Crab precocious puberty is when it has not yet reached the product specifications, has changed from the yellow crab clam shell to green crab, gonadal development and maturation, under the stimulation of salinity changes, can mating spawning offspring, this is not up to the product specifications on sex Mature crabs are often called "small old crabs." The individual size of "small crabs" is about 20 to 28 eggs per kilogram. Because they are about the same size as large-sized crabs, it is difficult to separate them. However, if this “small crab†is used as a crab species for breeding for two years, it will not only grow slowly, but also cause death due to indestructible shells, which will result in loss of breeding production. Therefore, the identification of crab species and the identification method of “small old crabs†is crucial for crab farming production. Now introduce some simple and easy identification methods for breeding reference:
First, look at the color of a dorsal armor crab, yellow-green; "small old crab" has a dark green armor and a dark gray color.
Second, look at the female abdomen shape and surrounding abdomen, appendage bristly crab species navel is smaller, not long, triangular, can not cover the head pleural abdominal surface, the edge of the villi thin and short, looks thin, and with the head and chest stickers It's tight and not easy to open. In addition, the base of the umbilicus is relatively narrow and far away from the base of the gingival 4 on the base of the dentition. The female “small old crab†has a large and round umbilicus. It covers almost the entire face of the head and thorax, and is long and elliptical, covering the ventral surface of the cephalothorax. The edges of the umbilicus are densely villous and look thick (long and dense), but not as tightly attached to the head breastplate, and the base of the umbilicus is very wide, approaching even to the base of a 4-foot step.
Third, look at the female crabs, the female crab type relay hose, without ossification; and female "small old crab" transfer device (can be seen open to see the abdomen) hard, for the bone of the tubular body, and the end of the week Raw hair.
Fourth, look at the female crab chewing foot down and step foot bristle female crab species chewing foot down and step foot bristles are short and sparse; "small old crab" dense villi, bristly thick long.
V. Looking at the back of the flesh-formed crabs, the back lines are flat and undulating; the “small old crabs†are uneven and undulating.
6. Open the head and see the gonadal development. The liver of the gonads is yellow and the gonads are not visible. The female crab of the “small old crab†has two purple strips and ovules in the liver area. The male crab has above the liver area. Two white blocks.
VII. Weighing Crabs weighing less than 15 grams are basically not sexually precocious; the “small old crabs†are generally between 15 grams and 50 grams. When selecting the crab species, a crab species with a weight ranging from 10g to 15g should be selected in the north, and generally about 5g in the south, so that it can guarantee to meet the market specifications and avoid the selection of “small old crabsâ€.
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