How to raise mackerel culture techniques and matters needing attention

Recently, many farmers who want to join the culture of herring are asking how to raise herring well. Generally speaking, herring lives at the bottom of fish pond most of the time, and the bottom layer is also the area where oxygen debt first appears. Therefore, the requirements for dissolved oxygen in the breeding process are very high. If there is insufficient dissolved oxygen, it will affect the digestion and absorption of feed in slight cases, increase the breeding cost, and also bring some dark damage to the fish body. In serious cases, it will float and flood the dead fish.

How to raise fish

The fingerling pond covers an area of 3/15 hectares to 5/15 hectares and the water depth is 1.3 to 1.5 meters. Clean and disinfect the pond one week before stocking. The stocking time is generally from July to August. There are two stocking methods: monoculture and polyculture with silver carp and bighead carp. Polyculture is better, and silver carp and bighead carp can control water quality. stocking density should be determined according to expected pond size and pond conditions. - 5000~7000 summer flowers were planted per 1/15 ha, and 500~1000 summer flowers of silver carp and bighead carp of similar specifications were also planted. During fingerling rearing period, artificial feed was mainly fed, and the crude protein content of feed should reach 35%. The feeding amount is generally 3%~ 5% of the total weight of fish, feeding once in the morning and afternoon. To do a good job in daily management, keep the dissolved oxygen in the pool water above 3 mg/L.

Techniques and precautions for culture of herring

I. Breeding technology

1. Pond conditions

The water quality is fresh, the dissolved oxygen is high, and the pH value is 7~8.2. Therefore, the pond should be selected in a place close to the water source, convenient for drainage and irrigation, and quiet. The pond area is generally 1000~3000 square meters, the water depth is 1.5~2 meters, rectangular, east-west direction, the pond wall is hardened with masonry or cement, the sludge at the bottom does not exceed 10 cm, and each pond is equipped with a 3kW impeller aerator.

2. Fish stocking

Select artificially domesticated breeding of a winter age fish species, healthy physique, neat specifications. Generally, 800~1200 fingerlings of 70~ 100g are put per mu, 250~300 silver carp and 75~100 bighead carp of 150~ 200g are matched, and 5 mandarin fish or bass are put to control wild miscellaneous fish in the pond. Competitive fish such as carp, grass carp and tilapia are not allowed. Fish stocking is generally good in early March. 10 days before fingerling stocking, 100 - 150 kg/mu quicklime slurry is used to sprinkle the whole pond, and water is discharged to the required water level after 7 days. Before stocking, fish bodies are soaked in 15~20 mg/L potassium permanganate solution or 3~5% saline for 15 minutes to kill pathogens and harmful organisms.

3. Feed feeding

After the fish is domesticated at the seedling stage, the fish is mainly fed with compound feed, the crude protein content of which should reach 40~45%, and the main raw materials are imported fish meal, dried fish, bean cake, peanut cake, wheat bran, yeast powder, mineral salts, vitamins, etc., which are made into hard pellet feed with particle sizes of 3 mm, 4 mm and 5 mm. The feed size was 3 mm at the beginning, and changed to 4 mm and 5 mm later as the fish gained weight. Feeding should be fixed, timed and quantitative, and a feed table should be set up at one side of the pond. After stocking, fish species are domesticated. First, sound training is used at the feed table to form conditioned reflex, and then hand sprinkling is used to feed slowly. Feeding twice a day is 8:00 a.m. and 8:00 p.m., the ratio of feeding amount in the morning and afternoon is 4:6. Every operation should be careful until the fish are full and leave. The daily feeding amount is generally 1.5~3%.

4. Water quality regulation

The fish likes fresh water and high dissolved oxygen pool water. At ordinary times, water quality management should be strengthened, new water should be added frequently, aerator should be started in time, and biological agents should be used reasonably to adjust water quality. June to September is the peak season for fish growth, flushing once every other day, and changing water once a month for sewage, the amount of water changed is 1/4 of the pool water. Increase aeration equipment as much as possible, start the aerator in due time, start at noon on sunny days, start in the morning on cloudy days, start in the middle of the night on continuous rainy days, do not open in the evening, float early, open every day in the growth season, run for short noon, long midnight, cool short, sultry long, load large, long time, load small, short time. Photosynthetic bacteria are regularly applied at a rate of 10 - 20 g/m3. Sprinkle quicklime water regularly, generally every half month or so during the breeding period, the dosage per mu is 5~10 kg. Always keep the dissolved oxygen in the pool water not less than 5 mg/L, pH value of 7.2~8.2, water transparency of 30~40 cm is appropriate, but according to the season and pond water quality fertility flexible control, water quality should not be too thin, should be moderate fertility is better. If the water is abundant and the temperature is appropriate, it can also be used with micro-running water supplemented by regular flushing.

