CZ EN
SEARCH  

Taxon profile

species

Hexagon Grouper
Epinephelus hexagonatus (Forster, 1801)

kingdom Animalia - animals »  phylum Chordata - chordates »  class Actinopterygii - ray-finned fishes »  order Perciformes - perch-likes »  family Serranidae - sea basses and groupers »  genus Epinephelus

Scientific synonyms

Holocentrus hexagonatus Forster, 1801
Serranus hexagonatus (Forster, 1801)
Epinephalus hexagonatus (Forster, 1801)
Epinephelus hexagonathus (Forster, 1801)
Serranus parkinsonii Valenciennes, 1828
Serranus stellans Richardson, 1842
Epinephelus stellans (Richardson, 1842)

Other names

= Hexagon Rockcod
= Honeycomb Reefcod
= White Specked Rockcod

Least Concern

Description

Body depth contained 2.8 to 3.4 times in standard length (for fish 10 to 17 cm standard length). Head length contained 2.5 to 2.6 times in standard length; interorbital area flat, the dorsal head profile convex; preopercle rounded, the ventral serrae slightly enlarged; upper edge of operculum convex; nostrils subequal; maxilla reaches to or past vertical at rear edge of eye: ventral edge of maxilla smoothly curved; midlateral part of lower jaw with 3 to 5 rows of teeth. Gill rakers 7 to 9 on upper limb, 17 to 19 on lower limb. Dorsal fin with XI spines and 15 to 17 rays, the fifth to ninth spines subequal (their length contained 2.5 to 2.8 times in head length) and slightly shorter than longest rays, the interspinous membranes incised; anal fin with III spines and 8 rays, the second spine contained 2.1 to 2.5 times in head length, distinctly longer than third spine or depth of peduncle; pectoral-fin rays 17 to 19; pectoral-fin length contained 1.6 to 1.9 times in head length; pelvic fins not reaching past anus, their length contained 1.8 to 2.1 times in head length; caudal fin rounded. Lateral-body scales ctenoid, with auxiliary scales; lateral-line scales 61 to 70; lateral-scale series 93 to 114.
Colour: Head and body covered with polygonal (mostly hexagonal) brown spots that tend to merge, leaving only conspicuous triangular white dots at corners of the polygons; spots on belly and ventral part of head more rounded and separated and often reddish brown; 4 or 5 brownish black saddle blotches (formed by groups of darker spots) on dorsal part of body and caudal peduncle, the first 4 extending onto base of dorsal fin; irregular dark bar, formed by darker polygonal spots, on lower part of body below each saddle blotch; dark spots on head progressively smaller anteriorly; large dark brown or olive spot just behind eye, sometimes joined to a horizontally elongate spot of the same colour on opercle; all fins with close-set dark brown or reddish brown spots and white dots, except outer half of pectoral fins with faint dark spots and no white dots; leading edge of pelvic fins and distal margin of anal fin with pale edge and dark brown submarginal band; margin of interspinous dorsal-fin membranes with a blackish brown triangle and short white or pale yellow filament behind tip of each spine. The conspicuous white dots on the body and fins often persist on preserved specimens.

Distribution

E. hexagonatus is one of the most widely distributed groupers, occurring from the western Indian Ocean to Henderson Island in the Pitcairn Group. It is an insular species, and its absence in the Red Sea and Persian Gulf may be due to its avoidance of continental shelf environments. It is known from most of the tropical Indo-Pacific islands; however, the 112 mm standard length specimen from the Chagos Islands that was illustrated by Winterbottom et al. (1989:fig. 135) is E. spilotoceps. E. hexagonatus occurs at Latham and Zanzibar islands off the coast of Tanzania, but none have been taken on the African coast, except for the specimen recorded by Randall and Heemstra (1991) from the Kenyan coast north of Kilifi Creek. Heemstra and Randall (1993) have examined specimens from the Comoros, Mauritius, Reunion, Japan (Ryukyu and Izu Islands), and most of the islands of the western and central Pacific region (both on and off the Pacific Plate). It is known from islands of the Great Barrier Reef, but no specimens have been collected from the mainland coast of Australia. Heemstra and Randall (1993) know of no verifiable records from Indonesia, the Philippines, Taiwan, or the Hawaiian Islands.

