What are the common problems in cage farming of river snails?

I think everyone is very familiar with river snails. They are a fairly common dish in daily life, and are especially popular in the late-night snack industry. When eating late-night snacks or at food stalls in summer, I think everyone will definitely order river snails, so their market demand needs no explanation from me; everyone can see it.

Cage problems in river snail farming

For river snail farming, cages can be set up to raise snails in ponds with a large and deep water surface and good water quality. The cages for cultivating river snails are generally made from 20-mesh netting. The cage area can be large or small, but the depth of the cage should be less than that of fish-farming cages, generally 50 cm is suitable. The stocking density can be slightly higher. Raising river snails in rice fields is technically simple and is an effective way to comprehensively utilize rice fields and increase returns. The rice field is required to hold water about 50 cm deep.

Ditch problems in river snail farming  

The ditches for river snail farming are generally 100 cm wide and 50 cm deep. Idle and miscellaneous land can be used to dig ditches for raising snails, and the irrigation ditches of melon fields, vegetable plots and vegetable gardens can also be used to raise snails. If the ditch is newly dug, drainage and irrigation facilities must be built so that water can be drained and irrigated. After the ditch is dug, use fences to divide it into ditch sections for convenient management. On the ridge surface of the ditch for river snail farming, economic plants such as melons, vegetables, fruit trees, grass and beans can be planted.

River snail farming techniques  

1. Site selection for farming  

River snails have strong stress resistance, few diseases and a high reproduction rate, and have low requirements for farming sites. In rural areas, many ditches, flooded fields and ponds can be used for stocking. If it is an open pond, red azolla, duckweed, water hyacinth and other plants can be grown on the water surface for shade, and bamboo poles, wooden strips and the like can be inserted in the pond for river snails to rest on. This can both harvest aquatic green manure as feed and raise river snails to increase income.  

2. Collection of seed snails  

River snails mostly reproduce naturally. For artificial farming, they can be picked from rice fields, wild rice stem fields and muddy ditches, or bought from the market, and then live snails with light brown color, thin shells, round bodies and blunt tails are selected as seed snails. Generally, river snails with a body weight of 15-25 g reach sexual maturity and can reproduce at temperatures above 15°C. Female snails are large and round, while male snails are small and pointed.  

3. Stocking and reproduction  

The optimum growth temperature for river snails is 20-25°C. If it is below 15°C or above 30°C, river snails stop feeding, and below 10°C they burrow into the soil to hibernate. South of the Yangtze River, stocking can be done from March to November. If stocked in a natural area, 11 seed snails per sq m is enough (3 males and 8 females). If a pond is dug for single-species farming, 100-500 can be stocked per sq m, and the water depth should preferably be 0.8-1 m. A layer of more than 10 cm of mud should be kept at the bottom of the pond to facilitate crawling, feeding and resting by river snails. When stocking, males and females can be stocked together and they will reproduce naturally. 

4. Feeding  

River snails are omnivorous animals. Rice bran, vegetable scraps, melon leaves, animal carcasses and commercial feed can all be fed to them. Generally, aquatic plants, soil humus and vegetable and melon peels are the main food. In fertile rice fields, in fish-snail mixed farming, or in low-lying areas where red azolla, green azolla, water hyacinth and the like are grown on the water surface, feed can be given sparingly or not at all.  

5. Reproduction management  

River snails are viviparous animals. In the south, April-May and September-November each year are the breeding periods. Female snails generally give birth in batches, and each river snail can produce 20-30 small river snails at a time. After giving birth, the mother snail needs 14-16 months before it can reproduce again. Newly born small snails weigh 0.5-1.5 g, can reach more than 3-5 g after 6 months of rearing, and can reach about 9 g after 9 months.  

6. Capture and harvest  

When capturing river snails, adult snails should be selectively taken, and more female snails should be left. Harvesting can be done in batches. In midsummer and early autumn, when the water temperature is relatively high, river snails mostly hide in the soil and among grass at noon, so they must be picked in the morning and evening, and can also be picked after draining the water. For every 100 female snails stocked, the annual yield can reach 100 kg.

Which varieties of river snails are sold on the market  

There are many varieties of river snails. The common types with relatively high economic value include five: Cipangopaludina cathayensis, Cipangopaludina chinensis, Cipangopaludina ventricosa, Cipangopaludina longispira and Cipangopaludina ussuriensis.  

These five common varieties respectively belong to two genera, Cipangopaludina and Margarya. The snails of the genus Margarya have 7 whorls, are not inflated, and have spiral color bands. Representative varieties include Cipangopaludina longispira, Cipangopaludina ventricosa and Cipangopaludina ussuriensis. The shells of the genus Cipangopaludina are smooth on the surface and have inflated whorls. Representative varieties include Cipangopaludina cathayensis and Cipangopaludina chinensis. At present, the common one in North China, the Yellow River Plain and the Yangtze River basin in China is Cipangopaludina cathayensis.

Although there are many kinds of river snails, their nutritional value is roughly the same. Generally, river snails are farmed in cages. On the one hand, this is to prevent the river snails from escaping, and on the other hand, it is convenient for the farmers, allowing the river snails to get a living environment suitable for their growth.