Are Leeches Easy to Raise? A Detailed Guide to Cage Culture Techniques

Leeches are also called bloodsuckers, but in our impression, they are a terrifying animal that grows in rice paddies in midsummer, and if you are not careful, they may crawl onto your legs and suck blood in large mouthfuls. But in the eyes of farmers, leeches are very valuable treasures. Fresh leeches can fetch a high price in the city, so are leeches easy to raise? Let's take a look together.

Are Leeches Easy to Raise?

1. Leech farming is actually a process of death. As long as the mortality rate is controlled as low as possible, the yield will be higher. In the end, the success rate is only around ten to twenty percent. Think about it: even conservatively, one leech can reproduce at least 40 times in a year, which means one leech can reproduce at least 40 leeches. 100 jin can reproduce 4000 jin, and if the survival rate is 20%, that is 800 jin.

2. As for how high the cost of leech farming is, that depends on which farming model you use and the cost of introducing breeding stock and seedlings. If it is soil pond and cage farming, in the first year, land rent + infrastructure + seedlings + management tools and facilities cost about 20,000 yuan per mu. In the second year, the infrastructure, tools and facility costs can be saved, and only slight repairs are needed.

Leech Cage Culture Techniques

1. The fish ponds each have an area of 1000 sq m, longer east to west and wider north to south, with a flat pond bottom and no silt, convenient water inlet and drainage, and a year-round water level of no less than 1.0 m. In the pond, multiple rows are arranged in parallel and staggered, with 2 m between each row, no gap between cages within a row, and more than 1.5 m from the pond ridge. Each fish pond is set with 10 rows and 50 cages. The cages are submerged 0.2 m, exposed above water 0.8 m, and the bottom of the cage is about 0.2 m from the pond bottom.

2. The cage is a rectangular open-top cage made of knotless polyethylene mesh fabric, with the four sides of the upper opening extending inward 0.15 m to form an escape-prevention rim. It is fixed around with wooden stakes, and the upper end is tightened with soft steel wire rope.

3. After all the preparatory work is done, place 20 jin of leech egg cocoons that have been incubated for 20 days in foam box soil, cleaned, and are about to break out of the cocoons. In the 20 young leech cages, stock about one jin of egg cocoons per cage at about 400 per cage, then place 2 foam box lids in each cage; on the 10th day, put in 2-3 one-inch loaches and 4-5 summer grass carp.

4. On the second day after the leech egg cocoons are placed in the cages, cover 4 rows of five longitudinally arranged cages with polyethylene mesh sheets cut to a specification of 20.5 m × 2.05 m and a mesh size of 5 cm to prevent bird damage, and use a net needle to stitch and fix the bird-proof net onto the cages at a standard of 1 knot per 1 m.

What Do Leeches Eat?

1. Leeches are omnivorous animals. Their main way of life is sucking the blood or body fluids of animals. They often use plankton, insects, and mollusks in the water as their main bait. Under artificial conditions, various animal viscera, cooked egg yolk, compound feed, plant residues, freshwater snails and shellfish, miscellaneous fish, earthworms, etc. are used as bait.

2. Leeches grow fastest when eating river snails, which are also their main food. Young leeches begin to eat three days after entering the water. After about seven days, they begin to shed their skin. Each shedding is one instar. The best growth period for leeches is from instar 3 to instar 9 at a temperature of 25°C to 28°C. Young leeches grow from 5 cm--6 cm to finished leeches of about 10 grams, which takes about 20-30 days. About 200--300 leeches are raised per 1 sq m of water surface. Under normal circumstances, one young leech sucks one snail every three to five days. Taking 100 sq m as an example, about 35 kg of river snails are fed each week.

Leech Farming Prospects

1. Demand has increased substantially: China's elderly population is increasing, and the number of people suffering from cardiovascular and cerebrovascular diseases is rising year by year. The number of new drugs, special drugs, and Chinese patent medicines produced with leeches as the main raw material is increasing day by day, and the required leech raw materials have exceeded those of the 1980s to 1990s by dozens of times.

2. China began artificial leech farming in 1995 and achieved success. Although the current scale of development is not yet large, the benefits are very considerable. The net profit per mu is above 20,000 yuan, which is 7-10 times the current benefit of fish farming. Because the market prospects for artificially farmed leeches are promising and the benefits are considerable, some far-sighted people have begun to organize large-scale artificial farming to seize the market.

Leeches can also be dried and sold. One jin of air-dried leeches can fetch as much as 600 yuan, and leeches have high medicinal value. After preparation, they can be used in traditional Chinese medicine to treat stroke and high blood pressure, and can also be used to prevent and treat cardiovascular and cerebrovascular diseases. They have many uses and are in great demand.