Dwarf Sand Perch, Diplectrum bivittatum
The Dwarf Sand Perch, Diplectrum bivittatum, whose common Spanish name is serrano guabino, is a member of 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. This is one of the two Sand Perches found in the Atlantic and it is by far the smallest.
The Dwarf Sand Perches have elongated slender slightly compressed bodies with very similar dorsal and ventral profiles. They are pale brown on their back and sides and fade to white ventrally. They have a dark stripe that runs just under their dorsal fin and a second stripe that runs from the snout, through the eye, to the caudal fin base. They have nine to eleven vertical yellowish-brown to tan bars. They have three light blue lines on their cheek and under their eyes. Juveniles have two broad dark stripes, one from the gill cover to the caudal fin base and the other just above, that end in a dark blue or white-edged spot. Their head, eyes, and mouth are large. Their preoperculum has one cluster of radiating spines. Their anal fin has three spines and 6 to 8 rays; their caudal fin is concave with the upper lobe having an elongated second ray; their dorsal fin is low with 10 spines and 11 to 13 rays and is continuous without a notch; their pectoral fins have 14 to 16 rays; and their pelvic fins originate under the pectoral fins. They have a complete lateral line and are covered with small rough scales.
The Dwarf Sand Perches are a common and abundant species found in shallow bays over sandy bottoms and muddy silt at depths up to 375 feet. They reach a maximum length of 25 cm (10 inches). They feed primarily on benthic shrimps. In turn they are preyed upon by larger fish and are an important food source for drums, groupers, porgies, sharks, snappers, and various sea birds. They are synchronously hermaphroditic possessing both males and female organs and producing eggs and sperm at the same time. Eggs and larvae are pelagic and move to shallow waters as they mature.
In Mexican waters the Dwarf Sand Perch is found in all waters of the Atlantic.
Due to the two strong stripes on its sides, the Dwarf Sand Perch cannot be easily confused with any other species. In body structure and size, it is similar to the other Sand Perches of the Diplectrum genus and the Sea Basses of the Centropristis genus found in Mexican waters of the Atlantic.
The Dwarf Sand Perches are too small to be of interest to most. They are a fairly significant by-catch of the shrimp trawl fishery. They can be used as live bait for larger fish. They are caught by hook and line on cut bait from shores, bridges, and small boats and are generally unfriendly towards divers.
Dwarf Sand Perch, Diplectrum bivittatum. Both fish caught from coastal waters off Silver Palm Park, Boca Raton, Florida, February 2016. Length: 11.4 cm (4.5 inches) and 10.1 cm (4.0 inches), respectively. Catch, photo and identification courtesy of George Brinkman, Guelph, Ontario, Canada.