dungeness crab S N O H O M I S HD C O U N T Y M A R I N E F A C T S H E E T Description average size of 1 3/4 inches across Dungeness crab (Cancer magister) are the back a year after the crab takes crustaceans, having an exterior skel- up bottom life. As they grow, they eton or shell. The shell is purple- tend to move into progressively tinged, grayish-brown on the back, deeper water. (Small black or gray shore crabs found on the beach For more information with white tipped claws. They average should not be confused with young For more information on this six to seven inches across the back. on this topic or to Dungeness crab are found from Dungeness crabs). topic or to learn about the learn how you can Alaska to Mexico. They are most n Adult stage (3-8 years)—Adults Snohomish County Marine abundant in Puget Sound north of grow by shedding their rigid exte- Resourceshelp, please Committee, call visit Seattle, in Hood Canal, and along the rior skeleton (or shell). During this www.snocomrc.org.Snohomish County coast. process (called “molting”) a crab backs out of its hard shell with a Public Works, Surface Life cycle new, soft shell already in place. Water Management Crabs tend to molt about seven times during the first year of bottom n Mating and egg development at 425-388-3464 life and then about once a year after (0-4 months)—Mating occurs that. Molting periods vary within (TTY: 425-388-3700) between hard-shelled males and Puget Sound. In the Port Gardner newly molted, soft-shelled females or check www.co. and Port Susan area, crabs molt from the spring to the fall. Male from early January to mid-April. snohomish.wa.us/ crabs are polygamous—each male Crabs with soft shells are vulnerable crab may mate with more than one mrc.htm to predation, so they tend to hide in female crab. This may be an impor- the sand or mud on the bottom. It tant factor in maintaining the takes about 2 months for them to reproductive viability of this spe- form another hard shell. Crabs are cies since only male crabs can be sexually mature after their second harvested. The female crab stores year and reach legal harvest size (6 the sperm until her eggs are fully 1/4 inches across the back) in about developed. Fertilization of the eggs 4 years. occurs when the female extrudes them under her abdomen where they are carried several months Habitat until hatching. Large females can Larvae are subject to dispersal by carry over 2.5 million eggs. currents. Juveniles remain in intertidal n Larval stage (4-12 months)—Crab and shallow subtidal areas, hiding larvae are dispersed by currents beneath or among plants, rocks, shell and progress through a series of debris and eelgrass beds. Adults prefer stages in which their appearance eelgrass beds and sandy or muddy changes considerably. substrate. Breeding occurs in nearshore n Juvenile stage (1-2 years)—After areas and females may move to deeper one year the juvenile crab re- water to hatch eggs. Threats to crab sembles the adult form and settles habitat include modifications to the on the bottom of shallow intertidal shoreline from development (bulk- This paper is recycled & areas and estuaries. Crabs reach an heads), disruption of eelgrass beds, recyclable. 6/2001 and pollution. Food n Recreational management—Estimates of sustain- able harvest levels are made during each season. Dungeness crab prey includes clams, snails, eggs Closures occur during molting periods and when from fish or crabs, crustaceans, marine worms, squid necessary to limit catch levels. Phone surveys, and fish. voluntarycatch record catch cards records and buoy and countsbuoy counts are use ared used to estimate catch levels. Based on historical results, Predators the average catch for recreational crabbers is 0.5 to 2.5 crab kept per trap per day. Natural predators of Dungeness crab include: octo- pus, halibut, other Dungeness crab, dogfish, hake, n Tribal management—Tribes limit the amount of lingcod, salmon, shorebirds and waterfowl. fishing and use other conservation measures to protect crab populations. Each tribe can determine Harvest the number of commercial tribal fishermen allowed to participate. The Dungeness crab is an important commercial, n Local protection efforts—The Snohomish County recreational and tribal fishery. In Puget Sound, har- Marine Resources Advisory Committee (MRC) vest has increased steadily from over 2 million wants to protect Dungeness crab and habitat. The pounds in 1992-1993 to a record 7.7 million pounds in MRC is investigating potential crab habitat and 1999-2000. The increased harvest is due to increased issues related to Dungeness crab along the numbers of recreational crabbers, easy access to Snohomish County shoreline. crabbing areas, and the switch to crabs from dwin- dling fish species. Crabs are harvested using traps Status (crab pots), ring nets, by hand (scuba divers) or dip nets. They are also taken or harmed unintentionally Along the Snohomish County shoreline, the Dunge- when gillnetting for salmon, trawling for bottomfish, ness crab population appears to be healthy despite and dredging to maintain ship channels. pressure from the fisheries described above. However, harvest pressure is likely to increase and threats to Protection efforts crab habitat from shoreline development and pollu- tion are expected to continue. The Tribes and the Washington Department of Fish and Wildlife manage crab fisheries to maintain a How you can get involved 50/50 allocation of the harvestable crabs between tribal and non-tribal fisheries. The MRC was formed to recommend remedial actions n Commercial management—Closures during the to local authorities and build local awareness of the year limit harvest and protect softshell crabs issues and support for remedies. The MRC meets on a during molting periods. Other conservation mea- monthly basis and welcomes public participation. sures include biodegradable escapement devices to prevent derelict traps from “ghost fishing” and Resources escape holes to allow undersized crab out of traps. n WDFW Shellfish Hotline: (360) 796-3215 n WDFW web site: www.wa.gov/wdfw n MRCMRC web website: site: www.co.snohomish.wa.us/mrc.htm www.snocomrc.org

Sources

n Washington Department of Fish and Wildlife n Tulalip Tribes

Produced by Snohomish County for the Snohomish County Marine Resources Advisory Committee. Funded in part through a cooperative agreement with the National Oceanic and Atmospheric Administration. The views expressed herein are those of the authors and do not necessarily reflect the views of NOAA or any of its sub-agencies.