Artificial cultivation technology of yellow eel live bait water earthworm
Water earthworms (also known as silk earthworms, red worms, ditch worms, etc.) are commonly known as aquatic oligochaetes of the link animals and are an important part of the freshwater benthic fauna. Water earthworms are generally small, swinging in water, rich in nutrients, fresh body contains 8.85% crude protein, containing 18 kinds of amino acids. Because of its strong adaptability to the environment, easy to cultivate, fast proliferation speed, and its comprehensive nutrition, good palatability, not bad water quality, is an excellent natural food for yellow eels.
1． Common species of water earthworm
There are more than 70 species of aquatic oligochaetes in 5 families and about 28 genera in China, which belong to two orders. In the cultivation of water earthworms, there are the following species that are more common, have a wide distribution range, a relatively large number and are more suitable for aquaculture:
(1) Su's tail gill
It is widely distributed throughout our park. The body of the tail gill worm is thick, 1.2-2.2 mm in diameter, often curled, and the length of the live body is more than 100 mm. The living body is purplish-red, with a body segment of 18.5 or more, and each segment has bristles on the dorsal abdomen. Sexually mature individuals have a distinct ring band on the posterior head X-XII. body segment with a grayish-white bump. Starting at about 1/3 of the posterior part of the body, the midline of the dorsal abdomen has ... For filamentous gills, the first and shortest, gradually grow, with as many as 60-160 pairs, which is a clear difference between this species and other water earthworms. It is mostly distributed in the mud layer of 3 to 5' cm on both sides of the ditch flowing water, and belongs to the oxygen-loving species. The pale reddish tail gills protrude from the earth and sway up and down with the stretched gill filament as a plane, and its frequency reaches about 100 times per minute. When disturbed, the tail gills immediately shrink into the mud. At high temperatures or lack of oxygen, the tail gills protrude longer and the gills stretch more openly. 'The cocoons of the gills are oval or broad bean-shaped, with a length of 1.186-2.745 microns and a short diameter of 1.047-1.733 microns. Pale brown, the gel membrane is transparent, and an egg cocoon usually contains 1-4 eggs, up to 7. Depending on the degree of development, the eggs appear dark or light brownish yellow. At one end of the cocoon, there is a protruding "handle" that resembles a plug, and the hatched young worms break out of the cocoon. The incubation time of the cocoon varies with the water temperature, taking about 25 days at 25-30 °C and 28 days at 14-21 °C.
(2) Huofu water silk worm
It is also a widely distributed water earthworm. The body of the Huofu waterworm is slender, with a body diameter of 0.5-1.2 mm, a body length of 35-55 mm, and no gills. The body is brownish red and the posterior part is slightly yellowish-green , which is different from the Chinese frillary worm. The ring band resembles a ring. The waterworm is distributed in humus-rich mud, with a concentration of less than 20 cm and is more resistant to low oxygen. When oxygen is abundant in the water, the insect body is reddish brown, the mud is brown and yellow when there is little oxygen, and the lack of oxygen is often wrapped in a group to stay in the near water surface or deep mud. In ordinary life, the insect body sticks out of the soil and makes left and right serpentine swings, frequency, 80-90 times per minute. It is very sensitive to light and disturbances, and can quickly shrink into the mud, and its surface has a small mud pipe on the surface. The cocoon of the Horph water worm is slightly spindle-shaped, but has a prominent short stopper-like "handle" at both ends. The egg cocoon is dark brown, the gel membrane is not very transparent, and the egg particles are generally 4, and the number is 7. The incubation time of the vermix cocoon is 10-15 days at a water temperature of 26-31 ° C.
In addition, the Chinese frillus worm of the family Frillidae, the freshwater single-hole worm, and the caudal worm of the family Nymphidae are common. Chinese frillator body length 80-150 mm, width of about 1 mm, body color reddish, freshwater single-hole worm, body length 15-40 mm, body width of about 1 mm, life color pale white, rear reddish rear end, tail disc worm, the back end of the body has a gill disc.
