Epinephelus rivulatus (Valenciennes, 1830)
Halfmoon grouper
photo by Randall, J.E.

Family:  Epinephelidae (Groupers)
Max. size:  45 cm TL (male/unsexed); max.weight: 1,400.0 g
Environment:  reef-associated; marine; depth range 1 - 150 m
Distribution:  Indo-West Pacific: East Africa to the western Pacific, southward into temperate waters of South Africa, Australia, and New Zealand. Not known from the Red Sea or Persian Gulf.
Diagnosis:  Dorsal spines (total): 11-11; Dorsal soft rays (total): 16-18; Anal spines: 3-3; Anal soft rays: 8-8. Characterized by red-brown head; body mottled pale-brown color; 5-6 irregular dark brown bars on body; caudal fin dark brown with pale speckling; body scales ctenoid except cycloid anterodorsally above lateral line, on nape, thorax and abdomen; body with auxiliary scales only anterodorsally behind zone of small cycloid scales; greatest depth of body; 2.7-3.2 in SL; rounded caudal fin; pelvic fins, 1.9-2.4 in head length (Ref. 90102); body depth contained 2.7-3.2 times in SL; head length 2.3-2.6 times in SL; head length 2.3-2.6 times in SL; flat to slightly convex interorbital area, dorsal head profile convex; snout length 4.0-5.0 in HL; angular preopercle, with enlarged serrae at angle; straight upper edge of operculum, almost horizontal; posterior and anterior nostril subequal in size; maxilla reaches to or past vertical at rear edge of eye, ventral edge with slight step at distal expansion; 2-3 rows of teeth on midlateral part of lower jaw; pyloric caeca (Ref. 89707).
Biology:  Sedentary reef-associated species (Ref. 89707). Occurs on coral reefs, areas with rocky substrata, algal flats and seagrass beds. Feeds on fishes and crustaceans (Ref. 30573). A protogynous hermaphrodite (Ref. 55367). Forms spawning aggregations (Ref. 55367). Solitary (Ref 90102).
IUCN Red List Status: Least Concern (LC); Date assessed: 15 February 2017 Ref. (130435)
Threat to humans:  harmless


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