Bridled Sand Perch, Diplectrum rostrum
The Bridled Sand Perch, Diplectrum rostrum, whose common Spanish name is Serrano Frenado is a member of the Sea Bass or Serranidae Family, known collectively known as “serranos” in Mexico. It received its common name from the yellow-orange striping on the face.
The Bridled Sand Perch has a long slender body with an overall tan colored body, white belly, and a head covered with yellow-orange stripes. The head has a narrow bony cheek spur (preoperculum) with seven to eleven spines (as pictured below), whose shape is a key to identification. They have five to seven dark bars on the side, an indistinct black mid-lateral stripe, two black spots at the base of the symmetrical tail fin, two pink bars under the eye, an eye with a yellow ring, and a grey tail with clear spots.
The Bridled Sand Perch are found over sandy bottoms at depths between 50 and 250 feet. They reach a maximum length of 26.4 cm (10.4 inches), documented by a fish that we caught. In Mexican waters the Bridled Sand Perch is found from Magdalena Bay south along the Pacific side of Baja, the southern half of the Sea of Cortez, and along the coastal mainland south to Guatemala. They are a small, rare, deep water species and not much is known about their behavioral patterns.
The Bridled Sand Perch is difficult to correctly identify because there are eight very similar Sand Perches, all of the Diplectrum Genus, that live in Mexican waters of the Pacific. The key to a correct identification is the unique shape of the preoperculum. In addition to the Pacific Sand Perch we present five additional Sand Perches: the Bighead Sand Perch, Diplectrum euryplectrum; the Greater Sand Perch, Diplectrum maximum; the Highfin Sand Perch, Diplectrum labarum; the Mexican Sand Perch, Diplectrum macroproma; and, the Pacific Sand Perch, Diplectrum pacificum. There are two additional Sand Perches found in Mexican waters of the Pacific that we are seeking: the Orange-Spotted Sand Perch, Diplectrum eumelum (maximum length 31 cm – 12.2 inches, preoperculum wide with eight to fourteen long spines, face large covered with orange spots and stripes, caudal fin with bars of orange spots); and the Squirrel Sand Perch, Diplectrum sciurus (maximum length 17 cm – 6.7 inches, preoperculum square with five to ten large spines, body with two dark stripes and eight to ten dark bars, dorsal fin with two to three rows of yellow spots).
The Bridled Sand Perch is too small and too rare to be of interest to most.