Culture potentials of mola (Amblypharyngodon mola ), chela (Chela cachius) and punti (Puntius sophore) under monoculture system

To assess the production potentials of small indigenous fish species (SIS) in semi-intensive monoculture system, an experiment was carried out with Amblypharyngadan mala, Chela cachius and Puntius sophore. Three treatments each with three replications were tested with mola, chela and punti individually and the stocking density of each species was 100,000/ha. Organic fertilizer was applied to the ponds at the rate of 1,000 kg/ha at fortnightly and rice bran was supplemented daily at 3% of the total fish biomass. Partial harvesting was made after three months of stocking. Gross production of 805±52.94, 1,120±41.62 and 509±48.81 kg/ha, respectively for mola, chela and punti over a period of six months were obtained. The yield of punti was found to vary significantly (P < 0.05) from that of mola and chela.

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.

Fish-makhana (Euryale salisb) integration: a case study of sustainable aquafarming system in north Bihar

The paper deals with a technique to synchronize two crops, fish and makhana (Euryale ferox Salisb) in a pond. In such eco-friendly integration both crops are mutually benefited. Decomposed plant parts of makhana crop form organic matter that releases nutrients in the water to enhance plankton population. Organic detritus not only acts as food for bottom dwelling fishes (mrigal and common carp) but also provides a suitable substratum for the growth of zooplankton, insect larvae, nematodes and gastropods. Fishes contribute to the control of makhana pests. Their faecal matter acts as organic manure for makhana crop. Plankton population fluctuated between 1260 u/l to 4030 u/l in the control pond and 1630 u/l to 4722 u/l in the experimental pond. During the grand growth period of makhana crop (April to July) the dissolved oxygen content fluctuated between 5.02 mg/l to 6.68 mg/l in the covered areas and 6.04 mg/l to 6.92 mg/l in uncovered areas. Makhana leaves acting as blanket barrier over the water surface brought down the D.O. content in the covered areas of the pond. Free CO sub(2) content showed wider fluctuation in the experimental pond (25.2 mg/l to 30.9 mg/l) than in the control pond (25.1 mg/l to 28.6 mg/l). This could be due to decomposition of plant parts of the presiding crop lying as debris at the pond bottom. Autochthonous supply of nutrients enhanced the content of nitrogen, phosphorous and organic carbon in the soil of experimental pond. The experimental pond covering an area of 0.40 ha yielded 852 kg fish and 200 kg pops whereas the control pond covering the same area produced 777 kg fish only. The net profit per ha came out to be Rs.1,04,700 and Rs. 66,200 in integrated and non-integrated system respectively. Owing to crop diversification, the present integrated system was found to be more viable than the non-integrated system in terms of production and net profit.

Fish seed production and marketing in some selected areas of Bangladesh

The main objective of the study was to assess the production and marketing system of fish seed and examining the demand for and supply of fry and fingerlings in some selected areas viz. Mymensingh, Netrokona and Tangail in Bangladesh. The present study selected the related stakeholders like 20 Fish Seed Multiplication Farms (FSMF) owners, 80 nursery operators, 20 fry traders and 90 fish farmers who are the beneficiaries and directly involved with the fish seed production and supply chain, and marketing system of fish seed. In case of nursing and rearing fingerlings, only those stakeholders (nurserers and fish farmers) attached with NGOs were selected and the NGOs were GRAMUS, SARA and ORD from Mymensingh and SATU from Tangail district. Data were collected for the period 2004-2005 and most analyses were done by using tables and flow chart to determine production and marketing system of fish seed.

