Winter Flounder (Pseudopleuronectes americanus)

One of the most common and well-known flounder of shallow Atlantic coastal waters, the winter flounder belongs to the Pleuronectidae family of flatfish. It is a right-eyed flat-fish, with both eyes on the right side of its body, and gets its name because it retreats to cold, deep water in the summer and reappears in shallower water close to shore in the winter; its relative the summer flounder does the opposite.


The body is oval and flat with a tiny mouth. Color varies from reddish-brown to dark brown with small black spots. The underside is whitish and occasionally brown, tinged with blue around the edges. The caudal fin is slightly rounded. The winter flounder differs from the similar yellowtail flounder in its straight lateral line, no arch over the pectoral fin, thicker body, and widely spaced eyes.


Most winter flounder weigh between 1 and 1.5 pounds and average less than a foot in length, although they are capable of growing to 8 pounds and 2 feet. The alltackle world record is 7 pounds. Larger fish are sometimes called “sea flounder” to distinguish them from the smaller bay fish.

Life history/Behavior

Spawning occurs in shallow water over sandy bottoms from January through May. Winter flounder eggs stick together and sink to the bottom, where they hatch in roughly 16 days, depending on water temperature. These fish move from deep water toward shallow water during the fall and offshore again in the spring.

Food and feeding habits

When on a soft bottom, the winter flounder will lie buried up to its eyes, waiting to attack prey. Because of its small mouth, its diet includes only smaller food like marine worms, small crustaceans, and small shelled animals like clams and snails.

Other Names

flounder, lemon sole, sole, blackback, blueback, black flounder, dab, mud dab, flatfish, Georges Bank flounder; French: plie rouge; Italian: sogliola limanda; Spanish: mendo limon.


Winter flounder are common from Chesapeake Bay north to the Gulf of St. Lawrence. Stragglers occur south to Georgia and north to Labrador.


Winter flounder are found inshore in estuaries and coastal ocean areas. In the mid-Atlantic they stay inshore from January through April. Smaller fish occur in shallower water, although larger fish will enter water only a foot deep. They range anywhere from well up into the hightide mark to depths of at least 400 feet. Preferring sand-mud bottoms, they are also found over sand, clay, or fine gravel and on hard bottom offshore.