Detailed Explanation of Key Techniques for Artificial Breeding of River Snails
The flesh of river snails is tender and delicious, with a unique flavor, and is rich in protein, fat, phosphorus, calcium, iron and vitamins. Farmers can use small water surfaces or rice fields to breed river snails. The relevant techniques for river snail breeding are introduced as follows:
1. Living habits of river snails. River snails are gastropod mollusks that like to live in waters that are warm in winter and cool in summer, with soft bottom substrate, abundant food, and fresh water quality, and they especially like to gather in places with slight flowing water. River snails are omnivorous, mainly eating tender stems and leaves of aquatic plants, organic debris, and so on, and they like to be active and feed at night. The most suitable temperature for growth is 20-27°C.
2. Reproductive habits of river snails. When the water temperature rises to 15°C in late spring and early summer, river snails crawl out of their overwintering holes and feed and grow at the bottom of the water. They begin to reproduce in April, and July-August is the peak breeding season for river snails. Female snails aged 1-2 years can produce 20-30 offspring, and female snails aged 4 years or more can produce 40-50 offspring. Newborn snails grow rapidly and can reach sexual maturity in one year. The spawning season is from April to September each year.
3. Selection of river snail breeding sites. The breeding site for river snails should be chosen in places with sufficient water sources, good water quality, humus soil and convenient transportation, preferably with flowing water. The snail pond specifications are generally 1.5-1.6 m wide and 10-15 m long, or can be based on the terrain. Build ridges around the pond, with a ridge height of about 50 cm. Set up water inlet and outlet openings at both ends of the pond, and install anti-escape nets. At the same time, sparsely plant aquatic plants such as wild rice stem in the middle of the breeding pond. This can not only improve the land output rate, but also create a good ecological environment for the growth of river snails.
4. Stocking of breeder snails. Generally, from late March, breeder snails can be stocked successively. Ten days before stocking river snails, spread quicklime over the whole pond at 50-100 kg per mu to remove wild fish, shrimp and other miscellaneous snails. After 3-4 days, pile organic fertilizer in the pond and breed food organisms for river snails to feed on. Breeder snails can be purchased from markets or captured by oneself. Stock 100-120 breeder snails per sq m, and 4 summer fry of bighead carp can also be stocked in the pond. Before stocking breeder snails, first apply an appropriate amount of manure in the pond to cultivate food organisms. Stocking of breeder snails is best completed before the early stage of river snail reproduction. Breeder snails should be selected as live snails with light brown color, thin and complete shells, and round bodies with blunt tops. River snails can be bred alone, or partially polycultured with silver carp and bighead carp fingerlings, or mixed with river snails and loach.
5. Water quality regulation. The quality of the water in the breeding pond is one of the keys to the success or failure of river snail breeding. First, water quality must be guaranteed to be excellent. Water containing large amounts of iron and sulfur must never be used. Because in water with too high iron content, the mortality rate after stocking seedlings is very high, and the shells of those that survive also have red rust attached, and even the snail flesh appears reddish-brown. Sulfur water likewise gives river snails a sulfurous odor, making them unfit to eat. For breeding water, slightly turbid natural water bodies such as rivers or ponds are best. Do not use water that is too clear and transparent. The water body should contain abundant natural food and sufficient oxygen. The snail pond should frequently be filled with fresh water to regulate water quality. Especially in the breeding season, it is best to keep the pond water flowing. In high-temperature seasons, flowing water breeding gives better results. In spring and autumn, slight flowing water breeding is better. The water depth of the snail pond needs to be maintained at about 30 cm.
6. Feeding management. In extensive breeding methods in natural waters, it is only necessary to maintain water fertility. Applying an appropriate amount of organic fertilizers such as stable manure, chicken manure, cow manure, pig manure or rice straw at intervals can meet the growth needs of river snails. They can also be fed with vegetable leaves, rice bran, soybean cake, rapeseed cake and offal such as animal internal organs. Cake-type feeds should be soaked until soft before feeding, and other feeds should be chopped and mixed evenly before feeding. River snails do not have high nutritional requirements. Simply mixing rice bran, wheat bran and soybean cake in a ratio of 60%, 25% and 15% makes a first-class feed for river snails. Within the suitable growth temperature (20-27°C), river snails have a strong appetite and can be fed once every 2 days, with each feeding amount being 2%-3% of body weight. When the water temperature is 15-20°C or 28-30°C, feed twice a week, about 1% each time. When the temperature is below 15°C or above 30°C, feed less or not at all. Under natural conditions, river snails can grow to individuals of 6-8 g in the same year, while artificially bred individuals can reach 12-15 g.
7. Overwintering management. When the water temperature drops to 8-9°C, river snails begin hibernation. Hibernating river snails use clay to seal the shell apex, leaving only a small round hole on the soil surface and occasionally emitting bubbles. River snails do not eat during the overwintering period, but the breeding pond still needs to maintain a water depth of 10-15 cm. Generally, change the water once every 3-4 days to maintain an appropriate oxygen content.
8. Harvesting and transportation. After one year of careful rearing, stocked young snails can reach 10-20 g, and newly hatched snails in the same year can also reach a size of more than 5 g. When harvesting river snails, adopt the method of catching the large and leaving the small, and marketing in batches. Selectively scoop out adult snails, keep young snails for continued rearing, and pay attention to retaining some female snails so as to achieve natural reseeding, after which there is no need to stock seedlings again. According to their living habits, in the high-temperature seasons of summer and autumn, choose early morning or nighttime to pick them up from bamboo branches or grass bundles placed on the bank or in the water; in winter and spring, choose noon on sunny days to pick them up. In addition, methods such as feeling and catching in the pond or draining the pond and picking them up can also be used to harvest river snails.
The transportation of river snails is very simple. They can be held in ordinary bamboo baskets, wooden buckets, and so on, or packed in woven bags. During transportation, it is only necessary to keep the river snails moist and prevent exposure to the sun.