Reasonable polyculture: In order to save costs, white shrimp can be put into fish ponds for autotrophic culture or polyculture of tilapia summer flowers. Fish residues and feces are used as bait for white shrimp and tilapia, which are high-quality bait for fish ponds to balance the ecology of fish ponds.
Daily management: Water temperature 14 ~ 30℃, salinity 12 ~ 35%, PH 7.8 ~ 8.4, dissolved oxygen greater than 4 mg/L, and the daily variation range should not be too large. The general requirement for changing water every day is 1/3 ~ 1/4.
If the water exchange conditions are poor and the stocking density is too high, it is easy to appear anoxic floating head, so mechanical pumping or aerator should be used in time to increase oxygen. In addition, we should often patrol the pond and pay attention to safety in production.
Leptospira likes to live in rivers and streams with gravel bottom and fast flowing water, and often shovels moss and algae on stones with the stratum corneum with developed mandible. Laying eggs in shallow rapids from June to August every year. Mainly distributed in streams in Shanghai, Jiangsu, Anhui, Zhejiang, Fujian, Taiwan Province and other places.
Leptospira belongs to CYPRINIDAE, CYPRINIDAE and Leptospira. Commonly known as: grouper and rose fish. The body is slender, flat on the side, the back of the head is slightly convex, and the abdomen is round and shallow arc. The head is medium-sized, with flat sides and a slightly pointed front end.
Widely distributed, it is a small economic fish in the producing area with delicious meat. Eggs are poisonous, and eating them by mistake can cause diarrhea, abdominal pain, dizziness, vomiting and other poisoning symptoms; Cats, chickens and other animals will die if they eat fish eggs. Long-term heating can destroy toxins. Because of its bright body color, Zhejiang has chosen 3.5 cm juvenile fish of the same kind as ornamental fish for export, which has created considerable value.
Extended data
pond culture
1. Culture pond conditions: the pond can be built in the low and middle tidal areas of the reclamation area or the original shrimp culture pond can be used. The requirements are as follows: the bottom material is sandy, semi-sandy, and hard mud bottom is also acceptable; The surrounding waters are pollution-free and transparent; The fish pond area is 5- 10 mu, and the pond water depth is more than 1 m.
2. Clear ponds and artificial reefs are put into use. After exposure and dredging, some rocks or some worn tires and tile water pipes were put into use at the bottom of the pond to adapt to the habit of groupers like to make holes.
3. Fish socks. The cultured fish species are required to be strong, disease-free, black in color and cultured alone. Stocking density must adapt to local conditions. Generally, the specification of fish species is about 100g/ tail, and about 0.5 fish can be stocked per square meter.
4. Feeding management
Bait feeding. The bait is mainly fresh small miscellaneous fish, preferably live bait, which is cut into blocks with appropriate size according to the specifications of fish species for feeding. When feeding, quantitative feeding is adopted, which generally accounts for 10- 15% of the fish weight in the early stage and 5- 10% in the late stage.
The best feeding time is 5-6 am and 7-8 pm.
In order to save costs, white shrimps can be put into fish ponds to breed groupers, or tilapia and summer flowers can be mixed. The residual bait and feces of grouper are used as bait for white shrimp and tilapia, and white shrimp and tilapia are high-quality bait for grouper to balance the ecology of fish ponds.
Daily management. Grouper is very sensitive to the change of water environment, so we should pay attention to it in daily management. When cultivating, the water temperature should be 14-30℃, the salinity should be 12-35%, the PH value should be 7.8-8.4, the dissolved oxygen should be greater than 4 mg/L, the daily change range should not be too large, and the daily water exchange rate is generally 1/3- 1/4.
In the process of breeding, if the water exchange conditions are poor and the stocking density is too high, it is easy to appear anoxic floating head, so mechanical pumping or aerator should be used in time to aerate. In addition, we should often patrol the pond and pay attention to safety in production.
Harvest. Grouper has poor tolerance to low temperature, so it is generally appropriate to finish fishing before the arrival of cold current. A few groupers that don't meet the commercial specifications have to spend the winter.
net-cage culture
1, the selection of breeding grounds and cage production are similar to those of perch cage culture.
2. Breeding season. The growth period of grouper in Zhejiang sea area is generally 5- 1 1 month, and it takes16 months for grouper to grow from 50-100g fish to 400-600g commercial fish. Generally, two breeding cycles are adopted to arrange production.
One is to start raising fish from about100g purchased from May to July in the first year, until the weight reaches150-200g before winter, and put it on the market before winter in the second year; The other is to put 200 grams of large fish species in April-May, and 400-600 grams of commercial fish can be raised for sale before winter in that year.
3. Breeding density. According to the production practice and test results for many years, it is considered that the size of cage-cultured grouper is 3×3×3 m, and the stocking density is 10 kg/m2. This stocking density can obtain higher survival rate, higher total weight gain rate and net yield, and lower feed coefficient.
4. Bait and feeding techniques. It takes 7- 10 days for fish species to adapt to environmental conditions before they can start feeding. Tame before feeding, and the bait is mainly miscellaneous fish, and the bait coefficient is generally 7-8: 1. Several problems should be paid attention to when using compound bait: First, grouper has a strong feeding habit.
There is a great adaptation and transition process from feeding miscellaneous fish to feeding artificial compound bait. Secondly, the formula of compound bait should be reasonable, and its protein content should not be lower than 40%. Thirdly, the bait is not palatable or fresh enough, and the grouper will vomit, so palatability should be considered.
Fourth, it needs to be made into soft particles with the same size as the diameter of the grouper. Grouper is suspicious and has strong selectivity in foraging. Therefore, the feeding technology has a great influence on the feeding of grouper. At 8- 1 1 in the morning, the feeding amount accounts for about 5- 10% of the fish's weight, so the feeding method should be slow until the fish is finished. Groupers generally don't eat bait that sinks to the bottom of the cage.
5. Overwintering management. From February of 65438 to April of the following year, the water temperature dropped below 15℃, and the grouper basically did not eat or swim, and entered the wintering stage.
Selection of overwintering sea area and cage structure. Choose the sea area with slow flow, small wind and waves and the lowest water temperature above 8℃. In order to reduce the influence of tidal current and wind waves on overwintering fish, some empty cages are set around the overwintering cages to slow down the impact of tidal current and wind waves on the overwintering cages. At the same time, a certain number of overwintering equipment are set in the cages, and sacks or hard plastic cages and pipes are used.
Stocking density of overwintering fish species. Generally, 200g/ fish is stocked, and the density is 350-400 fish per box. Feeding should be done in windy and warm weather during the wintering period. The feeding amount is small, but the quality of bait is good. Try to feed live bait.
In addition, where conditions permit, indoor heating or land plastic greenhouses can be used for wintering.
Baidu Encyclopedia-Grouper Culture Technology