Highfin Sand Perch, Diplectrum labarum

Highfin Sand Perch, Diplectrum labarum. Fish caught from coastal waters off Point Palmilla, Baja California Sur, November 2013. Length: 25.8 cm (10.2 inches). Fish identification courtesy of Dr. Ross Robertson, Smithsonian Institute, Panama.

Highfin Sand Perch, Diplectrum labarum: preoperculum.

The Highfin Sand Perch, Diplectrum labarum, is a member of the Sea Bass or Serranidae Family, and is known in Mexico as serrano espinudo. Globally, there are twelve species in the genus Diplectrum, of which ten are found in Mexican waters, two in the Atlantic and eight in the Pacific Ocean.

The Highfin Sand Perch has a long slender body  with an overall gray-brown coloration and a silvery-white belly. Their head has a blunt snout with a slightly projecting lower jaw and a narrow squarish bony cheek spur (preoperculum) that is wider than long that has 8 to 13 large spines (pictured below), a key to identification. The species has a series of yellow lines: 2 on their anal fin, 5 on their caudal fin, 1 under their eyes, 1 on their dorsal spine, and 6 on their dorsal rays. They also have a purple spot on their gill covers and a black spot at the base of their tail. They have a series of 5 or 6 squarish dark blotches on their upper sides. The second to fourth dorsal spines are longer than the others and feature black filaments; the second spine is at least twice as long as the first. Their anal and dorsal fins are transparent, their pelvic fins are yellow, and their pectoral fins are yellow with red stripes. Their caudal fin is concave with a longer upper lobe.

The Highfin Sand Perch is found over sandy bottoms at depths between 23 m (75 feet) and 152 m (500 feet). They reach a maximum 29.7 cm (11.7 inches) length of established by a fish I caught in coastal waters off Puerto Adolfo Lopez Mateos, Baja California Sur in July 2018. The Highfin Sand Perch are synchronously hermaphroditic possessing both males and female organs and capable of producing eggs and sperm at the same time. They spawn in deep water as mating pairs. Their eggs and larvae are pelagic and move to shallower waters as they mature. The Highfin Sand Perch is a small, deep water species that is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Highfin Sand Perch is a resident of all Mexican waters of the Pacific but are absent from Guerrero Negro, Baja California, northward along the central and northwest coasts of Baja,.

The Highfin Sand Perch is difficult to correctly identify because there are 8 very similar Sand Perches, all of the Diplectrum Genus, living in Mexican waters of the Pacific Ocean. The key to a correct identification is the unique shape of the preoperculum. See Sand Perch Preoperculum 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 Ocean.

From a conservation perspective the Highfin Sand Perch is currently considered to be of Least Concern with stable, widely distributed populations. They are fairly abundant in the greater Los Cabos area and at times can become a pest. Efforts at “catch and release” normally do not go well as they will not return to the deep and float on the surface and are almost immediately consumed by the ever vigilant Magnificent Frigate Bird, Fregata magnificus, who post consumption, will always return to the ocean for drinks of water, providing for splendid entertainment.