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Taxon profile

species

Rankin's Cod
Epinephelus multinotatus (Peters, 1876)

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

Serranus multinotatus Peters, 1876
Serranus jayakari Boulenger, 1889
Epinephelus jayakari (Boulenger, 1889)
Epinephelus leprosus Smith, 1955
Epinephelus rankini Whitley, 1945

Other names

= Rankin's Rock Cod
= White-blotched Grouper
= White-blotched Rockcod

Least Concern

Images

Epinephelus multinotatus - Rankin's Cod

Author: Ivo Antušek

Description

Body depth contained 2.6 to 2.9 times in standard length (for fish 11 to 63 cm standard length). Head length contained 2.4 to 2.7 times in standard length; interorbital area distinctly convex, the dorsal head profile slightly convex; preopercle subangular, with a shallow notch (more distinct in adults) just above the angle, the serrae at angle not or only slightly enlarged; upper edge of operculum straight or nearly so; posterior nostrils of adults about twice the size of anterior nostrils; maxilla reaches vertical at rear edge of eye or thereabouts; ventral edge of maxilla of adults with distinct step distally; midlateral part of lower jaw with 2 rows of teeth. Gill rakers 9 to 11 on upper limb, 15 to 17 on lower limb. Dorsal fin with XI spines and 15 to 17 rays, the third or fourth spine longest, its length contained 2.3 to 2.9 times in head length, the interspinous membranes not incised, the anterior rays distinctly longer than last spine; anal fin with III spines and 8 rays, the third spine clearly longer than the second, length of third spine contained 3.4 to 4.6 times in head length and less than or subequal to peduncle depth; pectoral-fin rays 18 to 20; pectoral fins subequal to pelvic fins, pectoral-fin length contained 1.7 to 2.3 times in head length; pelvic fins not reaching anus; caudal fin truncate to slightly emarginate. Lateral-body scales distinctly ctenoid, with numerous auxiliary scales; lateral-line scales 64 to 81; lateral-scale series 130 to 162.
Colour: Head and body of live or fresh fish dark purplish grey, with scattered irregular whitish spots and blotches which are faint or absent on preserved fish; pelvic fins greyish black; rear margins of median fins with narrow white edge. Specimens from the western Indian Ocean (except the Persian Gulf and Gulf of Oman) usually have numerous small dark reddish brown spots over the ventral parts of the head and body. Juveniles (4 to 7 cm standard length) from the Persian Gulf are dark greyish blue with caudal fin, peduncle, soft dorsal, and rear part of anal fin yellow: pelvic fins and ventral margin of anal fin blackish.

Distribution

E. multinotatus is known only from the Indian Ocean (but not the Red Sea). Heemstra and Randall (1993) have examined specimens from Zanzibar, southern Mozambique, Madagascar, Mauritius, Réunion, St. Brandon’s Shoals, Seychelles, Persian Gulf, Gulf of Oman, and Western Australia (from Monte Bello Islands to Shark Bay). Literature records include Tanzania (Mafia and Pemba islands), Kenya, Comoros, Chagos, and the Maldive Islands.

Ecology

Juveniles are found on inshore coral reefs, and adults are more common in deeper water (to depths of 90 m). Morgans (1982) reported that females (identified as “E. leprosus”) were mature at 50 cm standard length (3.6 kg) and possibly at smaller size; stomach contents of 3 fish consisted of small fishes and crabs. The colour pattern of juveniles in the Persian Gulf (see above) is remarkably similar to that of the damselfish Neopacentrus sindensis (Day), which occurs from the Persian Gulf to Pakistan. Nigel Downing (pers. comm.) has suggested that the juveniles of E. multinotatus may be a mimic of N. sindensis. When it gets larger than the damselfish, it develops whitish spots on the body and begins to lose its yellow coloration. The basis for this mimicry, like that of hamlets (Hypoplectrus spp.) mimicking damselfishes in the Caribbean (Randall and Randall, 1960; Thresher, 1978), would seem to be that the grouper, in the guise of a herbivorous pomacentrid, is enabled to get closer to its unsuspecting prey.

Size

According to Allen and Swainston (1988), E. multinotatus attains a total length of 100 cm and a weight of 9 kg.

Interesting facts

Based on colour pattern and scale counts, E. multinotatus appears to have differentiated into 3 separate populations:

1) Western Indian Ocean (east coast of Africa, Comoros, Madagascar, Seychelles, Mauritius, Reunion, St. Brandon Shoals, and Chagos Archipelago);

2) Persian Gulf and Gulf of Oman;
3) Western Australia.
The population in the western Indian Ocean has small dark brown spots on the lower parts of the head and body, but these dark spots are absent in the populations in the gulfs and Western Australia. Australian specimens seem to have higher scale counts (lateral line 71 to 81, lateral-scale series 137 to 162, n = 5) than in the populations in the western Indian Ocean and gulfs (lateral line 62 to 77, lateral-scale series 130 to 151, n = 32).

Interchangeable taxa

E. multinotatus is closely related to E. flavocaeruleus of the Indian Ocean and E. cyanopodus of the Pacific. These 3 species share the same meristic and morphometric features, fin configurations and ctenoid scales; they are distinguished primarily by differences in colour patterns. The colour pattern of juveniles of E. multinotatus, at least in the Persian Gulf, is similar to that of E. flavocaeruleus juveniles; this led Randall and Whitehead (1985) to misidentify a 46 mm standard length E. multinotatus from the gulf as E. flavocaeruleus.

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 [7354]

Froese R., Pauly D. (eds.): FishBase [http://www.fishbase.org]
CZ AQUATAB. World Wide Web electronic publication [species/8499]

Plíštil J. (Ed.) (2009): AQUATAB. World Wide Web electronic publication [http://aquatab.net] [as Epinephelus multinotatus (Peters, 1876)]
Data retrieved on: 17 January 2010
EN IUCN Red List of Threatened Species 2018-1 [132740]

IUCN Red List of Threatened Species [http://www.iucnredlist.org/] [as Epinephelus multinotatus (Peters, 1876)]
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 multinotatus (Peters, 1876)]
Data retrieved on: 19 August 2019

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