Summer Flounder

Fascinating facts about the Summer Flounder

• The summer flounder can grow from about 38 cm to 51 cm and may weigh up to 9 kg (26 lb), making it a prized target for both commercial trawlers and sport anglers.
• When spring arrives, these flat predators abandon their deep-sea winter homes and sprint into shallow bays, inlets, and even canals, staying there until autumn or early winter – a seasonal migration that ties their life cycle directly to coastal ecosystems and the health of near-shore habitats.
• A typical summer flounder carries between five and fourteen eye-like spots on its side, each acting like a natural camouflage tag; combined with their ability to change skin color to match sand grains or even artificial checkerboards, they become nearly invisible ambush hunters on the seafloor.
• Despite being bottom dwellers, they can burst into short, rapid swims and even chase prey toward the surface, showing a surprising agility that contradicts their flat, buried appearance and highlights their role as aggressive, versatile predators.
• Summer flounder reach sexual maturity at about two years and can live up to twenty years; females may live up to 17 years while males up to 15 years.

At a glance

About the Summer Flounder

The summer flounder, Paralichthys dentatus, glides across the Atlantic seafloor with a laterally-compressed silhouette punctuated by five to fourteen eye-like ocellated spots that shimmer like tiny lanterns against the sand. Growing typically 38.1-50.8 cm (15-20 in) and weighing 0.4-1.3 kg (1-3 lb), the heaviest individuals can tip the scales at 9 kg (26 lb), their sharp teeth ready for a predatory lifestyle. In spring they abandon the deep-water spawning grounds and migrate inshore, threading through beaches, inlets, bays, estuaries, canals, and creeks where they linger until autumn, their dark side capable of dynamic camouflage that matches the grain of the substrate with astonishing precision. These left-eye flatfish lie buried with only their heads exposed, ambushing sand lance, menhaden, Atlantic silverside, mummichog, small bluefish, porgies, squid, shrimp, and crabs, yet they can burst upward as rapid swimmers to chase prey into mid-water or even the surface. Females, often the largest and oldest, reach sexual maturity at two years and can live up to 20 years, with females recorded at 17 years and males at 15. Their ability to burrow swiftly into muddy or sandy bottoms and to alter coloration on demand makes them masterful hunters in the shifting coastal ecosystems of the western Atlantic, from Nova Scotia to Florida.

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