5. Daily management

Patrol the pond frequently, insist on patrolling the pond every morning, noon and afternoon, remove residual feed, dirt and clean the material platform, observe whether the fish in the pond float head phenomenon, increase the number of night patrol or arrange night shift management in hot summer season and sudden weather change. Early feeding, feeding and domestication began the next day after stocking. Combined with the inspection of the pond, look at the weather, look at the color of the water, look at the food situation of the fish every day. Every 15 days, fish were randomly sampled to check their food intake, fat and lean conditions, and the growth rate of fish, the total amount of pond fish and the valence of feed were calculated by weighing and counting, so as to determine the feeding amount in the next stage.

6. Disease prevention

The whole pond is sprinkled with quicklime once every half month, the dosage is about 10kg/mu, allicin is added into the feed for a long time, and the fish sukang is used to make bait for feeding every month for 3 consecutive days to prevent enteritis. Chlormethamine and copper sulfate are alternately sprinkled into the whole pond every month, and the concentration of chlormethamine is 0.2~ 0.3g/cubic meter, and copper sulfate is 0.3~ 0.5g/cubic meter. In the feeding management, pay attention to observe the feeding situation of fish at any time, and find abnormal reactions or sick fish, and treat them as soon as possible.

II. Precautions

1, feeding precautions

The fish has an original stomach, can store food for a short time, very good food, must control the feeding amount, and its feeding has several periods to pay special attention to, one is before wintering, do not stop eating too early, in case of poor constitution after wintering and easy to get sick; one is early spring feeding period, must control the feeding amount, remember not to feed too much change caused by stimulation, thus causing coloboma disease.

2. Prevention of intestinal diseases

The intestinal tract of herring is short, and the size of the front and back is different. In order to improve the absorption and utilization rate of feed by the intestinal tract and reduce the incidence of intestinal disease, the intestinal health should not be ignored. Feeding small amount of meals; regular use of oral medicine, keep intestinal health and reduce feed coefficient.

3. Regularly prevent hepatobiliary diseases

In the case of feeding, the burden on the liver is very heavy. After excessive toxic substances in the water enter the fish body, they will also be degraded and excreted through the liver, which will further aggravate the burden on the liver. It is necessary to regularly eliminate toxins in the body, repair damaged liver, and effectively reduce the occurrence of bleeding disease (especially in May, September and October, the occurrence of bleeding disease should be prevented).

The main causes of water mold in channel catfish

1, bubble disease damage fish body, secondary water mold. Mainly because the spring water is shallow, most of the pond water depth is less than 1.5 meters, pond small algae multiply in large quantities, when the weather is fine, algae photosynthesis oxygen production capacity is strong, dissolved oxygen in the upper water layer is easy to appear supersaturation phenomenon, cultured fish are prone to bubble disease. In addition, a large amount of organic matter accumulated in the pond during winter, poor substrate quality, high nitrogen content, easy to appear nitrogen supersaturation caused bubble disease, resulting in fin, gill, eye, skin and other tissues damage, water temperature decreased when infected with water mold disease.

2, improper operation of the net, fish injured after infection with water mold. In the process of pulling net to screen fish, there will be cases where large fish are caught and small fish are kept or too many fish are online, and some of them cannot be sold at one time. Because the fish are in the net bag for too long, they are scratched and injured in the process; in addition, sometimes only fish (silver carp, etc.) are sold in the net, and the main fish are damaged after surfing the net, and the damaged parts are festered and then secondary water mildew occurs.

3. Insufficient supply of bait, fish eating each other, wound infection with water mold. The herring is omnivorous carnivorous fish. It can start feeding when the water temperature is above 5℃. At this time, if the feeding is insufficient, the herring may eat each other, and the tail fin is easily injured and rotten. In early spring, most pond nets will find that fish caudal fin is incomplete or a large number of red punctate ulceration, other parts are intact, caudal fin damage ulceration infected with water mold disease.

How to solve the spotted catfish water mold

1. Prevention of bubble disease. (1) Sufficient water level, water depth of more than 1.5 meters, stabilize water body, avoid microalgae mass reproduction, reduce photosynthesis;(2) timely open aerator aeration at noon after rain, balance dissolved oxygen in upper and lower water layers;(3) timely increase oxygen, normally open aerator when weather is fine, reduce bubble disease caused by excessive dissolved oxygen in upper water of algae photosynthesis;(4) regularly change bottom of old pond, reduce bottom pollution, avoid nitrogen supersaturation caused by excessive nitrogen-containing organic matter;(5) If necessary, use "quick-release" to alleviate and prevent bubble disease.

2. Reduce net damage. Select soft nets for net pulling operation, so as to reduce fish body damage as much as possible when pulling nets; at the same time, timely sterilize after net pulling, and continuously use "Yongle iodine" for "disinfection" and sterilization for 2-3 times to reduce bacterial diseases and water mildew induced by net pulling damage.

3) Timely feeding. At this time, the herring may not eat on the water surface, but in fact it still needs to eat bait. It can be fed according to the proportion of about 0.5% of the weight of the fish in the pond according to the situation. If the herring eats underwater, it can reduce the occurrence of mutual killing due to lack of bait and avoid fish injuries.

Raising herring is a very hard and troublesome thing. Therefore, people who are about to join the herring farming industry and farmers who are already raising herring must be able to raise herring scientifically and must be able to endure hardship, because farming is a long-term hard work. Only by persisting can they succeed.