Bullseye Jawfish, Opistognathus scops
The Bullseye Jawfish, Opistognathus scops, whose common Spanish name is bocón ocelado, is a member of the Jawfish or Opistognathidae Family, known collectively as bocones in Mexico. Globally, there are 43 species in the genus Opistognathus, of which 13 are found in Mexican waters, six in the Atlantic and seven in the Pacific.
The Bullseye Jawfish have elongated, compressed, and tapered bodies with a large bulbous head. They are brown overall with three or four dark longitudinal stripes and scattered elongated white blotches and spots, which give the appearance of broken wavy stripes on their sides. Their anal fin is black with a row of white spots along the base; their caudal fin is black with white spots; their first dorsal fin is black with irregular white lines and a prominent ocellus at the front; and their second dorsal fin has white spots. The inside of their mouth is unremarkable. Their head has large eyes, a simple unbranched cirrus over the front nostril, and a large mouth equipped with two teeth on the front roof. Their anal fin has three spines and 15 to 17 rays; their caudal fin is rounded; and their dorsal fin has 10 spines and 16 or 17 rays. They have 34 to 36 gill rakers and a lateral line on the first half of their body. They are covered with small and smooth scales.
The Bullseye Jawfish are found in sandy or rubble substrate within inshore shallow water at depths up to 65 feet. They reach a maximum length of 12.0 cm (4.7 inches). It is assumed that like other jawfish they live in elaborate burrows that are self-constructed by utilizing their mouth and powerful jaw to excavate sand, small stones, and medium-sized rocks and that they feed primarily on benthic and planktonic invertebrates. In addition, like other jawfish it is assumed that they exhibit the unusual habit of oral egg incubation. Although common in certain parts of their range, they are poorly studied and very little is known about their behavioral patterns.
In Mexican waters the Bullseye Jawfish have a limited distribution being found throughout the Sea of Cortez and along the coast of the mainland south to Guatemala; they are absent from along the entire west coast of Baja.
The Bullseye Jawfish is straightforward to identify and cannot easily be confused with any other jawfish due to the prominent ocellus spot at the front of the dorsal fin.
The Bullseye Jawfish are of limited interest to most, however, they are used on a limited basis in the aquarium trade. From a conservation perspective they are considered of Least Concern, being common with a wide distribution and stable populations.
Bullseye Jawfish, Opistognathus scops. Fish caught from coastal waters off Acapulco, Guerrero, February 2017. Length: 11.4 cm (4.5 inches). Catch, photo, and identification courtesy of Ben Cantrell, Peoria, IL.