Halibut

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Halibut
Pacific halibut (H. stenolepis). Halibut tend to be a mottled brown on their upward-facing side and white on their downside
Pacific halibut (H. stenolepis).
Halibut tend to be a mottled brown on their upward-facing side and white on their downside
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Pleuronectiformes
Family: Pleuronectidae
Genus: Hippoglossus
Species

H. hippoglossus (Atlantic halibut)
H. stenolepis (Pacific halibut)

Halibut is the common name for any flatfish (order Pleuronectiformes) belonging to the genus Hippoglossus from the family of right-eye flounders (Pleuronectidae), of which there are two extant species, the Atlantic halibut (H. hippoglossus) and the Pacific halibut (H. stenolepis). Demersal fish, that live near the bottom of the ocean as adults, halibut are characterized by having both eyes on their dark or upper side and somewhat more elongated bodies than other flatfish, with a somewhat lunate caudal fin. They also exhibit large size, being among the largest teleost (bony) fish in the world. They also are strong swimmers and can migrate long distances. The common name halibut also is used for some other species of flatfish.

The Atlantic halibut is native to the temperate waters of the northern Atlantic, from Labrador and Greenland to Iceland, the Barents Sea and as far south as the Bay of Biscay. The Pacific halibut is found on the continental shelf of the North Pacific Ocean and Bering sea.

very pouplar food


Overview and description

Halibut are a type of "flatfish." Flatfish are an order (Pleuronectiformes) of ray-finned fish (Actinopterygii,). (Flatfish sometimes are classified as a suborder of the order Perciformes.) Flatfish are a very distinctive group in that the adults are not bilaterally symmetrical, the only fish with such asymmetry and the only vertebrates that deviate so radially from the bilaterally symmetrical body plan (Grzimek et al. 2004). The young flatfish are bilaterally symmetrical and swim upright as with other fish, but early in development one of the eyes migrates to the other side of the cranium, across the top of the skull, and positions itself adjacent to the eye on the other side (Nelson 1994). The fish then swims with the two eyes on the upper side and lower side is blind. The metamorphosis also involves the upper side generally pigmented and the lower side light colored, and changes in dentition and fin placement.

Most species face either their "left" side upward (both eyes on the left side and lie on the right side) or else face their "right" side upward. Another distinguishing feature of the order is the extension of the dorsal fin onto the head. The body is highly compressed and somewhat flat on the blind side and rounded on the eyed side (Nelson 2006). Adults are almost always lacking a swim bladder (Nelson 2006).

Halibut belong to the family of flatfish that face their "right" side upward, the righteye flounder, family Pleuronectidae. As with other righteye founders, the halibut have a lateral line that is well developed on both sides and symmetrical pelvic fins (Nelson 2006). Nelson (2006) placed the halibut, genus Hippoglossus within the subfamily Hipoglossinae, along with the genera Atheresthes, Clidoderma, Reinhardtius, and Verasper. Halibut in general are a narrower fish than other flatfish, being only about one-third as broad as is long (Bigelow and Schroeder 1953).

Hippoglossus hippoglossus (Altantic halibut)

The Altantic halibut, Hippoglossus hippoglossus, is the largest flatfish in the Atlantic and one of the largest species of flatfish in the world, reaching lengths of up to 4.7 meters (15 ft) and weights of 320 kilograms (710 lb). Its upper surface (eyed side) is a uniformly dark brown, olive or black, though younger fish are lighter and more mottled or spotted with paler marks; the underside is pale, with the larger fish having an underside often blotched or clouded with gray (called "grays" by fisherman) and sometimes patches with the same color as the upper side, while the small fish having an underside that is pure white (Bigelow and Schroeder 1953). The end of the caudal fin is concave, not rounded. It lacks dorsal spines, but has about 98-110 dorsal soft rays, and 73-85 anal soft rays (Luna and Torres 2010). The anal fin begins shortly behind the pectorals; the small ventral fins are in front of the pectorals and separated from the anal fins by considerable space (Bigelow and Schroeder 1953). The Atlantic halibut has been reported to reach a maximum lifespan of 50 years (Luna and Torres 2010; Bigelow and Schroeder 1953).



