Dungeness Crab Management and Research
The Dungeness crab fishery in Alaska has historically been managed by size, sex, and season or 3-S management. The size limit is 6.5 inches (165 mm), only males are harvested, and the fishery is closed during the female molt and mating period from mid-August to the end of September, and during most of the male molt period.
While there is no active Dungeness crab stock assessment program as the species is managed by size, sex, and season, ADF&G has conducted Dungeness crab research projects in Kodiak, Central, and Southeast regions. Some more recent findings are summarized as follows.
A Dungeness crab survey was conducted from 2000 through 2004. Primary survey goals were to develop a method to index crab populations and to describe variability in life history timing. A total of 3,309 commercial pots were set during March/April, June, August/September, and November/December survey periods in nine survey areas: Stikine Flats, Duncan Canal, Kah Sheets Bay, Port Camden, Berners Bay, Peril Strait, Tenakee Inlet, St. James Bay, and Seymour Canal. Depth-stratified clusters of three or four pots were set in depths from 5.5–73.2 m. Clusters had alternately open then closed escape rings, and cluster locations were selected using a systematic sampling design with random start.
Survey catch per unit effort (CPUE) was regressed against commercial harvest. Effects of depth, survey period, and year on CPUE and mean carapace width were investigated using ANOVA. Effects of survey period on female reproductive stage, shell hardness, and leg loss were investigated using contingency analyses.
The only significant predictor of harvest was June legal CPUE for Duncan Canal. Female CPUE was generally highest in deep, August/September pots, and legal male CPUE in shallow, June pots. Egg hatch was complete by June for Duncan Canal and Stikine Flats, but later elsewhere. Soft shell peaked in August/September for females but from March/April through August/September for males. Leg loss increased between June and August/September survey periods. Bycatch species composition is described.
June legal CPUE has only limited ability in indexing population, as crabs in most areas are either not completely catchable or have not yet molted into the fishery at this time. The summer season overlaps male molt period.