Pacific Sand Perch, Diplectrum pacificum
The Pacific Sand Perch, Diplectrum pacificum, whose common Spanish name is serrano cabaicucho, is a species in the Sea Bass or Serranidae Family, known collectively as serranos in Mexico. Globally, there are twelve species in the genus Diplectrum, ten of which are found in Mexican waters, two in the Atlantic and eight in the Pacific.
The Pacific Sand Perches have long slender bodies with an overall tan coloration, a white belly, and a head covered with orange spots. Their head has a narrow bony cheek spur (preoperculum) with five to eight long spines (pictured below); the shape of their head is a key to identification. They have a series of nine dark bars along the lower half of their body. Their caudal fin has five rows of spots; the top border is red and the lower border is white. Their dorsal fins have two rows of spots. Adults have a large pink blotch on their abdomen above and just in front of their anus, a large purple spot on their gill covers, and a black spot at the base of their tail. They have yellow anal and pelvic fins.
The Pacific Sand Perches are found over sandy bottoms at depths up to 400 feet. They reach a maximum length of 28 cm (11 inches), as documented by a fish that I caught. They are a small and rare deep water species and very little is known about their behavioral patterns.
In Mexican waters the Pacific Sand Perch are found from Magdalena Bay southward along the southwest coast of Baja, throughout the Sea of Cortez, and along the coastal mainland south to Guatemala.
The Pacific Sand Perch is 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 a correct identification is the unique shape of the preoperclum. See Sand Perch Preoperclum for an interesting side-by-side look at some fish anatomy of seven very similar looking fishes of the Diplectrum Genus found in the Pacific.
The Pacific Sand Perch is too small and too rare to be of interest to most.
Pacific Sand Perch, Diplectrum pacificum. Fish caught from coastal waters off Puerto Los Cabos, Baja California Sur, April 2003. Length: 18 cm (7.0 inches). Fish identification courtesy of H.J. Walker, Jr., Scripps Institution of Oceanography, La Jolla, CA.