Guide to feeding Sparus macrocephalus

Pond selection: The experiment was conducted in a freshwater pond in Simen Town, Yuyao City. The pond covers an area of 6 mu, with a water depth of 1.5 ~ 2 meters, rich water sources and excellent water quality.

Pond preparation: drain the remaining water in the pond at the beginning of March to expose cracks at the bottom of the pond. At the end of March, clean the pond with 100kg/ mu of quicklime to kill harmful organisms such as bacteria and wild fish in the pond. After cleaning the pond, the water surface is 80 cm, and the water surface is fertilized with fertilizer. After water fertilization, 6 kilograms of river shrimp with seeds were put into the pond as bait organisms for black snapper fry. After a few days, the water in the pool was dark brown with a transparency of 30 ~ 40 cm.

Release of fry

Seedling purchase and specifications: 25 17 desalinated Sparus macrocephalus seedlings were purchased from Xiangshan bay nursery on April 12, 2005, with an average specification of 9.5 cm and an average weight of about 20 g. At this time, the water temperature in the temporary pond was 16 ~ 17℃ and the salinity was 0.

Seedling transportation and stocking: direct seeding transportation in inflatable iron drums. It takes about 4 ~ 5 hours to reach the test pool. After entering the pond, 230 dead fry were found, and the survival rate was 90.9%.

Cultivation management

Feeding: After the fry were released, the activities of the fry were carefully observed, and it was found that the fry died one after another, with a cumulative death of 334 in three days. Three days later, Sparus macrocephalus adapted to the pond environment and began to eat compound feed. There are four principles to feed: feed once every morning and afternoon, accounting for 60% of the total feed in the morning and 40% in the afternoon; In order to observe the feeding situation of Sparus macrocephalus, two feeding tables were specially set up, and the standard was to finish feeding within 2 hours: in view of the different palatability of fry to bait particle size at different stages, prawn compound feed was fed in the early stage of the experiment, and the feeding amount was 3% ~ 5% of the fish weight; In the middle and late stage, the compound feed of Pseudosciaena crocea and perch was changed, and the feeding amount was 2% ~ 3% of the fish weight.

Water quality management: in the early stage of stocking fry, the water quality was relatively stable due to the small amount of bait. In the middle and late stage, with the increase of water temperature, the amount of bait will increase, which will inevitably lead to the increase of metabolites in pool water and the growth and prosperity of bacteria. Therefore, the pool water will be disinfected regularly with disinfectants such as dibromohydantoin every month to improve the water quality and environment.

Disease control: According to the water quality and fish activity, feed bait mixed with allicin regularly to enhance the disease resistance of fish. Due to the preventive measures in place, no fish diseases occurred during the experiment. Early indoor cultivation: ① Parent fish cultivation: The parent fish is 3-4 years old, with an average weight of 0.5- 1kg/ fish, and the female fish is slightly smaller, with the male-female ratio of 1:2, ***50 fish and the cultivation density of 5 fish /m2. Change water every 3 ~ 5 days 1 time, and the water change rate is 100%. Parent fish regularly bathe with formalin and antibiotics. The food intake gradually increased from 0.5kg to 65438±0.5kg, and 22 animals survived, with a survival rate of 44%. (2) spawning and hatching: naturally spawning begins, but the number is small; Entering the peak spawning period, the spawning amount is 6.5438+0.208 million; When the water temperature naturally rises to 20.8℃, the amount of eggs laid is obviously reduced and the quality of eggs is poor. The fertilized eggs are hatched in the egg hatching barrel. 1 200,000 fertilized eggs are put in the egg hatching barrel, and the air is slightly flushed. The average hatching rate is 70%.

Larvae cultivation: during the cultivation period, the water temperature 16 ~ 23℃, the specific gravity of seawater1.016 ~1.020, the dissolved oxygen is more than 5mg/L, the pH value is 7.8 ~ 8.6, and the ammonia nitrogen is less than 0.1. The density of newly hatched fish in the pond is 25,000 ~ 46,000 fish /m2, with an average of 35,000 fish /m2, and * * * released 6,543,800 fish. The larvae began to feed rotifers 48 hours after hatching, and the feeding density was 10 /ml. Artemia nauplii were fed at the age of 15 days, the initial feeding amount was 0.5 /ml, and then the feeding amount was gradually increased according to the fry density in each pond. Cross-feeding rotifers and Artemia nauplii.

Later outdoor culture: (1) pond: the pond area is 300m2, the water depth is 0.8m, and the water temperature is 20 ~ 32℃ during culture. Disinfect with 100kg quicklime. (2) Fertilizer, water and bait: 15 ~ 20 days before seeding and seedling throwing, the outdoor soil pond began to filter with water net, apply chemical fertilizer and sprinkle soybean milk. After fertilization, rotifers were inoculated with a density of 0.5 ~ 1 /ml. (3) Seedling raising: the fry cultivated indoors are moved into an outdoor soil pond for cultivation, and when the total length of the fry reaches 20 mm, the bait is still rotifers; After the total length reaches 20mm, copepods are the main species; When the total length exceeds 30mm, the bait is granular feed. After the fry enter the pond, add some fresh seawater every day. Change the water when the water level is full. Change water 1 time in the first two days, and the water change rate is 20 ~ 30%; Change the water every day in the later period, and adjust the water quantity in time according to the water quality. Generally, the water exchange rate is 20 ~ 30%. In addition, a "quick oxygen essence" is prepared for rapid spraying when floating.

The overwintering fish species are prone to diseases after spring because of their low food intake and weak constitution. In order to prevent this from happening, Sparus macrocephalus overwinters in plastic greenhouses.

After several months' growth, summer flower fry reached 165438+ in late October, and the specifications were all around 150g/ tail, which did not meet the standard of commercial fish. For overwintering management, in order to make Sparus macrocephalus overwinter safely, we can dig an acre of rectangular pond with a bottom depth of 1.7 meters and build a steel pipe shed for overwintering fish.

Generally, a small amount of bait is fed during the wintering period. The bait is compound feed, and a certain amount of fish vitamins are added, which is fed regularly, and the food list is often checked, and the feeding amount is appropriately controlled according to the feeding situation and activities of Sparus macrocephalus. When the water temperature is lower than 5℃, feeding can basically be stopped. However, when the weather is clear and the water temperature is above 10℃, a small amount of bait should be fed.

I usually patrol the pond carefully in the greenhouse. When the weather is good and the temperature is high, open the plastic film at the bottom. When the weather conditions are poor and the temperature is low, cover with plastic film to keep warm. The doors on both sides are generally ventilated during the day and closed at night. The water level in the greenhouse should be kept full, and then 20 cm should be taken out every 7 days to replace 20 cm of fresh seawater to ensure the water quality and prevent the growth and overwintering of Sparus macrocephalus from being affected by the deterioration of water quality.