Pacific halibut

Species of fish

Hippoglossus stenolepis, the Pacific halibut, is a species of righteye flounder. This very large species of flatfish is native to the North Pacific and is fished by commercial fisheries, sport fishers, and subsistence fishers.

The Pacific halibut is found on the continental shelf of the North Pacific Ocean and Bering Sea. Fishing for the Pacific halibut is mostly concentrated in the Gulf of Alaska and the Bering Sea, off the west coast of Canada. Small halibut catches are reported in coastal Washington, Oregon, and California. Pacific halibut is broken up into 10 regularity management areas. Halibut are demersal, living on or near the bottom of the water and prefer water temperatures ranging from Pacific halibut belong to the family Pleuronectidae. From November to March, mature halibut concentrate annually on spawning grounds along the edge of the continental shelf at depths from
Halibut are strong swimmers and are able to migrate long distances. Halibut of all ages and sizes are involved in a predominantly clockwise (northwest to southeast) migration from their settlement areas (western part of the Gulf of Alaska and Bering Sea), and reproductive fish also make regular seasonal migrations from more shallow feeding grounds in summer to deeper spawning grounds in winter.

Pacific halibut have diamond shaped bodies. They are more elongated than most flatfishes, their width being about one third of their length. They have a high arch in the lateral line over the pectoral fin, and a lunate, or crescent shaped tail, which is different from other flatfishes. Small scales are embedded in the skin. Halibut have both eyes on their dark upper sides. The color on the dark side varies, but tends to assume the coloration of the ocean bottom. The underside is lighter, appearing more like the sky from below. This color adaptation allows halibut to avoid detection by both prey and predator. They are one of the largest flatfish (only surpassed by the closely related Atlantic halibut), and can weigh up to and grow to over 8 feet (2 m) long.

Being strong swimmers, halibut are able to eat a large variety of fishes, including cod, turbot, and pollock, and some invertebrates, such as octopus, crab, and shrimp. Sometimes, halibut leave the ocean bottom to feed on pelagic fish, such as salmon, sand lance, and herring, and even seal remains have been found in their stomachs.

As Pacific halibut grow longer, they increase in weight, but the relationship between length and weight is not linear. The relationship between total length (L, in inches) and total weight (W, in pounds) for nearly all species of fish can be expressed by an equation of the form:

Invariably, b is close to 3.0 for all species, and c is a constant that varies between species. A weight length relationship based on a least squares fit to data published in 2003 by the International Pacific Halibut Commission (IPHC) suggests, for Pacific halibut, c = 0.00018872 and b = 3.24. This relationship predicts a Pacific halibut will weigh about , a halibut will weigh about , and a halibut will weigh about .

Commercial halibut fishing probably began in 1888 when three sailing ships from New England fished off the coast of Washington. In 2018, the International Pacific Halibut Commission set the catch limit at 2,823 tonnes, of which 2,402 tonnes were for commercial fisheries and 421 tonnes were for recreational fisheries.

Sport fishing for halibut in Alaska is a very popular activity; it is a strong fighter and one of the world's largest bony fish with an impressive yield of firm, white flesh. Over 65% of the effort and harvest occurs in Cook Inlet, southeast Alaska, the Kodiak area, and near the mouth of Deep Creek in the Lower Cook Inlet. Halibut taken by anglers are generally in weight, but fish over are regularly caught. The current Alaska state record for a sport caught halibut is , and a fish must weigh at least to qualify for the state's trophy fish program. Anglers use stout saltwater gear to harvest halibut. Most anglers prefer to fish with bait, especially herring, but also squid, octopus, cod pieces, or other small bottom fish. To get the bait down to the halibut, it is usually fished on a wire spreader or a sliding sinker rig with sinker size to , depending on such factors as depth and current. Halibut, along with salmon, provide sustenance for several Pacific Coast native groups. Many of these groups smoke and dry the halibut for winter use. Sportsmen's effort and interest in catching these fish is increasing each year. In southeast Alaska, halibut are second only to king salmon in sport angler preference. Fishing for Pacific halibut is regulated by the International Pacific Halibut Commission. Members from the United States and Canada meet yearly to review research, check the progress of the commercial fishery, and make regulations for the next fishing season. The management of halibut fishing by this commission is intended to allow a sustainable yield.