Darkcheek Tonguefish, Symphurus chabanaudi
Darkcheek Tonguefish, Symphurus chabanaudi. Fish provided by the commercial fishermen of Bahía Kino, Sonora, March 2015. Length: 19.3 cm (7.6 inches). Photograph and identification courtesy of Maria Johnson, Prescott College Kino Bay Center, Kino Bay, Sonora.
The Darkcheek Tonguefish, Symphurus chabanaudi, is a member of the Tonguefish or Cynoglossidae Family, that is also known as Chabanaud’s Tonguefish and in Mexico as lengua cachet prieto. This fish was introduced in 1990 as a new species. Globally, there are sixty-six species in the genus Symphurus, twenty-five are found in Mexican waters, eleven in the Atlantic and fourteen in the Pacific Ocean.
The Darkcheek Tonguefish have elongated oval flat bodies that taper to a pointed tail and a body depth that is 23% to 27% of standard length. They are light brown with five to eight subtle wide dark bands across their body and a large dark blotch on their gill cover (after which they are named). Their blind side is cream color. Their anal and dorsal fins are dusky and their caudal fin is also dusky with a darker tip. Their head has a rounded snout with a small curved mouth and small beady eyes set closely together on the left side with the upper eye being slightly in front of the lower eye. Their anal and dorsal fins are confluent with the pointed caudal fin; their anal fin has 82 to 92 rays; their dorsal fin originates above the upper eye and has 98 to 109 rays; they do not have pectoral fins; and, they have only a left pelvic fin. Their body is covered with small rough scales. They do not have a lateral line.
The Darkcheek Tonguefish are found over and within soft sandy and muddy bottoms at depths up to 60 m (200 feet). They reach a maximum of 24.0 cm (9.4 inches) in length. They are uniquely colored to blend with the substratum. They feed on small fish and crustaceans. The Darkcheek Tonguefish 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 Darkcheek Tonguefish is a resident of Mexican waters of the Pacific Ocean but has a limited range being found only in the northern 70% of the Sea of Cortez and along the entire west coast of the mainland south to Guatemala.
The Darkcheek Tonguefish can be confused with a series of other Mexican Tonguefish of the Pacific including the California Tonguefish, Symphurus atricaudus (nine incomplete bars on body), the Drab Tonguefish, Symphurus melanurus (plain; no bars), the Elongate Tonguefish, Symphurus elongatus (gill cover area not dark), the Halfstriped Tonguefish, Symphurus prolatinaris (5 to 15 incomplete bars), and the Yellow Tonguefish, Symphurus williamsi (numerous faint thin complete bars).
From a conservation perspective the Darkcheek Tonguefish is currently considered to be of Least Concern with stable, widely distributed populations. They are small and seldom seen by humans, thus of limited interest to most. They are caught primarily as a by-catch of deep water shrimp trawlers and are normally discarded.