The newly built brick cement pool can't be put in immediately. Alkaline substances (Portland cement, calcium hydroxide, etc. It takes a long time (about 20 days) to desalt in the newly-built cement pool before it can be put into use.
The newly-built breeding pond can't feed enough seedlings at one time. Only when the overall environmental conditions of aquaculture ponds tend to be balanced in the food chain can the number of seeds be gradually increased. We can't mechanically think how many kilograms or fish can be put per square meter, but we should weigh them according to the specific conditions of the breeding pond and the growth of leeches.
Seed selection. Some damaged, abnormal, hybrid and pathological leech seedlings should be removed. For leeches with internal injuries and trauma, if they cannot be identified, they can be temporarily raised for 2-3 days and then identified. If you want to have a good harvest within one year after planting, you must choose leeches that are strong for more than two years as seedlings. The bigger leeches are, the stronger they are, the higher their egg production, and the higher their hatching rate and survival rate. Leeches over five years old are good, but old leeches are few.
Blood clots are not the only sensitive bait for leeches. When leeches are hungry, they swallow everything they can eat. Untreated blood clots may pollute the water quality, and the cost is high, so it should be considered comprehensively when using.
Leech has a wide range of feeding habits, including benthic mollusks such as snails, mussels, shellfish and their larvae, fish and insects, Daphnia and other organisms, aquatic mycelium algae and nutrient-rich humus. Leeches and aquatic organisms are interdependent. As long as the preliminary work is done well, fermented animal manure is often added, and sunshine, air and water are added, a virtuous circle of the food chain can be obtained to ensure adequate food supply. This has low cost and good effect, and can also optimize the ecological environment, which is more active and convenient than feeding and changing water on time.
If the food chain is properly matched, the water quality will be fresh, dissolved oxygen will be sufficient, plankton and benthos will grow rapidly, and the stocking density of leeches will increase. According to our experience, 50-80 kilograms of seedlings per mu of water surface can completely maintain a virtuous circle of the food chain.
As a supplement to the main food chain, some artificial feeds can be fed, including livestock, poultry and fish feeds. The feeding amount can be determined according to the cost, season and the dynamic proportional relationship between physical and chemical culture and culture density in the culture pond, such as water temperature.
If the water quality is fresh, more leeches can be fed at the peak of 22-27℃, and the leeches can spend less time before going out for food at night.
Throwing stones, branches, etc. is not a good idea. In the aquaculture pond, not to mention throwing them away at random to avoid side effects. The morphological substances in aquaculture ponds should be arranged in an orderly way, following the principles of convenience, labor-saving, time-saving, labor-saving and high efficiency.
In addition to setting up bank slopes, islands, beaches, planting grass and trees, aquaculture ponds should also set up shallow water areas and deep water areas. This is more conducive to the ecological cultivation of leeches and overcomes the limitation of simply setting water depth.
The reproduction of leeches varies with time, region, season and environment. In the middle and lower reaches of the Yangtze River, some leeches will nest in shallow soil near the water's edge from April, and May-June is the incubation period. During this period, quiet environmental conditions should be provided on the beach slope. After eating, leeches mostly dig holes during the day. When the food intake is insufficient, it will temporarily live among aquatic plants or adsorb on the wall of the pond, and with its sensitive sense of smell and hearing, it will attack and prey quickly at any time.
At present, the artificial cultivation of leeches should be mainly ecological cultivation, and the cultivation test and domestication test can be carried out in greenhouse if conditions permit. At least 1/2 of the aquaculture pond should be planted with plants.
As a sideline, raising leeches in water bamboo field, arrowhead field, lotus pond and rice field is also a desirable value-added method.
