Rankin Cod, Epinephelus multinotatus (Peters 1876)

Other Names: Brown Rock-cod, Rankin's Rock Cod, Rankin's Rock-cod, Rockcod, Whiteblotched Grouper, White-blotched Grouper, White-blotched Rockcod, White-spotted Rockcod

Rankin Cod, Epinephelus multinotatus, at Thevenard Island, NW of Onslow, Western Australia, May 2010. Source: Nigel Marsh / iNaturalist.org. License: CC By Attribution-NonCommercial

A dark purplish-grey rockcod with scattered irregular whitish spots and blotches that are smaller on the head. The markings fade with growth. Juveniles are brownish-grey to dark grey with large irregular white spots scattered on the body and fins.

Cite this page as:
Bray, D.J. 2020, Epinephelus multinotatus in Fishes of Australia, accessed 01 Oct 2022, https://fishesofaustralia.net.au/home/species/4416

Rankin Cod, Epinephelus multinotatus (Peters 1876)

More Info


Houtman Abrolhos, Western Australia, to the Arafura Sea, Northern Territory. Elsewhere the species is widespread in the Indian Ocean. 
Inhabits clear to turbid waters on drop-offs and deep rocky reefs. Juveniles prefer shallower inshore reefs, while adults usually occur around deeper offshore sandy areas and rocky reefs.


Dorsal fin XI, 15-17; Anal fin III, 8-9; Pectoral fin 18-20; Lateral line scales 64-81; Gill rakers 9-11 + 15-18; Longitudinal scale series 130-162. 

Body depth 2.5-3.0 in SL;  head length 2.4-2.7 times in SL; snout profile slightly concave; interorbit distinctly convex; maxilla reaching to below rear edge of eye, ventral edge of maxilla (adults) with distinct step distally; lower jaw with 2 rows of teeth midlaterally; preopercle subangular with a shallow notch just above the angle, serrations at angle not or slightly enlarged; upper edge of operculum straight; posterior nostrils (adults) twice size of anterior nostrils.
Body scales mostly ctenoid, cycloid dorsoanteriorly below anterior half of spinous dorsal fin, thorax, abdomen and above anterior anal fin; body with numerous auxiliary scales.
Caudal fin slightly emarginate to truncate; pelvic fins short, 1.7-2.3 in head length.


Rankin cod are protogynous hermaphrodites, with spawning occurring from August to October throughout the range with a peak in October (Table 1). Maturity of female fish is achieved after the first two years of life, with the larger and older fish in the population being all males. 


Rankin Cod are protogynous hermaphrodites, changing sex from female to male during the life cycle. In Western Australia, females mature after the first two years of age. Large, older fish are all male, and the life span is at least 22 years. The species may form spawning aggregations.


Fished commercially in north Western Australia - taken in multispecies demersal fisheries by a trawl fishery in Pilbara region, and by trap and line fisheries in the Broome region. The Rankin Cod is the most heavily fished grouper in Western Australia (Stephenson et al. 2001). The species is a highly prized table fish.

Similar Species

“Aquatic Protected Areas - What works best and how do we know?”, Proceedings of the World Congress on Aquatic Protected Areas - 14–17 August 2002; Cairns, Australia. University of Queensland Printery, St Lucia, Queensland.

Species Citation

Serranus multinotatus Peters, 1876, Monatsberichte der Königlichen Preussischen Akademie der Wissenschaften zu Berlin 1876: 435. Type locality: Mauritius.


Bray, D.J. 2020


Atlas of Living Australia

Rankin Cod, Epinephelus multinotatus (Peters 1876)


Allen, G.R. 1997. Marine Fishes of Tropical Australia and South-east Asia. Perth : Western Australian Museum 292 pp. 106 pls.

Allen, G.R. & Erdmann, M.V. 2012. Reef fishes of the East Indies. Perth : Tropical Reef Research 3 vols, 1260 pp.

Allen, G.R. & Swainston, R. 1988. The Marine Fishes of North-Western Australia. A field guide for anglers and divers. Perth, WA : Western Australian Museum vi 201 pp., 70 pls.

Boulenger, G.A. 1889. Second account of the fishes obtained by Surgeon Major A.S.G. Jayakar at Muscat, east coast of Arabia. Proceedings of the Zoological Society of London 1889(2): 236-246 pls 25-28 (described as Serranus jayakari)

Craig, M.T., Sadovy de Mitcheson, Y.J. & Heemstra, P.C. 2011. Groupers of the World: a Field and Market Guide. Grahamstown, South Africa : NISC Ltd 356 pp., Appendix 47 pp.

