California Tonguefish, Symphurus atricauda
California Tonguefish, Symphurus atricauda, Juvenile. Fish caught from within Monterey Bay, Monterey, California, November 2023. Length: 8.2 cm (3.2 inches). Catch, photograph and Identification courtesy of Vince Golder, Santa Cruz, California.
The California Tonguefish, Symphurus atricauda, is a member of the Tonguefish or Cynoglossidae Family, that is known in Mexico as lengua Californiana, and lenga de perra. 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 California Tonguefish have elongated oval flat bodies that taper to a pointed tail and a body depth that is 20% to 24% of standard length. They are light brown and covered with dark brown spots with the adults having nine incomplete dark cross-bars with the anal and dorsal fins are pale at the front. The blind side is cream color. Their anal and dorsal fins are transparent with dark brown spotting and caudal fin is transparent. Their head has a rounded snout with a small, curved mouth and small beady eyes set closely together with well-developed covers 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 77 to 83 rays; their dorsal fin originates above the upper eye and has 94 to 102 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 California Tonguefish are found over and within soft sandy and muddy bottoms as-well-as within eelgrass beds, estuaries, mangroves, bays and other coastal areas at depths up to 463 m (1,529 feet). They reach a maximum of 21 cm (8.3 inches) in length. They are uniquely colored to blend with the substratum. They feed on small fish and invertebrates. Their eggs and larvae are pelagic. The California Tonguefish is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, diet, growth, habitat, longevity, movement patterns, and reproduction.
The California Tonguefish is a resident of Mexican waters of the Pacific Ocean but has a limited range being found only along the entire coast of the Baja Peninsula and within the Sea of Cortez.
The California Tonguefish can be confused with a series of other Mexican Tonguefish of the Pacific including the Darkcheek Tonguefish, Symphurus chabanaudi (dark blotch on gill cover), the Drab Tonguefish, Symphurus melanurus (plain gray; no bars), the Elongate Tonguefish, Symphurus elongatus (minute eyes, slender with a body depth 19 – 21%), the Halfstriped Tonguefish, Symphurus prolatinaris (5 to 15 incomplete bars), the Imitator Tonguefish, Symphurus undecimplerus (black caudal fin), and the Yellow Tonguefish, Symphurus williamsi (numerous faint thin complete bars; dark blotch on gill covers.
From a conservation perspective the California Tonguefish is widely distributed and locally abundant and is currently considered to be of Least Concern with stable, widely distributed populations. They are small in stature and seldom seen by humans, thus of limited interest to most. They are caught primarily as a by-catch with nets and trawls and are normally discarded. Their long-term status is threatened by coastal development.