Carp artificial breeding technology

Squid, local name is three fish, three fish, etc., belonging to the é²±-shaped head, é²±, é²¥. Squid is a valuable food fish, its meat is delicious, nutritious, high fat content, Chinese and foreign famous, creating a high exchange rate.

The eel is widely distributed, and it is distributed in the Bohai Sea, Yellow Sea, East China Sea and South China Sea. It is an anadromous fish and lived in the sea for most of its life. Every year from April to May, sexually mature fishes cluster into rivers for the reproduction of the river, forming a salmon production period for each river. Since the 1970s, due to severe damage to resources, it has become extremely rare to fish in the upper and middle reaches of the Yangtze River. In order to protect and restore the resources of squid, artificial breeding of squid has also emerged while relevant departments have taken protective measures.

First, characteristics

Squid, body side flat, long garden-shaped. Kiss the tip, mouth big end position. The upper jaw has a short cut in the middle. The abdomen has large, sharp, serrated rib scales. Caudal fins deep fork-shaped, body and head grayish black, upper side bluish green luster, underside

And abdomen silver white. No sideline fish. Scales smaller.

Carp is a famous warm-water anadromous fish. It reaches the breeding season every year. It enters the rivers of the Pearl River, Qiantang River and the Yangtze River for genital migration. The eel that enters the Yangtze River reaches Yichang as far as possible, but the number is very small, mainly distributed in Jiangsu, Anhui, and Ganjiang along the Yangtze River. The squid that enters the river often activities in the middle and lower layers of the water and has a strong swimming ability. After the broodstock laid their eggs, the fish scattered and then they left the sea to get the bait and winter. Juveniles grow and develop in some sections of the Tongjiang Lake and the mainstream of rivers. From September to October in the autumn, the temperature of the water drops, and the water level of the rivers and lakes begins to decline. The young squid descends along with the river water, descends into the sea, grows to sexual maturity in the ocean, and then participates in upstream reproduction.

Squid is a filter-feeding fish and feeds on plankton, but at different stages of its life history, the type of feeding and the intensity of feeding are different. Young calamus before the river reaches the sea mainly eats cladocera, copepods, rotifers, hexapods, shrimp, microcystis, diatoms, green algae, etc.; pups descending from the river into the sea, along the coast Bait migration, the main intake of marine copepods, followed by the garden sieved diatoms, aphids, six-limb larvae and shrimp and so on. Carp grows faster, and after two months of incubation, body length can reach 6.0 cm. Females grow much faster than males. The eel is mature enough to reach maturity at 3rd age, about 46.5 cm in length when sexually mature, and 42 cm in males. Before the first maturity, it grew fastest and gradually slowed down later. The spawning period lasts from late May to late July. The spawning grounds in the Yangtze River system are mainly distributed in the middle reaches of the Minjiang River in Jiangxi Province. Most of the spawning grounds are sandy or pebbled; the flow velocity is about 1 m/s; and the flow rate is 1200-1800 cubic meters per second on the river section. Two to three days after the flood peak is the spawning peak of the eel. The water temperature at the time of spawning is 25-32°C and the optimum temperature is 27-30°C. Brooders generally prefer to spawn in the evening or early morning. The proportion of eggs is slightly larger than that of water. In still water, it often sinks to the bottom of the water, and the flowing water floats in the upper layer of the water. The number of eggs in common individuals ranges from 1.5-2.5 million eggs, and the largest number is more than 3 million, which is a type of spawning.

Second, artificial breeding

1, broodstock fishing. Many of the parents used for artificial breeding come from natural, mature salmon and are captured as soon as the spawning season approaches. The fishing gear commonly used is a three-layer gauze net with a woven fabric and a net length of 60 meters and a height of 2 meters. The cable diameter is 0.25 mm, the internal net is high and relaxed, and a pocket is formed during operation. Select the squid during the flood season and watch the patrols after the nets. When the storm is calm, there are fish nets. The upper stalks are shaken and the floats are pulled down. Fish should be taken immediately. Take care when picking fish. The action is light and fast. Take the fish without leaving the water and try to touch the fish as little as possible. Captured fish are immediately kept in the cabin and constantly changing or flushing to prevent lack of oxygen or injury.

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