Common Sole

The common sole (Solea solea), also known as the true sole, is a right-eyed flatfish in the family Soleidae found throughout coastal waters of Europe and the northeastern Atlantic. It is the most economically significant of the European soles and a member of a distinct family separate from the flounders and plaice, characterized by a more elongated body and small, asymmetric mouth. Common sole range from Norway and the Baltic Sea south along the Atlantic coast to the Mediterranean and parts of the eastern Atlantic off Africa. The species has long supported important European fisheries, with stock status monitored and managed regionally, varying from recovering to stable depending on the sea area.

Common sole are identified by their elongated shape and distinctive mouth structure.

• Body: elongated, narrow oval, more slender than plaice or flounder
• Eyes: both on the right side, set close together near the front of the head
• Mouth: small, curved, and set well below the eyes, adapted for detecting buried prey
• Coloration: uniform grayish-brown to sandy upper side with faint mottling, plain cream underside
• Pectoral fin: often marked with a dark blotch near the tip on the eyed side
• Size: typically 30-40 cm Its slender, elongated shape and small curved mouth distinguish it from the broader-bodied plaice and flounder.

Common sole inhabit sandy and muddy seabeds in coastal and continental shelf waters, typically from shallow depths of a few meters down to around 150 m. Their range spans the northeastern Atlantic from Norway and the Baltic Sea south through the North Sea, English Channel, and Bay of Biscay to the Mediterranean and Black Sea, with some populations along the northwest African coast. Common sole favor warmer temperate waters compared to some other regional flatfish and often move into shallower coastal zones and estuary mouths, particularly as juveniles. They tend to bury themselves in soft sediment during daylight hours, becoming more active at night.

Common sole are primarily nocturnal, bottom-dwelling feeders that remain buried in sediment by day and emerge at night to forage for worms, small mollusks, and crustaceans using well-developed chemical and tactile senses rather than vision. They are generally solitary and not strongly schooling, relying on camouflage and burial in sand or mud for protection from predators during inactive periods. Common sole undertake seasonal migrations between shallow coastal feeding and nursery grounds and deeper offshore waters used for spawning. Spawning occurs in spring in coastal waters, with females releasing large numbers of small pelagic eggs that drift with currents before larvae settle into shallow nursery habitats as juveniles.