The name is derived from haly (holy) and butt (flat fish), for its popularity on Catholic holy days.[1]

Physical characteristics

The halibut is the largest flat fish, averaging 11–13.5 kilograms (24–30 lb), but catch as large as Template:Kg to lb are reported; the largest recently recorded[2] was 211 kilograms (470 lb) and 2.5 meters (8.2 ft) long.[3][4] They are gray-black on the top side with an off-white underbelly and have very small scales invisible to the naked eye embedded in their skin.[5] At birth they have an eye on each side of the head, and swim like a salmon. After six months one eye migrates to the other side, making them look more like flounder. At the same time the stationary-eyed side darkens to match the top side, while the other side remains white. This color scheme disguises halibut from above (blending with the ocean floor) and from below (blending into the light from the sky) and is known as countershading.

Photo of several, near human-sized white fish. Two people hold halibuts.
Halibut caught off the coast of Raspberry Island, Alaska. The two fish being held up are 70 to 80 pounds (32 to 36 kg)

Diet

Halibut feed on almost any animal they can fit into their mouths. Juvenile halibut feed on small crustaceans and other bottom dwelling organisms. Animals found in their stomachs include sand lance, octopus, crab, salmon, hermit crabs, lamprey, sculpin, cod, pollock, herring, flounder as well as other halibut. Halibut live at depths ranging from a few meters to hundreds of meters, and although they spend most of their time near the bottom,[1] halibut may move up in the water column to feed. In most ecosystems the halibut is near the top of the marine food chain. In the North Pacific their common predators are the sea lion (Eumetopias jubatus), the orca (Orcinus orca), and the salmon shark (Lamna ditropis).

Halibut fishery

The North Pacific commercial halibut fishery dates to the late 19th century and today is one of the region's largest and most lucrative. In Canadian and U.S. waters, longline predominates, using chunks of octopus ("devilfish") or other bait on circle hooks attached at regular intervals to a weighted line that can extend for several miles across the bottom. The fishing vessel retrieves the line after several hours to a day. The effects of longline gear on habitats are poorly understood but could include disturbance of sediments, benthic structures, and other structures.

International management is necessary, because the species occupies waters of the United States, Canada, Russia, and possibly Japan (where the species is known to the Japanese as Ohyo), and matures slowly. Halibut do not reproduce until age eight, when about 30 inches (76 cm) long, so commercial capture below this length prevents breeding and is against U.S. and Canadian regulations supporting sustainability. Pacific halibut fishing is managed by the International Pacific Halibut Commission (IPHC).

For most of the modern era, halibut fishery operated as a derby. Regulators declared time slots when fishing was open (typically 24–48 hours at a time) and fisherman raced to catch as many pounds as they could within that interval. This approach accommodated unlimited participation in the fishery while allowing regulators to control the quantity of fish caught annually by controlling the number and timing of openings. The approach led to unsafe fishing as openings were necessarily set before the weather was known, forcing fisherman to leave port regardless of the weather. The approach limited fresh halibut to the markets to several weeks per year, when the gluts would push down the price received by fishermen.

Individual fishing quotas

In 1995, U.S. regulators allocated individual fishing quotas (IFQs) to existing fishery participants based on each vessel's documented historical catch. IFQs grant holders a specific proportion of each year's total allowable catch (TAC). The fishing season is nine months. The IFQ system improved both safety and product quality by providing a stable flow of fresh halibut to the marketplace. Critics of the program suggest that, since holders can sell their quota and the fish are a public resource, the IFQ system gave a public resource to the private sector. The fisheries were managed through a treaty between The United States and Canada per recommendations of the International Pacific Halibut Commission that was formed in 1923.

There is also a significant sport fishery in Alaska and British Columbia where halibut are a prized game and food fish. Sport fisherman use large rods and reels with 80–150 pounds (36–68 kg) line, and often bait with herring, large jigs, or whole salmon heads. Halibut are strong and fight strenuously when exposed to air. Smaller fish will usually be pulled on board with a gaff and may be clubbed or even punched in the head in order to prevent them from thrashing around on the deck. In both commercial and sport fisheries standard procedure is to shoot or otherwise subdue very large halibut over 150–200 pounds (68–91 kg) before landing them. Alaska's sport fishery is an element of the state's tourism economy.

