Paralithodes camtschatica
(alaskan) king crab

Paralithodes camtschatica is distributed throughout the northern Pacific Ocean. They can be found as far south as the Sea of Japan, and north up to the Kamchatka Peninsula. On the west coast of North America the southern limit is the Queen Charlotte Islands, and the most northern point is Barrow, Alaska. Paralithodes camtschatica is also found in the southeastern Bering Sea. While not native to the Atlantic Ocean, P. camtschatica was commercially introduced in the Barents Sea, north of Russia. (Bliss, 1982; Forrest Blau, Kuklok, and Compton, 2002; Jewett and Onuf, 1988)

Adults are found in the intertidal zone at depths of more than 200 m in the preferred sand and mud substrates. Annual migrations from the deep to shallow waters (50 m or shallower) occur in the late winter/early spring for mating. (Forrest Blau, Kuklok, and Compton, 2002; Jewett and Onuf, 1988)

Paralithodes camtschatica have a dark red body and are characterized by having a fan shaped tail. King crabs have 5 sets of appendages, the first two are pincers, the right is usually larger then the left. The last appendages are used for mating. For males the last two appendages are used to spread spermatophore over the genital opening of a female, and for females the appendages are used to aid in the spreading of the spermatophore. (Bliss, 1982; Jewett and Onuf, 1988)

Alaskan king crabs have two stages of development. In the first stage of development P. camtschatica are free-swimming zoea. Zoea are very small and do not resemble the adult crab. During 3 to 4 months, the zoea molt 5 times. After the fifth molt the larval zoea begin to resemble the adult form, they are about 1/8 of an inch at this point, and adopt a benthic, or bottom dwelling, lifestyle. (Jewett and Onuf, 1988)

The expected lifespan of P. camtschatica is 15 to 20 years. The biggest non-commercial threat is molting. Molting can be stressful and cause death. In addition, the days after a molt are the most dangerous for P. camtschatica, when the soft shell is vulnerable to predation. However, the main limit on life span for Alaskan king crabs is over-fishing. (Forrest Blau, Kuklok, and Compton, 2002; Jewett and Onuf, 1988)

Alaskan king crabs tend to be segregated by sex when at deeper waters. Social and colonial characteristics are seen in juveniles between the ages of 1 to 4 years old, when they pod, or form large groups of individuals. Podding occurs at shallow depths and is used for protection. Alaskan king crabs are natatorial, or adapted for swimming, when they are in their pelagic stage in the form of free-swimming zoea. (Forrest Blau, Kuklok, and Compton, 2002; Jewett and Onuf, 1988)

Alaskan king crabs communicate during mating when the female releases a chemical that signals a male that she is ready to ovulate. (Jewett and Onuf, 1988)

Larval P. camtschatica are planktivores. The adult form feeds on many different animals including some fish parts and are generalized carnivore. (Forrest Blau, Kuklok, and Compton, 2002; Jewett and Onuf, 1988)

During the first year Alaskan king crabs hide in crevices formed by rocks or kelp forests to avoid predation. From the ages of 1 to 4 Alaskan king crabs form clusters of up to 500,000 individuals called pods. The pods disperse only for feeding. This behavior is thought to be used for protection during molting, when a crab is most vulnerable. The adult Alaskan king crabs have few predators because of their heavily armored and bumpy carapace. Carcinonemertes (nemertean worms) feed on eggs while mother is incubating. Erimacrus isenbeckii (Korean hair crab), Enhydra lutris (sea otters), and Heimlepidotus or Myoxocephalus (sculpins) are possible predators for adults. (Bliss, 1982; Jewett and Onuf, 1988; Warner, 1977)

As adults, Alaskan king crabs are major predators. The mass numbers of zoea also serve as a food source for many organisms. (Bliss, 1982; Forrest Blau, Kuklok, and Compton, 2002; Jewett and Onuf, 1988; Pacific Seafood Group, 2001-2002; Warner, 1977)

There are no known adverse affects of P. camtschatica on humans.

From 1960 to 1970 Alaskan king crabs generated hundreds of millions of dollars in economic revenue. However, within two years of over fishing in a given area catch returns diminish to a fraction of the original catch. Now the United States gets the majority of its crab meat from the North Atlantic Ocean north of Russia. There is now a rule for fishers that they can only catch males. (Bliss, 1982; Forrest Blau, Kuklok, and Compton, 2002; Jewett and Onuf, 1988; Pacific Seafood Group, 2001-2002; Warner, 1977)

There is no special status on Alaskan king crabs. However, due to over harvesting the population of P. camtschatica is consistently low. A proposed possible solution is that crabbers are only allowed to catch male Alaskan king crabs.