Techniques of semi-artificial propagation of cultured Pelteobagrus fulvidraco

Because the male testes of Pelteobagrus fulvidraco are dendritic and unable to extrude semen, the male fish are usually killed in artificial reproduction, and the testes are cut up for artificial insemination. Most of the female fish will die after artificial egg squeezing. The cost of artificial breeding of parent fish is high, and the labor intensity is also high. Semi-artificial propagation is to let Pelteobagrus fulvidraco natural mating, spawning and fertilization after artificial spawning, with low labor intensity, parent fish can be reused or sold, which greatly reduces the cost of parent fish, and the spawning effect is very obvious, which is worth popularizing.

Parent fish selection is generally carried out in winter, requiring male tail weight of more than 100 grams, female tail weight of more than 75 grams, smooth body surface without injury or disease, complete fins, obtained by net catch or dry pond. The female-to-male ratio was 1 ∶ 1.5.

Cement pond is the best spawning pond for spawning pond preparation, the area should not be too large, it is convenient to enter and drain, and there are conditions of running water or flushing water. Wash thoroughly before spawning, disinfect with 20 mg / L potassium permanganate solution and set aside after rinsing with clean water.

The spawning nest is prepared to choose a PVC tube with a diameter of 15 cm / 30 cm, saw a short tube of 35 cm / 45 cm, cover one end with a sieve cloth of 40 cm / 60 mesh, disinfect it with 20 mg / L potassium permanganate solution, place it flat on the bottom of the spawning pool after cleaning, and fix it unshakably, with one end of the screen cloth facing the direction of the current.

When the water temperature is stable above 22 ℃ and there are several sunny days in a row, the well-developed parent fish are selected to induce spawning. The female-to-male ratio of parturient fish was 1 ∶ 1.3-1.5. The first injection of oxytocin was injected at 8 p.m., 40-50 micrograms of LRH-A2 per kilogram of male body weight plus 2000-2500 international units of HCG, and 60-70 micrograms of LRH-A2 per kilogram of female fish. The second injection was given at 7: 8 am the next morning. Each kilogram of female fish was injected with 80 μ g of LRH-A2 plus 4000 μ g of HCG, while the male fish was not injected. Each fish is injected with 0.2 to 0.3 milliliters.

The parent fish after injection was immediately put into the spawning pond to maintain micro-running water. About 8 hours after the second injection, the amount of water was increased, and the next morning the spawning nest was inspected. It was found that the spawning nest was immediately taken out and put into the incubator, while a spawning nest was added. 48 hours later, the spawning nest and parent fish were taken out.

After the hatching nest is taken out, it is put into the hatching pool, and a bubble stone is placed at the mouth of each egg-laying nest to inflate. The water level of the incubator is controlled at 60cm to 70cm, and the water is changed every 24 hours. Change the water in time when taking off the film and keep the micro-running water. When the water temperature is 24 ℃, the film can be removed in about 60 hours.

After the removal of the membrane, the fish eggs were managed to take out the spawning nest after the complete removal of the membrane. Replace the water with 1ax 2, absorb the dirt, and keep the water fresh. The difference between the temperature of the new water and that of the original incubator shall not exceed 1 ℃. After 72 hours of membrane removal, the rotifers were fed first, and then gradually transferred to large rotifers and cladocera.

When the fry size reaches 1.2 to 1.5 cm after 5-6 days of feeding, the fry should be transferred to the summer flower culture pond in time for culture or sale.