Breeding techniques of northeast leeches :
Wide-bodied goldenrod leeches overwinter in the mud and in the water at the bottom of the pond in winter, and are unearthed in late April or early May in the northeast. If the temperature is still low, the excavated wide-body goldenrod leeches often hide in the mud mass of dry grass and silt tangled up at the edge of the pond. When the weather gets warmer, they come out again. Leeches are hermaphrodites, two individuals mate with allogeneic fertilization, each leech can lay eggs, and the northeast leeches lay eggs in the cocoon period from mid-to-late May to late July. Tan spongy egg cocoons are laid in the soil near the pond, 2 to 8 cm above the ground and about 20 cm from the water surface, which of course varies with the drought of the weather and the level of the groundwater table. Mature individuals can lay an average of 4 to 5 egg cocoons after mating. After about half a month of hatching, the young leeches begin to drill out their cocoons until the beginning of August. Each cocoon can drill out 13 to 35 young leeches, with an average of about 20. Only mature individuals that have been dormant overwintering can mate and lay cocoons in the spring, and cannot reproduce offspring in summer or autumn. Leech bait Gold thread leeches mainly suck up body fluids such as field snails and river mussels (artificial breeding is not suitable for river mussels). The area of the breeding pond is wide and the snail can be stocked at one time, and the area can be released once in about half a month, and the stocking is generally 2 to 3 times the seed leech. The breeding period of the field snail coincides with the breeding period of the wide-body goldenrod leech, and the small leeches can eat the small field snail, and the field snail can be caught in the wild and purchased in the market.
After the leeches produce egg cocoons, they can generally hatch naturally froglets without artificial care. However, in order to improve hatching rates and reduce the harm of natural enemies, it is also necessary to carry out artificial incubation.
After a few hours of egg cocoons produced by naturally hatched leeches in the soil, the cocoon wall gradually hardens, and many foams outside the walls gradually dry out of the wind, and the original walls between the bubbles burst, leaving only a honeycomb or sponge-like protective layer composed of short columns connected into five or six corners. The egg cocoon of leech needs to hatch under natural conditions at a temperature of about 20 °C, and if the temperature is low, the incubation time is long, and if the low temperature below 10 °C occurs for a long time, it is possible to die, and the young leeches cannot be hatched. Incubation humidity (referring to the water content in the soil around the egg cocoon) is generally between 30% and 40%. The soil is too wet, easy to compact, not conducive to ventilation; the soil is too dry, easy to make the egg cocoon lose too much water, are not conducive to the hatching of eggs.
The cocoon is purple-red at first stage. Over time, it turns light red after a few hours and finally purple. The cocoon is 9 to 15 mm long and 6 to 10 mm wide. In nature, the initial incubation stage is about the end of May and the beginning of June, and the number of hatches accounts for 20% to 30% of the total; in the middle of June, the number of hatches accounts for 40% to 50% of the total; in late June, most of the egg cocoons have hatched, and the number of hatches during this period accounts for 30% to 40% of the total.
Artificial incubation Artificial incubation is a method of artificially controlling temperature and humidity, or by artificially creating an environment suitable for incubation to improve hatching rate.
(1) Full artificial incubation
This method relies entirely on artificial hatching and is mainly suitable for farmers who have produced few eggs or have just started breeding leeches. Full artificial hatching generally use plastic, wood, enamel and other pots, boxes, utensils, the bottom of a layer of 1 ~ 2 cm thick hatching soil (can be loose sand and loose loam soil mixed together), and then put the egg cocoon into the pot, box, in order to maintain a certain humidity, the top can be covered with another layer of cotton and other things. The temperature during incubation should be controlled between 20 °C and 23 °C, too high or too low is not conducive to the hatching of the egg cocoon. The humidity of the incubation soil is between 30 % and 40%, and the relative humidity in the air should be maintained between 70 % and 80%. When the humidity is insufficient, spray water directly onto the cotton cloth, but to prevent excessive wetness. In the case of suitable temperature and humidity, it generally takes about 25 days to hatch the young frogs. In order to prevent hatchlings from crawling and escaping, a large water tank or other water container can be set up under the incubator and the appropriate amount of water can be poured in. According to the water tendency of leeches, the hatched frogs naturally fall into the water. Then put some sticks or bamboo chips in the water for the young leeches to climb on and roost. After the egg cocoon has hatched, it can be transferred to the rearing site as a whole for wild rearing.
(2) Artificially create a suitable environment for natural incubation
When the amount of spawning cocoons is relatively large, the workload of incubation is larger, the hatching pond can be specially established, and the egg cocoon can be loaded into the incubator, placed directly on the shore of the hatching pond, using the natural temperature, and then adding the method of artificially increasing humidity, after 25 to 35 days, the young frogs can be hatched. The young leeches are then free to climb into hatchery ponds. However, it should be noted that on rainy days, the plastic sheet should be covered to prevent excessive rain from hatching the egg cocoon.
Northeast leech breeding network is located in Changchun City, Jilin Province, and now it is a comprehensive leech breeding network with scientific research and breeding, wholesale operation, technology promotion, market trade, leech seedlings and dried leech products as the main business items. Our northeast leech breeding base is the largest and most professional comprehensive breeding base in the north, and welcomes customers to come to consult and exchange.
In addition, in 2018, seedlings and young seedlings have begun to book, and the booking discount is preferential. At the same time, dried leech products are recycled and a series of techniques for leech culture are provided.