Oval Flounder

Oval Flounder, Syacium ovale

The Oval Flounder, Syacium ovale, whose common Spanish name is lenguado ovalado, is a member of the Sand Flounder or Paralichtyidae Family, known collectively as lenguados areneros in Mexico. Globally, there are only eight members of the genus Syacium, six of which are found in Mexican waters, three in the Atlantic and three in the Pacific.

The Oval Flounders are left-eyed flat fish with a straight lateral line that does not extend into their head. They have oval-shaped bodies with a depth that is 41 to 45% of standard length. Their eye side varies in color from a uniform brown to a light tan with numerous dark spots that extend into their anal and dorsal fins. Their blind side is yellow-white. Their head has a convex upper profile and a medium-sized mouth that ends under the middle of their eyes and is equipped with two rows of teeth on their upper jaw. Their eyes are set close together with the lower eye slightly in front of the upper eye. They have 64 to 71 anal rays and 83 to 91 dorsal rays. Their caudal fin has a wide base and is rounded. The pectoral fin on their eye side is 59 to 71% of head length. They have 7 to 9 fat serrated gill rakers on their lower arch. They are covered with large rough scales on their eye side and smooth scales on their blind side.

The Oval Flounders are bottom dwellers found over and within sandy and muddy bottoms at depths between 25 feet and 295 feet. They reach a maximum length of 25.0 cm (9.8 inches). 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.

In Mexican waters the Oval Flounder are found in all waters of the Pacific with the exception that they are absent from north of Magdalena Bay northward along the central and northwest coasts of Baja.

The Beach Flounder can be confused with a three Sanddabs and one Flounder found in Mexican waters of the Pacific: the Beach Flounder, Syacium latifrons (rounded head profile), the Five-Rayed Sanddab, Citharichthys mariajorisase (body depth >50% of standard length), the Gulf Sanddab, Citharichthys fragilis (body depth of 38 – 42% of standard length), the Pacific Sanddab, Citharichthys sordidus (12 to 16 gill rakers), and the Pompadour Flounder, Syacium longidorsale (first pectoral ray long).

The Oval Flounders are small, rare, and of limited interest to most. They are caught primarily as a by-catch of deep water shrimp trawlers.

Oval Flounder, Syacium ovale. Fish provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, July 2009. Length: 20.0 cm (7.9 inches).

Oval Founder, Syacium ovale. Fish provided by the commercial fishermen of Bahía Kino, Sonora, January 2015. Length: 22 cm (8.7 inches). Photo courtesy of Maria Johnson, Prescott College Kino Bay Center, Kino Bay, Sonora.