Bullseye Jawfish, Opistognathus scops
Bullseye Jawfish, Opistognathus scops. Fish caught from coastal waters off Acapulco, Guerrero, February 2017. Length: 11.4 cm (4.5 inches). Catch, photograph, and identification courtesy of Ben Cantrell, Peoria, Illinois.
The Bullseye Jawfish, Opistognathus scops, is a member of the Jawfish or Opistognathidae Family, and is known in Mexico as bocón ocelado. Globally, there are forty-three species in the genus Opistognathus, of which thirteen are found in Mexican waters, six in the Atlantic and seven in the Pacific Ocean.
The Bullseye Jawfish has an elongated, compressed, and tapered body 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 2 teeth on the front roof. Their anal fin has 3 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. They are covered with small smooth scales. Their lateral line is limited to the first half of the body.
The Bullseye Jawfish is a demersal species that is found in sandy or rubble substrate within inshore shallow water at depths up to 20 m (65 feet). They reach a maximum of 12.0 cm (4.7 inches) in length. Although not well documented 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. The Bullseye Jawfish 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 Jawfish is a resident of Mexican waters of the Pacific Ocean but has 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.
From a conservation perspective the Bullseye Jawfish is considered to be of Least Concern with stable, widely distributed populations. They are of limited interest to most, however, they are used in the aquarium trade on a limited basis.