Alaskan king crabs communicate during mating when the female releases a chemical that signals a male that she is ready to ovulate.
Communication Channels: tactile ; chemical
Other Communication Modes: pheromones
Perception Channels: visual ; tactile ; chemical
There is no special status on Alaskan king crabs. However, due to over harvesting the population of P. camtschaticus is consistently low. A proposed possible solution is that crabbers are only allowed to catch male Alaskan king crabs.
US Federal List: no special status
CITES: no special status
Alaskan king crabs have two stages of development. In the first stage of development P. camtschaticus 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.
Development - Life Cycle: metamorphosis
There are no known adverse affects of P. camtschaticus 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.
Positive Impacts: food
As adults, Alaskan king crabs are major predators. The mass numbers of zoea also serve as a food source for many organisms.
Larval P. camtschaticus are planktivores. The adult form feeds on many different animals including some fish parts and are generalized carnivore.
Animal Foods: fish; mollusks; aquatic or marine worms; aquatic crustaceans; echinoderms; zooplankton
Plant Foods: algae; macroalgae ; phytoplankton
Primary Diet: carnivore (Eats non-insect arthropods); planktivore
Paralithodes camtschaticus 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 camtschaticus is also found in the southeastern Bering Sea. While not native to the Atlantic Ocean, P. camtschaticus was commercially introduced in the Barents Sea, north of Russia.
Biogeographic Regions: nearctic ; palearctic ; arctic ocean ; atlantic ocean (Introduced ); pacific ocean
Other Geographic Terms: holarctic
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.
Habitat Regions: temperate ; polar ; saltwater or marine
Aquatic Biomes: benthic ; coastal
Other Habitat Features: intertidal or littoral
The expected lifespan of P. camtschaticus 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. camtschaticus, when the soft shell is vulnerable to predation. However, the main limit on life span for Alaskan king crabs is over-fishing.
Range lifespan
Status: wild: 20 to 30 years.
Typical lifespan
Status: wild: 15 to 20 years.
Paralithodes camtschaticus 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.
Range mass: 12.7 (high) kg.
Average mass: 10 kg.
Average length: 220 mm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: sexes alike
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.
Known Predators:
Females attract males with a chemical that is released after eggs have hatched. The male then clasps onto the female and they remain connected until the female molts, and produces new eggs. Females mate once a year while males may mate multiple times each spring.
Mating System: polygynous
Female Alaskan king crabs mate immediately after the eggs hatch. During this process a male is attracted by a chemical that is released by the female. The male then clasps onto the female and holds her until she molts. The female and male may remain connected for up to 7 days. After molting the male uses his fifth pair of legs to spread spermatophores over the females opening. The females eggs are then released and pass over the spermatophores and become fertilized. These fertilized eggs are attached by the female to her pleopods under the abdomen and are incubated for approximately a year before hatching.
Breeding interval: Females breed once annually, while males can possibly mate with 11 females during the breeding season.
Breeding season: Alaskan King Crabs breed in the spring after migrating to water depths of 50 meters or less.
Range number of offspring: 150,000 to 400,000.
Range age at sexual or reproductive maturity (female): 5 to 6 years.
Range age at sexual or reproductive maturity (male): 5 to 6 years.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External )
Female Alaskan king crabs incubate eggs for 1 year, providing protection. Within days of hatching, the female begins incubating next group of eggs.
Parental Investment: pre-fertilization (Provisioning); pre-hatching/birth (Protecting: Female)
