Artificial breeding technique of cultured puffer fish in early spring

In recent years, the artificial propagation technology of Fugu obscurus (puffer fish) has become more and more popular, and its seedling production level has also developed rapidly, gradually forming a new type of efficient aquaculture industry. In order to further improve the level of production technology, the artificial propagation experiment of Fugu obscurus in early spring was carried out in Baishu Shunlong Fish and Shrimp Seedling Farm in Changshu City, Jiangsu Province in February 2003, and satisfactory results were obtained. Now this technology is provided to the industry for reference. With a view to common practice, common discussion.

I. Test process and results

From February 15 to March 5, three batches of dark striped oriental mackerel were spawned, a total of 30 groups, about 1.8 million eggs were obtained, the average fertilization rate was 70%, and the number of fertilized eggs was about 1.26 million. About 960000 seedlings of Fugu striata were obtained by hatching, with an average hatching rate of 75%. By April 15, there were about 500000 dark striped oriental summer flowers, of which about 100000 seedlings with body length above 3.0cm and about 400000 seedlings with body length of about 2.5cm were cultivated.

On April 13, some dark oriental oriental summer flowers were placed in the soil pond in the plastic film greenhouse to continue to cultivate. The soil pond has an area of 180m (30m × 6m) and a water depth of 0.8m~1.0m, with a total of 4 ponds. Each pond is stocked with 15000 dark-striped oriental summer flowers with body length 2.5cm. In the process of stocking, feed the juvenile Fugu striatus, adhere to the "four fixed" principle, and pay attention to do a good job of water quality management. On April 21, 24 seedlings were sampled and tested, with an average individual weight of 3.4g and an average full-length 4.3cm. On May 21, 12 seedlings were sampled and tested, and the average individual weight was 25g. On May 23rd, a total of 57000 juvenile Fugu striata were captured and released from the greenhouse in open-air fish ponds to continue to breed. 2 open-air fish ponds, a total of 16 mu, with an average stocking density of 3600 fish per mu, were fed with formula feed for juvenile Fugu striata. By the middle of July, some of the specifications for the capture of the dark striped Oriental Fugu with the tail of 100g/ were sold.

2. Artificial propagation technology

1. Parent fish overwintering

On October 20, 2002, the parent fish of Fugu obscurus was selected and moved from the outdoor fish pond to the greenhouse fish pond to survive the winter. The area of the fish pond in the greenhouse is 100m (10m × 10m), the water depth is 0.8m~1.0m, the stocking density of parent fish is 1 / m3 ~ 2 / m3, and the male and female individuals are reared in separate ponds. During the overwintering period, the water temperature is relatively stable, the lowest is not less than 16 ℃ and the highest is not higher than 18 ℃. The main feed is clam meat, supplemented by artificial compound feed, and the daily feed accounts for 2%-3% of the body weight of parent fish. In water quality management, sewage is absorbed and discharged and water is added once a week, and the amount of water added each time is about 1 per 4 of the total water quantity. Prenatal cultivation began around January 20, 2003. the lowest water temperature was not less than 18 ℃ and the highest was not higher than 22 ℃. The water flow was about 15 cubic meters per hour, and the water flow was about 15 cubic meters per hour. The water source was mainly the migratory flow of water in the fish pond, and the feeding amount was increased appropriately.

two。 Induce labor

On February 15, 2003, the dark striated oriental mackerel parent fish with good gonadal development was selected to induce spawning. The female parent fish was injected with 2 μ g LRH-A2, but the male parent fish was not injected, and the second injection time was 24-36 hours from the first injection, and the female parent fish was injected with 10 μ g + PG2mg+DOMlmgLRH-A2, and the dose of male fish was halved. Artificial insemination was carried out within 12 hours to 36 hours after the second injection, and dry artificial insemination was used. The fertilized eggs were debonded for 10 to 15 minutes with 0.6% normal saline. After the saline was bleached, the number of fertilized eggs was estimated and then put into the incubator. During the period of induced labor, the water temperature was controlled at 20 ℃ ~ 22 ℃, and the temperature difference between day and night was less than 2 ℃.

3. Incubation

The incubator is a shallow water static incubator, which is a square foam container with a volume of 50cm × 50cm × 10cm. Each incubator is put into shallow water 4cm~6cm, and when the water volume is 6L~8L, 20 000 ~ 30 000 fertilized eggs can be put into the incubator. During the incubation period, the water temperature should be kept stable at 21 ℃ ~ 23 ℃, and the fertilized eggs should be changed and rinsed twice a day. The water for hatching should be treated with pre-storage, aeration, drug disinfection and temperature adjustment before being used. The fertilized eggs of Fugu obscurus hatched out of the membrane after 96 hours to 120 hours, and the larvae should be moved to the seedling culture pool in time.

3. Early cultivation of Fugu striata seedlings.

The seedlings of Fugu obscurus propagated in early spring must be cultivated in a pool in the greenhouse with a water temperature of 22 ℃ ~ 25 ℃, an area of about 20 square meters and a depth of 0.8m~1.0m. At the beginning of seedling release, the depth of water is 30cm~40cm, and 250000 ~ 300000 seedlings can be released in each pond. After 4 ~ 5 days of cultivation, the young fish should be fed to rotifers 4 ~ 6 times a day, and the density of rotifers in water should be 8 / ml~10 / ml. After 4 ~ 5 days of feeding rotifer, the young fish grow to body length 0.5cm and can be fed with harvest worms instead. The appropriate feeding amount should be 2 / ml~3 / ml in the water body, and during this period, the water level should be gradually increased to 80cm~90cm by absorbing sewage, draining water and adding fresh water. After 4 ~ 5 days of feeding, the juvenile fish grew to about 1.0cm of body length, and could be moved into a large pond for mid-term cultivation, and fed to Cladocera, copepod and other zooplankton. After 2.0cm of body length, the young fish can be domesticated with artificial formula feed.