King crabs are large marine crustaceans known for their impressive size and distinctive appearance. They belong to the family Lithodidae, often referred to as stone crabs. Found primarily in cold, deep ocean waters, they inhabit various seafloor environments. While resembling true crabs, king crabs possess unique anatomical features.
Physical Characteristics
King crabs have three pairs of walking legs, unlike the four pairs of true crabs. They also possess two claws, or chelipeds; one is often larger for crushing, the other smaller for tearing food. Their fifth pair of legs is small and tucked beneath the carapace, used for cleaning and, in females, for egg fertilization.
A thick shell, or carapace, covers their body, often adorned with sharp spines for defense. King crabs grow by molting, shedding their rigid exoskeleton for a new, larger one. Coloration varies among species, from brownish-blue to burgundy-red, often turning bright red when cooked. Their fan-shaped abdomen, or “tail,” is tucked under the shell, appearing asymmetrical in females.
Habitat and Behavior
King crabs thrive in the cold, deep waters of the North Pacific Ocean and adjacent seas, found on continental shelves at depths of 200 to 650 feet. Some species, like the golden king crab, inhabit even deeper environments, at depths of 600 to 2,400 feet. They undertake seasonal migrations, moving to shallower waters for molting and mating during late winter or early spring, then returning to deeper areas for feeding during summer and fall.
These crustaceans are opportunistic feeders, consuming invertebrates from the ocean floor. Their diet includes worms, clams, mussels, barnacles, sea stars, sand dollars, and smaller crabs and fish. Juvenile king crabs often form large aggregations called “pods,” where thousands stack upon each other, likely for protection. Adult king crabs cannot swim and move by walking across the seafloor.
Notable Species
Three species of king crabs are commercially important: the Red King Crab, Blue King Crab, and Golden King Crab.
Red King Crab
The Red King Crab (Paralithodes camtschaticus) is the largest and most sought-after. It is known for its brownish to bluish-red hue when alive, transitioning to a vibrant red upon cooking. They are found in areas such as Bristol Bay and Norton Sound.
Blue King Crab
The Blue King Crab (Paralithodes platypus) is a large species, characterized by its blue-gray shell with occasional orange highlights, which turns orange-red when cooked. These crabs inhabit rocky substrates near St. Matthew Island and the Pribilof Islands.
Golden King Crab
The Golden King Crab (Lithodes aequispinus), sometimes called brown king crab, is smaller than its red and blue counterparts and has a golden-orange to brown shell. They are found in deeper waters around the Aleutian Islands.
Commercial Importance
King crabs are prized as a seafood delicacy worldwide, particularly for their rich, sweet meat in their legs and claws. The commercial fishery is concentrated in regions like Alaska and Russia, with seasons occurring from October to January. Fishing vessels deploy large, steel-framed traps, known as pots, weighing between 600 and 800 pounds. These pots are baited, often with herring or cod, and lowered to the seafloor, remaining there for one to three days to attract crabs.
Regulations govern the fishery to promote sustainability, including restrictions on the size and sex of crabs harvested; only male crabs of a certain size are retained. The industry is known for its challenging and hazardous conditions for fishermen. Despite risks, king crab remains a valuable commodity, with millions of pounds harvested annually to meet global demand.