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. Its common name is derived from the yellow-orange striping on its face.
The Bridled Sand Perches have long slender bodies with an overall tan color, a white belly, and a head covered with yellow-orange stripes. Their head features a narrow bony cheek spur (preoperculum) with seven to eleven spines (pictured below); the shape of their head is a key to identification. They have five to seven dark bars on their sides, an indistinct black mid-lateral stripe, two black spots at the base of their symmetrical tail fin, two pink bars and a yellow ring under their eyes, and a gray tail with clear spots.
The Bridled Sand Perches are found over sandy bottoms at depths between 50 and 250 feet. They reach a maximum length of 26 cm (10.4 inches), as documented by a fish that we caught. In Mexican waters they are 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 and rare deep water species and very little is known about their behavioral patterns.
The Bridled Sand Perch is exceedingly difficult to correctly identify because there are eight very similar Sand Perches, all of the Diplectrum Genus, living in Mexican waters of the Pacific. The key to correct identification is the unique shape of their preoperculum as presented below.
The Bridled Sand Perch is too small and too rare to be of interest to most.