Bullseye Electric Ray, Diplobatis ommata
Bullseye Electric Ray, Diplobatis ommata. Fish provided by the commercial fishermen of the greater Los Cabos Area, Baja California Sur, February 2010. Length: 12.5 cm (5.0 inches). Disc Width: 5.2 cm (2.0 inches).
Bullseye Electric Ray, Diplobatis ommata. Underwater photographs taken in Zihuantanejo Bay, Guerrero, February 2019. Photographs courtesy of Maude Jette, Dive Zihuantanejo, www.Divezihuantanejo.com.
The Bullseye Electric Ray, Diplobatis ommata, is a member of the Electric Rays or Narcinidae Family, that is also known as the Pacific Dwarf Numbfish, and in Mexico as raya eléctrica diana. Globally, there are four four species in the genus Diplobatis, of which one, this species, is found in Mexican waters in the Pacific Ocean.
The Bullseye Electric Ray has an elongated oval discs that are slightly longer than they are wide and have a convex front margin. They are light brown with profuse leopard-like spotting and diffuse dark crossbars with a large “bullseye” ocellated spot on the center of their disc’s dorsal side. Some fish are uniformly brown while still displaying the large “bullseye”. Their head has small eyes, nostrils with two openings, and a protractile and tubular mouth. They have prominent well developed electric organs that are visible as kidney-shaped mounds on both sides of their head and that are capable of delivering strong jolts to stun prey. They have two rounded dorsal fins of equal size. They have stout, triangular, rounded, and well developed caudal fins with a narrow side fold; both lobes of the fin are continuous around the tip. Males have claspers that are stand alone and not continuous with the pelvic fins.
The Bullseye Electric Ray is a demersal species that is found over sandy and rubble terrain at depths up to 152 m (500 feet). They reach a maximum of 25.0 cm (9.8 inches) in length. They seek food by stirring bottom sediment with their pectoral fins and dislodging small crustaceans, small fish, mussels, and worms on which they feed. Pups are born alive as miniature adults and are independent at birth. The Bullseye Electric Ray 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 Bullseye Electric Ray is a resident of all Mexican waters of the Pacific Ocean with the exception that they are absent from north of La Bocana. Baja California Sur, along the central and northwest coasts of Baja.
The Bullseye Electric Ray cannot be confused with any other species due to its small stature and large ocellated spot on its back.
From a conservation perspective the Bullseye Electric Ray is currently considered to be VULNERABLE. The Bullseye Electric Ray is caught very frequently as a by-catch by of shrimp trawlers off the southwest coast of Baja and are normally discarded with catch levels unrecorded with a high mortality rate. Due to their size, they are of limited interest to most.