The lemon sole is one of the common flatfishes living off Britain’s coastline, although it is less numerous than the plaice. Though caught in large quantities by trawlers, it isn’t regularly captured by anglers. This may be because it lives mainly in rather deep water or because its mouth is too small to take easily the size of hook that sea anglers use.
Like the plaice, dab, flounder, and the soles, it is a right-sided flatfish. A useful check is to lay the flatfish white-side down with the anal vent and gut towards you. If it is right-sided, its eyes and mouth are to your right. The most noticeable feature is the lemon sole’s head, which is really very small, even though the eyes are fairly large. The outline of the body is a smooth oval, with just the front of the head and mouth protruding.
The lateral line is slightly curved above the pectoral fm on the coloured side; unlike the dab, which also has a curved lateral line, the lemon sole’s scales are not toothed and the skin feels smooth and slimy.
Colour is variable but quite distinctive.
Spawning occurs between April and July in moderate depths, often around 100m (330ft). The eggs and larvae float near the surface and drift inshore. The young fish begins to live on the sea bed when it is about 2cm (’Man) long. At a length of 2.5cm (lin) it is clearly recognizable as a lemon sole, although it may be rather pale in colour.
The topside is a warm brown with flecks of orange, yellow and green and irregular mahogany coloured patches. The underside is creamy white. This colouring provides excellent camouflage on the sea bed. When the fish is resting on rocks covered with pink encrusting algae, it develops quite distinct pink patches.
Life on the sea bed
The lemon sole is most abundant on offshore banks in depths of 40-200m (130-655ft), although young ones can be caught in shallower water. It is most common on firm sandy or gravelly bottoms but a few can be caught on mud and some are found resting motionless on rocky or stony sea beds, relying on their superb mottled camouflage for protection.
Not surprisingly in view of the small size of its mouth, the food organisms it eats are generally small – mainly worms but also small crustaceans such as sand hoppers and young crabs. Large lemon soles eat molluscs, sometimes taking the whole animal but more often using their sharp teeth to nip off the siphons of shellfish (such as cockles) when they are extended above the level of the sea bed.