The whitebait is the largest species in the family of the whitebait. The general specification is about 120mm, the largest individual is up to 210mm, the body is slender, colorless and transparent, there are no scales, the front is slightly cylindrical, the back side is flat, the snout The tip of the head is flat, the head is flat, the jaw is longer than the upper jaw, the dorsal fin has a fat fin, and the eyes look golden from the back and look silverish from the side. There are several black spots on the ventral surface and on both sides of the living body.

The silverfish lay eggs in winter and the spawning water temperature ranges from 2-8OC. The spawning period ranges from mid-December to mid-to-late March. The breeding individual has a male body length of 90-175mm and a female fish of 90-210mm. The difference is larger. The male side of the Great Whitebait has obvious sexual development along with the development of the gonads. Generally from the beginning of November, the anal fins appear with two rows of reproductive scales on the two sides of the anal fin, which are sticky and have an adsorption effect. Anal fin hypertrophy into a fan-shaped, a red dot on the front of the heart, the neck and chest and abdomen began to become rose red color, the female does not have side sexual characteristics.

The seedlings required for the first feeding of large whitebait can be collected in natural waters, and artificial insemination can be performed on site to obtain fertilized eggs (the fertilized eggs are sold on the fish farm). Fertilized eggs can be hatched in the indoor water, when the water temperature is maintained at 4-6 °C, 30-40 days film, the hatching rate is higher, the stocking effect is better. Controlling hatching time has important production significance. After the egg seedlings emerged at the end of the second month, it is easier to obtain foods to eat, which will help improve the survival rate of the seedlings.

Restocking methods

In the embryo of the fish eggs, the stocking effect is better than that of the fry. One week before filming, the eggs were hatched into the pool and 20,000 eggs per acre were placed. From September to October, 30 kg of large silverfish could be caught. If the stocking amount is too large, the juvenile fish will have insufficient feed. The depth of pool is 1-1.5 meters.

Cultivating technology

Fishes feed on rotifers and nauplii. Ten days after hatching, they ate and three days after eating, they died without food. Therefore, the stocking pond should be given enough fertilizer in advance to ensure that there is enough food during the start of food. The fully fermented manure is applied and lime water is properly applied. After 10-15 days, the water color is concentrated and the rotifers can reach a considerable density.

Juvenile fish staple foods no juvenile, Cladocera, copepods and Chironomid larvae. In this period, fertilization can be done. The fertilizer amount should be controlled according to the water color and the water temperature. The transparency of the pool water should be as large as 40 cm or more and the water depth should be kept at 2 meters.

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