Flatfish - Pleuronectidae

Representatives of this family feature asymmetric scull with eyes on one of its sides (left or right) and a body, squeezed from its sides and oval, as a rule. Most of flatfish are typically bottom-dwelling species.
From 30 (33) species of flatfish which habit in Kamchatkan waters only 7 (excluding halibuts) are marketable ones such as yellowfin sole, Alaska plaice, rock sole, flathead sole, starry flounder, longhead dab, and Sakhalin sole.

Yellowfin sole (Limanda aspera, Rus. – kambala zheltopyeraya)

Yellow sole has a relatively broad body, covered with small rough scales, with yellow back and anal fins. Along roots on the eye side there is a dark narrow streak. The eye side is light-brown, blind one is white. It is one of the most spread flatfish of Far East seas. It composes the dominant catch of flatfish near Western Kamchatka. It lives also near eastern coast and in western part of Bering sea.
It can be as long as 49 cm (19”), and weight up to 1.7 kg (3.8 lb). Its usual length is 24-35 cm (10-14”) and weight is .2-.5 kg (0.4-1.1 lb). It can live 18-20 years.
In waters of Kamchatka they spawn from late May to early September with boom in July.
Among all flatfish yellowfin sole is a benthos feeder with the most broad food range which includes bottom-dwelling, pelagic backboneless and fish.
It is marine bottom fish which does not avoid desalinated areas near river mouths, and it can be found down to 5-600 m (15-2,000 ft) and it performs seasonal migrations. Large mature individuals winter in depth of 100 m (328 ft), and in summer they migrate to smaller depths. Young fish habit in smaller depths during both seasons. While wintering flatfish, actually, does not feed at all.

Alaska plaice (Pleuronectes quadrituberculatus, Rus. – Kambala zheltobryukhaya)

This species differs from other flatfish by lemon yellow coloring of its blind side and with 4-6 bone curves behind the upper eye.
It widely spread near Okhotsk sea coast, eastern-Kamchatkan shores and also western part of Bering sea.
Alaska plaice is one of the largest flatfish. In Bering sea one can find individuals of 62 cm (24") and 3.5 kg (7.7 lb); and age up to 20 years. This fish usually weigh from .3 to 1.4 kg (.3-3.1 lb), with an average length of 24-35 cm (9.4-13.8”). Alaska plaice lives in the shelf and in upper part of mainland slope: it can be found down to 300 m (985 ft) in Okhotsk sea and to 500 m (1640 ft) in Bering sea. Seasonal migrations are typical. In spring it migrates to the shelf and in fall it goes down to currents in depth.
Mass spawning happen in April and May down to 500 m (1640 ft) depth.

Rock sole (Lepidopsetta polyxystra, Rus. – kambala belobryukhaya)

This flatfish can be easily defined by its lateral line with a high curve above the pectoral fin. The additional spinal branch is well seen from the blind white side of the body. Upper side is a brownish-grey with small dark spots.
In Kamchatkan waters it can reach 51 cm (20”) of length, 1.9 kg (4.2 lb) of weight, and age of 17 years. In catch its average size is 30-35 cm (12-14”), and weight is .4-.6 kg (.9-1.3 lb).
In December-April large mature rock sole winters down to 150-350 m (500-1150 ft). One-time spawning in waters of Kamchatka lasts from March to April. After spawning spring migration starts from wintering area into shelf zone where in depth of 30-100 m (100-330 ft) it actively feeds on shellfish and echinoderms. Rock sole dominates in catches of flatfish near the eastern coast of Kamchatka, in Karaginsky and Olyutorsky bays.

Flathead sole (Hippoglossoides robustus, Rus. – kambala paltusovidnaya)

Flathead sole differs from others by its lateral line that is almost straight in front part. Its eye side is dark-brown and back and anal fins has faint black streaks. Its blind side is white.
It is relatively large flatfish: it can be as long as 58 cm (24") and as heavy as 1.8 kg (4 lb). In commercial catch there are fish of 26-38 cm (10-15”) and .34-.46 kg (.8-1 lb).
Spawning has two stages with boom in May – early June in depth of 20-100 m (66-330 ft). The range of this flatfish is very broad and covers depths from 10 to 1000 m (33-3281 ft). In summer it distributes on the shelf between isobaths of 30-80 m (100-260 ft). In winter it descends in upper departments of continental slope (400-500 meters or 1300-1500 ft).
Main stocks of this flatfish are in western Kamchatka and in Bering sea.

