1. The back cover length of rare crabs should be no less than 16 cm, which is equivalent to 5 grams. Rare crabs can reach a maximum of 1.5 kilograms. Only male rare crabs can be caught (the male crab has a V-shaped belly cover, or crab navel, while the female crab has a large and round belly cover).

2. DungenessCrab's Chinese translation is called Treasure Crab, which aptly shows that as an important resource of American crab products, it is indeed a valuable treasure. This kind of crab is big and fleshy, and it is caught in waters from California to Alaska. Nowadays, there is a great market demand for rare crabs in both San Francisco and Shanghai. This crab only lives in the northeastern Pacific Ocean from the Aleutian Islands in Alaska to southern California.

3. Washington State is the main producing area of rare crabs. Fishing can be carried out in winter, and the fishing season is in the offshore waters of Pujie Bay in summer and autumn. In most years, the annual output of Washington State often exceeds 8, tons, one third of which comes from offshore fishing. Oregon and California each produce about 48 tons. Alaska produces about 21 tons, most of which are caught in the southeast waters of Alaska in summer.