Intermediate Flounder, Etropus ciadi
Intermediate Founder, Etropus ciadi. Fish provided by the commercial fishermen of Bahía Kino, Sonora, January 2015. Length: 10.1 cm (4.0 inches). Photograph courtesy of Maria Johnson, Prescott College Kino Bay Center, Kino Bay, Sonora.
The Intermediate Flounder, Etropus ciadi, is a member of the Sand Flounder or Paralichthyidae Family, that is also known as the Cortez Flounder and in Mexico as lenguado intermedio. Globally there are nine members of the genus Etropus, of which five are found in Mexican waters, two in the Atlantic, two in the Pacific, and one in both the Atlantic and the Pacific Oceans.
The Intermediate Flounder is a flatfish that has an elongated deep oval body that has a depth that is 51% to 55% of standard length. Their eye side is brown with dark brown speckles and spots on the body, anal fins, and dorsal fins. Their pectoral fins have a dark tip and a wavy bar. Their blind side is off-white to tan. They have a short pointed head with a relatively large mouth for this genus, which ends just before the front edge of their lower eye. Their eyes are on the left side and set very close together with the lower eye slightly in front of the top eye. They have one row of teeth on both jaws. Their anal fin has 52 to 62 rays; their caudal fin has a rounded point; and, their dorsal fin has 66 to 79 rays. They have 2wo to 7 gill rakers on their lower arch. They are covered with small rough scales and their lateral line is complete and relatively straight that originates at the top corner of their gill cover.
The Intermediate Flounder is a demersal species that is found over and within sandy and muddy bottoms at depths up to 43 m (140 feet). They reach a maximum length of 11.6 cm (4.6 inches). They are opportunistic and well-camouflaged ambush predators that lie in wait half submerged on the ocean floor. The Intermediate 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 Intermediate Flounder is a resident of Mexican waters of the Pacific Ocean but has a very limited range being found only along the east coast of the Sea of Cortez.
The Intermediate Flounder can possibly be confused with the Fringed Flounder, Etropus crossotus (small mouth) and the Peruvian Flounder, Etropus peruvianus (body depth less than 50% of standard length).
From a conservation perspective the he Intermediate Flounder is currently considered to be of Least Concern with stable, widely distributed populations. They are small in stature and too rare to be of interest to most.