Highfin Sand Perch

Highfin Sand Perch, Diplectrum labarum

The Highfin Sand Perch, Diplectrum labarum, whose common Spanish name is Serrano Espinudo is a member of the Sea Bass or Serranidae Family, known collectively as “serranos” in Mexico. It received its common name from length of the second, third and fourth dorsal spines which are significantly longer than the same dorsal spines of the other Sand Perches.

The Highfin Sand Perch has a long slender body with an overall grey-brown coloration, silvery-white belly, and a head with a blunt snout with a slightly projecting lower jaw. The head has a narrow bony cheek spur (preoperculum) that is wider than long, squarish, with 8 to 13 large spines (as pictured below), whose shape is a key to identification. The species has characteristic markings including a series of yellow lines: two on the anal fin, five on the caudal fin, one under the eyes, one on the dorsal spine, and six on the dorsal rays. They also have a purple spot on the gill covers and a black spot at the base of the tail which is more prominent in juveniles. They have a series of 5 or 6 squarish dark blotches on the upper sides. The second to fourth dorsal spines are longer (for which the fish is named) with black filaments with the second spine being at least twice as long as the first. The anal and dorsal fins are transparent, the pelvic fins yellow and the pectoral fins are yellow with red stripes. The caudal fin is concave with a longer upper lobe. They have transparent anal and pelvic fins.

The Highfin Sand Perch are found over sandy bottoms at depths between 75 and 500 feet. They reach a maximum length of 26 cm (10.2 inches). In Mexican waters the Highfin Sand Perch is found south of Guerrero Negro along the Pacific side of the Baja, throughout 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 Highfin 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 Highfin Sand Perch we present five additional Sand Perches: the Bighead Sand Perch, Diplectrum euryplectrum; the Bridled Sand Perch, Diplectrum rostrum; the Greater Sand Perch, Diplectrum maximum; 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 Highfin Sand Perch is fairly common and at certain times of the year and in various locations can become a pest. They are too small to be of interest to most, however, 10 inch fish will be retained for food by subsistence fishermen. When released, they will not return to the deep and are almost immediately consumed by the Magnificent Frigate Bird, Fregata manificus, who post consumption will always return to ocean twice for drinks of water which provides splendid visual entertainment.

Highfin Sand Perch, Diplectrum labarum: Fish caught out of 300 foot water off Point Palmilla, Baja California Sur, November 2013. Size: 25.8 cm (10.2 inches). Fish identification courtesy of Dr. Ross Robertson, Smithsonian Institute, Panama.
Highfin Sand Perch, Diplectrum labarum: Fish caught out of 300-foot water off Point Palmilla, Baja California Sur, November 2013, on cut squid utilizing traditional bottom rigs. Size: 25.8 cm (10.2 inches). Fish identification courtesy of Dr. Ross Robertson, Smithsonian Tropical Research Institute, Panama.
Highfin Sand Perch, Diplectrum labarum: preoperculum.
Highfin Sand Perch, Diplectrum labarum: preoperculum.