As food

Hot smoked Pacific halibut

Halibut are often broiled, deep-fried or grilled while fresh. Smoking is more difficult with halibut meat than it is with salmon, due to its ultra-low fat content. Eaten fresh, the meat has a clean taste and requires little seasoning. Halibut is noted for its dense and firm texture.

Halibut have historically been an important food source to Native Americans and Canadian First Nations and continue to be a key element to many coastal subsistence economies. Accommodating the competing interests of commercial, sport, and subsistence users is a challenge.

The Atlantic population is so depleted through overfishing that it may be declared an endangered species. According to Seafood Watch, consumers should avoid Atlantic halibut.[6] Most halibut eaten on the East coast of the United States are from the Pacific.

Species of the genus Hippoglossus (proper halibut)

Photo of a stamp displaying a painting of the brown side of a halibut
Atlantic halibut (Hippoglossus hippoglossus) on a Faroese stamp
  • Atlantic halibut, Hippoglossus hippoglossus
  • Pacific halibut, Hippoglossus stenolepis

Other species sometimes called "halibut"

  • Of the same family (Pleuronectidae) as proper halibut
    • Kamchatka flounder, Atheresthes evermanni - sometimes called "Arrowtooth halibut"
    • Roundnose flounder, Eopsetta grigorjewi - often called "Shotted halibut"
    • Greenland turbot, Reinhardtius hippoglossoides - often called "Greenland halibut"
    • Spotted halibut, Verasper variegatus
  • Family Paralichthyidae
    • California flounder, Paralichthys californicus - sometimes called "California halibut"
    • Olive flounder, Paralichthys olivaceus - sometimes called "Bastard halibut"
  • Family Psettodidae
    • Indian spiny turbot - sometimes called "Indian halibut"
  • Family Carangidae (jack family, not a flatfish)
    • Black pomfret, Parastromateus niger - sometimes called "Australian halibut"

References
ISBN links support NWE through referral fees

  • Clover, Charles. 2004. The End of the Line: How overfishing is changing the world and what we eat. Ebury Press, London. ISBN 0-09-189780-7
  • Oxford English Dictionary, second edition, ed. John Simpson and Edmund Weiner, Clarendon Press, 1989, ISBN 0-19-861186-2.

"FishWatch - Pacific Halibut." NOAA :: National Marine Fisheries Service. Web. 14 Dec. 2010. <http://www.nmfs.noaa.gov/fishwatch/species/pacific_halibut.htm>.


Atlantic halibut

Atlantic halibut
Hippoglossus hippoglossus1.jpg
Conservation status
200px
Endangered

(IUCN2.3)

Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Pleuronectiformes
Family: Pleuronectidae
Genus: Hippoglossus
Species: H. hippoglossus
Binomial name
Hippoglossus hippoglossus
(Linnaeus, 1758)

The Atlantic halibut, Hippoglossus hippoglossus, is a flatfish of the family Pleuronectidae. They are demersal fish, that live on or near sand, gravel or clay bottoms at depths of between 50 and 2,000 meters (160 and 6,600 ft). The halibut is among the largest teleost (bony) fish in the world. Halibut are strong swimmers and are able to migrate long distances. Halibut size is not age-specific, but rather tends to follow a cycle related to halibut (and therefore food) abundance.

The native habitat of the Atlantic halibut is the temperate waters of the northern Atlantic, from Labrador and Greenland to Iceland, the Barents Sea and as far south as the Bay of Biscay.


Role in ecosystem

The Atlantic halibut occupies a relatively high trophic level in the food chain.

