Chionoecetes opilio
Opilio crab, Chionoecetes opilio, is a snow crab found in cold shelf waters of the Northwest Atlantic and North Pacific. It is a common species for commercial fishing, often caught with traps or trawls.
What it looks like: Snow crabs have long, wide bodies with bumpy shells. They are usually brown to light red on top and yellow to white underneath. Males are larger than females. In this species, males can reach a carapace width of about 16.5 cm (6.5 inches); females are smaller, up to about 9.5 cm (3.7 inches).
Where they live: Opilio crabs live on sandy or muddy bottoms on the continental shelf and upper slopes, from shallow to deep waters (about 13 to 2,187 meters, or 43 to 7,175 feet). In the Atlantic, they’re common off Greenland, Newfoundland, the Gulf of St. Lawrence, and the Scotian Shelf. In the North Pacific, they’re found from Alaska to northern Siberia, across the Bering Strait to the Aleutians, Japan, and Korea. They prefer very cold water, usually between -1 and 5 °C, but can tolerate a bit warmer.
What they eat: These crabs feed on many bottom-dwelling invertebrates, such as crustaceans, mollusks, brittle stars, worms, and even some algae. They are scavengers and can eat a variety of prey. Predation varies with size, and occasionally they will eat one another. Cannibalism happens from time to time.
Life cycle and growth: Opilio crabs grow slowly. There are many growth stages, especially in males. They live about 14 to 16 years. Females carry tens of thousands of eggs under their abdomen (up to about 150,000) after mating and lay them in deep, detritus-rich waters. Eggs hatch into free-swimming larvae and later settle to the sea floor.
Fisheries and spread: Snow crabs are heavily fished in Canada and elsewhere. In 1996 they were found in the Barents Sea, where they are considered invasive and may affect native species. There has been international fishing and legal debate over who can catch them in that region. In 2022, Alaska banned commercial snow crab fishing for a season due to a sharp population drop from about eight billion to one billion crabs, driven by overfishing and warming waters.
In culture: Snow crabs are an important seafood in South Korea, with markets, festivals, and villages dedicated to them, such as Yeongdeok and Uljin.
This page was last edited on 3 February 2026, at 01:36 (CET).