No abstract

The experiment was conducted to evaluate the production performance of freshwater mud eel (Monopterus cuchia) with supplementary feed for a period of 5 months in field level. Two ponds were selected for this experiment in Maulovibazar district. Baby cuchia having weight of 50-70 g were stocked in ponds at a stocking density of 10/m2 in filter net. Liming (CaO) was done in all the ponds at rate of 250 kg/ha. A safety shelter for cuchia was developed by installing bamboo root, plastic and bamboo-made hollow pipe, aquatic vegetation and necessary objects in the pond. Different physico-chemical parameters were found to be within the acceptable ranges for M. cuchia culture in all ponds. Supplementary feed composed of fish paste (50%), fish meal (40%), rice bran (5%) and wheat flour (5%) was applied at the rate of 2-3% of body weight. After 5 months of rearing, total production obtained were 28.3±1.09 and 31.9±2.56 kg from pond-1 and pond-2, respectively. The highest production was obtained from pond-2 and lowest production was obtained in pond-1. The net profit gained from pond-1 and pond-2 were tk 2559 and 3211 per decimal, respectively.

The study was carried out infourselected farmer’s pond in Netrokona sadarand Barhatta upazillas(sub district) under Netrokona district during April to September 2019 having average pond area of 0.14 haeach. The ponds were prepared by removing aquatic vegetation and unwanted fish and other animals, andapplying with lime at the rate of 250 kg/ha. Five days after liming, water was supplied from shallow tubewell to the ponds and filled up to the depth of 1.5 m. The fry of Pabda (Ompok pabda) and Gulsha (Mystuscavasius) with Rohu (Labeo rohita) were stocked at the rate of 175000; 87,500 and 2000/ha, respectively.After stocking, fish were fed at a rate of 5-12% of body weight with supplementary feed (30% crudeprotein). Fish sampling were done at monthly interval to know the fish growth status and also to adjust feedration. After six months rearing, fish were harvested by repeated seine netting. Total bulk weight and numberof fish from each pond was recorded. Survival and gross production of fish of each pond were estimated. Theharvesting weight of pabda ranged from 33 to 36g. While the harvesting weight of Gulsha and Rohu rangedfrom 26-27g and 591-614g, respectively. Based on the number of fish harvested at the end of the experiment,survival ranged from 75 to 88%.Total production of Pabda (O. pabda) and Gulsha (M. cavasius) with Rohuwas estimated at 5202, 1772 and 1066 kg/ha, respectively. The total production of fish as recorded in trialponds were 8043 kg/ha

Quality diet as food for raising freshwater snails under laboratory conditions has a significant effect on their growth and the number of egg clutches laid as well as on the size of the snail. Now a days, some innovative farmers of Bangladesh started snail culture within their fish farms in the view of producing snail to use as feed for their Prawn (Macrobrachiam rosenbergii), indigenous catfish (Clarius batrachus) farms, domestic duck farms and also as a protein supplement for preparing fish feed. From previous study we know that Bulinus nyassanus growth and survive rate was found well on locally formulated fish diet consisting of 30% crude protein with ingredients comprising fish meal, maize bran, rice bran, soya bean, wheat bran, hemicellulose (binder), vitamin premix and mineral premix.  But no such research has been done in case of apple snail. The present study was aimed to investigate the feed formulation preferred by Pila globosa species and their effects on survival and growth of these snails in laboratory condition. Three type of formulated feed viz., pellet feed, fish meal and 50% fish meal + 50% crusted khudipana were used for the experiment in high and low stocking density of baby snails. The present findings shown that the diets in order of preference based on their effects on growth and survival of snails were formulated pellet feed, fish meal and 50% fish meal+ 50% crushed khudipana. After rearing of 28 days, highest growth found 0.32g with 86.66% survival with formulated diet in 60nos/L stocking density and 0.35g with 90% survival with formulated diet in 30nos/L stocking density. It`s indicate that the snails reared on formulated pellet feed diets and lower stocking density gave better performance in terms of survival and mean growth rate than those reared on other diets.

The effect of peripheral canal on growth, survival and production of shrimp (Penaeus monodon) has been assessed. The depth of peripheral canal was varied as 0.7 m (T1) and 0.9 (T2), while the width of canal kept similar (1.5 m) in all the treatments. There was also a set of experimental plots without peripheral canal (T3). Each treatment had two replications. The experiment was designed for a culture period of 120 days with the stocking density of 3PL/m 2 . Results on growth, survival and production performance revealed no significant difference (p>0.05) among the treatments, but apparently higher body weight gain (23.42±0.735g), survival rate (31.90±14.959%) and production (225.79±112.140kg/ha) were obtained from T2 (peripheral canal of 1.5 m x 0.9 m). In case of survival rate and production, greater deviations were found in all the treatments that indicated differences among the replicated plots in each treatment. The plot under T2 provided highest production of 305.05 kg/ha of shrimp with the highest survival rate of 42.48%. It has been an indication of combined effect of depth and canal on the production. Though direct effect of peripheral canal on production was not observed, but strong correlation between water depth on platform area with production (r=0.935); survival rate (r=0.923) and weight gain (r=0.912) was ascertained.