Dungeness Crab Facts

During the crab season, that traditionally begins on November 15, the Dieushok leaves port in the early morning hours to return with fresh Dungeness Crab. Each and every crab is measured and checked for a hard shell. A spongy shell indicates that a crab has recently molted, or shed it’s shell and has less meat. To be an educated shopper/consumer for crab is important and this comes with knowing the crabs life cycle.

DUNGENESS CRAB
DID YOU KNOW? Male Dungeness crab find females with the use of pheromones (chemical scents) and after mating the male may remain with the soft-shelled female for two days to insure her protection.

In California, the most abundant crab is the Dungeness crab, Cancer magister. Related to this crab are several other species that are caught by commercial and recreational fishermen in southern California and northern California. South of Monterey Bay, the Dungeness crab decreases rapidly in abundance. In southern California, where only an occasional Dungeness crab is caught, considerable quantities of several crabs collectively referred to as "rock crabs" are caught and sold. These are: the yellow crab, Cancer anthonyi, the rock crab, C. antennarius, and the red crab, C. productus. The latter two species also are common in northern California, but only a limited number are caught for sale because of the presence of the larger, meatier, and more abundant Dungeness crab Sport fishermen and women do, however, take "rock crabs" for home consumption. In northern California there is one other related species, the slender crab, C. gracilis, small in size, with which the young of the Dungeness crab may be confused. It is with the gross descriptions of the related species mentioned above that this article is concerned, the aim being to aid identification by a few readily observed characteristics rather than by detailed scientific descriptions.

1. These crabs are all of the family Cancridae and the genus Cancer, meaning hard shell, and are characterized by a carapace that is broadly oval and saw-toothed on the front side. In all, nine species of this family and genus are found in California, but the other four species, Cancer jordani, C. oregonensis, C. amphioetus, and C. gibbosulus, are not described here as they are small and comparatively rare. In California, all the crabs of the above family and genus have black-tipped pincers, except the Dungeness crab and the slender crab which have white-tipped pincers.

Molting of Crabs
Molting is general among crustaceans. The hard shell of the crab prevents growth and so at intervals of about one year the entire hard shell of the crab is cast off or molted. Before the actual molt, a new protective covering is started, but this is uncalcified and therefore soft. During the period when the shell is cast off, the crab is known as a "soft" crab and it is during this interval of a few days that the crab undergoes a period of rapid growth before the new shell becomes calcified and fixes the size of the crab until the next molt. At molting time the old shell slits at the junction of the carapace and the abdomen, or tail flap, and the crab, now in the soft shell stage, backs out of the old shell through this slit. It is during the molting period that missing legs are rejuvenated. Following the first molt, after such a mishap, a replaced leg is considerably smaller than the original, but with succeeding molts it attains its normal size.

Distinction Between Male and Female Crabs
The abdomen, or tail flap, which is folded closely against the underside of the crab, is much broader in the female than in the male crab. This broad tail flap is necessary in the female to accommodate at spawning time the huge numbers of eggs that are attached and receive protection between this flap and the body until hatched. In the adult stage, the comb-like fringe of hair around the edges of the tail flap is quite long in the female but rather short and hardly noticeable in the male. The average size of female Cancer crabs is significantly less than that of the male crabs in the adult stage. The female Dungeness crab seldom attains a width much greater than 7 inches measured just anterior of the tenth anterolateral spine. The legal measurement for crabs is defined as the shortest distance through the body from the edge of the shell to the edge of the shell directly from front of points (lateral spines). Distinguishing Characters: White-tipped pincers on the claws (chelipeds). The top edges of the claws and upper pincers are prominently saw-toothed, there being more than a dozen teeth along each edge. The last three joints of the last pair of walking legs (in particular) have a comb-like fringe of hair on the lower edge, and the joint previous to these has hair on both top and bottom edges, but with a much greater amount on the top edge. In both male and female, the tip of the last segment of the tail flap is rounded as compared to the pointed last segment of the male and female of all the other crabs herein described.

Color: Light reddish brown on the back, with a purplish wash anteriorly in some specimens. The characteristic pattern of lighter streaks and spots on the back is shown in the photograph (Figure
1) . Underside whitish to light orange, the inner and upper sides of the anterior legs with crimson or purple.
Size: Attains a width of 9 inches across the back. One of the largest edible crabs along the Pacific Coast of America.
Distribution: Unalaska, Alaska, to Magdalena Bay, Baja California, but seldom seen south of Santa Barbara.
SCIENTIFIC NAME: Cancer magister, cancer is Latin for crab.
COMMON NAMES: Pacific edible crab, Dungeness crab, market crab, commercial crab, and edible crab.
ECONOMIC VALUE: An important commercial shellfish harvested along the coast from California to Alaska, Dungeness crab are usually caught in nearshore marine waters under 120 feet deep with baited crab pots. An average of 17,000 tons, worth tens of millions of dollars, are caught annually, usually in the first two months of an average nine month season.