Culture potentials of bata, Labeo bata under semi-intensive management system

Small indigenous fish species (SIS) provide food, nutrition, subsistence and supplemental income to a great majority of the people particularly the poor and disadvantaged people of Bangladesh. To date nobody explored the possibilities of culturing these species in combination with the indigenous major carps viz. catla, Catla catla; rohu, Labeo rohita, and mrigal Cirrhinus cirrhosus and grass carp, Ctenopharyngodon idellus. An experiment on the polyculture of carps with a popular SIS, bata (Labeo bata) was carried out to evaluate the production performance of carp-SIS culture in on-farm condition during 15 March to 15 September 2003. Three treatments each having three replications with different stocking densities of bata were tested keeping the carp species combination and stocking density similar in all the treatments viz. treatment 1 (T1), bata (5,000/ha) + catla, rohu and mrigal (5,000/ha at the ratio of 1:1:1) + grass carp (250/ha); treatment 2 (T2), bata (7,500/ha) + catla, rohu and mrigal (5,000/ha at the ratio of 1:1:1) + grass carp (250/ha); and treatment 3 (T3), bata (1 0,000/ha) + catla, rohu and mrigal (5,000/ha at the ratio of 1:1:1) + grass carp (250/ha). After six months rearing, the production obtained were 2,466±77, 2,395±85 and 2,074±72 kg/ha from T1, T2 and T3, respectively. The highest production was obtained from T1, where the stocking density of bata was the minimum (5,000/ha) while the lowest production was obtained from T1 [sic], where the stocking density of bata was maximum (10,000/ha). Significant difference (P<0.05) exists in the production levels as obtained from different treatments. The contribution of bata to total production was 10.31%, 13.96% and 14.38% in case of T1, T2 and T3, respectively.

Culture potentials of climbing perch, Anabas testudineus (Bloch) under different stocking densities at semi-intensive management

Anabas testudineus was cultured at different stocking density for the period of five months from May to September. Three stocking densities such as 50,000 (Treatment-1, T1), 56,250 (Treatment-2, T2) and 62,250/ha (Treatment-3, T3) were tested with three replications. After five months rearing, the mean weights of koi were 46.74±2.59, 40.44±2.98 and 37.27±3.01 in T-1, 2 and 3, respectively. The calculated production of native koi in T1 T2 and T3 were 1,916±314, 1,774.31 ±260 and 1,431 ±297 kg/ha, respectively which were significantly different (p<0.05) from each other.

Seawater irrigation systems for intensive marine shrimp farming in Thailand

The aim of the seawater irrigation system (SIS) is to clean up shrimp pond effluent and provide high quality seawater for shrimp farming. The system has 3 components: water intake; treatment reservoir and discharge system. There are criteria for site selection because shrimp farmers are required to form associations so they can work closely together. The construction site must be on the coastal area outside a mangrove forest and located away from a production agricultural area. All construction sites must have undergone an environmental impact assessment, and should be located on the area listed in Thailand's Coastal Zone Management Plan. Five SIS projects, which cover a culture area of 6,500 ha with 1,300 farmers (families), were completed and operated. The Department of Fisheries has planned for another 28 projects, that will cover almost 44,000 ha of culture area.