One, crab selection
1. Identification of crab species: Different types of crabs and different types of crabs should be identified. The crabs in the middle and lower reaches of the Yangtze River should be cultured. The crabs in the Yangtze River system are the best, and the crabs in the water systems of the Minjiang River, Liaohe River and Lijiang River are the best ones. It is appropriate to adapt to the local conditions. Under normal circumstances, the crabs below the third stage are extremely difficult to distinguish, and the young crabs are distinguished mainly by their length, body color, and body shape. In terms of body color, the crabs of the Yangtze River are blue-green with a bright and shiny body and a ventral, milky white surface with transparent body surface.
Evenly distributed; L. crabs body color is darker, the surface of the Minjiang River crab, especially step foot pattern is obvious, uneven pigment distribution, abdominal rust color. Judging from the characteristics of body type, the juvenile crab of the Yangtze River has a flat body with little bulging amplitude of the cephalothorax. The length, width, and proportion of the step foot are coordinated with those of the cephalothorax. Other crabs do not have this condition.
2. Quality identification: Regardless of the type of crabs that are stocked, all crabs are required to have strong constitution, neat specifications, and complete limbs. The crab species should be caught, transported, and released now, and the holding time should not be too long. Sustaining rest for a long time, it is very easy to injury and break, and greatly affect the survival rate. Buy crabs on the market or crabs at the hawker office. Be cautious and cautious. You should purchase seed directly from the cultivation pond or the bow. "Precocious Crab" should not be put into place regardless of the size of the individual. In the Yangtze River natural fishing crab
There are few cooked crabs, and many are artificially cultivated. Where the belly of a female crab has grown into a umbilicus, the umbilicus is covered with bristles as "precocious crabs," which are sexually mature and no longer grow. Sharp umbilicus, if the base on both sides of the prominent, mostly "precocious crab" should be removed.
3. Specification selection: The specifications of the crab species to be put in should be comprehensively considered in terms of breeding methods, breeding time, stocking capacity, and economic costs. If the young crabs are cultivated in the first year and the adult crabs are grown in the second year, it is advisable to purchase the small-size ones before the end of July. It is advisable to invest 400-1000 or so kg after August. When you grow crabs, you should purchase 200 or less kg/kg.
Second, paddy fields cultivate young crabs
From May to June, 0.5-1kg of crab seedlings will be put in the mu, and about 7 days before the crabs are put into the pond, 300kg of fermented cow manure and other organic fertilizers will be applied in order to cultivate live bait-like zooplankton of crabs. After entering the pool, several days of splashing the egg-yolk paste, soymilk, fish paste, etc.; after the metamorphosis is juvenile crab, the fish, soybeans, etc. can be made into a paste-like, even feeding, the daily amount according to the pool crab weight 1 - 1.5 times flexible grasping; when the specification reaches 2000/kg, it is changed to feeding aquatic grass, south
Melon, etc., mainly control animal diets and try to maintain the water depth. If the water quality permits, reduce the number of flushes properly, so that the young crabs are in a state of semi-pregnant and half-hungry, inhibiting the growth of their shells, and reducing the “early-maturing crabsâ€.
In June-August, 1-1.5 million juvenile crabs of 2000-4000/kg can be cast. Just after the beginning of the pool feeding fish, oysters, snail meat and so on, half a month later to be fully restored to their constitution, after the basic shelling once again have to strictly control the feeding of animal feed. 1000-2000 mu were put in control and feeding was conducted in that year, and crabs were cultivated directly in the second year.
After the winter solstice, some straw should be put in the crab ditch for wintering.
Prior to fishing, the crabs should first lower the water level, then quickly flush water, set a net in the water inlet, and use the habit of juvenile crabs against the water to arrest. If the water temperature is too low, dry crabs should be gently excavated from holes, grass or soil.
Third, adult crab breeding
1. The release of crab species: The stocking densities will be determined according to factors such as specifications, growing requirements, cake materials and feeding and management levels. Before and after the Spring Festival, about 100-300 birds per kg of natural fishing crab species in the Yangtze River will be planted with 500-600 acres. The number of individual crabs will reach more than 150g in autumn and more than 50kg per mu. If the stocking capacity is increased, the discharge specifications will decrease. The increase in production is not very obvious, due to small individuals and low prices. Put small-sized crab species or artificially cultivated crab species, Liaohe crab, etc.
Appropriate increase in the amount of about 30%, not more than 1,000 per mu. Before the Spring Festival, it is not appropriate to put the crabs in the river; in the beginning of June-July, the crabs in the current year will be released in the same year. The specifications will be about 400 birds per kg and 500-600 birds per mu, and most individuals can grow to over 75 grams. Before the release of the crab species, temperature regulation is required to increase the survival rate.
2. Day-to-day management: Daily management must be regular and institutionalized.
(1) Strengthen feeding: Daily feeding should be done in combination with coarse and coarse, and animal and vegetable baits should be matched to ensure the needs of young crabs for plant food (mainly water grass). Scabs, snails, etc. crush the shell, hawthorn, potatoes, etc. must be cut into pieces. Usually fed once a day, in the early evening crab ditch sprinkled. During the growing season, feeding is done once at about 9:00 a.m., which accounts for 1/4 of the total feeding amount. Each pool is equipped with 2-3 oyster-type food tables. The leftover food can be removed to check the eating situation.
It is necessary to master the "two-headed and middle-green" foods on the bait mix; appropriate animal feeds should be added in the early stages; both the animal and the plant should be weighed during the growing season to ensure that the juvenile crabs eat well; late feeds with higher starch content are controlled. The feeding of animal foods to prevent deterioration of the water quality leads to shelling. The amount of feeding depends on the season, weather, water quality, and the eating and feeding conditions of the crabs to control the degree of basic eating on the day. Insufficient water plants in the pond. To make a make-shift investment, eat leftover grass and fish it out at any time.
(2) Control of water quality: Frequent refilling of fresh water, 1--2 times per month in early spring, 3--4 per month in late spring and early summer, high temperature in summer, 3- or 5-days plus or 1 round of water. Quicklime should be used to regulate water quality.
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