Halibut are large flatfish belonging to the right-eye flounder family. The term “halibut” originates from “haly” (holy) and “butte” (flat fish), reflecting its historical popularity on Catholic holy days. These bottom-dwelling fish are found in the cold, deep waters of the North Pacific, North Atlantic, and Arctic Oceans.
Distinctive Features
Halibut have flattened, diamond-shaped bodies, allowing for effective camouflage on the ocean floor. Their upper side ranges from mottled gray to dark brown, blending with sandy or muddy bottoms, while their underside remains white. This coloration is part of their predatory strategy.
A fascinating aspect of halibut development is the migration of one eye. Halibut larvae are born with an eye on each side, swimming upright like other fish. Within about six months, during a larval metamorphosis, one eye moves across the head to join the other on the right, pigmented side of the body. This transformation allows them to observe their surroundings while lying flat.
Halibut are among the largest flatfish, with some individuals reaching substantial dimensions. Pacific halibut can grow over 8 feet long and weigh up to 500 pounds. Atlantic halibut can be even larger, with recorded specimens reaching up to 15 feet in length and over 700 pounds. Female halibut generally grow larger and live longer than males, with some reaching over 50 years. Their scales are small and embedded, giving their surface a smooth appearance.
Habitat and Behavior
Halibut are demersal fish, living on or near the seabed in cold, deep waters of the North Pacific, North Atlantic, and Arctic Oceans. They are found over various bottom types, including mud, sand, or gravel banks, at depths ranging from 160 to over 6,500 feet. While they spend most of their time near the bottom, halibut can move up in the water column to feed, preferring water temperatures between 37 and 46 degrees Fahrenheit.
As predatory feeders, halibut consume almost any fish or animal they can fit into their mouths. Their diet shifts as they mature; juveniles feed on small crustaceans and other bottom-dwelling organisms. Larger adults primarily prey on other fish species like cod, pollock, herring, sand lance, and even smaller halibut. They also consume octopus, crabs, and clams.
Halibut are ambush predators, lying still and blending with the bottom, waiting for unsuspecting prey to swim too close. They use their senses of smell and sight to locate food, with scent being important for attracting prey from a distance. Halibut are strong swimmers capable of migrating long distances, including seasonal movements from shallower feeding grounds in summer to deeper offshore spawning grounds in winter. Spawning occurs from November to March in deep waters along the continental slope, where females can release millions of eggs.
Varieties and Human Connection
There are three primary species of halibut: the Pacific halibut (Hippoglossus stenolepis), the Atlantic halibut (Hippoglossus hippoglossus), and the Greenland halibut (Reinhardtius hippoglossoides). Pacific halibut are found across the North Pacific Ocean, from Alaska to Japan. Atlantic halibut inhabit the North Atlantic, from Labrador to the Bay of Biscay. Greenland halibut live in the cold northern Atlantic, Pacific, and Arctic Oceans, sometimes called turbot.
Halibut are valued as a food source, prized for their firm, white, lean, and mild-flavored flesh. They are a popular choice for culinary preparations, often grilled, baked, or pan-seared. This makes them a significant component of commercial fisheries, particularly in the North Pacific. The commercial fishery for Pacific halibut has a long history, dating back to the late 1880s, managed with strict regulations to promote sustainability.
Halibut also hold cultural significance, having been an important food source for Indigenous coastal peoples for centuries. Recreational anglers seek them due to their size and the challenge they present. While Pacific and Greenland halibut populations are robust and well-managed, the Atlantic halibut population has faced challenges due to overfishing and is at a low level in some areas, with rebuilding plans in place. This highlights the importance of continued sustainable fishing practices for these fish.