Now In-Season, Winter Flounder are 'Right-Eyed' and That's No Fluke

Some animals, like the striped bass and bald eagle, were named after distinguishing marks on their bodies.  Others, like Thompson’s gazelles and Fraser’s dolphins, were named for the people who “discovered” them.

A few creatures, however, were named simply to be identifiable by the people who pursued them. Two of the simplest examples are in the flounder family. To fishermen off our Atlantic shores, flatfish commonly caught in the summer became known as summer flounder and those abundant in colder months were named – that’s right – winter flounder.

Winter flounder spend the summer months in cooler deeper water but come in closer to shore at this time of year to spawn. So now is the legal time to catch them: Connecticut’s winter flounder season opened Monday and continues through May 30.

But there’s more that distinguishes winter and summer flounder than the time of year that they’re within casting range of fishermen.  To explain, we have to start at the beginning of their lives, shortly after a tiny flounder “fry” has hatched.

At this early stage of its life, a flounder isn’t a flatfish at all. It looks like a “normal” fish. But as it develops, one eye moves to the other side of its body! The little flounder can then lie flat on the sea floor and keep two sharp eyes out for predators and prey.

As if having a migrating eye isn’t wild enough, the eye that moves is different depending on the flounder species. There are “left-eyed” and “right-eyed” flatfish. With summer and windowpane flounder, the right eye shifts over next to the left eye, so they are “left-eyed.” With winter flounder, it’s the left eye that moves, so they are “right-eyed” (as are most halibut and sole).

How do you tell them apart? Imagine lifting a flounder straight up off the bottom, and trying to tilt it on its side so that its mouth is lower than its eyes. With a winter flounder, you would tip it so the eyes are on its right. Left-eyed summer flounder would get tipped to the left.

Another difference: summer flounder, or fluke, have a wide mouth with big sharp teeth. Winter flounder have a tiny mouth and small (or no) teeth.

Winter flounder (Pleuronectes americanus) are a muddy reddish brown but have hints of olive green and even black. Their underside is white. Within their range from Canada to the Carolinas (including Long Island Sound), they seek out bottoms of soft mud or sand, which they kick up over their bodies to aid in camouflage. Their prey includes worms, small crabs, mollusks and many of the sea’s tiniest swimming creatures.

Winter flounder are tasty enough to make fishing in the cold worthwhile. However, some long-time fishermen will tell you that there aren’t nearly as many winter flounder in Long Island Sound as there used to be. To try to help give the species a chance to rebound, only winter flounder 12 inches or longer can be legally kept in Connecticut. And you can only bring home two keepers per day.

(Summer flounder grow bigger and are more abundant. Their season runs May 15-Oct. 31. They have to be at least 17.5 inches long, but you can keep up to 5 per day.)