Key Technical Points for the Breeding and Grow-out Management of River Snails

Although river snails are a relatively easy species to breed, and their investment cost is relatively low, and the number bred is also relatively large. Therefore, in the process of breeding river snails, there are still many techniques and skills, and only by reasonably mastering these techniques and skills can one effectively avoid some unnecessary risks.

Grow-out Management of River Snails

1. Stocking density: Generally, 1000 young snails are stocked per square meter. In addition, 5 silver carp and bighead carp fingerlings can be polycultured, but omnivorous and carnivorous fish must not be present. Algae, water hyacinth, azolla and other aquatic plants should be grown on the pond surface to provide food, shade from the heat and habitat for the river snails.

2. Water quality: The water source for breeding river snails is best unpolluted water from rivers and ditches, because the water from these sources has an appropriate water temperature and is rich in dissolved oxygen and natural food. During the feeding and management of river snails, the water depth can be kept at 30--40 cm, and it is generally required to change the water 2 times per week. The suitable pH value of the pond water is 7--8. When the pH value is low, apply 0.15—0.18 kg of quicklime per square meter, applying once every 10—15 days. When the pH value is high, apply 0.05-0.06 kg of dried chicken manure per square meter of pond, applying once every 10 days, for 2—3 consecutive applications. It is strictly forbidden to apply pesticides in snail-farming fields, or to let water sources containing pesticides flow in.

3. Topdressing in the grow-out management of river snails: For newly built breeding ponds, before stocking river snails, 100-150 kg of decomposed compost can be applied per 100 square meters of pond to improve the soil. The method for making compost is: pile rice straw, quicklime and chicken manure layer by layer alternately on land, seal it with plastic film, and use it after it is fully decomposed. During the river snail breeding process, a certain amount of farmyard manure should be applied as appropriate according to the water quality to breed plankton, so as to ensure that the river snails can often have sufficient natural food.

4. Preventing escape: River snails have the habit of climbing over water to escape, so the escape-prevention facilities at the water inlet and outlet must be repaired frequently.

5. Preventing natural enemies in the grow-out management of river snails: Do not let omnivorous and carnivorous fish such as common carp and black carp mix into the pond, so as to avoid harming the river snails. Birds, cats, rats, moles and other animals will all eat or harm river snails, so measures must be taken to prevent their harm. (6) Harvesting in the grow-out management of river snails: After 1 year of careful rearing, river snails generally can reach more than 10 grams each. They can be harvested by draining the pond, and at the same time large individuals can be selected as parent snails for breeding.

The Prospects for River Snail Farming  

At present, naturally grown river snails are far from meeting market demand, while river snail farming has fast growth and high yield. To farm river snails, first do market research. Most river snails sold on the market are caught for sale. To put it simply, this is making a profit without capital, and they are not mainly selling river snails, only selling them as a side item, so the price of caught river snails will not be very expensive.  

In addition, late-night snack shops eat relatively many river snails. But relatively speaking, very few households eat river snails. River snails are not clean, and for housewives, removing the tails is troublesome to handle. Even if the river snail sellers help remove the tails, hygiene is a problem. First, one does not want to wait for them to finish handling it; second, if an order is placed to buy again the next day, how the customer handles it becomes another problem.  

River snails generally cannot enter households as an ingredient. They are also rarely used in hotels, and cannot be presented on formal occasions. In the end they flow into late-night snack shops, because most people eating late-night snacks hold the mindset of "big bacteria eating small bacteria, and small bacteria being regarded as tonic," but they will not eat them frequently.  

Therefore, sales direction and sales volume must be considered well. For farming river snails, it is best to first do local market research and a cost budget, and only then determine whether river snail farming is feasible. 

What Are the Nutritional Requirements for Farming River Snails  

1. Protein. Protein is a nutrient necessary for the growth of golden apple snails, for maintaining life and for forming body tissues. It not only constitutes their physique, but also serves as a component of enzymes and hormones, playing a very important role. Main sources of protein: Protein is divided into two major categories, plant protein and animal protein. Plant protein mainly comes from cereals, beans and so on; animal protein mainly comes from livestock meat, poultry meat, fish, eggs, milk and so on.  

