A brief discussion on how to improve the survival rate of herring artificial reproduction

The mature stage of herring is later than that of silver carp, bighead carp and grass parent carp, and the gonadal development is generally difficult to reach the standard of induced delivery at the end of Ⅳ. Therefore, the method of ripening should be taken. The maturation of parent fish was checked by net 15-20 days before spawning, and the less mature female and male parent fish were ripened 1-3 times in time. The effect of ripening hormone LRH-A3 was the best, and the dose was controlled at 0.1-0.2ug / kg of parent fish weight.

The surrounding environment of the parent fish culture pond is quiet, there is no interference, and the water depth is more than 1.5 meters. Herring collocation in grass parent fish pond, with 1-2 groups per mu of water surface, no mixed culture of carp; feed mainly with live snails, supplemented with a small amount of concentrate; the water quality is kept fresh, pollution-free, sufficient oxygen, transparency in more than 35 cm, parent fish culture pond is best to maintain uninterrupted microflow for a long time, gradually increase the flow rate 1 month before spawning, stimulate parent fish and promote gonadal development, so as to make parent fish mature.

Keep the water clean, non-toxic and oxygenated. To prevent the enemy from entering the ring road to harm fish eggs and fry, take 80-100 mesh copper sieve silk to filter hatching water. Adjust the hatching flow speed, the flow rate before and after dissolving the film is controlled at 0.25 m-0.3 m / s, and when dissolving the film, it is adjusted to 0.3 m-0.5 m / s. Wash and filter sand windows frequently to prevent screen clogging and avoid escaping eggs and seedlings.

The female parent fish with no injury, strong physique, soft and elastic abdomen, reddish reproductive foramen, slightly prominent relaxation, liquid feeling in the abdomen by hand touch, egg development to the end of Ⅳ, and milky semen outflow from the abdominal reproductive foramen were selected to induce artificial spawning. The mixed injection of LRH-An and PG0.6 kg has the best effect on oxytocin. Two injections were given. The first dose was 2-4 micrograms of LRH-A per kilogram of parent fish weight plus 0.1-0.2 PG, and the second dose was 15-20 micrograms of LRH-A plus 0.5-1 PG. The male dose was halved. The distance between the two stitches was 8-12 hours. The effect time of water temperature is 8-10 hours when water temperature is 25-27 ℃. About an hour before the effect time, the estrus dynamics of parent fish should be carefully observed and artificial insemination should be carried out in time.