Starry flounder (Platichthys stellatus, Rus. - Kambala zvezdchataya)

The skin of this flounder is covered with scales modified into tiny star-shaped plates. There are black streaks on the back and anal fin, and they are seen from both sides of the body.
It is large flounder with up to 58 cm (23”) of length and 3.1 kg (6.8 lb) of weight. It has two ecological forms such as coastal one, which enters river mouths and staying there for winter, and marine one, which lives in summer and winter deeper than the first one.
It spawns in spring-summer with boom in Kamchatkan waters.

Longhead dab, Snout sole (Myzopsetta proboscidea, Rus. – kambala khobotnaya)

Snout of this sole is long and upturned, the head and mouth is normal size; blind part of the body has yellow-orange color. It is small sole. It reaches 30-35 cm (12-14”) of length; at average take fish is 15-20 cm (6-8”) of length and .06-.3 kg (.13-.7 lb). It ranges everywhere in waters near Kamchatka.
Longhead dab is a coastal species and can be found near river mouths and down to 100 m (330 ft) or deeper. It winters in deep currents down to 500 m (1600 ft). Mass spawning starts in June-August.

Pacific halibut (Hippoglossus stenolepis, Rus. – paltus belokory)

It can be found everywhere near western Kamchatka but in general it is not numerous. It is more often found near eastern Kamchatka and in western part of Bering sea. Pacific halibut is one of the largest fish. In some cases individuals of 239-267 cm (94-105”) and 230-345 kg (507-761 lb) were caught. Such unique examples are relatively rare but halibuts of 100-180 cm (39-71”) and 50-80 kg (110-176 lb) are rather frequent especially in western part of Bering sea. Regular catches have individuals of 40-90 cm (16-35”) and 6-8 kg (13-18 lb). Their maximum age is 35 years. 5-12 year old individuals prevail in schools.
Pacific halibut can be easily distinguished by its appearance from other species since it has solid diamond-shaped body colored brownish-olive-green, sometimes grey, resembling marble. Its blind side is white. The mouth is big with developed teeth; scales on body are small.
Pacific halibut, like all flatfish, perform seasonal migrations. In summer it lives down to 10-400 m (33-1300 ft), with its maximum density in depths of 30-150 m (100-500 ft) and in fall it moves to depths of 300-700 m (1000-2300 ft). Young fish (3-5 years old) permanently lives on the shelf.

Pacific black halibut (Reinbardtius hippglossoides matsuurae, Rus. – paltus cherny)

It is more often found in deep currents and adjoin the shelf of Okhotsk sea and western Bering sea coasts. It was also registered in oceanic waters of eastern Kamchatka.
Pacific black halibut differs from other species with dark blind and eye sides of its body. Its eyes are located not at one side of the body like pacific halibut or arrow-toothed halibut but in a different way. Its upper eye is on the very top of the head and is seen from all sides of the body. The head is big and has large fang-like teeth. The skin is smooth and covered with small scales.
It belongs to large flatfish and lives up to 24 years with maximum size of 120-130 cm (47-51”) and weight of 13.5 kg (30 lb). At average take fish is 45-80 cm (100-176”) of length and 1-5 kg (2.2-11 lb).
This halibut lives in the most wide range of depths from 50 to 1,600 m (165-5,250 ft), but it can also be found in smaller depth. Its maximum density is found down to 450-650 m (1,500-2,132 ft). All year round only young fish habits on the shelf, though with negative temperature of water. In lower departments of the shelf and in deep current mature fish prevail which rise higher (but not higher than 200 meters or 660 feet).
Black halibut is an active predator. Fish (Alaska Pollack) and cephalopods (squid) are its main food. It is valuable marketable fish.

Arrow-toothed halibut, Kamchatka flounder (Atheresthes evermanni, Rus. - paltus strelozuby)

It is widely spread in western part of Bering sea and Okhotsk sea.
Arrow-toothed halibut has light-brown body coloring, big head with strong teeth resembling arrows (that is why it was named arrow-teethed). Its body is covered with large and easily removed scales.
It rather yields to pacific halibut in length and weight. Its maximum length is 94 cm (37") and weight is 8.5 kg (18.7 lb) when it gets 20 years old. At average take fish is 41-67 cm (16-26”) of length and 0,7-3,3 kg (1.5-7.3 lb) in the age of 5-12 years.
It lives in depth ranging from 20 to 1,200 m (66-3,940 ft). Maximum density is down to 300-700 m (1,000-2,300 ft).