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A summer flounder is a bottom dwelling flatfish with camouflage capabilities that has both eyes on the left side of its head. It rests on its right side on the marine floor and is found chiefly in the western Atlantic Ocean. It is a carnivore and feeds by hiding and waiting for prey to swim close. Breeding season is often from late summer to mid winter, and larvae have eyes on both sides of their heads which will migrate to the left side as they mature.
The summer flounder has a unique appearance. When viewed from the side, it has a rounded profile with a long dorsal fin that stretches from its head to its tail; if viewed from the other direction, it looks flattened with just two eyes protruding from the left side. It lies on its pale right side with the left facing up; the visible side has a mottled, speckled appearance in various shades of brown with several larger spots that resemble eyes scattered on it. It is able to change from light to dark coloration to match the marine floor. The average size of the summer flounder is 15 to 22 inches (40 to 56 cm) long, and it usually weighs 3 to 6 pounds (1.4 to 2.7 kg).
The scientific name for the summer flounder is Paralichthys dentatus and it is also known as a fluke. It is found primarily in the western Atlantic Ocean in estuaries and waters near the coast ranging from Nova Scotia to Florida. It migrates to waters further offshore in the winter, at depths of 100 to 600 feet (30.5 to 183 m).
While resting on its side on the marine floor, the summer flounder partially buries itself in the sand, taking advantage of its flattened shape. This habit, combined with the ability to match color with its surroundings, serves as effective camouflage. Hidden this way, it waits for prey to swim nearby and strikes quickly when it does, capturing and eating small creatures with its sharp teeth. Its diet consists mainly of small fish, squid, and crustaceans like shrimp.
Breeding, or spawning, of the summer flounder occurs from late summer to mid winter. When the larvae emerge from their eggs, they resemble most fish, with eyes on both sides of the head. During their first year of life in shallow coastal waters, they undergo a gradual change, or metamorphosis, with the flattening of the body and the right eye moving to the left side of the head. They also begin to lie on their sides as bottom dwellers and join in the winter migration. The young summer flounder will be ready to spawn once they are about two years old.