from each category) were selected for this study. Data had been collected through face to face interview by using a structured questionnaire during April to September 2015 from the selected farmers of Dinajpur districts. The results from the survey revealed that both the tilapia monoculture and polyculture farming were profitable. However, the average total cost per hectare per production period was found higher (Tk. 332,712.08) in tilapia monoculture than tilapia culture with carps (Tk. 241,722.34). Moreover, the net margin was also found higher in tilapia monoculture with benefit cost ratio 1.51. Whereas, the benefit cost ratio in polyculture farming was 1.34. J. Bangladesh Agril. Univ. 17(1): 117–121, March 2019

An investigation was carried out on the limnological aspects of Ashura beel at Dinajpur district in Bangladesh. Several limnological parameters were evaluated from March 2013 to October 2013 from three sampling sites namely Kajladoho, Burirdoho and Sonnasydoho. Physical, chemical and biological parameters were analyzed fortnightly both at the field level and departmental laboratory of Fisheries Management, Hajee Mohammad Danesh Science and Technology University, Dinajpur. Findings revealed that only water level in three sampling sites varied significantly. The ranges of water temperature, transparency, water level at three sampling sites were 24 to 35.50°C, 17 to 27.50 cm and 0.58 to 2.44 m, respectively. Moreover, the dissolved oxygen concentration, pH, total alkalinity, total hardness and phosphate-phosphorus concentration were also remained within optimum ranges. Thirty four genera were recorded where phytoplankton includes 29 genera belonging to four groups such as euglenophyceae, cyanophyceae, bacillariophyceae and chlorophyceae and five genera of zooplankton in the four groups namely copepoda, rotifera, cladocera and crustacean larvae. Phytoplankton was dominated by chlorophyceae and zooplankton dominated by copepoda. The abundance of phytoplankton was positively correlated with water temperature, water level, dissolved oxygen, alkalinity, hardness, pH, and phosphate-phosphorus. On the other hand, abundance of zooplankton negatively correlated with water temperature, transparency and water level. However, from the findings of this study suggested that the water quality parameters of the selected sites were found to be suitable for the survival of aquatic organism.

Abstract:Among different water quality parameters dissolved oxygen, transparency, pH, PO 4 -P and depth varied significantly among the sampling sites. The pH value in the present investigation remained a buffer condition (6.50-7.90). Dissolved oxygen was ranges from 3.80 to 11.60 mg/l throughout the study periods. PO 4 -P concentration was observed highest (0.30 mg/l) in sampling site 2. On the basis of physical, chemical aspects sampling site 3 and sampling site 5 (situated in gosaipur and chandandoho) found in better condition in terms of limnological aspects. However, it could be concluded that Dhepa River will play important role in riverine fisheries and for further fisheries management.

Abstract:The study was conducted to assess the socio-economic condition of the crab fatteners in the southwest part of Bangladesh. About 52% farmers have an experience of 5 to 10 years of indicating that involvement in mud crab fattening is the recent development and innovation in those areas. The Hindus in the coastal region found to have more interest in crab farming. On the other hand, about 27% Muslim were also found to involve in this farming. Comparatively higher involvements of Hindus farmers were found in Khulna region. Mostly young people found to have more involvement ranging from 26 to 35 years old which constituted more than 38% of the total interviewed population. About 40% farmers showed higher satisfaction by crab fattening while, few farmers reported some negative perception. Most of their farming were small scale and the farmers also accounted the higher seed cost with low profitability. However, well developed co-operation and partnership between farmers, fishermen, middlemen and wholesaler can also improve this sector for sustainable development.

Limnological aspects of the Ramsagar lake, a manmade lake of Dinajpur district was studied from January 2013 to August 2013. In this experiment, five sampling points inside the Ramsagar lake were selected and water quality parameters were analyzed fortnightly. Among different physico-chemical parameters, water temperature, dissolved oxygen, total alkalinity, total hardness, phosphate-phosphorus and concentration of Chlorophyll-a did not differ significantly except the water level and pH. A total of 29 species of plankton were recorded where phytoplankton comprised of 21 species and zooplankton comprised of 8 species. Chlorophyceae was found dominant throughout the study period followed by Bacillariophyceae, Cyanophyceae and Euglenophyceae. The highest plankton cell density was observed in the month of July and lowest plankton density was observed during the month of January. The study revealed that on the basis of physical, chemical, biological and environmental conditions the water of the lake was found to be suitable for survival of aquatic flora and fauna and also suitable for fish culture.