Gulf Sanddab, Citharichthys fragilis
The Gulf Sanddab, Citharichthys fragilis, whose common Spanish name is lenguado flaco, is a member of the Sand Flounder or Paralichthyidae Family, known collectively as lenguados areneros in Mexico. Globally, there are twenty-four species in the genus Citharichthys, seventeen of which are found in Mexican waters, nine in the Atlantic and eight in the Pacific.
The Gulf Sanddabs have elongated narrow bodies that taper toward the tail; their body depth is 34 to 38% of standard length. They are left-eyed flat fish with a straight lateral line that very gradually arches over their pectoral fin. Their eyed-side is brown with darker brown mottling and scattered bluish spots. Their fins are paler than the body. Their blind slide is off-white to tan. They quickly fade to a uniform brown color upon collection. Their head is relatively short with a medium-sized mouth that ends under the center of the lower eye. Their eyes are large and separated with the lower eye preceding the upper eye. They have one series of immovable teeth on each jaw and no canines. Their anal fin has 61 to 73 rays; their caudal fin is slightly rounded; their dorsal fin has 76 to 92 rays; and their pectoral fin has 10 to 12 rays. They have 14 to 21 long slender gill rakers on their lower arch. Their lateral line is straight from the gill covers to the caudal fin base. They are covered with mid-sized rough scales on both sides of their body.
The Gulf Sanddabs are normally bottom dwellers found over sandy and muddy bottoms in bays and estuaries at depths between 60 and 1,140 feet. They reach a maximum length of 25.0 cm (9.8 inches). They consume a wide variety of crustaceans and small fish. In turn they are preyed upon by various marine mammals, larger fish, and sea birds. They are masters at camouflage and can rapidly change colors to match their substrate.
In Mexican waters the Gulf Sanddab are found in all waters of the Pacific with the exception that they are absent from along the coast of the mainland from Mazatlán south to Guatemala.
The Gulf Sanddab can be easily confused with the Beach Flounder, Syacium latifrons (7 or 8 lower gill rakers), the Bigmouth Sanddab, Citharichthys gilberti (deep oval body), the Five-Rayed Sanddab, Citharichthys mariajorisae (15 to 17 lower gill rakers), and the Pacific Sanddab, Citharichthys sordidus (deep oval body).
The Gulf Sanddabs are too small and too rare to be of interest to most. They are a minor by-catch of deep water trawls.
Gulf Sanddab, Citharichthys fragilis. Fish courtesy of the commercial fishermen of Bahía Kino, Sonora, March 2015. Length: 22.5 cm (9.0 inches). Photo and identification courtesy of Maria Johnson, Prescott College Kino Bay Center, Kino Bay, Sonora.