Northern Australian grouper found on reef and rubble from the Houtman Abrolhos north through WA to the Arafura Sea, also recorded in southeast Indonesia, with rare strays as far south as Perth. Often comes up alongside red emperor on the same demersal rigs and shares the same 40–100m depth range. One of the better-eating grouper species on the WA coast and a regular guest in the mixed northern demersal bag.
Overview
Rankin cod (Epinephelus rankini) occur from the Houtman Abrolhos (about 28°29'S) north through WA to the Arafura Sea, and in southeast Indonesia, with occasional strays recorded as far south as Perth — the Australian Faunal Directory gives the Abrolhos as the southern limit, and they only really come into their own from Carnarvon north. The species was separated from the western Indian Ocean E. multinotatus in a 2022 taxonomic revision. They live on rubble, broken reef and coral edges in 30–100m, often holding alongside red emperor, spangled emperor and goldband snapper, and they're a routine catch on the same paternoster rigs that target reds. The Gascoyne and North Coast bioregions hold the bulk of the recreational fishery — charter boats out of Coral Bay, Exmouth, Onslow and Dampier put clients onto rankin most trips. Despite the shared 'cod' label with the unrelated coral trouts (Plectropomus species), rankin cod is a true Epinephelus grouper with a paler, mottled body and a dark tail margin.
Identification
Rankin, Rankin's cod, white-blotched grouper
A solid, big-mouthed grouper with rounded fins, pale grey-brown to olive, covered in irregular white blotches that fade in and out with the fish's mood, plus scattered darker flecks and a dark margin along the tail. The tail edge is the detail worth remembering — it stays put when the blotching does not. Coral trout share the reef but are more streamlined, distinctly blue-spotted and a different colour entirely. Other Epinephelus rockcods coming up on the same rigs are generally more heavily spotted or barred. Breaksea cod are a different species; their south-western range overlaps the southern part of the Rankin cod range.
How to Catch
Whole squid, butterflied mullet, slimy mackerel fillet, octopus, large pilchards
Slow-pitch jigs 150–300g, large soft plastics on heavy jigheads, vertical knife jigs
Paternoster rig with two 8/0–10/0 circle hooks on heavy droppers and an 80–100lb mono leader — the same rig you'd run for red emperor. Use 16–32oz of lead to hold bottom in deep water and current. Strong knots and quality terminals are non-negotiable; rankin cod fight hard for the bottom on the strike.
Drift or lightly anchor over rubble and reef edges in 40–100m, working baits hard on the bottom with a couple of cranks up. Rankin hold around the corners and edges of structure rather than the peaks, the same as reds. Slow-pitch jigging produces well when fish are aggressive, with short sharp lifts off the bottom. They strike decisively and try to bury you in the reef — lock up immediately and lift them clear before they get their head down. Carry a release weight; barotrauma is real at depth and undersized or surplus fish need to go back properly.
Year-round in northern WA, with the cooler April–October window offering the best weather for the Gascoyne and Pilbara grounds. Tide changes trigger the bite; neaps make bottom-fishing easier than springs. Dawn and dusk are most productive, but rankin will feed through the middle of the day on the right tide.
Up to 15kg, commonly 3–8kg
Year-round (Gascoyne, Pilbara)
Size & Growth
Commonly 3–8kg on the Gascoyne and Pilbara grounds, with a 10kg fish a very good one and the biggest around 15kg and a bit over a metre. They are slow-growing and long-lived — a couple of decades is normal for the larger fish — and protogynous, maturing as females and changing to male with age, so a big rankin is an old male that took a long time to get there. That combination is the whole reason the demersal bag sits at 4 across all species and why release weights matter more here than the size of any individual fish.
Diet & Habitat
An ambush predator that sits in cover and inhales whatever swims past — small reef fish, squid, octopus and crabs. They hold on rubble bottom, broken reef and coral edges in roughly 30–100m, favouring the shoulders and corners of structure rather than the peaks, and they share that water with red emperor, spangled emperor and goldband snapper, which is why all four come up on the same paternoster rig. In WA their range extends from the Houtman Abrolhos through the Gascoyne and Pilbara into Kimberley waters, with the charter fleets out of Coral Bay, Exmouth, Onslow and Dampier working the core of it. Perth-area fish are occasional strays rather than the southern edge of the range.
WA Size & Bag Limits
| Minimum size | No minimum size |
|---|---|
| Bag limit | 4 (Gascoyne and North Coast bioregions); 2 in the West Coast bioregion |
| Counts toward | Counts within the demersal scalefish total mixed daily bag of 4. No minimum size applies (DPIRD lists Rankin cod on its own, still under the older name Epinephelus multinotatus). Totally protected in the Rowley Shoals Marine Park. A Recreational Fishing from Boat Licence is required when fishing from a powered boat. |
No minimum legal size (DPIRD lists Rankin cod on its own, still under the older name Epinephelus multinotatus). Individual daily bag limit: 4 in the Gascoyne and North Coast bioregions where the species lives (2 in the West Coast bioregion), taken within the demersal scalefish TOTAL mixed daily bag of 4. The West Coast boat-based demersal closure (south of Kalbarri) runs until spring 2027, and the species range also extends into the West Coast Bioregion, so use the rules for the actual fishing location. Rock cods, Rankin cod included, are totally protected in the Rowley Shoals Marine Park. A Recreational Fishing from Boat Licence (RFBL) is required when fishing from a powered boat.
Eating Quality
Excellent — firm, white, mild flesh that holds together on the grill, in a curry or under a batter without breaking up, and some of the cleaner-tasting grouper meat on the WA coast. Skin it rather than scaling it; the fillets are thick enough to cut into portions and cook like steaks. Fish in the 3–6kg range are the pick, giving usable fillet thickness without the coarser texture the big old males develop. Bleed at the gills and ice on capture — tropical reef fish deteriorate faster than they look, and a rankin left in a warm kill tank loses its edge within the hour. The cheeks are worth taking on the larger fish. Fillets freeze well vacuum-sealed for a couple of months, which suits a species you will often catch alongside a bag of reds.
Perth Tips
Rankin cod are a routine bonus when targeting reds — same rig, same depth, same grounds. Charters out of Coral Bay, Exmouth, Onslow and Dampier put them on the deck most trips through the cooler months. Keep a release weight on board and use it; rankin pulled from 80m don't recover unassisted.