Latin name

Scophthalmus maximus

Other names

Brat, britt, britt, butt.

Identification

The body is diamond-shaped, strongly compressed at the sides, and the body height is only 1.5 times the body length. Scales are absent. The ocular side of the body and head is covered with small pointed tubercles, the diameter of which is smaller than the diameter of the eye (sometimes tubercles are present on the blind side). The upper profile of the head is concave near the anterior margin of the upper eye. The muzzle is relatively short, slightly longer than the diameter of the eye. The eyes are set on the left side of the body, widely apart; the distance between the eyes is about twice the diameter of the eye in adults, not more than the diameter of the eye in juveniles. The mouth is large, terminal, strongly oblique, the posterior edge of the upper jaw extending to a vertical line passing through the centre of the lower eye. The lower jaw protrudes slightly forward. The teeth are small, pointed and arranged in several rows. There are teeth on the coxae. There are 10-12 gill stamens on the lower half of the first gill arch. The lateral line is well developed on both sides of the body, with a steep bend above the pectoral fin. There are 30-31 vertebrae, of which 19-20 are in the caudal spine.

Features of fish fins

The dorsal fin begins on the head, with its origin on a vertical line running well in front of the eye margin. The dorsal fin has 57-80 soft, unbranched rays. The anterior rays are not longer than the other rays of the dorsal fin. The distal parts of the rays are not connected by a membrane. The long anal fin has 43-58 soft rays. The ends of the dorsal and anal fins reach the beginning of the caudal peduncle and are not connected to the caudal fin. The middle rays of the dorsal and anal fins are slightly longer than the others. The dorsal and anal fin rays are slightly longer than the others. The pectoral fin has 11-12 rays on the eye side of the body; the rays in the pectoral fin on the blind side of the body are much shorter than on the eye side. The bases of the pelvic fins are of equal length and elongated. The fins are asymmetrical, with the first ray of the right pelvic fin opposite the second or third ray of the left fin. The caudal fin is rounded.

Fish colouring

The colouration of the ocular side of the body varies considerably depending on the colour of the surrounding substrate, but generally ranges from light grey or yellowish to dark grey or dark brown with numerous dark and light round spots. The blind side is usually whitish, sometimes with scattered vague dark spots. The fins are dark brown, mottled with light dots and spots.

Distribution

Widespread in the eastern Atlantic from Norway (range extends beyond the Arctic Circle); in the North Sea, most of the Baltic Sea; along the west coast of Europe, including the British Isles, and south to Boujdour (Western Sahara); in the Mediterranean. Rare off the coast of Iceland. Absent from the coasts of Greenland and North America. 

Habitat

Sea bottom fish. They live on sandy, shell or pebble bottoms at depths of 2 to 80 metres. Juveniles up to one year old stay close to the coast in desalinated areas of bays and inlets. Adults can tolerate considerable fluctuations in salinity and are found in the Baltic Sea at salinities of up to 2 ‰.

Size

Maximum length 100 cm, usually 40-70 cm, body mass up to 25 kg.

Behavior

Tends to live in groups. Most of the time it lies on the ground with its eyes up. As soon as it senses danger, it begins to burrow deeper. This camouflage technique allows it to successfully hunt. 

Food and feeding habits

Juveniles feed on invertebrates (Calanoida, Euphausiacea, Balanus and gastropod larvae). Adults switch to feeding on fish (Ammodytidae, European sprat, mackerel, mackerel, Trisopterus esmarkii, juvenile haddock, flounder; sea bream and others). Molluscs and polychaetes are sometimes found in the stomachs.

Reproduction

Males reach sexual maturity at 3 years of age, females at 4-5 years. They spawn from February to April in the Mediterranean, from April to August in the North and Baltic Seas, and from May to July in the more southerly parts of the Atlantic. Spawning is batch spawning, with individual batches of eggs hatching every 2-4 days. Spawning is observed at depths of 10-80 m over gravelly bottoms. Female fecundity varies from 5 to 10 million eggs. Eggs are pelagic, spherical with a single fat droplet 0.9-1.2 mm in diameter. Embryonic development lasts 7-9 days, depending on water temperature. At hatching, the larvae vary in length from 2.2 to 2.8 mm.

The larvae have a symmetrical body and live a planktonic lifestyle for several months. When they reach a length of 25-27 mm, metamorphosis is complete, the eye moves to the left side of the body and the juveniles switch to a bottom-dwelling lifestyle.

The turbot grows rather slowly. In the Baltic Sea, both females and males reach a length of 20 cm by the end of the first year of life. After that, females grow faster than males. At the age of 3, females reach 36 cm and males 31.5 cm.

According to different authors, the maximum life expectancy is between 15 and 25 years.

Fishing

Valuable commercial fish. Subject of aquaculture.