Diet

The diet of the Atlantic halibut consists mainly of other fish, e.g. cod, haddock, herring, pogge, sand eels and capelin, but it will also eat cephalopods, large crustaceans and other benthos organisms.[1][2]

Predators

Atlantic halibut are eaten by seals, and are a staple food of the Greenland shark.[2]

Commercial fishing

The Atlantic halibut was formerly a very important food fish, but due to its slow rate of population growth it is unable to recover quickly from overfishing, and the fishery has largely collapsed. Consequently, fish labelled as "halibut" is usually one of the other large flatfishes, often Pacific halibut, Hippoglossus stenolepis.

Farming

Due to its popularity as a food fish, Atlantic halibut has attracted investment in fish farming. As of 2006, five countries - Canada, Norway, the UK, Iceland and Chile - were engaged in some form of Atlantic halibut aquaculture production.[3]

Conservation status

Following overfishing the Atlantic halibut now faces a high risk of extinction in the wild, and in 1996 the IUCN rated it as Endangered and placed it on its Red List.[4]

The Atlantic halibut is a U.S. National Marine Fisheries Service Species of Concern. Species of Concern are those species about which the U.S. government’s National Oceanic and Atmospheric Administration, National Marine Fisheries Service, has some concerns regarding status and threats, but for which insufficient information is available to indicate a need to list the species under the U.S. Endangered Species Act(ESA). The American Fisheries Society has classified the species as "Vulnerable".

In 2010, Greenpeace International has added the atlantic halibut to its seafood red list. "The Greenpeace International seafood red list is a list of fish that are commonly sold in supermarkets around the world, and which have a very high risk of being sourced from unsustainable fisheries."[5]

Pacific halibut

Template:Automatic taxobox

The Pacific halibut is found on the continental shelf of the North Pacific Ocean and Bering sea. They are demersal, living on or near the bottom. The halibut is among the largest teleost (bony) fish in the world. Halibut are strong swimmers and are able to migrate long distances. Halibut size is age and sex-specific, but also follows a cycle that has been related to halibut and other species abundance.

Pacific halibut have diamond-shaped bodies. Halibut have both eyes on their dark or upper side. The color adaption allows halibut to avoid detection from both prey and predator. Being strong swimmers, halibut are able to eat a large variety of fishes such as cod, turbot, pollock, and some invertebrates such as crab and shrimp. Most spawning takes place off the edge of the continental shelf in deep waters about Template:Convert/Dual/LoffAoffDbSoffNa. At six months of age, the young have their adult form and are about 1.4 inches (3.6 cm) long. Young halibut, up to 10 years of age, are highly migratory. Older, reproductively mature halibut move seasonally across areas and between shallower and deeper waters during and around the winter reproductive season. The oldest halibut on record (both males and females) are 55 years old[6] based on otolith (ear bone) measurements.

There is a thriving commercial fishery for Pacific halibut, mainly in Alaska but also along the western coast of North America south to Oregon. Sport fishing for halibut in Alaska is a very popular activity; it is a strong fighter with an impressive yield and firm, white flesh.[7] Over 65 percent of the effort and harvest occurs in Kachemak Bay, Southeast Alaska, the Kodiak area, and near the mouth of Deep Creek in the Lower Cook Inlet. Most halibut caught weigh 15–20 pounds (6.8–9.1 kg), although individuals weighing more than 150 pounds (68 kg) are regularly caught. The International Pacific Halibut Commission (IPHC)[8] manages these fisheries based on large amounts of data taken annually.

Distribution

The Pacific halibut, Hippoglossus stenolepis, 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 to ten regularity management areas.

Halibut are demersal, living on or near the bottom of the water and prefer water temperatures ranging from Template:Convert/Dual/LoffAnoneDbSoffT. Pacific halibut belong to a family called Pleuronectidae. They are among the largest teleost fishes in the world. From November to March, mature halibut concentrate annually on spawning grounds along the edge of the continental shelf at depths from Template:Convert/Dual/LoffAnoneDbSoff.

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), reproductive fish also make regular seasonal migrations from more shallow feeding grounds in summer to deeper spawning grounds in winter [9]. Although halibut size is age and sex specific it also follows a cycle that has been related to halibut abundance. The average fish size seems to reflect density dependence in growth rate, where slower growth is associated with higher halibut (or other species) abundance, potentially due to less food available per fish.