Giacomello, E. & Amorim, P. 2018. Epinephelus multinotatus. The IUCN Red List of Threatened Species 2018: e.T132740A46628015. https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T132740A46628015.en. Downloaded on 28 July 2020.

Gloerfelt-Tarp, T. & Kailola, P.J. 1984. Trawled Fishes of Southern Indonesia and Northwest Australia. Jakarta : Dir. Gen. Fish. (Indonesia), German Tech. Coop., Aust. Dev. Ass. Bur. 406 pp.

Heemstra, P.C. & Randall, J.E. 1993. Groupers of the World (Family Serranidae, Subfamily Epinephelinae). An annotated and illustrated catalogue of grouper, rockcod, hind, coral grouper and lyretail species known to date. FAO Fisheries Synopsis No. 125 Vol. 16. Rome: FAO. pp. 1-382

Heemstra, P.C. & Randall, J.E. 1999. Family Serranidae. pp. 2442-2548 in Carpenter, K.E. & Niem, T.H. (eds). The Living Marine Resources of the Western Central Pacific. FAO Species Identification Guide for Fisheries Purposes. Rome : FAO Vol. 4 2069-2790 pp.

Hutchins, J.B. 2001. Biodiversity of shallow reef fish assemblages in Western Australia using a rapid censusing technique. Records of the Western Australian Museum 20: 247-270.

Kailola, P.J., Williams, M.J., Stewart, P.C., Reichelt, R.E., McNee, A. & Grieve, C. 1993. Australian Fisheries Resources. Canberra : Bureau of Resource Sciences and the Fisheries Research and Development Corporation 422 pp.

Larson, H.K., Williams, R.S. & Hammer, M.P. 2013. An annotated checklist of the fishes of the Northern Territory, Australia. Zootaxa 3696(1): 1-293

Newman, S.J., Hyndes, G.A., Penn, J.W., Mackie, M.C. & Stephenson, P.C. 2003. Review of generic no-take areas and conventional fishery closure systems and their application to the management of tropical fishery resources along north-western Australia. pp. 75-85 in Beumer, J.P., Grant, A. & Smith, D.C. (eds) Aquatic Protected Areas - What works best and how do we know? Proceedings of the World Congress on Aquatic Protected Areas, Cairns, Australia, 14–17 August 2002. St Lucia, Queensland: University of Queensland Printery

Peters, W.C.H. 1876. Übersicht der von Hrn. Prof. Dr. K. Möbius in Mauritius und bei den Seychellen gesammelten Fische. Monatsberichte der Königlichen Preussischen Akademie der Wissenschaften zu Berlin 1876: 435-447.

Ramm, D.C. 1997. Assessment of groundfish stocks in northern Australian waters between 127–137°E. Final report to the Fisheries Research and Development Corporation on project 90/15, and the Fisheries Management Authority. Northern Territory Department of Primary Production, Fishery Report 38: 1–85

Randall, J.E. & Heemstra, P.C. 1991. Revision of Indo-Pacific groupers (Perciformes: Serranidae: Epinephelinae), with descriptions of five new species. Indo-Pacific Fishes 20: 1-332.

Sainsbury, K.J., Kailola, P.J. & Leyland, G.G. 1985. Continental Shelf Fishes of Northern and North-Western Australia. Canberra : Fisheries Information Service 375 pp. figs & pls.

Stephenson, P.C., Edmunds, J.S., Moran, M.J. & Caputi, N. 2001. Analysis of stable isotope ratios to investigate stock structure of red emperor and Rankin cod in northern Western Australia. Journal of Fish Biology 58: 126-144.

Whitley, G.P. 1945. New sharks and fishes from Western Australia. Part 2. The Australian Zoologist 11(1): 1-42 figs 1-15 (described Epinephelus rankini)

Whitley, G.P. 1947. New sharks and fishes from Western Australia. Part 3. The Australian Zoologist 11(2): 129-150 figs 1-3 pl. 11 (as Altiserranus jayakari)

Yearsley, G.K., Last, P.R. & Ward, R.D. (eds) 1999. Australian Seafood Handbook. Hobart : CSIRO Marine Research 460 pp.

Quick Facts

CAAB Code:37311010

Biology:Protogynous hermaphrodite

Conservation:IUCN Least Concern

Depth:10-110 m

Fishing:Commercial, recreational fish

Fishing:Reef associated

Max Size:100 cm TL; 9 kg

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CAAB distribution map