Rankin Cod, Epinephelus rankini (Whitley 1945)

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 rankini, 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.
This species was long considered to be a junior synonym of Epinephelus multinotatus, which occurs in the central and Western Indian Ocean (Cao et al. 2022).

Cite this page as:
Bray, D.J. 2023, Epinephelus rankini in Fishes of Australia, accessed 16 Apr 2024, https://fishesofaustralia.net.au/home/species/4416

Rankin Cod, Epinephelus rankini (Whitley 1945)

More Info


Off the Perth area, Western Australia, north to the Arafura Sea, Northern Territory. Elsewhere the species occurs in southern Indonesia. 
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.



Feeds on small fishes and crustaceans.


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.


The species is "named after Mr. F. J. Rankin, postmaster at Onslow, Western Australia, in appreciation of his valued specimens and notes of fishes from his district".

Species Citation

Epinephelus rankini Whitley 1945, Australian Zoologist 11(1): 24. Type locality: off Onslow, Western Australia.


Bray, D.J. 2023


Atlas of Living Australia

Rankin Cod, Epinephelus rankini (Whitley 1945)


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

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

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. (as Epinephelus multinotatus)

Cao, X.-Y., Wu, H.-H., Zhang, H.-R., Wu, L. & Ding S.-X. 2022 Epinephelus rankini Whitley, 1945, a valid species of grouper (Teleostei, Perciformes, Epinephelidae) from Western Australia and southeast Indonesia. Biodiversity Data Journal 10(e90472): 1-19. https://doi.org/10.3897/BDJ.10.e90472

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. (as Epinephelus multinotatus)

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. (as Epinephelus multinotatus)

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 (as Epinephelus multinotatus)

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. (as Epinephelus multinotatus)

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. (as Epinephelus multinotatus)

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. (as Epinephelus multinotatus)

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 (as Epinephelus multinotatus)

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 (as Epinephelus multinotatus)

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 (as Epinephelus multinotatus)

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. (as Epinephelus multinotatus)

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. (as Epinephelus multinotatus)

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. (as Epinephelus multinotatus)

Whitley, G.P. 1945. New sharks and fishes from Western Australia. Part 2. The Australian Zoologist 11(1): 1-42 figs 1-15 See ref at BHL

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. (as Epinephelus multinotatus)

Quick Facts

CAAB Code:37311010

Biology:Protogynous hermaphrodite

Depth:10-110 m

Fishing:Commercial, recreational fish

Fishing:Reef associated

Max Size:100 cm TL; 9 kg

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