Effects of C/N controlled periphyton based organic farming of freshwater prawn on water quality parameters and biotic factors

The effects of C:N controlled periphyton based organic farming of freshwater prawn on water quality parameters and biotic factors were investigated. The experiment had two treatments: T1 and T2 each with three replications. Stocking density was maintained at 20,000 juveniles ha-1. In T1, only commercially available prawn feed was applied and in T2, a locally formulated and prepared feed containing 24% crude protein with C:N ratio close to 20 was used, and maize flour and bamboo side shoots were provided for maintaining C:N ratio 20. Mean values of water quality parameters did not vary significantly (P>0.05) between treatments. Periphytic biomass in terms of dry matter, ash free dry matter (AFDM) and chlorophyll a showed significant difference (P<0.05) among different sampling months. Individual harvesting weight, individual weight gain, specific growth rates, gross and net yields of prawn were significantly higher (P<0.05) in T2 than T1. Therefore, it was concluded that freshwater prawn might consume periphyton biomass in C:N controlled periphyton based organic farming practices resulted a significantly (P<0.05) higher production of freshwater prawn than traditional farming

Pond fish culture and socio-economic status of fish farmers in Parbatipur upazila of Dinajpur district, Bangladesh

This study investigates the socio-economic conditions of the fish farmers and aquaculture status in Parbatipur of Dinajpur district during May to October 2016. Majority of the fish farmers belonged to the age group of 31 to 40 years (44.3%) and represented by 68.6% Muslims. Among them 40% had secondary level of education and most of the families were nuclear (64.3%). Farmers were involved in fish culture as their primary (24%) and secondary occupation (53%). Over 80% of the farmers had electricity facilities and 41% of them received health services from the village doctors. Only 9% of the fish farmers received formal training on fish culture. The average aquaculture pond size was 0.18 ha, where 84% ponds were perennial. The average stocking density was 23208 fingerlings ha–1 whereas organic fertilizer, urea and TSP were applied at 8665.4 kg ha–1 yr–1, 210.1 kg ha–1 yr–1 and 133.5 kg ha–1 yr–1 respectively. Pre and post stocking liming doses were 205.7 kg ha–1 yr–1 and 138.4 kg ha–1 yr–1 respectively. Necessary training facilities with institutional supports, credit facilities and extension services could play an important role in improving the fish production

Study on the Socio-Economic Condition of Fishermen of the Punorvaba River under Sadar Upazila, Dinajpur

The present study was conducted to evaluate livelihood status of fishing community of the Punorvaba River under Dinajpur Sadar Upazila during the period from January to August, 2013. The livelihood status of fishermen were studied in terms of age structure, family size and type, occupation status, educational status, housing condition, drinking water facilities, sanitary facilities, health facilities, credit facilities and monthly income. It was found that most of the fishermen were belonged to the age groups of 36-45 years (40%), represented by 90% Muslim. The family size of fishing community is usually consisted of 5-7 members. Over 45% of the fishermen primarily engaged in fishing. Among them 50% was illiterate and 7% was SSC and above group. About 40% of the fishermen received health service from village doctors, 23% from upazila health complex and remaining 7% got health service from MBBS doctors. Some management strategies such as prohibition of catching brood fish, control of destructive gears, establishments of fish sanctuaries, release of fish fry have been suggested by the fishermen to stop the decreasing trend in the fish catch and to enhance fish production

Effects of C/N controlled periphyton based organic farming of freshwater prawn on water quality parameters and biotic factors

The effects of C:N controlled periphyton based organic farming of freshwater prawn on water quality parameters and biotic factors were investigated. The experiment had two treatments: T1 and T2 each with three replications. Stocking density was maintained at 20,000 juveniles ha-1. In T1, only commercially available prawn feed was applied and in T2, a locally formulated and prepared feed containing 24% crude protein with C:N ratio close to 20 was used, and maize flour and bamboo side shoots were provided for maintaining C:N ratio 20. Mean values of water quality parameters did not vary significantly (P>0.05) between treatments. Periphytic biomass in terms of dry matter, ash free dry matter (AFDM) and chlorophyll a showed significant difference (P<0.05) among different sampling months. Individual harvesting weight, individual weight gain, specific growth rates, gross and net yields of prawn were significantly higher (P<0.05) in T2 than T1. Therefore, it was concluded that freshwater prawn might consume periphyton biomass in C:N controlled periphyton based organic farming practices resulted a significantly (P<0.05) higher production of freshwater prawn than traditional farming

Study on the Socio-Economic Condition of Fishermen of the Punorvaba River under Sadar Upazila, Dinajpur

The present study was conducted to evaluate livelihood status of fishing community of the Punorvaba River under Dinajpur Sadar Upazila during the period from January to August, 2013. The livelihood status of fishermen were studied in terms of age structure, family size and type, occupation status, educational status, housing condition, drinking water facilities, sanitary facilities, health facilities, credit facilities and monthly income. It was found that most of the fishermen were belonged to the age groups of 36-45 years (40%), represented by 90% Muslim. The family size of fishing community is usually consisted of 5-7 members. Over 45% of the fishermen primarily engaged in fishing. Among them 50% was illiterate and 7% was SSC and above group. About 40% of the fishermen received health service from village doctors, 23% from upazila health complex and remaining 7% got health service from MBBS doctors. Some management strategies such as prohibition of catching brood fish, control of destructive gears, establishments of fish sanctuaries, release of fish fry have been suggested by the fishermen to stop the decreasing trend in the fish catch and to enhance fish production

Invasion of African Clarias gariepinus Drives Genetic Erosion of the Indigenous C. batrachus in Bangladesh

The African catfish Clarias gariepinus has been introduced for aquaculture in Bangladesh due to the scarcity of indigenous C. batrachus fingerlings. However, the government of Bangladesh has banned the farming of C. gariepinus due to the carnivorous nature of this species. Recently C. gariepinus has been reported by fish farmers and consumers in Bangladesh, and unplanned hybridization between native and exotic species has been suspected. This study attempts to know the purity of C. batrachus by analyzing mitochondrial genes. Both directly sequenced and retrieved Cytochrome C Oxidase subunit I (COI) and cytochrome b (Cytb) genes from C. gareipinus and C. batrachus were analyzed by MEGA software. The morphologically dissimilar C. batrachus showed the least genetic distance (0.295) from C. gariepinus, which provided evidence of hybridization between the two species. Maximum likelihood (ML) phylogenetic trees showed that C. batrachus from Bangladesh did not cluster with C. batrachus of other countries, instead C. batrachus clustered with the exotic C. gariepinus. The suspected hybrid formed sister taxa with the exotic C. gariepinus. The study corroborates the genetic deterioration of C. batrachus by unplanned hybridization with the invasive C. gariepinus. Unplanned hybridization has deleterious consequences; therefore, immediate action is necessary for aquaculture sustainability and biodiversity conservation in Bangladesh