Barred knifejaw

Barred knifejaw
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Centrarchiformes
Family:	Oplegnathidae
Genus:	Oplegnathus
Species:	O. fasciatus
Binomial name
Oplegnathus fasciatus (Temminck & Schlegel, 1844)
Synonyms
Scaradon fasciatus Temminck & Schlegel, 1844

The barred knifejaw (Oplegnathus fasciatus), also known as the striped beakfish or rock bream, is a species of marine ray-finned fish, from the family Oplegnathidae. It is commonly native to the north-western Pacific Ocean, though a smattering of records exist from other localities in the eastern Pacific such as Hawaii and Chile. Recently introduced – likely via ballast water – in the central Mediterranean, it is found very rarely from Malta to the northern Adriatic.^[1] There is no listed conservation status for this species, though it is farmed for consumption and angling in many Asian countries suggesting it is common.

The barred knifejaw is an inhabitant of rocky reefs and occurs at depths from 1 to 10 m (3 to 33 ft). Juvenile members of this species can be found with patches of drifting seaweed. This species can reach a total length of 80 cm (31 in), with the greatest recorded weight for this species of 6.4 kg (14 lb). As with all members of the Oplegnathus family, the barred knifejaw has a beak-like structure formed by the fusion of its teeth. One of the biggest identifying characteristics of O. fasciatus is the 7 vertical black bars along both sides of its body, from which it derives its name. The first bar characteristically begins over the eye of the fish and the last is on the body’s narrowing towards the caudal peduncle. The end of the caudal fin is also typically black-tipped.

Overall, the fish is easily identifiable due to the black stripes and otherwise solid white/grey body color, however large adult males have been observed with black snouts and no striping.^[2] The dorsal and anal fins are oriented posterior on the fish while the pectoral and pelvic fins are before the midline of the fish. Adults of the species utilize their beak-like mouth structure to effectively feed on hard-shelled invertebrates such as crustaceans and mollusks, while juveniles heavily depend on zooplankton. It is a commercially important species and is farmed throughout many East Asian countries for many aquaculture purposes including fishing, fish ranching, and genetic analysis and/or selective breeding of the fish to yield larger fish and therefore a better food source.^[3]