Fluke is a flatfish whose common name often causes confusion among consumers and anglers. This species is known for its delicate texture and mild flavor, making it a favorite for many dining applications. Understanding its scientific identity and physical characteristics helps clarify how it differs from its relatives.
The Biological Identity of Fluke
The name “fluke” is the commercial and recreational fishing term for the species officially known as the Summer Flounder. Scientifically, this fish is classified as Paralichthys dentatus and belongs to the order Pleuronectiformes, which encompasses all flatfishes. The species is part of the family Paralichthyidae, commonly referred to as the large-tooth flounders. Fluke is a significant species along the eastern seaboard of the United States.
Like all flatfish, the fluke begins its life swimming upright with eyes on opposite sides of its head. Over its larval development, a metamorphosis occurs where one eye migrates to the other side of the head, and the fish settles to the ocean floor to live on its side.
Key Physical Traits and Atlantic Habitat
A defining physical trait of the fluke is its “left-eyed” nature, meaning both eyes are situated on the left side of its body when viewed from above. The upper, or ocular, side of the fish is mottled with a blend of olive green, gray, brown, and tan to aid in camouflage. This side is also marked by five to fourteen distinct, ocellated (eye-like) spots, often arranged in a five-dot pattern near the tail. The blind side that rests against the ocean bottom remains a flat, pale white.
Fluke are bottom-dwelling ambush predators that bury themselves in sandy or muddy bottoms, often leaving only their eyes exposed to wait for prey. They are known for their ability to rapidly change the color and patterning of their skin to match the surrounding substrate. Their primary geographic range extends along the Western Atlantic, from the Gulf of Maine down to Florida, with the greatest concentrations found between Massachusetts and North Carolina.
Clarifying Fluke and Flounder Confusion
The common practice of referring to Paralichthys dentatus as the Summer Flounder causes confusion, differentiating it from the Winter Flounder, which belongs to a different genus. One major distinction is the position of the eyes, which determines whether a flatfish is considered “left-eyed” or “right-eyed.” Fluke is a left-eyed flatfish, meaning the right eye migrates to the left side during development.
Conversely, the Winter Flounder (Pseudopleuronectes americanus) is a right-eyed flatfish, with both eyes ending up on the right side of the body. Fluke also possess a much larger mouth lined with sharp, exposed teeth, reflecting its aggressive, predatory nature. In contrast, the Winter Flounder has a smaller mouth and is less aggressive. These species also follow different seasonal patterns, with fluke being more common in inshore, warmer waters during the summer months, while the Winter Flounder prefers cooler temperatures.
Culinary Use and Flavor Profile
Fluke is valued in the culinary world due to its delicate composition and clean flavor. The flesh is lean, white, and thin, offering a delicate texture that flakes apart easily when cooked. Its flavor is described as mild and slightly sweet, making it an excellent choice for individuals who prefer a fish that is not strongly “fishy.”
The subtle flavor profile lends itself well to preparation methods that do not overpower its natural taste. Common cooking techniques include light searing, baking, or broiling with simple additions like olive oil and lemon. Fluke’s delicate texture is also suited for raw applications, making it popular for sashimi, sushi, and crudo preparations.