2． Habits of life
Water earthworms usually live in micro-flowing water, organically rich bottom silt. In places with a lot of humus, organic pollution is often serious, oxygen is often lacking, they are in the hypoxic environment towel, from the mud bottom out of most of the body, constantly swinging, very rhythmic, in order to promote the formation of water flow, in order to facilitate the insect body gas exchange, the less oxygen in the water, the faster the swing. Once frightened, they shrink into the mud. Water earthworms devour soil while ingesting bacteria, organic detritus particles, and benthic algae from the soil, as well as some miniature animals in the soil. Worm feces are excreted through the anus. Water earthworms are hermaphrodites, allogeneic fertilized. During mating, the anterior ends of the two individuals are combined with the ventral surface, and each male foramen discharges semen into the other's fertilized sac for storage. Separate after exchanging semen. After the eggs mature, the links secrete mucus to form banded egg sacks (egg cocoons). The eggs are laid in the egg sack, which moves forward to the hole of the fertilized sac, and the sperm flows out to fertilize the egg. The egg sacks fall off from the front of the body and sink into the mud under the water. The openings at both ends of the egg sac automatically contract and close into an oval-shaped cocoon. The fertilized egg develops into a small earthworm in the cocoon. The time it takes to hatch from a fertilized egg to hatch a young worm varies with the water temperature and species, and the rate of growth and development varies depending on the water temperature. Water earthworms usually live to about 80 days, with a few surviving to 120 days. Water earthworms are extremely fertile. Like terrestrial earthworms, water earthworms are highly regenerative and can quickly regenerate into complete individuals after cutting.
3. Cultivation and harvesting technology of water earthworms
The cultivation of water earthworms can be carried out by pond culture, field culture, and water bodies such as ditches, canals and pits. Pond culture is the highest yield.
(1) Build ponds and cultivate ponds
It is advisable to choose a place with sufficient water sources, convenient drainage and irrigation, and sit north to south to build a pond. The scattered starry sky next to the suburban domestic sewage discharge ditch, the wastewater pool of the thermal power plant, the side of the creek and the river, and the leakage water distribution center of the fish seed farm station under the reservoir dam are all good places to build ponds. The water earthworm pond is 10-30 m long, 1-1.2 m wide and 0.2-0.25 m deep. The bottom of the pond is best to lay a layer of stone slabs or marked with "triad soil", set up a water inlet ditch and mouth at the higher end, set up a drainage ditch and mouth at the lower end, and set up a metal net barrier at the inlet and drainage outlet to prevent fish, shrimp, snails and other predators from breaking into the pool with the water, pay attention to the fact that the worm pond must have a certain length, otherwise the feed and fertilizer put in are easily taken away by the water flow and lost. If you can't build a long strip. Circular manifold ponds or curved manifold pools can be built according to local conditions. The water layer of submerged medium in the culture tank is generally maintained at about 10 cm, and too shallow or too deep is not conducive to the life activity and reproduction of water earthworms.
(2) Preparation of culture medium
High-quality media is the key to shortening the harvest cycle of water earthworms and thus achieving high yields. The raw materials in the cultivation period can be selected from three types of substances: sludge rich in organic matter (such as fish pond silt, rice field fertilizer mud, black mud by the sewage ditch, etc.), loosening agent (such as bagasse, etc.) and organic manure (such as cow manure, chicken manure, etc.). The filling procedure is: first lay a layer of bagasse or other loose agent at the bottom of the pool, the dosage is 2-3 kg per square meter, then lay a layer of sludge, so that the total thickness reaches 10-12 cm, add water to submerge the base surface, soak for 2-3 days and apply cattle, chicken, pig manure, about 10 kg / m2. Before receiving the worm seed, a layer of sludge with a thickness of 3-5 cm is applied to the surface, and at the same time, it is thinly sprinkled on the mud surface. Layers of fermented bran mixed with rice bran, corn flour, etc., sprinkle 150-250 grams per square meter. Finally, add water so that there is a water layer 3 to 5 cm deep on the surface of the medium. At this time, water earthworm species can be introduced. Production practice has proved that the medium of the new tank can generally be used continuously for 2-3 years.
(3) Introduction
Water earthworms are highly adaptable to various environments, and their species sources are abundant everywhere. Sewage ditches, harbor wharves, livestock farms, slaughterhouses, canteen restaurants, sewers in residents' living areas, sewers where tanneries, food factories, sugar factories discharge waste, etc., often live a large number of water earthworms, which can be harvested according to local conditions. The introduction time is generally in the middle and late September, when the temperature drops to about 28 ° C, you can introduce the seeds into the pond, and the seed worms can be transported back together with sludge and waste residue, because it contains a large number of worm eggs, and the inoculation work is relatively simple, that is, the recovered worm seeds are evenly sprinkled on the medium surface of the worm pond. 500-750 g of worm species per square meter of culture area is appropriate. Such inoculation is cultivated for 30 days at a water temperature of 25-28 ° C, and the daily production of worms per square meter can reach about 500 grams.
(4) Daily management
After vaccination, daily management is one of the most important aspects of obtaining high yields.