Characteristics

Pacific halibut have diamond-shaped bodies. They are more elongated than most flatfishes, the width being about 1/3 of the length. There is a high arch in the lateral line over the pectoral fin, and it has a lunate, or crescent shaped tail, which is different from other flat fishes.[10] Small scales are embedded in the skin. Halibut have both eyes on their dark or upper side. 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.

Food

Being strong swimmers, halibut are able to eat a large variety of fishes including cod, turbot, 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.

Life cycle

Spawning takes place during the winter months with the peak of activity occurring from December through February. Most spawning takes place off the edge of the continental shelf in deep waters of 600 to 1,500 feet (183 to 457 m). Male halibut become sexually mature at 7 or 8 years of age while females attain sexual maturity at 8 to 12 years. Females lay half a million to four million eggs annually, depending on the size of the fish.[11]

Fertilized eggs hatch after about fifteen days. Free-floating larvae float for up to six months and can be transported several hundred miles counter-clockwise by North Pacific currents. During the free-floating stage, many changes take place in the young halibut, including the movement of the left eye to the right side of the fish. During this time the young halibut rise to the surface and are carried to shallower water by prevailing currents. At six months, the halibut has its adult form and is about 1.4 inches (3.6 cm) long.[12] In the shallower water, young halibut then begin life as bottom dwellers. Most young halibut ultimately spend from five to seven years in rich, shallow nursery grounds like the Bering Sea.

Young halibut are highly migratory and generally migrate in a clockwise direction east and south throughout the Gulf of Alaska. Halibut in older age classes tend to be less migratory but continue to move predominately on a clockwise direction. Mature fish are also involved in winter spawning migrations towards deeper waters migrating across several areas in some instances [13]. Research indicated that there may be small, localized spawning populations in deep waters such as in Chatham Straight in northern Southeast Alaska. However, because of the free-floating nature of larvae and subsequent mixing of juvenile halibut from throughout the Gulf of Alaska, there is only one known genetic stock of halibut in the northern pacific.

Halibut growth rates vary depending on locations and habitat conditions, but females grow faster than males. The oldest recorded female and male were 55 years old. The largest recorded sport caught halibut was 459 pounds (208 kg) near Unalaska, AK, in 1996.[14]

Length and weight

As Pacific halibut grow longer, they increase in weight. 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 among species.[15] A weight-length relationship based on a least-squares fit to data published in 2003 by the International Pacific Halibut Commission (IHPC)[16] suggests that, for pacific halibut, c = 0.00018872 and b = 3.24.

This relationship predicts that a 20 inch Pacific halibut will weigh about three pounds, a 36 inch halibut will weigh about 20 pounds, and that a 58 inch halibut will weigh about 100 pounds.

Commercial fishing

Smoked Pacific halibut on smoker racks

Commercial halibut fishing probably began in 1888 when three sailing ships from New England fished off the coast of Washington State.[17] As the industry grew, company-owned steamers carrying several smaller dories, from which the fishing was actually conducted, dominated the halibut industry. Subsequently, smaller boats of schooner design from 60 to 100 feet (18.3 to 30.5 m) were used by fishermen. These boats carried crews of five to eight and were specifically designed for halibut fishing. Today, many types of boats are used in the halibut industry. Most of the old-style halibut schooners have been replaced by more versatile craft that may also be used in commercial salmon serine, troll, gillnet, and crab fisheries.

Halibut gear consists of units of leaded ground line in lengths of 100 fathoms (Template:Convert/ft m) referred to as “skates.” Each skate has approximately 100 hooks attached to it. “Gangens,” or the lines to which the hooks are attached are either tied to or snapped onto the ground line. A “set” consists of one or more baited skates tied together and laid on the ocean bottom with anchors at each end. Each end has a float line with a buoy attached. Hooks are typically baited with frozen herring, octopus, or other fresh fish. Depending on the fishing ground, depth, time of year, and bait used, a set is pulled 2 to 20 hours after being fished. Longlines are normally pulled off the ocean floor by a hydraulic puller of some type. The halibut are cleaned soon after being boated and are kept on ice to retain freshness. Homer, Alaska claims the title of "Halibut Capital of the world" because of the large volume of both sport and commercial halibut fishing in the area.

