Speckled Sanddab, Citharichthys stigmaeus
The Speckled Sanddab, Citharichthys stigmaeus, whose common Spanish name is lenguado pecoso, 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, nine of which are found in Mexican waters, one in the Atlantic and eight in the Pacific.
The Speckled Sanddabs are left-eyed flat fish with a straight lateral line that gradually arches over their pectoral fin. They have elongated oval bodies with a depth that is 40 to 46% of standard length. They are tan to olive-brown in color and their body and fins are covered with numerous black specks on the dorsal side. Their ventral side is off-white. They also have three dark blotches along their lateral line (not visible in the juvenile pictured below). They have the ability to change colors to match their surroundings. Their head has large eyes, which are set above the body and are close together with a flat space in-between. They have a medium length mouth that ends under the center of the lower eye. They are equipped with one series of immovable teeth on each jaw and have enlarged front teeth. Their anal fin has 58 to 77 rays; their caudal fin is rounded; their dorsal fin originates two or three rays before the upper eye and has 75 to 97 rays; their pectoral fins are short and do not reach the eye when folded forward; and the pelvic fin on their eye-side is found on the midline of the body. They have 8 to 10 short slender gill rakers and are covered with rough scales.
The Speckled Sanddabs are found demersal over sandy and muddy bottoms at depths up to 1,200 feet. They can survive in brackish waters and in temperatures as low as 8.2ºC (47ºF). They reach a maximum of 19.2 cm (7.6 inches) in length and 450 grams (1 pound) in weight. Females grow faster and are larger than males. They are non-migratory ambush predators that spend the majority of their time half-submerged in substrate awaiting prey to pass. They are daytime feeders and consume a wide variety of crustaceans and small fish. In turn they are preyed upon by a variety of marine mammals, larger fish, and sea birds. Reproduction is oviparous with females producing between 4,100 and 30,800 eggs three times a year. They have a lifespan of up to four years.
In Mexican waters the Speckled Sanddabs have a limited distribution being found from Magdalena Bay northward along the central and northwest coasts of Baja. There is also an isolated population found in Conception Bay north of Loreto within the Sea of Cortez.
The Speckled Sanddab can be easily confused with the Gulf Sanddab, Citharichthys fragilis (long pectoral fin; 18 lower gill rakers), the Longfin Sanddab, Citharichthys xanthostigma (pelvic fin reaching snout tip when folded forward), and the Pacific Sanddab, Citharichthys sordidus (pectoral fins reaching eyes when folded forward; 15 or 16 gill rakers).
Due to their small stature, the Speckled Sanddabs are primarily of interest to subsistence fishermen. They are sold commercially on a very limited basis in the fish markets of Baja California. They are a minor target of recreational fishermen and are also caught as a by-catch by bottom trawlers, however, the majority of fish is discarded. They have not been evaluated from a conservation perspective but have a wide distribution and are common with stable populations. They date to the Late Pliocene Period, 1.8 million years ago.
Speckled Sanddab, Citharichthys stigmaeus, Juvenile. Fish caught off the Municipal Wharf #2, Monterey, California, August 2012. Length: 7.6 cm (3.0 inches). Catch, photo, and identification courtesy of Kenneth Tse, Toronto, Ontario, Canada.