Chionoecetes opilio, commonly known as the opilio, queen or snow crab, is a marine decapod crustacean in the family Oregoniidae. It inhabits cold continental shelf waters of the North Pacific and North Atlantic Oceans, including the Bering Sea, Sea of Okhotsk, Gulf of Alaska, eastern Canada, and Greenland. The genus name Chionoecetes derives from Greek chionoiketes (via Latinized form) meaning “snow dweller”, reflecting its cold-water habitat. The species epithet opilio is Latin for “shepherd,” possibly referring to the crab’s long, slender legs resembling a shepherd’s staff.

Snow crabs prefer sandy or muddy substrates at moderate depths and are adapted to cold environments. Historically, they were harvested by coastal and Indigenous communities of the North Pacific and North Atlantic for subsistence, but large-scale commercial fisheries developed primarily in the 20th century, especially in Japan, Alaska, and Atlantic Canada. Today, Chionoecetes opilio is a major commercial seafood species in northern fisheries. As a food source, Chionoecetes opilio is prized for its sweet, delicate, white flesh, particularly from the body, legs and claws. The crab is typically harvested, cooked (usually boiled or steamed) at sea or shortly after landing, and then sold fresh, frozen, or processed. In Japanese cuisine, snow crab (known as zuwai-gani) is served as boiled crab, in hot pots, as sashimi when extremely fresh, or incorporated into sushi and rice dishes. In North American cuisines, especially in Alaska and Atlantic Canada, snow crab legs are commonly steamed or boiled and served with butter, and the meat may be used in salads, cakes, and soups.

Chionoecetes opilio contains high-quality marine proteins, omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA, taurine, vitamin B12 (cobalamin), zinc, selenium, and astaxanthin. As with other marine crustaceans, snow crab may accumulate environmental contaminants depending on habitat conditions, but when sourced from regulated fisheries it is widely regarded as a nutritious and culturally significant cold-water seafood.