Blacktip Grouper

The blacktip grouper, scientifically designated as Epinephelus fasciatus, also referred to by various alternate names such as redbanded grouper and black-tipped rockcod, is a significant species within the marine ray-finned fish category. This grouper belongs to the Epinephelinae subfamily under the larger Serranidae family, which encapsulates species like anthias and sea basses. The blacktip grouper is predominantly native to the tropical Indo-Pacific region and serves as the type species for the Epinephelus genus.

This species can reach a total length of up to 40 centimeters (16 inches), though the more frequently observed length is approximately 22 centimeters (8.7 inches), accompanied by a weight of 2.0 kilograms (4.4 pounds).

Morphologically, the blacktip grouper exhibits a body whose standard length is about 2.8 to 3.3 times its depth. The interorbital area is flat with a convex dorsal head profile. Key features include a finely serrated rear margin on its rounded preopercle, with more pronounced serrations at the bottom. The gill cover's upper edge maintains a straight line. The dorsal fin consists of 11 spines and 15-17 soft rays, while the anal fin has 3 spines and 8 soft rays. The dorsal fin's spiny membranes are notably indented, and the caudal fin is moderately rounded, with 49-75 scales present along the lateral line. The species' color varies from pale greenish-grey to scarlet, often featuring 5 or 6 faint dark bars across the body. A distinct checked pattern emerges from the scales on the upper body due to pale centers and dark rear margins. Particularly in Western Australian specimens, the outer membrane of the spiny dorsal fin appears black or dark red, punctuated by a pale yellow or white spot at the tip of each spine.

In terms of distribution, the blacktip grouper boasts a wide presence across the Indo-Pacific. Its range extends from the 🌊 Red Sea to 🇿🇦 South Africa and as far east as the Pitcairn Islands, reaching northward to southern 🇯🇵 Japan and Korea, and southward to 🇳🇨 New Caledonia (🇫🇷 Overseas France) and 🇦🇺 Australia. The species is also prevalent in areas like 🇲🇬 Madagascar, the Mascarenes, Comoros, and the 🇸🇨 Seychelles. Within 🇦🇺 Australia, it is found from the Houtman Abrolhos in Western Australia, stretching around the tropical coastline to Port Hacking in New South Wales. Furthermore, it inhabits reefs in the Coral Sea, Elizabeth Reef, around Lord Howe Island in the Tasman Sea, and on Christmas Island. Notably, a single occurrence was documented in 2012 off the coast of Lebanon in the eastern Mediterranean Sea.

Biologically, smaller individuals of this species may exhibit simultaneous hermaphroditism, while larger specimens typically lose female reproductive capabilities.

The dietary habits of the blacktip grouper include ambushing crustaceans and smaller fish. Their habitat comprises coral reefs at depths ranging from 4 meters (more commonly starting at 15 meters) to 160 meters, within both marine and brackish waters, occasionally forming groups of 10-15 individuals. Juvenile groupers may utilize mangrove swamps for shelter.

The blacktip grouper is fished by the Bedouin in the 🌊 Red Sea region and is occasionally linked to Ciguatera fish poisoning.

Parasites documented in association with the blacktip grouper include Pseudorhabdosynochus species (diplectanid Monogeneans) located on the gills. Additionally, the philometrid nematode Philometra fasciati is parasitic within the ovaries of female fish, with the adult female parasite appearing as a red worm reaching lengths of up to 40 centimeters but with a diameter of merely 1.6 millimeters. The males are considerably smaller. Another parasite, Raphidascaris (Ichthyascaris) fasciati, a nematode measuring 20 mm in length, inhabits the intestine and was identified in 2020, named in relation to this grouper species.

The blacktip grouper was initially classified as Perca fasciata in 1775 by explorer Peter Forsskål, with the type locality cited as Ras Muhammad in southern Sinai Peninsula, 🇪🇬 Egypt. The naturalist Marcus Elieser Bloch later established the genus Epinephelus by describing E. marginalis in 1793, which is now recognized as synonymous with Perca fasciata, making this species the foundational type species for the genus.