| The study was conducted in an aquaculture farm named Afil Aqua Fish Ltd. at Boromandertola, Sharsha in Jessore district of Bangladesh. This study was done to evaluate the economic feasibility of C. striatus culture. For this aspect C. striatus was cultured in monoculture system in three same sized culture ponds and sold. To get an overview of the actual profit from the C. striarus monoculture, rapid growing monoculture of Thai koi (Anabus testudineus) and Tilapia (Oreochromis niloticus) was also considered from the same ecological area. Fortunately it was able to do within the same farm as these were running simultaneously. |
| The area of each striped snakehead fish stocking ponds was 65 decimal with 1.5 ± 0.1 to 1.8 ± 0.1 m depth. Live food fish (fingerlings of some low-value fish, Labeo bata, Cirrhinus cirrhosis, and Hypophthalmicthys molitrix) stocking pond was prepared with an area of 30 decimal with 0.5 to 0.8 m depth. Ponds were completely dried, ploughed and embankments were repaired by eradicating bushes and extra aquatic weeds. Lime was used at one kg per decimal to improve the pH of the water and also the pond productivity. Inorganic fertilizers urea 300 g/decimal and triple superphosphate (TSP) 700 g/decimal were applied after 5 days of water intake to increase the plankton density in pond waters. After 5 days of fertilization cowdung 5 kg/decimal was applied. Then after two days mustered oil cake 2 kg/decimal was applied. In the next 7 days, Horra (Metal chain) was pulled every day to prevent the fertilizers from being settled down which may create gas in pond bottom. Then the pond water became greenish color with the abundance of phytoplankton and zooplankton and was ready for the stocking of desired fish fingerlings. |
| Fingerlings were collected from beels (natural depression) and baors (oxbow lakes of Jessore district, especially from Boromandertola, Jhikorgacha, Jessore after the complication of parental care with a length of 11 ± 0.75 cm and weight of 45 ± 10 g. About 7800 seeds were collected within 4 to 5 consecutive days and the price was 0.06 US$ per fingerling and at least 500 fingerlings were carried in each earthen pots with 10 to 12 L water holding capacity. As C. striatus fish is very hardy there was no need of a special oxygen supply. The stocking density was 40 fingerlings/decimal, and fingerlings were stocked directly into the culture pond with proper conditioning in the month of April and then fingerlings were cultured in the same pond for 6 months up to harvest. |
| The fingerlings were fed on live fry of Bata (Labeo bata), Mrigal (Cirrhinus cirrhosus) and Silver carp (Hypophthalmicthys molitrix). The fry of Bata, Mrigal and Silver carp were collected from 30 to 40 hatcheries of Jessore district and reared in another pond to feed the culture species at least 10 to 15 days ahead of C. striatus fingerlings stocking. They were stocked at 2,000 to 3,000 pieces per decimal and were fed with mustered oil cake and commercial feed (nursery-1) at the rate of 20% of body weight for the first week and it was gradually decreased with the extension of the culture period. The initial and final lengths of three live feed species (fish fry) were recorded 2.5 ± 0.25 and 2.75 ± 0.50, 2.5 ± 0.75 and 5 ± 1.5, 5.5 ± 1.75 and 6.25 ± 1.25 cm, respectively during the culture period. Live feed was supplied at the rate of 1 to 3% of the total biomass of C. striatus fish and it was adjusted after every bi-weekly sampling. |
| A supplementary feed made of rice polish, mustered oil cake and fish meat at the ratio of 10:10:01 also applied. Normally it was found that excess or uneaten feed remain floating up to 3 to 4 hours which allowed adjusting the feeding regime accordingly. The C. striatus fish are usually nocturnal feeder. This supplementary feed was applied every day in the evening by using 7 to 8 feeding tray at a different sides of the pond at the rate of 3 to 5% of the total body weight of fry. |
| In general, no sampling was done but for the experimental purpose, the sampling of C. striatus fish fingerlings was done at 15 days intervals to adjust the feeding rate, to observe the health condition and to keep the record of length and weight of fish. Fishes were caught by seine net and about 10% of each species was sampled. Various water quality parameters were recorded bi-weekly throughout the culture period. Water temperature was recorded from the study area with the help of a Celsius thermometer (°C). The transparency of water was measured by a secchi disc of 20 cm in diameter. To determine the dissolved oxygen, water samples were collected in dark bottles and measured the amount of DO by using DO meter (HANNA instruments, Model: HI 9146). pH of pond water was determined by color comparative disc through HACH Test Kit (Model FF-2). To keep the pond environment congenial for fish farming and to avoid potential C. striatus fish disease application of lime at 500 g/decimal, TSP at 30 g/ decimal, sodium chloride salt at 1.5 kg/decimal were applied once in every month. |
| At the end of October the C. striatus fish were harvested at good marketable size and price. By dragging net and drying the pond, fishes were harvested. Some uneaten live food fish like Bata, Mrigal and Silver carp in the culture pond were also attained marketable size and they were also collected with C. striatus fish and sold in market. The record of their average weight, length, number and total amount of production were kept. Survival rate, specific growth rate (SGR), weight gain, food conversion ratio (FCR), Benefit cost ratio (BCR) were calculated to evaluate fish growth by using formula. |