Flounder

Flounder, any of numerous species of flatfishes belonging to the families Achiropsettidae.Included among the approximately 100 species of the family Pleuronectidae are the European flounder (Platichthys flesus), a marine and freshwater food and sport fish of Europe that grows to a length of 50 cm (20 inches) and weight of 2.7 kg (6 pounds); the starry flounder (Platichthys stellatus), a North Pacific species that averages about 9 kg (20 pounds) in weight; and the winter flounder (Pseudopleuronectes americanus), an American Atlantic food fish, growing to about 60 cm (23 inches) in length. Flounders in that family typically have the eyes and colouring on the right side.

Flounders are a group of flatfish species. In the families Bothidae and Paralichthyidae, which together contain more than 240 species, the better-known flounders include the summer flounder (Paralichthys dentatus), an American Atlantic food fish growing to about 90 cm (35 inches); the peacock flounder (Bothus lunatus), a tropical American Atlantic species attractively marked with many pale blue spots and rings; the brill (Scophthalmus rhombus), a relatively large commercial European species, reaching a length of 75 cm (29 inches); and the dusky flounder (Syacium papillosum), a tropical western Atlantic species. Flounders in those families typically have eyes and colouring on the left side.

In its life cycle, an adult flounder has two eyes on one side of its head, and at hatching one eye is on each side of its head. One eye migrates to the other side of the body through a metamorphosis as it grows from larval to juvenile stage. As an adult, a flounder changes its habits and camouflages itself by lying on the bottom of the ocean floor as protection against predators. As a result, the eyes are then on the side which faces up. The side to which the eyes migrate is dependent on the species type.

The flounder is a typical flatfish with flattened fins that wrap around the oval-shaped body. Its eyes are positioned on the right side of the head (if you imagine the fish swimming upright) but, identification can be quite difficult because

•  some have been found with eyes directed towards the left
•  flounders have been known to interbreed (hybridise) with plaice giving rise to coloured variations
•  there are also flounders which have undersides exactly the same colour as their backs (normally they have white undersides).

The tail of a flounder is quite square at its end and there are bony tubercles around both sides of the body, at the bases of both the elongated dorsal and anal fins.
Flounders are very widely distributed around the coast of Britain. It lives from the shoreline down to depths around 165 feet deep, favouring muddy bottoms but will also live over sandy bottoms.

Flounders are amazingly tolerant of variations in the salt content of water. They can be found living in the sea, they can be found living in estuaries where slat water meets fresh, and they can even be found (and caught) in the freshwater of rivers well away from the sea shore. Flounders can be caught anywhere with flat shallow beaches and scars favoured spots. Although they can be caught at any time, by far the most prolific period for flounder fishing is within the first 3 hours of an incoming tide.

As far as anglers are concerned the flounder is primarily a spring, summer and autumn species as it is at these times of the year when flounders live within casting range. In the depths of winter they migrate into the warmer and deeper water well away from the shoreline. Flounders are at their most abundant from mid spring through until late summer. The onset of warmer weather sees the flounder arrive en masse for a summer feeding frenzy.