Experience of temporary culture of Pelteobagrus fulvidraco fry

The temporary cultivation stage of Pelteobagrus fulvidraco fry refers to the short process of newly hatched larvae which can not swim freely and can swim and feed on their own by meticulous nursing. Temporary rearing of fish fry is also called temporary rearing of larvae.

(1) conditions of facilities

The temporary cultivation of fish fry is characterized by short time and small temporary culture area, which can be carried out in hatching facilities, in small cages made of 30mm 40 mesh mesh or in cement incubators and other facilities. No matter which kind of facilities, there must be micro-flow conditions, so as not to let the larvae stand still, resulting in death.

(2) cultivation methods

1. The temporary cage is processed into a rectangle with 40-50 mesh net cloth, the method is to disinfect the pond and kill wild miscellaneous fish, the water injection depth is 0.6-0.8 meters, and the water quality of the pond is fertilized until there are a large number of zooplankton. When the transparency of the water is more than 40 cm, the cage is fixed with wood (bamboo) piles, and all the top and bottom of the cage are fastened firmly, so that the cage does not shake in the wind and waves. The upper mouth of the cage is 10 to 12 centimeters above the water surface. If it can carry out micro-running water, it can raise 8000 to 10000 larvae per square meter, and when there is no running water, the cage can put 3000 to 5000 fish fry per square meter. When the fry can swim freely, they will start to feed on yolk slurry for 2 days. When the fry has strong activity ability and can normally feed on zooplankton in the water, the upper mouth of the cage will be sunk about 10cm below the surface of the water. Let the fish fry automatically leave the cage to the pond. After sinking the cage for about 1-2 days, remove the inactive fish fry from the cage and put them into the pond. Attention must be paid to keeping the water quality in the pond good and the water should not be turbid, so as to avoid death caused by mud sticking to the fish fry, and keep the dissolved oxygen content in the pond water above 5 mg / L.

two。 The running water cement pond temporarily cleans up all sundries and dirt in the running water cement pond, and the depth of water injection is 0.6-0.8 meters. The larvae with yolk sac are put into the cement pond with 15000-20,000 fish per cubic meter of water. For the first 2-3 days, only continuous running water is needed to maintain sufficient oxygen. At this time, all the fish fry are clustered around the bottom of the pool. When the fish fry absorbed almost the nutrients in the body and began to eat exogenous nutrients, that is, the fish fry began to swim in free clusters, the egg yolk was fed for one day, and the next day began to be fed with the combination of egg yolk and zooplankton. Zooplankton, such as rotifer, Cladocera and copepod and other live feed feeding effect is better, the feeding method is a small number of times. In the process of cultivation, sufficient oxygen must be kept in the water body. In addition to running water, an air compressor is used to increase the oxygen in the pond, and the sundries and feces in the cement tank are removed every 2 days.

3. The management of yellow croaker larvae is delicate, the ability to adapt to the environment is poor, the activity ability is weak, and it is difficult to open mouth. Therefore, the management of temporary maintenance phase needs to be careful.

The main results are as follows: (1) the density of patrolling pool should be increased in the temporary cultivation stage, especially from 4: 00 a.m. to dawn, because the dissolved oxygen content of water is the lowest and the activity ability of fish is the worst during this period. Attention should be paid to water intake and drainage, bait density, power supply, fish activity, water temperature variation and fish diseases.

(2) Water quality requires fresh water quality, no pollution and excessive organic matter, pH is 7: 8, dissolved oxygen is about 6 mg / L, and the lowest is not less than 5 mg / L. The influent should be filtered to prevent pollutants and enemy organisms from entering. In order to ensure the amount of dissolved oxygen, an oxygen pump should be set up in the temporary tank.

(3) the sunshaded Pelteobagrus fulvidraco seedlings have the property of avoiding light and like to live in low light environment. Therefore, the temporary culture pond should be shaded to give the larvae of yellow croaker a suitable habitat.

(4) when there are many residual baits and feces in sewage discharge and water exchange, the siphon method should be used to discharge sewage. When discharging sewage, pay attention to the speed of siphoning is not too fast, do not suck out the larvae. If any Pelteobagrus fulvidraco is sucked out, it should be put back in the temporary culture pond.