The King Crab, primarily belonging to the genus Paralithodes, is a group of large marine crustaceans highly valued globally for their distinct flavor and impressive size. These animals are decapod crustaceans classified within the family Lithodidae, making them closer relatives of hermit crabs rather than true crabs. Their existence is restricted almost entirely to cold, often deep, marine waters. The distribution of these commercially important species is limited to specific geographic areas that provide the narrow range of conditions necessary for their survival and reproduction.
Primary Global Habitats
The majority of the world’s King Crab population is concentrated in the North Pacific Ocean and its adjacent seas, forming the native range for these cold-water species. The Bering Sea is the foremost habitat, divided between the United States (Alaska) and Russia, and constitutes the primary fishing ground for the Red King Crab (Paralithodes camtschaticus). This vast, cold body of water provides the broad, shallow continental shelf environments that support the most abundant populations.
Moving west, the King Crab range extends along the Russian Far East, encompassing the Sea of Okhotsk and the Sea of Japan, where significant stocks are also found.
A secondary, commercially significant habitat was established in the Barents Sea, located in the Arctic region between Norway and Russia. Red King Crabs were intentionally introduced there by the Soviet Union during the 1960s to create a new fishery resource. This transplanted population successfully colonized the area and spread westward along the Norwegian coast, becoming a permanent fixture in the North Atlantic region.
Distinct Locations of Major Species
While the North Pacific is the general domain for King Crabs, the three most commercially relevant species inhabit distinct geographical niches defined by depth and location.
The Red King Crab (Paralithodes camtschaticus) is the most widespread, found across the entirety of the North Pacific rim. Its range spans from the Sea of Japan and the Kamchatka Peninsula to the Gulf of Alaska, the Aleutian Islands, and down to the Queen Charlotte Islands off British Columbia.
The Blue King Crab (Paralithodes platypus) has a more disjunct and northerly distribution, preferring colder waters than the Red King Crab. In Alaskan waters, significant populations are found near isolated islands in the Bering Sea, such as the Pribilof Islands, St. Matthew Island, and the Diomede Islands. This species also occurs along the Kamchatka Peninsula and in the Sea of Okhotsk.
The Golden King Crab, or Brown King Crab (Lithodes aequispinus), occupies the deepest habitat of the three major species. Its primary range is concentrated around the Aleutian Islands and the Gulf of Alaska, extending across the Pacific rim to the Russian Far East and Japan. Unlike its counterparts that frequent the shallower continental shelf, the Golden King Crab is generally found along the continental slope, inhabiting depths that typically range between 300 and 1,000 meters.
Environmental Factors Influencing Distribution
The primary factor restricting King Crabs to their northern habitats is the requirement for low water temperatures throughout their life cycle. Red King Crabs prefer a narrow temperature range, with ideal conditions generally falling between 3.2 and 5.5 degrees Celsius. The survival and growth of the larvae and juveniles are particularly sensitive to these thermal limits, dictating the ultimate success of a population.
The depth of the habitat also plays a significant role, as it relates directly to temperature stability and substrate. Adult Red King Crabs are migratory, moving from deep overwintering waters on the continental shelf, often between 150 and 300 meters, into shallower areas for mating and molting in the spring. They prefer soft substrates, such as sand or mud, which are common on the shelf.
In contrast, the Golden King Crab is adapted to the deeper, colder, and more stable temperatures of the continental slope, usually dwelling at depths exceeding 300 meters. These deeper-dwelling crabs tend to avoid open sand, instead favoring complex, sloping, and rocky habitats where they can find structure-forming invertebrates like corals and sponges. The distinct temperature and depth preferences of each species prevent them from extensively co-existing, even where their geographical ranges overlap.