Greenland Halibut

The Greenland halibut is a right-eyed flatfish in the family Pleuronectidae, more closely related to flounders than to true halibut despite its common name. It inhabits cold, deep waters of the North Atlantic and Arctic Ocean, ranging from the Barents Sea and Greenland to the Grand Banks and parts of the North Pacific. The species is notably elongated for a flatfish and, unusually, is not fully flattened; it retains a somewhat compressed, less horizontal posture and can swim well off the bottom. Greenland halibut, sometimes marketed as "turbot" in parts of Canada, support important commercial fisheries in northern waters and are managed through international quotas due to their slow growth and deep, cold-water habitat.

• Elongated, moderately compressed body, less flattened than typical flatfish
• Eyes set close together on the upper (right) side of the head
• Uniform dark brown to grayish-black coloration on the eyed side, dusky gray on the blind side (unlike most flatfish, which are pale underneath)
• Large mouth with sharp teeth, extending past the eye
• Deeply forked or concave tail fin
• Adults typically reach 50-100 cm, with large individuals exceeding 1 m

The dark coloration on both sides, rather than a pale underside, and the less flattened body separate it from Atlantic and Pacific halibut, and its smaller size and deeper habitat distinguish it from Pacific halibut.

Greenland halibut occur in cold waters of the North Atlantic and Arctic Ocean, including the Barents Sea, waters around Greenland and Iceland, the Grand Banks, and Baffin Bay, with a related population in the North Pacific and Bering Sea. They live at considerable depths, commonly between 400 and 1,500 meters on the continental slope, though they range from around 100 meters to over 2,000 meters. The species tolerates near-freezing bottom temperatures and is associated with soft mud bottoms of the outer shelf and slope in subarctic and Arctic seas.

Unlike most flatfish, Greenland halibut spend considerable time swimming in the water column rather than lying flat on the bottom, behaving more like a typical fish in an upright or angled posture. They are active predators, feeding on small fish such as capelin and redfish, as well as squid and crustaceans found at depth. The species undertakes seasonal depth and latitudinal migrations tied to feeding and spawning. Spawning occurs in deep water during winter months, with females releasing pelagic eggs that drift at depth before hatching; larvae and juveniles gradually move to shallower shelf areas as they grow.