Techniques for natural propagation of Pelteobagrus fulvidraco in ponds

In recent years, the artificial propagation technology of Pelteobagrus fulvidraco has made a breakthrough, and many places have tried to produce fry and fry on a large scale. However, due to the particularity of the gonad structure of Pelteobagrus fulvidraco, the fertilization rate of artificial reproduction and the survival rate of seedlings are lower, so the price of seedlings is higher. Since 1999, Zhenglu Farm in Changzhou, Jiangsu Province, according to the breeding habits of Pelteobagrus fulvidraco in natural water, explored the natural reproduction technology of Pelteobagrus fulvidraco in pond and achieved success. Pelteobagrus fulvidraco has high natural mating rate, egg fertilization rate and seedling yield rate. The quality of seedlings is good, and good economic benefits have been achieved over the years.

I. preparation of breeding ponds

The breeding pond should choose a pond with water and fertilizer conservation, convenient water source, good water quality, shallow sediment (15-20 cm) and flat, with an area of 1-2 mu. Make a water outlet in the corner of the pond and dig a pond on the edge to collect seedlings. From November to December before the year, the pond water was drained, exposed to the sun and frozen, sterilized and insecticidal. After the 15th day of the first lunar month, it is recommended to be used as a concealment and adjust the water quality. It is generally better to plant the grass in a small flowerpot, and then move the flowerpot into the pond with a distance of 100 cm × 100 cm. If you have the conditions, you can spread a layer of sterilized pebbles in the shallow water around the pond, and at the same time put in about 20 cm of water (filtered by 60-mesh sieve silk) and apply a small amount of organic fertilizer to cultivate water plants. Before releasing the parent fish, clean the pond with quicklime or bleach to kill the wild fish and enemy organisms in the pond. after the toxicity disappears, the fish pond will add water to 60cm. When adding water, the inlet is filtered with 60-mesh sieve silk to prevent the entry of wild fish fry.

II. Selection and stocking of parent fish

1. The source and selection of parent fish

The parent fish of Pelteobagrus fulvidraco mainly come from sexually mature individuals caught in rivers and lakes or commercial fish cultured in ponds. Parent fish used for breeding should choose individuals with pure germplasm, large size, strong physique, disease-free, injury-free and sexually mature. The female weighs more than 75g and the male weighs more than 100g. The ratio of female to male is 3 ∶ 2. In December every year, the selected parent fish were put into a temporary culture pond of 0.2 mu and 0.5 mu, and the stocking capacity was 15000 fish / mu.

two。 Stocking and intensive cultivation of parent fish

At the end of February and early March, the breeding pond was filtered to 60cm and 80cm. At the same time, the gonadal development of parent fish was examined, and the well-developed parent fish were put into the breeding pond with a density of 80,100 fish / mu and a female-to-male ratio of 3 ∶ 2. Intensive cultivation was carried out from March, and self-made soft feed was fed during the cultivation period to ensure that the feed protein content was 40%-42%, while adding appropriate amount of feed premix; feeding twice a day, 8: 9 a.m. and 4: 5 p.m., the feeding amount was 1 pm 3 in the morning, 2 pm in the afternoon, and 5% and 8% of the body weight. After entering April, we should also strengthen the stimulation of prenatal running water, pay attention to the regulation and control of water quality, maintain the transparency at 30-35 cm, gradually add new water, and the water level is controlled at 1.2-1.3 meters at breeding time. From the middle of May to the first ten days of June, the abdomen of female fish is full and soft, the outline of ovary is obvious, the reproductive foramen is round and red and swollen, and the maturity is consistent, and the reproductive process of male fish is obvious.

III. Reproduction and fish fry cultivation

1. Reproduction

When the water temperature reaches 22-24 ℃, the parent fish begin to chase, mate in estrus and lay eggs on the nests. Pelteobagrus fulvidraco has the habit of protecting young. After spawning, the parent fish is guarded at the edge of the nest to prevent other fish from swallowing the eggs. 6-8 days later, it was found that there were seedlings in the pond and began to collect seedlings after swimming, that is, drawing water with a small pump, collecting seedlings at the outlet and putting them into the nursery pond. At the same time, manure or green manure is applied in the breeding pond about a week before breeding to cultivate zooplankton for feeding after the fry opens. General mu application of rotten manure 300kg to 400kg, or mu of green manure 350kg.

two。 Preparation of cultivation pool

Pelteobagrus fulvidraco likes low light, so the fry culture pond is an indoor cement pond with an area of 300 square meters and a water depth of 0.8 square meters. When adding water, the inlet is filtered with 60-mesh sieve silk to prevent the entry of wild miscellaneous fish fry. At the same time, a biological food culture pool of about 1 mu was built outdoors to cultivate food organisms such as rotifers and copepods.

3. Seedling cultivation

The fry collected from the breeding pond were put into the breeding pond with a density of 15000 fish / square meter, and the cultivated bait organisms were often introduced into the breeding pond; at the same time, the fresh low-value fish were mashed with a beater, filtered and sprinkled in the fry pond. At the beginning, the feeding amount is 100% to 150% of the body weight, once every 4 hours, about 60% of the whole day in the afternoon, and once every 6 hours after 2 days. After 7-8 days of temporary rearing, the fry grows to 1.2 cm, which can be divided into ponds or sold. After 7-8 days of cultivation, such fry will form a 1.8-centimeter-2.0-centimeter fry, that is, black larvae, and then carry on the cultivation of large-scale fry.

The key to the success or failure of natural reproduction of Pelteobagrus fulvidraco in ponds is that the breeding ponds and nursery ponds should be cleared thoroughly, the aquatic plants as fish nests should be planted well, and the incoming water must be filtered through a sieve of 40 to 60 mesh.