Techniques of fish culture in river

River fish culture refers to a mode of fish culture in rivers and channels with fish blocking facilities. As a new type of fish culture, it is deeply welcomed by farmers because of its low investment (only for pond fish culture), low production cost and considerable economic benefits. Let's take a look at the river fish culture technology.

Location selection

Generally suitable for fish culture, the water quality of the river should not be seriously polluted, and the dikes on both sides of the river should be firm and not affected by floods and other disasters. There are fewer water inlets and outlets in the river, and can ensure that these inlets and outlets do not escape fish. In addition, the bottom of the river should be flat and easy to manage and fish. The perennial water level drop is relatively small, preferably no more than 2 meters, and the water depth in fish season should not be less than 0.8 meters. The flow rate of water should not be too high, preferably within 0.5 meters per second. There are abundant aquatic organisms in the river or the adjacent waters of the river, which can be easily used. It is also necessary to understand the irrigation, water storage and flood discharge of the surrounding farmland, and solve the contradiction between water use and water conservancy in fish culture when building fish interception equipment and fish culture.

Fish interception equipment

The equipment for fish culture in the river is generally simple and can be intercepted in stages according to local conditions. Select the conditional river section to raise fish species, and solve the fish species needed for river stocking on the spot. The river with relatively open water surface, fertile water quality, quiet environment and convenient management can also build fish intercepting equipment and put artificial bait separately from other parts to carry out intensive cultivation of the river and improve the yield of fish culture.

Encircling and clearing

The main purpose of the cleaning of the river in the enclosure is to remove sludge and ferocious fish. the bottom pollution can be removed by dredgers or small dredgers, or manually dug out in dry or dry seasons. The removal of sludge will improve the water environment and prevent the deterioration of water quality. The ferocious fish in the river are mainly warped-mouth red mackerel, Mongolian red snakehead, snakehead, etc., which can be cleaned up by medicine, hook fishing, repeated fishing with nets and other methods to ensure the safety of fish species.

Fish species selection

River fish culture generally choose river sections with stable water level, fatter water quality and less navigation, and breed silver carp, bighead carp, carp, crucian carp, grass carp, Wuchang fish, etc., mainly rely on natural bait to make fish grow. The river with small water surface and convenient management can be fed with artificial bait properly. At ordinary times, it is necessary to strengthen the inspection and management of fish arresting equipment to prevent damage and escape fish.

Fish species specification

Although the river fish culture also pays attention to eliminate the enemy, because it is an open water area and the rivers are connected, some ferocious fish such as mandarin fish, snakehead, mackerel, sea bass, and other ferocious fish such as eel, rice field eel and soft-shelled turtle can also devour small fish. therefore, if the fingerling is too small, it will be hostile, affecting the survival rate and recapture rate of the species. Secondly, as the river fish blocking equipment to adapt to the current, so the mesh should not be too small, the river should be more than 13.2 cm, 19.8 cm or more better, about 0.25 kg of silver carp, bighead carp hot water fish is better, grass carp better 19.8 cm above 0.25 cm 0.5 kg, grass carp, bream generally more than 9.9 cm, carp, crucian carp more than 6.6 cm.

Fish stocking

200 million fish per mu of water in the coarse river and 300 fish per mu in the intensive river, and then adjusted according to the growth of fish at the end of the year. The river with fatter water quality should mainly breed silver carp and bighead carp, usually accounting for 70% (bighead carp ∶ silver carp = 6 ∶ 4), with 30% green carp, grass carp, carp and carp (510% of carp, crucian carp and carp). The stocking time is generally winter, because the temperature in winter is low, the transportation of fish species is convenient, and the survival rate is high. In addition, the river is rich in natural food, which can accelerate the growth after stocking.

Equipment management

Before fish stocking and heavy fishing in winter, special attention should be paid to checking whether there is a fish escape, controlling the height of the foil door on weekdays, and ensuring that it is often 8cm above the water surface. If the weather changes or flooding, you should pay attention to adjusting the foil door. Usually, you should often remove the dirt in front of the fish blocking equipment, so that the flow of water is smooth, check and maintain the fish blocking equipment at any time, and the relevant materials for maintenance should be prepared at any time.

Segmented fish culture

According to the characteristics of the water surface, the river fish culture should be divided into several sections with net foil, and each section can be tens of mu, hundreds of mu or thousands of mu according to the characteristics of the water surface, so that the species can be evenly distributed and artificially fed. It is convenient for breeding, management and fishing. In order to carry out intensive farming in the river, to ensure the source of fertilizer and feed, pig stables can be built by the river, ducks can also be raised in the river, and powder residue water or waste water from food factories can also be introduced.

Feeding and management

The bait is generally the same as the pond, the principle is to take the main fish culture as the object, take care of mixed fish, and reasonably match natural bait and commercial bait according to different seasons. When feeding, the bait should be put in the table, food field, food frame, all kinds of feed should be fresh. The size of pellet feed should be appropriate, and the content of various nutrients should meet the needs of fish. As the water in the river is flowing, it is best to feed it with pellet feed, and other kinds of commercial feed should be soaked in water before feeding. The concentrate table should be built at the side of the inlet to reduce the loss of feed. In the river where it is suitable for fertilization, some manure, chemical fertilizer and fermented green manure can be applied to turn the water into fertilizer, and attention should also be paid to putting the fertilizer into the inlet.

Disease prevention and treatment

Due to the frequent exchange of river water bodies, the incidence of fish disease in river fish culture is lower than that in ponds, but with the increase of stocking density, fish diseases also occur in intensive culture and high-yield rivers, so the policy of giving priority to prevention and control should be taken. At the same time, the river is often the drainage channel of all kinds of sewage, especially the river near the town, some toxic industrial sewage and waste residue enter the river, causing the death of fish. Therefore, to prevent toxic sewage from flowing into the river is one of the important management work of river fish culture.