2. Fat. Main functions of fat: supplying heat. Fat tissue plays roles in regulating body temperature, preventing body heat from dissipating, and protecting internal organs. Therefore, during growth and development, snails must continuously take in a certain amount of fat from feed to meet physiological needs.  

3. Carbohydrates. The carbohydrates in bait are mainly starch and cellulose. The main function of carbohydrates is to supply heat energy. All nerve tissue, cells and body fluids contain carbohydrates. Carbohydrates can assist the oxidation of fat and promote growth and development.  

4. Vitamins. Vitamins are a class of compounds essential for maintaining the normal physiological functions of snails. There are many kinds of vitamins, usually divided into two major categories, fat-soluble and water-soluble. Fat-soluble vitamins include vitamin A, vitamin D, vitamin E and vitamin K, while water-soluble vitamins include B-group vitamins and vitamin C.  

5. Energy. To maintain life and metabolic activities, snails must obtain energy from bait every day to meet the body's needs. The main energy substances in feed are carbohydrates, lipids and proteins. In the body, through biological oxidation, they combine with the oxygen inhaled by the gills and release energy.  

6. Inorganic salts and trace elements. Although inorganic salts and trace elements cannot supply the body with energy, they are of great significance to normal life activities. They not only constitute tissue components, but are also substances necessary for maintaining normal physiological functions, so meeting the needs of snails for inorganic salts and trace elements is extremely important. Apart from ammonia, nitrogen, hydrogen and carbon, all other chemical elements are collectively called inorganic salts. Among them, calcium, magnesium, potassium, sodium, phosphorus, sulfur and chlorine are present in relatively large amounts, while others such as iron, iodine, copper, zinc, manganese and cobalt are present in extremely small amounts, but they have a great influence on the nutrition and functions of the body.

The Breeding Period of River Snails  

The initial reproductive age of river snails is 1 year old, and they begin to reproduce above 15 °C. Each snail produces about 20-30 young snails each time, parent snails 4 years old or above can produce 40-50, and those 5 years old or above can produce 50-60. The number of offspring produced is related to the age of the parent snail and environmental conditions. From fertilized egg to the birth of the young snail, it takes about 1 year of gestation in the mother's body.  

Every year from March to April, river snails begin to reproduce, and thereby become lively and frequently mate. When female and male river snails are seen embracing each other and turning up and down horizontally, that is the movement of river snails when mating. Sperm and eggs fertilize at the top part of the oviduct. The fertilized egg passes through the blastula stage and gastrula stage, then through the developmental stages of trochophore larva and veliger larva, and finally develops into a young snail. The embryonic development of river snails, up to the development of the young snail, all takes place inside the snail's body, so river snails are ovoviviparous.  

The breeding period of river snails: July--August is the season of vigorous reproduction for river snails. They conceive in their abdomens the young snails to be produced the next year, give birth to the young snails in March-April of the next year, then mate again and conceive young snails in their bodies again.  

In river snail populations, female snails are often more numerous than male snails. Among 100 river snails, female snails account for about 75%-80%, while male snails are only 20%-25%. During the reproductive season, because male snails frequently mate with female snails, the lifespan of male snails is only half that of female snails. The lifespan of male snails is generally only 2-3 years old, while the lifespan of female snails can reach 4-5 years old, and some female snails can reach more than 6 years old.  

The breeding period of river snails: young snails 15-20 days after birth weigh 0.025 grams each. Young snails born early can grow to a body weight of 6-8 grams in the same year, and under artificial farming can reach 12-15 grams, especially with relatively fast growth in the first 3 months.

From the above analysis by the editor, presumably everyone can see that the market prospects for river snails are very good, and the market demand for river snails is very large, mainly in the late-night snack sector. As people's nightlife becomes richer and richer nowadays, especially among some young people, river snails are also deeply loved by some young people!