Pacific halibut

What it is

This species belongs to the righteye flounder family and possesses a distinctive diamond-shaped body that is more elongated than most flatfishes. Its width measures roughly one-third of its total length. Both eyes sit on the dark upper side, which varies in colour to match the ocean floor, while the underside remains light to blend with the sky when viewed from below. Small scales are embedded directly in the skin. They feature a high arch in the lateral line over the pectoral fin and a crescent-shaped tail. Females can reach lengths exceeding 2.4 metres and weigh up to 230 kilograms, making them among the largest flatfish.

Where it lives

These fish inhabit the continental shelf of the North Pacific Ocean and the Bering Sea. Fishing activity concentrates heavily in the Gulf of Alaska and off the west coast of Canada. Smaller catches occur along the coastal regions of Washington, Oregon, and California. The population is divided into ten management areas. They prefer cold water temperatures between 3 and 8 degrees Celsius. During winter months, mature individuals gather on spawning grounds along the continental shelf edge at depths ranging from 183 to 457 metres.

How it lives

Pacific halibut are powerful swimmers capable of long-distance migrations. They generally move in a clockwise direction from northwest to southeast across their settlement areas. Seasonal movements involve shifting from shallow feeding grounds in summer to deeper waters in winter. Their diet includes various fish like cod, pollock, and salmon, as well as invertebrates such as octopus, crab, and shrimp. Occasionally, they feed on pelagic species or even seal remains. Older fish tend to be less migratory but continue moving predominantly in a clockwise pattern.

Breeding and life cycle

Spawning occurs during winter, peaking from December through February. Eggs are laid in deep waters off the continental shelf edge. Males reach sexual maturity at seven to eight years, while females mature at eight to twelve years. A female produces between half a million and four million eggs annually depending on her size. Fertilized eggs hatch after approximately fifteen days. Larvae float freely for up to six months, drifting counter-clockwise before rising to shallower waters where they develop into bottom-dwelling juveniles.

Fish and people

Commercial fishing likely began in 1888 near Washington. The industry historically used steamers and schooners, now replaced by versatile vessels. Gear consists of longlines with hundreds of hooks baited with frozen herring or octopus. Homer, Alaska, is known as the Halibut Capital due to high catch volumes. Sport fishing is popular in Alaska, particularly in Cook Inlet and southeast Alaska. Anglers target these strong fighters using stout gear. Native groups traditionally smoke and dry the fish for winter sustenance. An international commission sets annual catch limits to maintain sustainable yields.

Relatives and look-alikes

The Atlantic halibut is closely related and slightly larger. Both species share similar physical characteristics and ecological roles within their respective oceans. Management strategies differ based on regional commissions, but both aim to balance commercial interests with conservation needs. Genetic studies suggest only one stock exists in the North Pacific despite localized spawning populations.

Questions people ask about Pacific halibut

Good reading and sources

• Pacific halibut on WikipediaEncyclopedia
• More photos on Wikimedia CommonsPhotos
• Wikidata recordOpen data