Redmouth Grouper

The redmouth grouper, scientifically identified as Aethaloperca rogaa and commonly known as the red-flushed rock cod, is a notable species within the subfamily Epinephelinae of the family Serranidae, which also comprises the anthias and sea basses. This species enjoys a broad distribution across the 🇮🇳 Indian and 🌊 Pacific Oceans and is recognized for its significance in recreational fishing.

Morphologically, the redmouth grouper exhibits a laterally compressed, oval-shaped body, characterized by a substantial depth that represents approximately half of its standard length, complemented by a sizable head. The cranial dorsal profile is either linear or marginally concave, while the profile between the eye and the dorsal fin's origin is convex. Notably, the jaw extends beyond the eye, and the dorsal fin consists of nine spines alongside 17-18 soft rays; the anal fin is equipped with three spines and 8-9 soft rays. In adults, the middle soft rays of both the dorsal and anal fins are elongated, producing an angular fin profile. The truncate caudal fin and asymmetrical pectoral fins, coupled with pelvic fins extending beyond the anus, further define its anatomy. The species' coloration ranges from dark brown to black, occasionally exhibiting orange tinges with a pale vertical band on the lower flank. The posterior section of the spiny dorsal fin is variably colored from dark orange to reddish-brown. The oral and gill cavities, along with the membranes of the upper jaw, are distinctly reddish to orange, contributing to the species' nomenclature. Juvenile specimens are marked by a conspicuous white rear margin on the caudal fin and a slender white margin on the dorsal fin's soft-rayed portion, with the maximum total length reaching 60 centimeters.

Geographically, the redmouth grouper inhabits the Indo-West Pacific region, stretching from the 🌊 Red Sea and 🌊 Persian Gulf, extending southwards along the East African coast to 🇿🇦 South Africa, eastward to Kiribati's Phoenix Islands, and northward to southern Honshu, 🇯🇵 Japan. In 🇦🇺 Australia, its presence is noted from Western Australia's Rowley Shoals and Kimberley region, Ashmore Reef, Timor Sea, and the northern Great Barrier Reef, extending south to Wheeler Reef in Queensland. Although distribution around all 🌊 Indian Ocean tropical islands is probable, its presence in 🇲🇺 Mauritius remains unconfirmed. The species has been observed around Europa Island in the 🇲🇿 Mozambique Channel.

Ecologically, the redmouth grouper occupies tropical coastal reefs and lagoons, thriving over silt substrates and within reef caves and crevices, at depths ranging from 1 to 60 meters. Juveniles of this species exhibit mimicry of Centropyge angelfish. As a predator, the redmouth grouper predominantly preys on small fishes like Pempheris spp., as well as stomatopods and crustaceans. It engages in year-round spawning activities, achieving sexual maturity at approximately 35 centimeters in standard length, without evidence of forming spawning aggregations.

Fishing practices surrounding the redmouth grouper indicate capture via line and spear methods throughout its range, though it is not a primary target and is typically classified as low-value. It is part of line fisheries in regions such as the 🇸🇧 Solomon Islands, 🇫🇲 Micronesia, the 🇲🇻 Maldives, 🇮🇳 India, and 🇦🇺 Australia. Although infrequently available in markets, it constitutes a significant component of the fresh-chilled grouper fishery in the 🇲🇻 Maldives.

The species was first scientifically described by Swedish naturalist Peter Forsskål (1732-1763) under the designation Perca rogaa, with Jeddah denoted as the type locality. The description, published by Carsten Niebuhr in 1775 based on Forsskål's field notes edited by Johann Christian Fabricius, is occasionally ascribed as Perca rogaa Fabricius (ex Forsskål) in Niebuhr 1775. Some scientific authorities classify the redmouth grouper as the sole species within the genus Aethaloperca, initially introduced in 1904 by American ichthyologist Henry Weed Fowler as a subgenus of Bodianus. However, recent molecular studies, employing analyses of five distinct genes, propose its inclusion in the Cephalopholis clade, suggesting the potential reclassification of the species as Cephalopholis rogaa.