1. Historical market review of leeches: From 1998, there was only 7-8 yuan at that time, and it began to rise in the second half of the year, reaching the first peak 19 1 50 yuan in February and April. Then it fell back to 65-70 yuan, and fluctuated between 70-80 yuan during the six years from 65438 to 0997. Three years later, in 2000, the price soared to the high price of 200-220 yuan, and the second peak appeared. In this century, it fell to the low price of 150- 160 yuan in February-March, 2002, and then rose step by step, and climbed to 270-280 yuan in the second half of 2004, setting a record high. The high price continued until April 2005. Then slowly fell to the first half of 2007 160- 170 yuan. From the historical market analysis of leeches, low prices and high prices are rising in every fluctuation period; Second, the high price lasts longer and longer. Second, the output of leech is 1. Most species of leeches live semi-parasitically, and some species prey in childhood and live as blood-sucking animals in adulthood. The host of bdelloid rotifer is often a class, not an animal. For example, medical leeches like to suck the blood of all vertebrates. On land, it moves like an inchworm and is agile because of the antagonistic contraction of the longitudinal muscle and the annular muscle alternately attached to the body by the front and rear suction cups. Young leeches feed on plankton, but when they don't suck blood, they feed on larvae of small insects, worms and snails, and also eat mud humus, so their diets are miscellaneous. When leeches suck human and animal blood, anticoagulant water elements are first released from the sucker, so that the host's blood can be sucked smoothly. Under certain temperature conditions, leeches are full of vitality. After the water dries up, some species can dive to the bottom of the mud and lose 40% of their weight to survive. After the leech is cut off horizontally, two new individuals can regrow from the fracture site. This is the unique regeneration ability of leeches. Leech has strong adaptability, hunger tolerance and disease resistance. Slow-flowing streams, ditches, potholes, ponds, paddy fields, swamps and lakes, as well as warm and humid grasslands, are all places where leeches live, feed and breed. Leeches are found in lakes, ponds and paddy fields in most parts of China, but they are mainly found between 32 and 38 north latitude, which is the most suitable range for leeches to grow. Such as Taihu Lake, Hongze Lake, gaoyou lake Lake and Weishan Lake in Jiangsu, especially the rivers and lakes south of Huaihe River are widely distributed. Over the past 20 years of reform and opening up, the rapid development of China has been extensive, at the expense of consuming a lot of resources. Farmers grow crops and use a lot of chemical fertilizers and pesticides, and the soil quality has changed. It has been a fact for more than ten years that beneficial insects and birds have decreased and insect disasters have been serious; A large amount of industrial sewage has been discharged, most rivers and lakes have been polluted and the water quality has deteriorated. This year's Taihu Lake bloom is the epitome. The living space of leeches is constantly being squeezed. Coupled with the drying up of some rivers and lakes, the reduction of wild resources has been aggravated. In this regard. Second, leeches generally have to be three years old to be sexually mature and have reproductive ability. Every spring and autumn, when the water temperature exceeds 15 degrees, they mate, climb ashore at about 20 degrees, and lay eggs on wet soil 30 centimeters above the water. At this time, it is also the time for people to catch leeches. Driven by interests, predatory capture, large and small, led to a decrease in population, and reproduction declined after many years. The supply of commodities in some producing areas has fallen sharply. Especially the small leeches in the northeast, the new goods entering the market this year are obviously lower than those in 2006. 2. Leech reproduction status Leeches are hermaphroditic, and different species are fertilized. Leeches of each species can reproduce, and they can reproduce 2-3 times a year. Leech has strong adaptability, hunger tolerance and disease resistance. It has been reported that leeches can be raised artificially, in ponds, pits, tanks and barrels, regardless of geographical conditions. However, a large number of aquaculture products have not been listed for many years, but some merchants have falsely reported their aquaculture income, thus buying wild young leeches and reselling leech seedlings to obtain illegal income, while few deceived farmers have gained considerable benefits. Leech farming still needs to solve the practical application problems in technology, and it will take longer for large-scale development and batch listing. It is difficult to make up for the decline of wild supply and alleviate the development trend of tight supply in the future. It can be seen that the above are the main reasons for the decline of leech production in recent two years. The decline in leech production is not a problem in recent two years, but it has recovered slowly. It is estimated that the output in 2007 is between 200 and 250 tons. Third, the sale of leeches Leeches are special medicinal aquatic animals, which have many medicinal functions in medicine and can treat many diseases. It has the effects of removing blood stasis, dredging channels and activating collaterals, and can be used for amenorrhea due to blood stasis and traumatic injury. In recent decades, modern medical research has found that the saliva of fresh leeches contains hirudin, which can inhibit the activity of blood enzymes. Hirudin inhibits thrombin, that is, prevents fibrinogen from forming fibrin, thus inhibiting the formation of thrombus. The components contained in leech are helpful to the blood circulation of replantation of severed limbs, which can improve the success rate of operation and eliminate sequelae. Using this characteristic of leech, we can use it to suck pus from trauma patients to clean up blood stasis. Studies have proved that leeches have special effects in preventing and treating cardiovascular and cerebrovascular diseases and anti-cancer. For example, pharmaceutical factories in Shanxi, Shaanxi, Hebei, Henan, Heilongjiang, Jilin, Guangdong, Hong Kong and other places use a large number of Chinese patent medicines for treating cardiovascular and cerebrovascular diseases, such as Xinfukangrong Capsule, Instant Zhishuan Decoction, Han Shi Tansukang Capsule, Huoxue Tongmai Capsule, Zhuyu huoxue capsule, Shuxuetong Injection and so on. In April 2008, about 80 pharmaceutical companies were developing similar drugs. However, from the analysis of market sales in recent three or four years, the processing quality of leeches is different, and the impact of small leeches in Northeast China is fast and slow. Its sales volume has not increased significantly in some reports, but there are many statements about the annual sales volume, which is estimated to be between 300-400 tons. Fourth, the market prospect of leeches In the past 20 years, the price of leeches has increased by more than ten times, especially in recent years, the price of leeches has fluctuated, and there are many artificial factors. In the future, there will be more merchants purchasing leeches in the market, which will stimulate the recent market development. Under the influence of some favorable factors, some producers are reluctant to sell, thinking that there is still room for growth after the output declines. It's just that the production and sales of leeches have changed now. Does the price match its value? It is also an aspect that affects the development of the market outlook. Therefore, 2008 is a crucial year for the development of leech market, which may usher in a new peak. With the development of modern biotechnology, pharmaceutical companies pay more and more attention to the research and development of pharmacology, so the cultivation of leeches has also begun to diversify. The discovery of the medicinal value of leeches in Philippine cattle may lead to a revolution in leech breeding.