(1) Preparation and feeding of water earthworm bait. All non-toxic organic substances can be used as bait for water earthworms after fermentation. Water earthworms especially like to eat sweet and sour wheat husks, rice bran, corn flour and other grain feed, and human and livestock manure, domestic sewage, and waste after processing agricultural and sideline products are also their high-quality feed after fermentation and decomposition. But whatever... Kind of bait, before feeding (especially manure), must be fully fermented, decomposed, 'mountain is conducive to the decomposition and transformation of nutrients and earthworm feeding, the second is to avoid the fermentation of raw material in the worm pond thermogenic and cause earthworm death. Manure can be naturally decomposed in the pit according to the convention, grain feed in the first 16-20 hours before feeding with water fermentation, mixed at room temperature above 20 ° C, added water to the hand kneaded into a ball, dropped that is scattered as a degree, and then shoveled into a pile, patted firm, covered with plastic sheet. If the room temperature is below 20 ° C, yeast flakes need to be added to promote its fermentation, the dosage is about 1 tablet per 1-2 kg of dry feed. On the first day, from 15:00 to 16:00, the ingredients are mixed. On the morning of the third day, it can be fermented and matured: the thick sweet and sour wine aroma of the plastic sheet is unveiled and the worms can be fed. Usually the feeding time is arranged after harvesting water earthworms, when feeding fertilizer, it should be diluted and stirred with water first, remove debris such as grass residue, and then evenly sprinkled on the surface of the medium. Do not pile up in clumps in a pool of worms. The inlet should be closed before feeding to avoid the loss of feed drifting. In order for water earthworms to reproduce quickly and produce high yields, it is necessary to feed them regularly. Every 10 to 15 days after inoculation and before harvesting, 200-' 250 kg of decomposed manure should be applied every 667 m2. Since the beginning of harvesting, about 300 kg of manure and an appropriate amount of grain feed have been applied after each harvest to promote the rapid multiplication and growth of water earthworms. When feeding, the feed should be filled, stirred, weed residue removed, and then evenly sprinkled on the medium surface. Do not let the feed clump or pile up in the worm pond. When feeding, it is necessary to close the inlet and outlet water to avoid causing the feed to drift and scatter.
(2) Cultivate environmental control. Environmental factors such as water, air temperature, pH, oxygen, medium (soil), and feed are closely related to the survival, growth and reproduction of water earthworms. In the management of breeding, it is necessary to conscientiously do a good job in regulation and control to ensure the healthy and rapid growth and reproduction of water earthworms and achieve the purpose of stable and high yield. Water depth regulation is more appropriate at 3 to 5 cm. In the early spring, the pond water can be shallower during the day to use solar energy to increase the temperature of the pool, and at night it is appropriate to deepen to facilitate heat preservation and antifreeze; in the middle of summer, the pool water should be deeper to reduce the irradiation, and it is best to plant vine crops over the grasshopper pond in advance. In winter, the temperature of the vermicore pond can be increased by the method of plastic film covering. The water flow for aquaculture should not be too large or too small. Too much water flow will aggravate the unnecessary energy consumption of the water earthworm itself, and it will also take away nutrients and cocoons from the pool, which is not conducive to increasing production. Too small water flow or even a long time to maintain a static water state will make the dissolved oxygen content in the water insufficient, but also not conducive to the elimination of water earthworm metabolic waste and other harmful substances, which may lead to deterioration of water quality, destroy the living environment of water earthworms, and cause a large number of deaths of water earthworms in serious cases. Generally speaking. The flow rate of 0.005-0.01 m3 per second per mu of breeding pond is more appropriate. The average daily temperature from July to September is about 28 °C, and the production of earthworms in this season accounts for about 45% of the annual production. There is considerable potential to increase the production of water earthworms at low temperatures. According to the test, the use of high-heat substances such as cow dung as a culture medium, and the construction of plastic greenhouses on the earthworm pond can greatly increase the yield of water earthworms. Water earthworms have a strong tolerance to acidic or alkaline environments, and its adaptation range to pH is 5-9, and the most suitable range is 6.6-8.3. Due to factors such as continuous fertilization and bait, the pH in the pool water tends to be high or low for a short period of time. Too high or too low a pH can cause water earthworms to dry knot, dehydrate and wither, darken their body color, and become sluggish and die. Since the water earthworm has a wide range of adaptation to pH, and the flow water plays a role in regulating the pH, the pH in the pool water under artificial cultivation conditions will not cause harm to the water earthworm, and usually no special measures are required to adjust the pH in the pool water. Water earthworms need to suck in oxygen dissolved in water for metabolism. If the flow is cut off, the weather changes or the density of the worm is too large, the worm will leave the medium and float in a lumpy form, which is a sign of severe hypoxia. Hypoxia usually resolves itself after sunrise or after increasing the amount of water inlet. If it cannot be released all day long, there may be a problem with the medium and the need to immediately beat the pool or replace the medium. Production practice proves that the medium of the new pool can generally be used continuously for 2-3 years, and it should be completely updated when it expires. In addition, water earthworms are very sensitive to harmful substances in water, such as pesticides, herbicides, fertilizers, heavy metals, etc. Therefore, industrial wastewater, farmland water with pesticide residues, and other medicinal waters cannot be used.
