Culture Technology of Erythroculter ilishaeformis

Warped-mouth red mackerel, commonly known as white strips, Heshun and Taihu Lake white fish, is one of the well-known "three whites of Taihu Lake". Its large size, fast growth, white meat, delicate and delicious meat is the top grade of fish, fresh or pickled food is very delicious. at present, the market price is relatively high in Jiangsu, Zhejiang and Shanghai, and it will be one of the most popular breeding varieties in 2002. The resources of red carp in lakes and reservoirs are decreasing day by day, which can not meet the needs of the market. Therefore, to carry out the research on the biological characteristics, artificial reproduction, embryonic development, pond culture technology, cage adult fish culture technology and key points of medication, it is very beneficial to the adjustment of agricultural industrial structure, the development and utilization of new varieties and the protection of natural wild red mackerel resources.

The living habits of the warped-mouthed red carp

Since the 1970s, China has mainly studied it as a harmful and ferocious fish, mainly on how to limit the development of its population in the reservoir. The fish lives in the upper and middle layers of the water body, and the wild white fish are mainly carnivorous. In recent years, our practice has proved that red mackerel with raised mouth can also eat artificial formula feed. The biological characteristics of red carp with warped mouth are as follows:

The main results are as follows: 1. Roosting habits: warped-beaked red mackerel is a fish that lives in lakes, reservoirs and other large bodies of water. Adult fish generally move in the middle and upper layers of the open water area, swimming fast, sexually violent, and good at jumping; young fish live in groups in shallow water where the current is slow.

2. External characters: upper mouth, thick and upward mandible; slightly curved top of hypopharyngeal teeth, slender Gill rake, 3 chambers, large middle chamber; ventral ribs from the base of ventral fin to anus, hard thorns of dorsal fin thick; gray on the back and upper part of the body, silvery white on the abdomen; long and flattened on the side.

3. Feeding habits: high feeding frequency, feeding as usual in the cold winter and during the reproductive period. Mainly feed on fish, food selectivity is very strong, mostly pelagic small fish, such as Coilia ectenes, mullet, Coilia ectenes, and other fish, insects, cladocera, copepods, have a great chance to devour aquatic plants. With the growth of the individual, the eating habits will change significantly; small individuals mainly feed on algae, aquatic insects, etc., and those with a body length of more than 24 cm take fish as the main food, and the full-length specification of palatable bait fish and the total length of warped-mouthed red mackerel can be expressed as: y: palatable bait fish 5X (Y: full-length of palatable bait fish; X: full-length of warped-beaked red mackerel. Unit of length: centimeters). Under artificial conditions, surimi can be eaten by domestication, chilled fish and shrimp and artificial formula feed.

4. Reproductive characteristics: red mackerel with warped mouth has obvious habit of spawning by tracing the river. It gradually enters the stage of sexual maturity in the middle of May every year, and the reproductive peak period is from mid-June to mid-July (10 days after Grain in Beard of the lunar calendar to 10 days after Lesser Heat) and ends in early August. The male fish matured at the second winter age, the female fish matured at the third winter age, and the female fish matured at the second winter age. The number of eggs laid by female fish is 150000-200000 eggs / kg. Most of the spawning sites are located in the upstream of the reservoir and the upwind nearshore zone of the lake, and the spawning time is advanced or backward due to the difference of water temperature, water level, running water and other conditions. The water temperature for spawning is 20 ℃ and 30 ℃, and the suitable water temperature for spawning is 25 Mel. The current velocity suitable for spawning is 0.1-1.5m/s. Each oestrus lasts for about 2 hours and lays sticky eggs with a yellowish gray egg diameter of 0.7-1.1 mm. The eggs developed on the aquatic plants, gravel and hard mud in the inshore shoals of the lake, and the larvae were hatched after about 48 hours.

5. Growth: rapid growth, large body size, up to 10-15 kg, common individual 0.5 kg 1.5 kg. In general, the body length is the fastest in the first year and the second in the second year. Since the third year, the annual growth of body length has gradually declined. The annual weight gain rate also gradually decreased. We can use the formula W=aLb in which W (g) and L (cm) can grow into commercial fish of more than 0.5kg after 8-10 months of breeding. The fish of 1 and 2 years old were in the period of vigorous growth, and those of more than 3 years old entered the period of slow growth. After sexual maturity, the growth rate of female fish did not decrease significantly, and the growth rate of female fish was faster than that of male fish.

6. Age: in general, the age of the warped mouth can be identified by scales. The age of natural warped mouth red mackerel can reach 9 years old. The relationship between age and body length and weight is complex, but the body length is proportional to the diameter of scales. It can be expressed by the formula L=a+bD.

Pond conditions of red mackerel with warped mouth

The pond should choose a place with sufficient water source, good water quality, convenient transportation and power supply, with an area of 5 to 6 mu, which is too large, with great differences in specifications at the beginning of capture, and difficult to master feed specifications during culture; the area is too small and the yield is low. The water depth is more than 1.5 meters, and about 1 meter can also be farmed.