Sport fishing

Sport fishing charter captain fileting an approximately 20-pound Pacific halibut caught in Cook Inlet, Alaska.

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 and firm, white flesh.[18] Over 65 percent of the effort and harvest occurs in Kachemak Bay, Southeast Alaska, the Kodiak area, and near the mouth of Deep Creek in the Lower Cook Inlet.

Halibut taken by anglers are generally 15 to 20 pounds (6.8 to 9.1 kg) in weight; however, fish over 150 pounds (68 kg) are regularly caught. The current Alaska state record for a sport-caught halibut is 459 lb (208 kg),[19] and a fish must weigh at least 250 lb (113 kg) 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 4 ounces (113 g) to 4 pounds (1.81 kg), depending on such factors as depth and current. [20]

Halibut, along with salmon, provide substinence 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 delicious fish is increasing each year. In Southeast Alaska, halibut are second only to king salmon in sport angler preference.[21] 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 of halibut.

References

  • Grzimek, B., D. G. Kleiman, V. Geist, and M. C. McDade. Grzimek's Animal Life Encyclopedia. Detroit: Thomson-Gale, 2004. ISBN 0307394913.
  • Nelson, J. S. 2006. Fishes of the World, 4th edition. Hoboken, NJ: John Wiley & Sons. ISBN 0471250317.

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  1. Cite error: Invalid <ref> tag; no text was provided for refs named Fishbase
  2. 2.0 2.1 Cite error: Invalid <ref> tag; no text was provided for refs named FishGulfMaine
  3. Atlantic Halibut. Fisheries and Oceans Canada (2006-05-31). Retrieved 2009-06-22.
  4. Sobel, J (1996). [[[:Template:IUCNlink]] Hippoglossus hippoglossus]. IUCN Red List. International Union for the Conservation of Nature and Natural Resources. Retrieved 2009-06-22.
  5. Greenpeace International Seafood Red list
  6. http://www.iphc.int/research/biology.html
  7. Schultz, Ken. Ken Scultz’s Essentials of Fishing.John Wiley and & Sons, Inc., Hoboken, New Jersey, 2010. ISBN 9780470444313, pp. 66-67
  8. International Pacific Halibut Commission
  9. http://www.iphc.int/publications/annual/ar2009.pdf
  10. Schultz, Ken. Ken Scultz’s Essentials of Fishing.John Wiley and & Sons, Inc., Hoboken, New Jersey, 2010. ISBN 9780470444313, pp. 66-67
  11. The Pacific Halibut: Biology, Fishery and Management IPHC Technical Report No. 40, 1998
  12. The Pacific Halibut: Biology, Fishery and Management IPHC Technical Report No. 40, 1998
  13. http://www.iphc.int/publications/annual/ar2009.pdf
  14. Bethers, Mike. Pacific Halibut. Alaska Department of Fish & Game. Read Online Accessed 5/23/2010
  15. R. O. Anderson and R. M. Neumann, Length, Weight, and Associated Structural Indices, in Fisheries Techniques, second edition, B.E. Murphy and D.W. Willis, eds., American Fisheries Society, 1996.
  16. Halibut weight/length chart (Imperial) published by the IHPC 2003
  17. Bethers, Mike. Pacific Halibut. Alaska Department of Fish & Game. Read Online Accessed 5/23/2010
  18. Schultz, Ken. Ken Scultz’s Essentials of Fishing.John Wiley and & Sons, Inc., Hoboken, New Jersey, 2010. ISBN 9780470444313, pp. 66-67
  19. Bethers, Mike. Pacific Halibut. Alaska Department of Fish & Game. Read Online Accessed 5/23/2010
  20. Schultz, Ken. Ken Scultz’s Essentials of Fishing.John Wiley and & Sons, Inc., Hoboken, New Jersey, 2010. ISBN 9780470444313, pp. 66-67
  21. Bethers, Mike. Pacific Halibut. Alaska Department of Fish & Game. Read Online Accessed 5/23/2010