Ecology

E. hexagonatus is a coral-reef species, which is usually found in shallow outer-reef areas exposed to surge. It feeds mainly on fishes and crustaceans (especially stomatopods and brachyuran crabs).

Size

Maximum total length about 26 cm.

Interchangeable taxa

E. hexagonatus is one of 9 shallow-water coral reef species that have a rounded caudal fin and close-set dark brown spots, with the pale interspaces forming a network on the body. These “reticulated groupers” have been much confused in the literature, and many museum specimens have been misidentified. These other species differ from E. hexagonatus as follows:

E. bilobatus has 3 bilobed dark blotches or close-set pairs of dark brown spots on body and base of dorsal fin, no white dots on body, dorsal-fin rays 17 or 18; second and third anal-fin spines subequal, and lateral-line scales 48 to 52.

E. faveatus has the lateral-body scales smooth (except for area covered by pectoral fins), no white dots on body, midlateral part of lower jaw with 2 rows of teeth, and lateral-line scales 48 to 52.

E. macrospilos has the lateral-body scales mostly smooth, lateral-line scales 48 to 52, lower gill rakers 14 to 17, no triangular white dots on the body, and pectoral fins dusky with narrow white edge.

E. maculatus has the dorsal-fin membranes not incised between the spines; third or fourth dorsal-fin spine longest (its length contain&d 2.1 to 2.6 times in head length and usually longer than dorsal-fin rays), no white dots on body, and juveniles have a few large white blotches on body and dorsal fin.

E. melanostigma has a single black blotch at base of last 4 dorsal-fin spines and no white dots on the body, second anal-fin spine subequal to third, its length contained 2.6 to 3.6 times in head length and not more than depth of peduncle.

E. merra has the pectoral fins with small black spots largely confined to the rays, no white dots on body, no black blotches at base of dorsal fin, and 48 to 53 lateral-lines scales.

E. quoyanus has lateral-line scales 48 to 52, lower gill rakers 14 to 16, larger pectoral fins (its length contained 1.2 to 1.7 times in head length), second and third anal-fin spines subequal and not much longer than depth of peduncle, and no triangular white dots on body.

E. spilotoceps has distinct black dots on the snout, no triangular white dots on body, no large olive-brown spot behind eye, shorter second anal-fin spine (its length contained 2.4 to 3.4 times in head length), and a distinct notch in rear edge of preopercle just above the corner.

Sources

Food and Agriculture Organization of the United Nations, 1993, Heemstra, P.C.; Randall, J.E., FAO species catalogue. Vol. 16. Groupers of the world (Family Serranidae, Subfamily Epinephelinae). An annotated and illustrated catalogue of the grouper, rock cod, hind, coral grouper and lyretail species known to date.
Author: Petr Čech

Links and literature

CH DE EN FR IT NL PR SP FishBase [6660]

Froese R., Pauly D. (eds.): FishBase [http://www.fishbase.org]
CZ AQUATAB. World Wide Web electronic publication [species/8475]

Plíštil J. (Ed.) (2009): AQUATAB. World Wide Web electronic publication [http://aquatab.net] [as Epinephelus hexagonatus (Forster, 1801)]
Data retrieved on: 17 January 2010
EN IUCN Red List of Threatened Species 2018-1 [132778]

IUCN Red List of Threatened Species [http://www.iucnredlist.org/] [as Epinephelus hexagonatus (Forster, 1801)]
Data retrieved on: 3 August 2018
CZ Hanel L., Plíštil J., Novák J. (2011): České názvy živočichů V. Ryby a rybovití obratlovci (Pisces). 7. Paprskoploutví (Actinopterygii) Kostnatí (Neopterygii) [Ropušnicotvaří (Scorpaeniformes) – ostnoploutví (Perciformes) – Percoidei], Národní muzeum (zoologické oddělení), Praha, 148 str. [as Epinephelus hexagonatus (Forster, 1801)]
Data retrieved on: 19 August 2019

Contributions to BioLib

Help us to expand this encyclopedia! If you are logged in, you can add new subtaxa, vernacular and scientific names, texts, images or intertaxon relationships for this taxon.

Comments