lobster traps crab traps cultivate high dissolved oxygen in the water

Data:2013/10/23 0:22:51

crab crab crab aquaculture farming technology farming methods crab farming techniques
section overview
common crab, crab, fresh water crabs, crabs, etc., is one of the rare fish. crab meat tender and delicious, nutritious, containing essential protein, calcium, iron and other nutrients, is the unique flavor of aquatic share, its medicinal value is also high, is the traditional diet prescription, crab shell is made of chitin textile, printing and dyeing, pharmaceutical, plastics industry, good raw materials. in recent years, the use of water resources throughout the development of the pond crab, crab rice, crab and crab net enclosures lake pool cover support rare aquatic breeding patterns, and in practice has achieved good production results and accumulated many successful technical experience.
section morphological and biological characteristics
first, the taxonomic status and distribution
chinese mitten crab scientific name, taxonomic genus arthropoda, crustacea, decapoda, suborder crawling, square crab branch, bow legs subfamily, genus eriocheir. crab is widely distributed in china, liaoning, north from the south coast of fujian province, zhu tong hai rivers are distributed, especially in the yangtze river cross lakes, rivers have traces of it.
second, the morphological characteristics
　　 ⒈ external morphology of the head and chest crab healing together, said the head and chest, the main part of the body, the back covered with a hard carapace; chelipeds covered with fluff, carapace significantly elevated, flat forehead, the bezel has four sharp teeth, the amount of width not exceeding half the width of the carapace, forehead six warts rear, front side edge with four teeth strong enough, the abdomen (called crab umbilical) shape (male narrow triangular, females showed a circular) is the main indicator of the difference between male and female gender.
　　 ⒉ internal characteristics crab inside a complete digestive, respiratory, circulatory, nervous and reproductive systems. the liver is the only abdominal digestive gland, but also nutrient storage warehouse, crab breathe with gills, blood colorless, ovaries were "h" shaped, when ripe purple or red bean paste color, well developed, testis milky; ovary and liver collectively, the "crab", the male gonads collectively, the "crab cream", are the essence of people food.
third, the biological characteristics
　　 ⒈ habits crab dwelling with various developmental stages varies. zoea stage must live in brackish or seawater environment, enter the crab stage, will be able to leave the marine environment, living in fresh waters. its main benthic and burrowing lifestyle, generally live in gravel, plants leaves.
　　 ⒉ crab is omnivorous diet and animal feed, animal feed eclipse. animal bait fish, shrimp, snails, clams, mussels, worms, etc.; plant food with duckweed, aquatic plants as well as the malay potamogeton vegetables bean, groundnut cake, wheat, corn and other commodities bait. crab big appetite and bulimia, and have a strong ability to endure hunger. crab also fought and aggressive behavior, and has since cut and regeneration.
　　 ⒊ crab breeding habits generally two years to reach sexual maturity, the annual autumn reproductive migration, spawning in brackish water at mating, hatching and development, crab during development, larval period is divided into zoea, megalopa and crab three phase. zoea after fivemoults to become a megalopa. crab in the crab molting stage more frequently, with the shell and grow faster, increasing the individual to become a crab.
　　 ⒋ crab molting and growth of larval stages into life, yellow, and green crab crab period of three growth stages. crab molting is a sign of growth and development in the crab and yellow crab stage, molting more times, the growth on the fast, the body is also larger. in the case of environmental suitability, especially when food is abundant, every shape after molting growth rate to large. completed around mid-october each year of life the last molting, entered the green crab period. once the yellow turns green crab shell crab, you enter the stage of sexual maturation and subsequently no longer molting, the individual is no longer increased. reproductive one end, crab life is terminated. mature crab year, the second year after hatching died, the majority of crab life of only 2-3 years.
third seed production
a, crab crab cultivation is to cultivate 150,000 / kg or so crabs (also known megalopa) cultivate more than one month, after more than five times moult and grow into 3000 / kg or so crab ( commonly known as stage Ⅴ crab, bean crab) process. nurturing a lobster traps cultivation, cultivation and soil cement pond pond cultivation.
　　 ⒈ lobster cultivate lobster traps crab traps cultivate high dissolved oxygen in the water, fast growth, survival advantages. lobster trapswith polyethylene or nylon mesh woven silk screen, usually lobster traps specifications use a long 4m, height 2m, width 1m. stamped open network, the short side of the lid side of network loading seam zipper, easy opening for feeding and operation. lobster traps can be located at a depth of 1.5-2m, there are micro water, clean water unpolluted lakes, ponds, etc., generally submerged in the water 0.7m. crab stocking density5000-6000 only / m3 of water. lobster traps and other aquatic plants that need investment as crabs attachments.
　　 ⒉ foster circular or rectangular concrete ponds cement pond, an area of 20-50 square meters, pool depth 40-50 cm, depth of 20-30 cm, fangmiao scrubbing disinfection carried out before the pond, put a certain amount of water plants, and make red gas per m3 of water fangmiao20,000 or so.
　　 ⒊ earthen ponds pond cultivation requires plenty of water injection to facilitate drainage, sediment hard, pool ridge watertight, fangtao facilities to be built around the pool, an area of 2-5 acres, depth 0.8m. acre water fangmiao 5-10kg. crab xiatangji best use of tank-reared daphnia and other zooplankton, such as natural food shortage, the available eggs and surimi steamed 1:5 mix, knead with water, fish paste evenly sprinkle the whole pool, megalopa stage can be fed once every 4 hours, daily feeding amount of the total pool of crabs 150% -200%. becomes the stage Ⅰ crab, you can use surimi, shrimp mi, soy paste feeding, after increasing investment crushed snails clam, soybean meal and other bait class at feeding times from 3-5 times gradually changed to 1 - two times. the amount of feeding larvae accounted 80% of total pre-, mid-and late50% -20%. during cultivation often inflatable, add new water to maintain adequate dissolved oxygen.