(3) Stir the pool. Also known as "rolling pond" and "flipping pool", it is an important part of breeding management. The role of the pond is to prevent the culture medium from being compacted, the second is to drive away the harmful gases produced by the decomposition of the metabolic waste and feed (fertilizer) of the water earthworm, the third is to effectively inhibit the multiplication of moss, duckweed and weeds, and the fourth is to keep the culture medium flat and smooth, which is conducive to the smooth flow of water. The method of stirring the pond is to use a wooden rake, bamboo rake or other rake to stir the medium comprehensively and gently pool by pool to improve the living environment of the water earthworm. The interval between stirring ponds depends on the water temperature, water flow, water earthworm growth and harvesting conditions. 'It is usually stirred every 3-4 days during the peak production season, and can be extended to 5-7 days in other seasons. When stirring, it is necessary to consciously bury moss and weeds in the soil of people.
(4) Prevent and eliminate predators. The predators of water earthworms are mainly fish (loach, yellow eel, carp, crucian carp, etc.), frogs, birds, domestic ducks and other carnivorous or omnivorous animals, which will directly feed on water earthworms. The field snails, large bottle snails, ring snails, river clams and various mussels in the breeding pond will compete with water earthworms for resources such as feed, fertilizer and living space; if they grow and reproduce in large quantities, they will consume a lot of nutrients from the culture medium, and will also cover the water earthworms, making the living space of water earthworms smaller or even lost. These are the predators of water earthworm farming, and if found in the pond, they should be removed in time.
(5) Harvesting
The reproductive ability of water earthworms is extremely strong, and the hatched young earthworms can spawn and reproduce in more than 20 days: each adult earthworm can lay a few to dozens of egg cocoons once, and can lay 1 million to 4 million eggs in a lifetime. After 30 days of inoculation, the new earthworm pond enters the peak breeding period and can remain prosperous for a long time (but the lifespan of the water earthworm is not long, generally only about 80 days, and a few can live to 120 days. Therefore, timely harvesting of worms is also one of the key measures to obtain high yields. The harvesting method can be taken to cut off the water or reduce the water flow the night before, resulting in lack of oxygen in the worm pond, and the next morning it is easy to scoop the water worm masses with a small copy net made of polyethylene mesh. The amount of harvest of each worm is based on the "worm mass" on the surface of the fishing medium. Such harvests do not affect their population fertility, nor do they reduce yields due to the untimely death of the worm body.
In order to purify the water earthworm, you can first pour a bucket of earthworm balls in the water in a square filter cloth, remove most of the sediment, and then pour a large basin to flatten it, so that its thickness does not exceed 10 cm, the surface is covered with 1 piece of threaded gauze, flooded 1.5-2 cm, covered tightly with a basin lid, closed for about 2 hours (when the temperature exceeds 28 ° C, the sealing time should be shortened, otherwise it will suffocate the water earthworm), and the water earthworm will drill up from the eye of the gauze. Lift the lid of the pot and lift the four corners of the gauze to obtain pure water earthworms that are completely separated from the dregs. This method can be repeated 1-2 times to bring up the water earthworms in the dregs. The remaining residue at the bottom of the basin contains a large number of egg cocoons and a small amount of worm body, which should be poured back into the culture tank.
(6) Temporary maintenance and transportation
If the water earthworm cannot be used up or sold out on the same day, it should be temporarily raised. During temporary rearing, the water earthworms temporarily raised in each square meter of temporary pond should be 10-20 kg, stirred and dispersed regularly every 3-4 hours, and the water needs to be changed once a day to prevent it from gathering into clumps for a long time and causing hypoxia death. The temporary period is generally not more than 3 days. When long-distance transportation is required, the time on the way is more than 3 hours, and the double-layer plastic film oxygen bag packaging, each bag contains no more than 10 kg of water earthworms, add 3 kg of clean water, sufficient oxygen, when the temperature is high, it is best to add an appropriate amount of ice cubes to reduce death and ensure safe transportation to the destination.