River crabs can't be eaten when they are dead.

The river crab is a large crustacean, the body is divided into 21 sections, due to the head and thorax sections of the mutual fusion, so the body is divided into the cephalothorax and abdomen two parts. Adult crab back ink color, cephalothorax average length 7cm, width 7.5cm.

River crabs often burrow in the river, river, lake and marsh mud bank, and this in the night activities, to fish, shrimp, animal carcasses and grains for food, and this often migrate to the mouth of the estuary out of the sea in the fall of each year to spawn, the next year, May hatch, develop into juvenile crabs, and then back upstream back to the swim. Its meat is tender and is a favorite food.

Precautions:

River crabs are freshwater growth, seawater breeding crabs. Before the reproductive migration are young crabs, because of its shell color yellow, commonly known as "yellow crab", its gonads are very small, basically undeveloped, the weight of the liver is much greater than the weight of the reproductive glands.

When it completes the last molt, it develops into a "green crab", with dark green shell color, full gonad development, the male crab chelicerae with silky dense downy hairs and long thick setae on the stepping feet, and the female crab with her abdomen completely covering the ventral surface of the cephalothorax, and with the setae on the edge of the abdomen being long and dense.