Bishawnath Sarker
Department of Aquaculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
M. Ahsan
Department of Aquaculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
B. Habib
Department of Aquaculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
Fish, Lake, Dikes, Community participation
Basurhat, Noakhali.
Socio-economic and Policy
Adoption of technology
To manage properly and to facilitate under controlled condition, the 70 acres water area (Elahi Aquaculture Farm) was artitioned by dikes into 24 ponds of which five were nursery, ten for rearing ponds and six for stocking ponds. The area of ponds were varied from 1.0 to 8.0 acres. The entire aquaculture farm was divided into Block A, Band C for proper management with supervisor and labourers. Rest of the 30 acres land were used for crop production. There was a small dairy farm inside the complex where about 60 cows are farmed and resulted cow dung was used as organic fertilizer in the ponds and crop field. A community with 40 local people was formed to produce fish through modern aquaculture practice with the technical help of Agro-Based Industries and Technology Development Project II (ATDP-II), Dhaka. The Elahi Aquaculture Complex was found very suitable for fish culture and overall culture and production system were monitored and analysed in the laboratory of Department of Aquaculture, Bangladesh Agricultural University, Mymensingh, Bangladesh. Hand on training: The supervisors, skilled labourers and labourers were trained for different aspects of fish culture management. They were trained how to measure temperature, transparency (secchi reading), pH, dissolved oxygen, to observe plankton growth, to grow plankton in ponds as live food for fishes, fry weighing, to minimize oxygen deficiency, use of decomposed cow dung etc. A list of optimum ranges of different physico-chemical characteristics were supplied with tolerable and toxic levels so that the farm people could understand the quality of water. Preparation of stocking ponds: Ponds were prepared with lime after drying. In respect to pH of pond bottom soil, it was suggested to apply 500g lime/dec .However, according to the content of organic carbon and total N, 2kg/dec. cow dung and 1.5 kg/33 dec. urea were used in bottom soil and advised to use this. doses fornightly during whole culture period. Then all the stocking ponds were filled with underground water. P:K at the ratio of 1.5: 0.75 kg/33 dec. were administrated monthly. Depending on water quality then N:P:K was administrated weekly at the ratio of 3.0:1.50:0.75. Physico-chemical properties analyses of pond water and bottom soil: Water and soil samples were collected from ponds for analyses. Different physicochemical properties of water were analysed following the standard methods. For convenience, samples were collected from nine locations of three blocks of the farm. The physico-chemical properties of water samples were analysed in site. On the other hand, soil samples were carried to the laboratory for process before analyses of chemical properties. Water colour of ponds was recorded by eye estimation. Temperature of pond water was determined by centigrade thermometer. Turbidity (Transparency) was measured by turbidity meter. pH of water was measured by a digital pH meter (HANNA instruments, Model: HI 8314). Electric conductivity of water was analysed by conductivity meter after some chemical treatment. Dissolved oxygen was measured by digital oxygen meter (HANNA Instruments Model: HI-9142). Alkalinity of water was estimated using alkalinity meter after chemical treatment. Nitrate-N (ppm) was determined after filtering 100 ml water through glass microfilter paper using Nitrogen-5 powder pillow and then direct reading using Spectrophotometer, DR 2010. Similarly Phosphate-P (ppm) was determined from filtered water using reagent pillow Phosver-3 and then direct reading using Spectrophotometer, DR 2010. Collection and identification of plankton For collection of plankton, 10 litres of water from each location of farm was filtered through consecutive three nets of different mesh sizes (1 0, 30 and 120 m). The collected plankton samples were preserved in 6% buffered formalin. These samples identified using Sedwich Rafter Counting Chamber under microscope. Fifty ml of pond water was filtered through 0.45 p,m mesh and the filter paper was mashed with 10 ml acetone in 25 ml plastic tube. The tube was wrapped with aluminium foil and brought to the laboratory and kept in the refrigerator. It was then centrifused at 5000 rpm for five minutes. The supernatant was taken in cuvette and readings at three different wavelengths were taken in spectrophotometer. Then chlorophyll.a was estimated. Chemical analyses of bottom soil of ponds: Pond bottom soil from nine location of whole site was collected. Texture of bottom soil was determined after treatment dry soil with 5% calgon solution using hydrometer. pH was measured by a digital pH meter (HANNA instruments, Model: HI 8314). Organic carbon was calculated following wet oxidation method. Total N was analysed by Microkjeldahl method. Phosphate-P was determined from filtered water using reagent pillow Phosver-3 and then direct reading using Spectrophotometer, DR 2010. Collection and analysis of artificial feed: Commercial feed was analysed for proximate composition such as moisture, crude protein, crude lipids, crude fibre and nitrogen free extract in the laboratory. Release of fry in ponds The spawn was collected from the local hatchery and released in nursery ponds. The nursery reared fish fry (3-8 mg/fish) of Thai Pangus (Pangasius hypophthalmus) @ 20,000/acre, and then fry and fingerlings @ 500/acre of different types of fishes such as catla (Catla catla), rohu (Labeo rohita), mrigal (Cirrhina mrigala), grass carp (Ctenophmyngodon idella), bighead (Aristichthys nobilis), silver carp (Hypophthalmichthys molitrix), common carp (Cyprinus carpio) and rajpunti (Puntius gonionatus) were stocked on the middle of May 2006. Artificial feed was used twice daily in these ponds.
Bangladesh J. Fish. Res., 13(1), 2009: 19-26
Journal