Scientific name
Platichthys flesus (Linné, 1758)
Morphology
Flounder are oval-shaped flatfish when viewed from above. Their mouths are armed with small, rough teeth. As for the body of these popular flatfish, it is filled with discreet cycloid scales. Both eyes are located on the same side, almost always on the right. While flounder closely resembles plaice, it lacks a bony ridge behind the eyes and displays two rough lines (tubercles) to the touch at the base of the tail and at the base of the anal fin. The flounder also has bony plates that reinforce its lateral line. Its back is dark, sometimes dotted with whitish or even slightly orange spots. These are more discreet than those of plaice, and disappear quickly once the fish is dry.
Flounder fishing grounds
The flounder is a benthic flatfish living on rather flat bottoms: sandy, muddy or gravelly. It is commonly found near the coast, particularly in harbors and estuaries. In fact, it can swim far upstream in freshwater rivers. In harbors, it abounds in hollows on sandy-muddy bottoms.
Fishing techniques
Note that this fish is lazy by nature. It prefers to lie flat on the lookout for the slightest movement of food emerging from the sand. Worms are flounder's favourite bait, whose visual attractiveness is boosted by the accompaniment of a phosphorescent pearl: luminescence is useful near bottoms laden with suspended sediment. As for the touch, flounder, like their closely related species called plaice, know how to be discreet. In fact, these flatfish produce a tiny touch and then settle on the bottom. That's why it's not uncommon to discover a large flounder when reeling in the rod for a bait change, especially with heavy tackle and sinkers weighing over 150 g.
Reproduction
Flounder spawn between December and May, depending on geographic location, and can lay up to 2 million eggs less than 2 mm in diameter. Larvae have symmetrical eyes on either side of the head. However, as they grow, the left eye moves to the right and the young flounder settles on the sandy bottom. Flounder reach 10 cm at 1 year, 15 cm at 2 years, 20 cm at 3 years, then reach their sexual maturity at 4 years and 30 cm. Flounder can live up to 50 years!
Size and weight
- Catch size (legal minimum): none, I recommend 30 cm
- Size at sexual maturity: 30 cm
- Average size: 25 to 40 cm
- Maximum size / weight: 60 cm / 4 kg
- French record: 2.58 kg (Corsept, Pays de Loire, 07/02/2000)
Good to know
Flounder are often a good safe bet when surfcasting or landing from a boat. In fact, they are the delight of competition anglers, especially when a large flounder is caught. Some coastal sandbanks are carpeted with flounder, and some anglers in northern France hook them by scraping the bottom with a sinker fitted with a treble hook as a grappling hook, a less-than-honorable catch...