Channel Flounder

Channel Flounder, Syacium micrurum

Channel Flounder, Syacium micrurum. Fish caught from coastal waters off Key West, Florida, August 2014. Length: 16.5 cm (6.5 inches). Catch, photograph and identification courtesy of Dean Kimberly, Atlanta, Georgia.

Channel Flounder, Syacium micrurum. Fish caught from coastal waters off Sebastian, Florida, December 2022. Length: 18 cm (7.1 inches). Catch, photograph and identification courtesy of Ben Cantrell, Sebastian, Florida.

The Channel Flounder, Syacium micrurum, is a member of the Sand Flounder or Paralichtyidae Family, that is known in Mexico as lenguado anillado. Globally, there are eight members of the genus Syacium, of which six are found in Mexican waters, three in the Atlantic and three in the Pacific Ocean.

The Channel Flounder has an elongated oval body with a depth that is 37% to 41% of standard length. Their eye side is multicolored with various shades of tan and brown mottling. They have two dark blotches on their lateral line, the first under the tip of their pectoral fin and the second at their caudal base. Their blind side is yellow-white. Their head is short with mid-sized eyes found on the left side that are set fairly close together with the lower eye being well before the upper eye. They have a notch on their snout before their top eye and a large mouth which ends under the middle of their lower eye. They have fixed teeth with two rows on their upper jaw and one row on their lower jaw with their front teeth being larger than their rear teeth. Their anal fin has 64 to 74 anal rays; their caudal fin is rounded; and, their dorsal fin has 82 to 92  rays. In males, the first two rays of the pectoral fins on the eye side are elongated. They are covered with large rough scales on their eye side and smooth scales on their blind side and their lateral line is straight.

The Channel Flounder is a demersal species that is over and within sandy and muddy bottoms at depths between 12 m (40 feet) and 400 m (1,300 feet). They reach a maximum of 30 cm (12 inches) in length. They are opportunistic and well-camouflaged ambush predators that lie in wait half submerged on the ocean floor. They prey on small fish and a wide variety of crustaceans. The Channel Flounder is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Channel Flounder is a resident of all Mexican waters of the Atlantic Ocean including the Gulf of Mexico and the east coast of the Yucatán Peninsula in the Caribbean.

The Channel Flounder can be confused with the Dusky Flounder, Syacium papillosum (eyes widely separated and not offset; pectoral fins with three or four dark bars) and the Shoal Flounder, Syacium gunteri (deep body; 46-50% of standard length).

From a conservation perspective the Channel Flounder is currently considered to be of Least Concern with stable, widely distributed populations. They are small in stature and caught as a by-catch by deep water trawlers and by artisanal fishermen. They are deemed to be of limited valve but when caught in abundance utilized in the pet food industry.