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Pacific halibut fish identification, Habitats, Fishing methods, fish characteristics
Pacific halibut is a bottom-dwelling ground-fish that nestles into the sandy seafloor, often seen with only its eyes and mouth uncovered. It is one of the biggest fish species, 2.7 m long; weighting 345 kg, maximum age of life is 35 years. Like other flatfishes Halibut are flattened laterally, and swim sideways, with one side facing down and the other facing up. Primarily found in the coastal North Pacific Ocean and Bering Sea, at depths from 20 to 3,600 feet, it migrates hundreds of miles from shallow coastal waters to the deep, open ocean to spawn in winter. Most return, year after year, to the same coastal feeding grounds.
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Pacific Halibut, Hippoglossus stenolepis, is a Right-eyed flounder
family Pleuronectidae, also known as Northern Halibut, Alabato and Right Halibut, Genuine Halibut, Real Halibut, is the largest flatfish in family, widely distributed from Santa Rosa Island, California, to the Bering Sea and the Sea of Japan. They occur in the coastal waters of Alaska, British Columbia, and Washington, Oregon and northern Pacific Ocean, from California northward to the Chukchi Sea and from the Gulf of Anadyr, near eastern Kamchatka, Russia southward to Hokkaido, Japan. The center of abundance is the central Gulf of Alaska, particularly near Kodiak Island.
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Description:
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Pacific halibut are the largest flatfish in
family Pleuronectidae. The body of the Pacific halibut is elongate, rather slender, diamond shaped and highly compressed. They are more elongated than most flatfishes, the width being about 1/3 of the length. The head is elongate and the mouth is large to medium-sized extends to the middle of the lower eye or beyond, and is nearly symmetrical. Mouth has large conical shaped sharp teeth with double row on top and one row on bottom. Both eyes are on the right side of the body. Virtually all halibut are right-eyed, left-eyed halibut are rare.
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The dorsal fin origin above anterior middle part of pupil in upper eye, generally low, higher in middle, and is continuous from near the eyes to the base of the tail. The anal fin extends from just behind the anus to the same point on the other side, longest soft rays of dorsal and anal fins at about middle of body. The tail is broad, symmetrical, and slightly forked (lunate, or crescent shaped tail) which is different from other flat fishes. The lateral line has high arch over the pectoral fin. Pectorals are small. Pelvic fins symmetrically placed. The scales are quite small and embedded in the skin, making the skin appear smooth to touch.
Key characters
Flat, diamond-shaped bodies; their colored side is mottled brown. Caudal fin spread and slightly lunate.
90-106 Dorsal soft rays
69 – 80 Anal soft rays
49 – 51 Vertebrae
Max length: over 8 feet
Max weight: over 500 pounds
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The color of the body is gray to dark brown, or nearly black with fine mottling and numerous spots on the eyed side, tends to assume the coloration of the ocean sandy or muddy bottom. The blind side is pigmented, lighter brown or typically white. This color adaptation allows halibut to avoid detection by both prey and predator.
The Pacific halibut can be distinguished from the California halibut by looking at the end of the jaw. In the Pacific halibut, it extends to the front edge of the eye, while in the California halibut it extends beyond the eye. Also it is easy to confuse Pacific halibut with Arrowtooth flounder. Unlike halibut, Arrowtooth flounder have coarse scales and prominent, needle-like teeth. The lateral line of Arrowtooth flounder is barely curved over the pectoral fin. When cooked, Arrowtooth flounder turn mushy and are generally considered inedible.
Habitats:
Pacific halibut are demersal, typically found on or near the bottom over a variety of bottom types on or near the continental shelf, and sometimes swim up in the water column to feed. They water temperatures in the range 37-46 ºF (3-8 ºC) and usually inhabit waters between 20 and 1,000 ft, but have been found at depths up to 3,600 ft. Halibut prefer rocky bottoms where they ambush food.
Juveniles (1 inch and larger) are common in shallow, near-shore waters 6.5 to 164 feet deep. Young are found near shore, moving out to deeper waters as they grow older. Older individuals typically move from deeper water to about 3600 ft (1000 m) along the edge of the continental shelf where they spend the winter, to shallow coastal water (27-274 m) for the summer. Halibut are strong swimmers and often migrate wide-ranging to long distances. They are involved in a predominantly clockwise migration from their settlement areas primarily eastward and southward; mature fish also make regular seasonal spawning migrations from more shallow feeding grounds in early summer to deeper spawning grounds in fall-winter.
Pacific Halibut feed on plankton during their first year of life. Young halibut (1 to 3 years old) feed on euphausiids (small shrimp-like crustaceans), other bottom-dwelling organisms and small fish. As halibut grow, fish became a larger part of their diet. Larger halibut prey on other fish, such as herring, sand lance, capelin, smelt, pollock, sablefish, cod, rockfish, turbot, sculpins, other flatfish, occasionally even smaller halibut. They also consume octopus, crabs, clams, squids, and other invertebrates.
Spawning:
Females become sexually mature at 8 to 16 years of age (average 12), males mature earlier, at 7 to 8 years of age. Spawning takes place during the winter months from November to March with the peak occurring from December through February in deep water from 600 to 1,500 feet (180 to 460 m) along edge of the continental shelf. Females spawn once per year and release eggs anywhere from few thousand to few millions depending on the size of the fish. A 50-pound female can produce about 500,000 eggs, a large female of 140 pounds may produce as many as 2.7 million eggs; a female over 250 pounds can produce 4 million eggs. They release their eggs in batches over several days during the spawning season, which are fertilized externally by the males. Eggs hatch after 12 to 15 days.
The eggs and larvae are pelagic; slowly drift casually with the deep ocean currents gradually rising closer to the surface currents to shallower, more nourishing coastal waters, where they remain in the water column for about 4 to 6 months until they reach their adult form. When first hatched, the young swim upright; however, they soon start to turn to their left side and the left eye migrates to the right side of the head when the larvae are about one inch long. During the free floating period many changes occur and by early spring, the transformation is complete and the young settle to the bottom in shallow waters. At the same time, the coloration on the left side of the body fades. The fish end up with both eyes on the pigmented upper side of the body, while their underside is white. By the age of 6 months, young halibut has its adult form and is about 1.4 inches (3.6 cm) long and settle to the bottom in shallow near-shore areas then begin life as bottom dwellers. Most young halibut ultimately spend from 5 to 7 years in rich, shallow nursery grounds. Female halibut grow faster and reach larger sizes than male halibut.
Fishing Methods:
Halibut is a very popular target for sport fishermen and an important part of commercial fishing. These fish fight like mad, and anglers use good strong saltwater tackle to harvest halibut with bait like herring, mackerel, but also use squid, octopus, cod pieces, or other small bottom fish. The fish are typically caught on crab, shrimp, squid, and other invertebrates. Halibut is also cached with long-line gear; a vessel lays out a long fishing line which is anchored to the bottom of the ocean. Several baited hooks are attached to this line at regular intervals. Once the halibut is hooked, it will generally put up a struggle to stay on the bottom, but they are not very aggressive once hooked. Keeping bait floating above them will convince them that the prey is coming across them making landing them easier.
Halibut is utilized fresh, dried or salted, smoked and frozen; eaten steamed, fried, broiled, boiled, microwaved and baked.
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