10 20 40 60 cm

mittakaava < 40 cm

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Gösta Sundman: Suomen Kalat (Kansalliskirjasto, The National Library of Finland), Lauri Urho, Jouko Lehmuskallio

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Platichthys flesus

  • Family: Righteye flounders – Pleuronectidae
  • Similar species: brill, dab, plaice, turbot
  • Size: 20–35 cm, seldom exceeds 1 kg in weight.
  • Appearance: Characteristically usually has both eyes on right side of head. Not a certain means of identification, since some members of this family may be left-sided in the same way that some people are left-handed. Left-sided flounders may represent up to a third of individuals. Flounders are best distinguished from other flatfish by the angle at the mid-point of the dorsal and anal fins. Other members of the family have more rounded fins. Also distinguished by bony tubercles along the lateral line, which makes only a slight upward curve over the pectoral fin.
  • Colouring: Underside almost always whitish, eyed side varies according to type of bottom from brown to greyish and from uniform colouring to spotted. Spots often a rusty red (possible confusion with the plaice).
  • Reproduction: Depends on water salinity. At salinities exceeding 1%, as in the southern Baltic, flounders spawn in deeper water and the eggs float. Along Finland’s coasts flounders breed in shallow water in May-June, the eggs remaining on the bottom due to the low salinity. The male’s sperm are mobile only when the salinity reaches about 0.6%, restricting spawning to southwest coastal areas.
  • Food: Bottom invertebrates, especially shellfish.
  • Distribution and habitat: Fairly common in the seas around Finland, though less frequent in the northern Gulf of Bothnia and eastern Gulf of Finland. Although essentially a saltwater species, flounders cope amazingly well in water with no salt content. In summer, flounders from the Arctic Ocean regularly run up the river Tenojoki as far as lake Pulmankijärvi. Flounders spend most of their time in moderately shallow water preferring a muddy or sandy bottom, where they lie partly concealed. Leave warm water in late summer for depths of 10-30 m.
  • Endangerment: Near threatened.

A familiar catch for offshore netsmen. A good table fish, and popular smoked. Right-sided flatfish caught in Finland’s sea areas are almost invariably flounders, while left-sided individuals with large mouths and a more rounded shape are turbot. The two are easy to identify, even if the flounder happens to be left-sided. Any unusual-looking flatfish should always be inspected carefully in case there happens to be a dab, plaice or brill among them. Reddish spots are not a completely reliable means of identification.

Other species from the same family

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