Orange-spotted Sand Perch, Diplectrum eumelum
Orange-spotted Sand Perch, Diplectrum eumelum. Fish provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, May 2008. Length: 15.0 cm (5.9 inches).
Orange-Spotted Sand Perch, Diplectrum eumelum: preoperculum.
The Orange-spotted Sand Perch, Diplectrum eumelum, is a member of the Sea Bass or Serranidae Family, and is known in Mexico as serrano carabonita. 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 Orange-spotted Sand Perches has an elongated body with an overall gray-brown color with gold speckling with 5 to 8 indistinct narrow dark bars on the sides. They have 3 to 5 orange spots along the cheek that join an orange bar that angles from the eye down across the gill cover. There are also orange spots behind the eye and on the gill cover. The caudal fin has vertical rows of small orange spots and there is a black blotch at its base. They have white anal fins with yellow marks and yellow pectoral and pelvic fins. The dorsal fin has a black margin with the spiny portion being dusky, and the second part having 2 orange stripes that transition to spots at the rear. Their head has a blunt snout and a narrow bony cheek spur (preoperculum) with 8 to 14 long spines (pictured above); the shape of their preoperculum is a key to identification. All their fins are transparent with the exception of the upper portions of their caudal fin and their pectoral fins, which are yellow. Their anal fin has 3 spines and 7 or 8 rays; their caudal fin is concave; their dorsal fin has 10 spines and 12 to 13 rays; and, their pelvic fins are under the pectoral fins. They are covered with small rough scales.
The Orange-spotted Sand Perch is found over sandy bottoms at depths between 10 m (35 feet) and 100 m (330 feet). They reach a maximum of 31 cm (12 inches) in length. The Orange-spotted 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 Orange-spotted Sand Perch is a small, rare, 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 Orange-spotted Sand Perch is a resident of Mexican waters of the Pacific Ocean but has a limited distribution being found from Magdalena Bay, Baja California Sur, southward along the southwest coast of Baja, in the southern three-fourths of the Sea of Cortez, and along the coastal mainland south to Guatemala.
The Orange-spotted 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 7 very similar looking fishes of the Diplectrum Genus found in the Pacific Ocean.
From a conservation perspective the Orange-spotted Sand Perch is currently considered to be of Least Concern with stable widely distributed populations. They are too small to be of interest to most.