A.K.M. Sayduzzaman
Department of Aquaculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
M.R. Hasan
Department of Aquaculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
M. Das
Department of Aquaculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
Carps, Catch per unit effort, Macrophytes, Oxbow lake
Moheshpur thana, Jhenaidah District
Resource Development and Management
The study was conducted in Nasti baor. The baor is situated in Moheshpur thana of Jhenaidah District. The total area of the baor is 66 ha. The average depth of the baor is 2.64 m during winter and 4.32 m during monsoon. The study was conducted from August to December'95. Data for water quality parameters - Water quality parameters (temperature, Secchi depth, water colour, water depth, pH, TDS and conductivity) were recorded once a week at three selected sample sites. Water temperature were taken by holding a thermometer under water for 3 minutes to the nearest 0C. Representative water sample was collected by bottom water sampler for the estimation of bottom water temperature. The bottom water sampler was hand made by the authors. The sampler was nothing but a bottle with a cork connected to each other by ropes. The operational technique was very simple. The bottle, shut down with the cork, was dipped under water (with the help of a weight) and loosen the cork with a sudden and forceful pull. The bottle was then filled with bottom water and then pulled out of water quickly. Secchi depth was measured by lowering the Secchi disk into undisturbed water until it disappears and was recorded to nearest em. Water colour was also recorded as clear, brown, green etc. as was seen by the naked eye. Water depth was measured with the help of a graduated bamboo pole adjacent to fish landing complex in em. pH, TDS (Total dissolved solids) and conductivity were measured by pH meter, TDS and conductivity meter (M-90 CIBA CORNING, UK) respectively.Data on macrophyte - By dipping a wooden quadrant (0.25 sqm) at random in aquatic vegetation area a minimum of six samples were collected and lifting all plant within the quadrant were weighed on a spring balance (SALTER 235 65, UK) after species-wise sorting of macrophytes. Data were taken for the period from September to November'95. Stocking and harvesting data - Stocking and harvesting data of three Indian major carps: rohu Labeo rohita, catla Catla catla and mrigal Cirrhinus mrigala and three exotic carps: silver carp Hypophthalmichthys molitrix, grass carp Ctenopharyngodon idella and common carp Cyprinus carpio were collected from Baor Record Book prior to the start of the research project for the analysis of stocking and harvesting data of the period of 15 months. Stocking data were recorded for the period from July'94 to September'95 and harvesting data for the period from October'94 to December'95. The stocking data from July to September'95 and the harvesting data during November and December'95 were collected during the present study. Data recorded for stocking analysis were: total weight (kg), total number, no/kg, size range and weight range, mean size and mean weight. Lenght-weight data - A total 2196 fishes of different species were collected randomly from the catches of fishermen, of which 248 were ruhu, 386 were catla, 243 were mrigal, 1013 were silver carp, 56 were grass carp and 252 were common carp. The total length in nearest em and weight in nearest gram of individual fish of each species were measured by using a scale and spring balance (SALTER 235 65, UK) respectively. Total length was measured from the tip of the snout to the end of caudal fin squeezed together. Catch per unit effort data - The catch per unit effort (CPUE) data of six species were collected during fishing time from November and December'95. The data recorded for the calculation of CPUE were type of fishing gear, number of gear used during each fishing, number and weight of total fish harvested in each fishing, number and weight of individual fish species harvested in each fishing, number of fishermen attended in each fishing, time interval between shooting and hauling of each gear, number of shooting in each fishing and number of hours of fishing. Gear inventory for kotchal (purse seine) fishing was carried out by collecting information on no. of gear, manpower, length and width of the gear, stretched mesh size of the gear, diameter of upper and lower rope, number of float used, boat particulars (such as, size, number etc.) Kothcal jal (a seine net), the length of which varied from 64.4-331.2 m, width from 4.6-165.5 m and mesh size varied from 30-120 mm, were used for fishing.
Bangladesh J. Fish. Res., 3(2): 113-122, 1999
Journal