HACCP based management system for improving quality of freshwater giant prawn, Macrobrachium rosenbergii

The study was conducted on the present status of HACCP based quality management system of golda, Macrobrachium rosenbergii farms in Fulpur region of Mymensingh. Information was collected on general condition of farms, culture systems and post-harvest quality management. In almost all farms, there is no or inadequate infrastructure facilities such as, road access, electric supply, telecommunications, ice, feed storage facility, vehicle for golda transportation, washing and toilet facilities. The problems associated with sanitation and hygiene was: widespread use of cow dung, poultry manure and construction of open toilet within the vicinity of prawn culture pond. Different grades of commercially available and locally prepared feeds were used for golda culture in the pond. Golda post-larvae (PL) of 40-50 days old were stocked with carp species. The price of golda PL ranged from Tk. 1.00 to Tk. 1.25/piece. The pond size varied from 50 decimal (0.2 ha) to 2.5 acre (1.0 ha) with an average depth of 2-2.5 m. The culture period of golda varied from April-May to November-December and survival rate ranged between 75 and 80%. Production of golda varied from 250-500 kg/acre (625-1,250 kg/ha). Harvested golda were transported to city market within 4 h. Two size grading were generally followed during pricing, e.g. Tk. 500 to 550/kg for >100 g size and Tk. 300/kg for <100 g size. The cost-benefit ratio was found to remain around 1:1.25 depending on availability of PL. Water quality parameters such as, water temperature, pH, dissolved oxygen, total alkalinity and chlorophyll a in five golda farms in Fulpur region were monitored. Water temperature ranged from 29°C to 33°C, dissolved oxygen from 2.28 to 4.13 mg/l, pH between 6.65 and 7.94, alkalinity from 44 to 70 mg/l and chlorophyll a concentration from 61.88 to 102.34 µg/l in the five investigated ponds. The Aerobic Plate Count (APC) of the water sample was within the range of 2.0x10^6 - 2.96x10^7 CFU/ml and of soil samples within the range of 6.9x10^6 - 7.73x10^6 CFU/g. Streptococcus sp., Bacillus sp., Escherichia coli, Staphylococcus sp., Pseudomonas sp. and Salmonella sp. were isolated from pond water and sediment. Different feed samples used for golda was analyzed for proximate composition. Moisture content ranged around 14.14-21.22%, crude protein 20.55-44.1%, lipid 4.67-12.54% and ash 9.7-27.69%. The TVB-N values and peroxide values of feeds used as starter, grower and fish meal were found within the acceptable ranges and samples were free from pathogenic organisms. A training was organized for the golda farmers on HACCP, water quality and post-harvest quality management of prawn.

Demonstration of some selected aquaculture technologies under farming system research in Jessore and Santahar, Bangladesh

BFRI evolved some selected aquaculture technologies viz. polyculture of carps in perennial ponds, monoculture of short cycled fish species (BFRI super strain) in seasonal ponds and prawn seed production through backyard hatchery system have been demonstrated under Farming System Research (FSR) component in Jessore and Santahar regions. Both polyculture of carps and monoculture of short cycled fish species technologies were tested in farmer's ponds in Kaium Kula village near Jessore town. In polyculture trials, seven species comprising of silver carp (Hypophthalmichthys molirrix), catla (Catla catla), rohu (Labeo rohita), grass carp (Ctenopharyngodon idellus), common carp (Cyprinus carpio), mrigal (Cirrhinus cirrhosus) and silver barb (Barbonymus gonionotus) were stocked @ 9,500 (ratio 6:2:4:2:1:5:5); 10,750 (ratio 6:2:4:2:1:5:5) and 12,000 (ratio 6:2:4:2:1:5:4) fish/ha respectively in ponds of T1, T2 and T3 having three replications of each. The mean highest fish production was 3,148 kg/ha in T3, followed by 2,899 kg/ha in T1 and 2,875 kg/ha in T2. Production of T3 was significantly different (P<0.05) than both T1 and T2, while there was no significant differences (P>0.05) between the production of T1 and T2. In case of trial of short cycled fish species, two treatments were tested: T1 (comprising of BFRI super strain of Nile tilapia, silver carp, common carp and silver barb; ratio 3:5:1:1) and T2 (having only BFRI super strain of Nile tilapia). Stocking density in both the treatments were same (20,000 fish/ha). In this trial average production was higher in T1 (2,743 kg/ha) than that of T2 (2,369 kg/ha) but the production figure in these two treatments was not significantly different (P>0.05). Demonstration of backyard prawn hatchery technology was tested at Santahar region of Bogra district, North-west part of Bangladesh. This hatchery consisted of three main components i) bio-filter, ii) rearing tank unit (chari) and iii) air blower/air pump unit. Plastic drum of 200-250 l capacity and cemented chari of 200-250 l capacity were used as bio-filter and larval rearing containers respectively. A 0.5 hp air blower with 6 aquarium air pump were used to operate the aeration system in the hatchery. Diluted sea water (10-12 ppt) made from brine solution (200-250 ppt) collected from salt-bed was used in the backyard hatchery system of hatching of eggs and rearing of larvae. Rearing of first stage zoea-larvae was reared in three rearing tanks following the stocking densities of 40, 50 and 60/l of water respectively. Production of post-larvae were 20±0.82, 22±1.12 and 28±1.63/liter of water in treatments I, II and III respectively in 38, 40 and 39 days rearing period.

