Dungeness Crab (Metacarcinus magister)

Species overview

Physical description

Dungeness Crab is oval in shape. It is yellow-brown to purplish in colour. It has 4 pairs of walking legs and a pair of claws. Its claws have sharp saw-like teeth along the edges. The tip of its claws are light in colour with a hook at the end.

Dungeness Crab can weigh up to 2 kilograms (kg). It can grow 220 millimetres (mm) wide. Most Dungeness Crab caught in British Columbia (BC) are less than 200 mm or 1 kg. It can live for up to 9 years.

Distribution

Dungeness Crab is found from Alaska to Mexico. It lives in:

bays
inlets
estuaries
eel-grass beds

It prefers habitat with:

sand
mud or silt
cold water
sandy bottoms
moderate to strong current

Dungeness Crab is usually found in less than 50 metres (m) of water, but it can live deeper than 250 m. In spring, it moves inshore to shallower waters. In late summer, it moves into deeper waters.

Life cycle

Dungeness Crab moults as it grows, meaning it grows a new shell under its old one. Old shells are cast off. New shells are:

15 to 30% larger
soft
can easily be damaged

New shells harden after 2 or more months. Young crabs moult multiple times per year. Older crabs moult annually or biannually. Female Dungeness Crab are smaller than males.

Dungeness Crab reaches sexual maturity after 2 years and more than 10 moults. Male crabs moult in spring and females moult in summer so hard-shell males can breed with soft-shell females. Mating occurs between April and September. Female crabs can produce 2 or more batches of eggs from a single mating. Females produce between 200 thousand to 2 million eggs.

In the fall, female crabs release bright orange eggs that attach to their abdomen. Through the winter, female crabs are inactive. They burrow in sand to protect their eggs. Eggs develop faster in warmer water. They hatch in early spring.

Larvae are released and spread by ocean currents. After 3 to 4 months, they settle on the bottom.

Fishery history

Dungeness Crab is the most important crab species harvested in BC. It is the most valuable invertebrate fishery on the west coast of Canada. While a few species of crab are caught in BC, 99.9% of the crabs caught are Dungeness.

Recreational and Indigenous food, social, and ceremonial (FSC) fishing typically occurs near-shore in waters shallower than 100 feet (ft). The recreational and FSC fisheries are open year-round.

Dungeness Crab is commercially fished by trap from vessels. Major fishing areas include:

Fraser River delta
Gulf Islands
inside waters of the Strait of Georgia
west coast of Vancouver Island off Tofino
Skeena River estuary
Hecate Strait and McIntyre Bay

There are 7 Crab Management Areas in BC. Size restrictions have been in place since 1907. Only males are harvested. Small male crabs mate once or twice before they are fished. Fishing is limited during male moulting season. Licences were introduced in 1966. In addition to federal regulations, many First Nations have developed their own best management practices.

Ecosystem context

Dungeness Crab is an important prey and predator in marine and estuarine food webs. Larvae are eaten by fish and whales. Juveniles are eaten by:

demersal fish
other crabs
seabirds

Adults are eaten by:

Octopi
Lingcod
Cabezon
Wolf Eels
Rockfish
Halibut
Dogfish
Sculpin
Sturgeon
Sea Otters
other crabs

Dungeness Crab larvae eat zooplankton and phytoplankton. Juvenile crabs eat:

clams
molluscs
mussels
small fish
shrimp
other crabs

Adults scavenge for food and eat live prey, including:

fish
crustaceans
clams
molluscs
mussels
worms

Science advice and research

Science advice and research for Dungeness Crab

Integrated Fisheries Management Plan

Integrated Fisheries Management Plan for Crab by Trap

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