Information on Alaskan King Crab

There are three species of king crab (also called stone crabs) in Alaskan waters--red, blue and golden (or brown). Each is found in different areas of the ocean. King crabs have their own categorization in the biological classification system, lithodoidea. All three species are fished commercially.

  1. Characteristics

    • All three species of king crab found off the coast of Alaska share certain characteristics with each other. They have five pairs of legs, the front pair carrying their claws. They have a distinctive carapace (the shell covering their back) with a fan-shaped "tail" tucked underneath the rear of the shell. This asymmetry to their body shape has led scientists to conclude that the king crab is a descendant of hermit crab-like ancestors, whose body shape was similar in order to wedge into spiral shells.

    Habitat

    • Each of the three present species lives on the sea floor, although inhabit different areas of Alaskan waters. The red king crab is found from British Columbia across to Japan, with Bristol Bay, Norton Sound and the Kodiak Archipelago being the areas of greatest density. The blue king crab is generally found off the Pribilof Islands and St. Matthew Island, while the golden king crab is most abundant in the waters around the Aleutian chain of islands.

    Diet

    • King crabs eat other animal organisms that live on the ocean floor. These include worms, mussels, clams, snails, brittle stars, barnacles, sea urchins, sponges and algae. They are also known to eat other crabs, including, occasionally, members of their own species. King crabs will also feed upon dead fish and sea mammals that die and fall to the ocean floor.

    Predators

    • King crabs are part of the diet of many other sea creatures. Aside from their own cannibalistic tendencies, king crabs are eaten by a variety of marine organisms. Predominant among them are fish such as halibut, cod, sculpin and yellowfin sole, but also include octopuses and sea otters (within coastal waters). Several species of nemertean worm are known to eat king crab embryos.

    Fishing For Alaska King Crab

    • Humans are the species that have the greatest effect on king crab numbers in Alaskan waters. Red, blue and golden king crabs are all fished commercially and are highly prized menu items, being low in fat and calories while high in protein. Only males can be legally sold. King crab are usually fished with large, baited pots that are dropped from a boat, allowed to sink to the bottom and collected one or two days later. The heavy pots, rough sea conditions, coils of rope and long hours make Alaskan king crab fishing a dangerous (though potentially very profitable) profession to pursue.