Effects of black Bengal goat manure on growth and production of Genetically Improved Farmed Tilapia (GIFT) starin [sic], Oreochromis niloticus

In a goat-tilapia integrated farming system, the effect of Black Bengal goat manure on the growth and production of Oreochromis niloticus was studied at the Freshwater Substation, Shantahar, Bogra for 4.5 months. The stocking density used in three treatments were, 200 goats and 15,000 GIFT strain/ha (T1); 300 goats and 15,000 GIFT strain/ha (T2); and only 15,000 GIFT strain/ha (T3). The initial individual total length and weight of stocked tilapia were 7.6 cm and 11.34 g, respectively. Twelve ponds each having an area of 40 square meters were used for this trail [sic]. On one side of each pond goat shed was constructed and the space allocated for each goat was 0.75 m x 1.5 m. Newly weaned black Bengal goats of average weight 8.45 kg was used in the trial. Every morning the goats manure was swiped out in ponds through the fixed opening of bamboo made floor of goat shed. Water depth of the ponds was maintained at 0.75 m. The highest fish production was in treatment 1 (1,750 kg/ha) followed by treatment 2 (1,455 kg/ha) and treatment 3 (621 kg/ha). The difference in individual goat weight was not significant (P>0.05) among treatments 1 and 2.

Survival, growth and production of Penaeus monodon and P. indicus at different density combinations with milkfish

Penaeus monodon and P. indicus juveniles were stocked and reared for about 3 months in earthen ponds at different density combinations with Chanos chanos. The presence of either Penaeus species at any density ratio did not affect significantly the C. chanos survival. Survival rates of the penaeids indicated that intraspecific and interspecific competition occurred and were reduced with the reduction in stocking rate. It is concluded that further studies on higher density ratios and feeding and economic consideration would be of help to the development of this kind of fishpond management system.

Suitable stocking density of tilapia in an aquaponic system

An aquaponic system was studied through the integrated culture of mono-sex GIFT and two types of vegetables viz. morning glory, Ipomoea reptans and taro, Colocasia esculenta in a recirculating system for 15 weeks. Tilapia fry of uniform size of 0.76 g were released in three treatments (stocking densities): 106 fish/m³ (T1), 142 fish/m³ (T2) and 177 fish/m³ (T3) to assess the effect of stocking density on the growth performance of fish. Fish were fed with a commercial feed containing 25% protein. Weight gain (g) of tilapia ranged from 19.41 to 32.67 g and was inversely related with stocking density. Percent weight gain varied between 2553.99 and 4298.68% and was significantly different among the treatments. SGR ranged from 3.09 to 3.59% per day and varied significantly. FCR varied from 2.19 to 2.69 and had a positive correlation with stocking density. The highest survival rate (%) was achieved in T1 (99%) followed by T2 (98%) and T3 (96%). Production of fish ranged from 3.43 to 3.52 kg/m³ and was inversely related with stocking density. The present study demonstrated that 106 fish/m³ was the best stocking density in terms of growth, food conversion ratio, survival and production for tilapia culture in the aquaponic system.

