About Aethaloperca rogaa (Forsskål, 1775)
Aethaloperca rogaa, commonly called the redmouth grouper, has a laterally compressed, oval, relatively deep body where body depth is around half of its standard length, and a large head. The dorsal profile of the head is straight or slightly concave, while the anterior dorsal profile between the eye and the dorsal fin origin is convex. Its jaw extends past the eye. The dorsal fin has 9 spines and 17 to 18 soft rays, and the anal fin has 3 spines and 8 to 9 soft rays. In adult redmouth groupers, the middle soft rays of the dorsal and anal fins are elongated, giving these fins an angular profile. They have a truncate caudal fin and asymmetrical pectoral fins, and their pelvic fins extend beyond the anus. Their body colour ranges from dark brown to black, and is sometimes tinged with orange, with a pale vertical bar on the lower flank. The rear part of the spiny section of the dorsal fin ranges in colour from dark orange to brownish red. The oral cavity, gill cavity, and upper jaw membranes are reddish to orange, which is how the species got its common name. Juveniles have a wide white rear margin on the caudal fin and a thin white margin along the soft-rayed portion of the dorsal fin. The maximum total length of this species is 60 centimetres (24 in).
The redmouth grouper has an Indo-West Pacific distribution. Its range extends from the Red Sea and Persian Gulf south along the East African coast to South Africa, east to the Phoenix Islands in Kiribati, and north to southern Honshu, Japan. In Australia, it has been recorded from Rowley Shoals and the Kimberley region in Western Australia, Ashmore Reef, the Timor Sea, and the northern Great Barrier Reef as far south as Wheeler Reef in Queensland. It is likely found around all tropical islands of the Indian Ocean, though it has not yet been reported from Mauritius. It has been recorded from Europa Island in the Mozambique Channel.
This is a tropical species that lives in coastal reefs and lagoons, and has been found over silt substrates, as well as in and around caves and crevices in reefs. It occurs at depths between 1 and 60 metres (3.3 to 196.9 ft). Small juvenile redmouth groupers mimic angelfish of the genus Centropyge. This is a predatory species that feeds mainly on small fishes, including species in the genus Pempheris, and also eats stomatopods and crustaceans. Redmouth groupers spawn year-round, and reach sexual maturity at a standard length of around 35 centimetres (14 in), but they have not been reported to form spawning aggregations.
Throughout its range, the redmouth grouper is likely caught by line and spear fisheries, but it is not a targeted species and is generally considered to be of low value. It has been recorded caught by line fisheries in the Solomon Islands, Micronesia, the Maldives, India and Australia. It is rarely sold in markets, but it is an important component of the fresh-chilled grouper fishery in the Maldives.