Feasibility study of biofuel production from freshwater fern, Azolla sp in Anzali Wetland

Production of bioethanol through acidic and enzymatic hydrolysis of aquatic Azolla sp., as a new source of bio-mass, has been performed, as a means to control increasing growth and reducing undesirable effects of this plant in Anzali lagoon. After sampling, drying and crushing, Azolla was hydrolyzed, using diluted acid and enzyme. Diluted acid hydrolysis was done using both autoclave and a high-pressure system (Batch Synth® Microwave synthesizer). The effects of temperature and time (in autoclave) and concentration of acid (in both) were compared. Cellubrix®, a ommercial cellulase source, was used for enzymatic hydrolysis process. The amounts of reducing sugars, glucose and furfural, released from hydrolyzate, were measured. To produce alcohol, Sacchromyces cerevisiae (to ferment sixcarbon sugars), Zygowilliopsis californica and Pichia stipitis (to ferment five-carbon and sixcarbon sugars) were used. Maximum amounts of glucose (4.83% w/w) and reducing sugars (14.15% w/w) were obtained using acid hydrolysis in autoclave. In the microwave oven, maximum glucose (5.04% w/w) and reducing sugars (13.27 w/w) were obtained at 180 and 200 °C, respectively. Under these conditions, maximum produced furfural was 1.54 g/L. The difference between amounts of furfural obtained from acid hydrolysis of Azolla in microwave oven compared to autoclave was statistically significant. Amounts of alcohol produced and its yields were 3.99 g/L and 33.13% for S. cerevisiae in 48 hours, 3.73 g/L and 30.45% for Pichia stipites in 48 hours, and 3.73 g/L and 30.45% for Z. californica in 24 hours after inoculation, respectively, with significant differences. Statistical comparison of results showed significant differences (P<0.05) in glucose production, at different conditions. Amounts of reducing sugars and glucose increased after optimization of levels of acid, time, and temperature. The overall optimum released sugar and glucose were obtained with 1.67% (w/v) acid using autoclave. Higher temperatures in microwave oven caused a significant increase (P<0.05) in furfural. Furfural severely inhibits fermentation. Hence, regarding the issues of energy consumption and time, amounts of inhibiting substances and sugar production, autoclave is found to be superior to the high temperature and pressure, generated in microwave oven, for hydrolyzing Azolla. Furthermore, given the amounts of Azolla in Anzali lagoon, it may be recommendable to use this plant as a biomass resource.

Assessing potential of production in Lake Choghakhor

Phytoplankton productivity is the common and important factor being considered in determining the overall status of a given body of water. This is because they are found at the base of an energy or food chain, being the basic source of primary food in a given aquatic system. Hence, information on their contribution is essential in indicating how much biomass energy will be available to all other living resources in the system. Though the primary productivity of shallow lakes is characterized by mixed populations of phytoplankton and submersed aquatic vegetation in the open water. Lake Choghakhor, is a shallow lake, located in Chaharmahal-Bakhtiyari Province. This lake is the most important ecosystem in the region especially for waterfowl populations, has a recreational value and supports tourism and fisheries. During last decade Choghakhor has been influenced by some man-made impacts such as water level fluctuation, agricultural discharge and fish (Cyprinids) introduction causing a serious problem in its trophic states. So water quality for physical, chemical and biological was monitored in five sampling stations, from April 2003 to March 2004. As biological parameters we studied phytoplankton, epiphytic algae, and zooplankton and macrobenthose community structure. Chlorophyll a content for phytoplankton and epiphytes was measured to estimate production of these groups (biomass over time). Also we determined biomasses of submersed macrophytes and macrobenthose and primary production of phytoplankton (dark and light bottles technique) to estimate fish production. The results of this study showed Lake Choghakhor did not undergo stable thermal and oxygen stratification, and the lake water was mixed throughout the study (the lake mixing regime is polymictic). Now submerged plants especially Myriophyllum spicatum has covered almost the entire lake and dense macrophyte beds (Polygonom amphibium), located on the east southern end of the lake appear to act as a sink for these nutrients. Lake Choghakhor appeared to be in a macrophyte dominated clear water state with low TP (annual mean: 24± 15μg.l-1) and chlorophyll a (annual mean: 3±1.28μg.l-1) concentrations and very high Secchi depth. The grazing pressure of dominant pelagic filtering zooplankton Daphnia longespina did not seem to be significant in determining the low phytoplankton crop expressed as chlorophyll a. We expect that sequestering of nutrients by submerged plants and associated epiphytes are the dominant stabilizing mechanisms suppressing the phytoplankton crop of Lake Choghakhor.