Shark Mackerel
Pelagic / Reef edgeA fast, schooling mackerel of WA's tropical north — big-eyed, dark-backed, and named for the faint shark-like smell of its flesh. Found over reefs and current lines from the Gascoyne up through the Pilbara and Kimberley, often in big surface-feeding schools. A hard, fast fighter on light gear and, despite the name, good eating when bled and iced immediately.
Overview
Shark mackerel (Grammatorcynus bicarinatus) are a distinct, large-eyed member of the mackerel clan found across WA's tropical north — Ningaloo, the Pilbara, the Montebello and Mackerel Islands, and into the Kimberley. They school heavily over reefs, bommies and current lines, often busting bait on the surface in numbers, and they hit fast-moving lures and baits hard. They're a smaller, faster target than Spanish mackerel but a genuinely fun light-tackle fish that fights well above its weight. The name comes from the slight ammonia or shark-like odour the flesh can develop — which is exactly why prompt bleeding and icing matters. Handled right, they're good eating. They're often found in mixed schools with other mackerels and tuna.
Identification
Shark macks
Shark mackerel are easy to separate from the other tropical mackerels once you know the two markers: a notably large eye, and a double lateral line — one branch running high over the pectoral, the other low along the belly — which no Scomberomorus mackerel has. The body is dark blue-green above and silvery below, without the bold spots of a spotted mackerel or the wavy bars of a small Spanish, and the head is blunter and the body stockier. The last giveaway is the smell: the flesh carries the faint ammonia or shark-like odour that names the fish, and settles the identification at the cleaning table.
How to Catch
Whole gar or pilchard on a wire-trace gang, slimy mackerel, live yakka or mullet, fish strip baits
Chrome slugs and metals (Halco Twisty, Raider), small skirts and minnows trolled fast, slow-pitch jigs, stickbaits to surface schools
A short wire bite trace is wise — shark mackerel have sharp teeth and will bite off mono. 30–40lb single-strand or coated wire to a single hook or stinger, run under a heavier mono leader for casting. Gang hooks for whole baits. Medium spin gear handles them well; they run fast but aren't a Spanish-sized tackle test.
Cast metals and stickbaits into surface-feeding schools with a fast, erratic retrieve — shark mackerel chase down speed and the strike is immediate. Trolling small skirts and minnows along reef edges and current lines at 5–7 knots finds active schools when nothing's showing on top. Watch for birds and bait spraying. When you find a school, they often stay up for a while — keep casting.
Year-round in the tropical north, with the warmer months most consistent. In the lower west, summer is the realistic window when warm water pushes south. Tide changes and current lines concentrate bait; early morning and late afternoon are most productive.
Up to 1.3m and 13kg, commonly 2–6kg
Year-round (Pilbara/Kimberley); summer in the lower west
Size & Growth
Most shark mackerel are 2–6kg and 60–90cm — good light-tackle size, and the bulk of what a school produces. A very good one is 8–10kg; the species reaches about 1.3m and 13kg, but a fish at that end is uncommon in recreational catches. They're a fast-growing tropical pelagic with a short life compared with a reef demersal, putting on size quickly in warm water. Practically, expect a school to be one size class — if the first three are 3kg fish, the rest usually are too, so enjoy the light-tackle fishing rather than waiting on a monster that isn't there.
Diet & Habitat
Shark mackerel hunt small pelagic baitfish, squid and pilchard-sized schooling fish, working in fast packs that push bait to the surface. They hold along reef edges, bommies, shoals, headlands and the current lines and pressure edges where bait stacks up, usually in the top of the water column rather than on the bottom. In WA they're a tropical-north fish: Ningaloo and the Muiron Islands out of Exmouth, the Mackerel and Montebello Islands, the Dampier Archipelago and the Pilbara reefs, and on into the Kimberley. They show further down the coast in a warm summer, but the north is where you'd plan a trip around them.
WA Size & Bag Limits
| Minimum size | 50 cm |
|---|---|
| Bag limit | 3 — within the large pelagic finfish mixed bag |
| Counts toward | Counts within the statewide large pelagic finfish mixed daily bag of 3, shared with the other mackerels, mahi mahi, wahoo, tuna and cobia. |
Shark mackerel (Grammatorcynus bicarinatus): minimum size 500mm, within the statewide large pelagic finfish mixed daily bag of 3 (shared with other mackerels, mahi mahi, wahoo, tuna and cobia).
Eating Quality
Good eating despite the name, but entirely dependent on handling. Bled and iced the moment it's landed, the flesh is firm and moderately oily, pink-grey raw and cooking up pale and meaty — well suited to grilling, thick barbecued steaks, curries and smoking, where the stronger flavour is an asset. Left ungutted in the heat, the faint ammonia odour that gives the fish its name gets worse by the hour and no cooking method will fix it. Mid-sized fish of 2–4kg are the pick for the table; big ones are stronger-flavoured and, like all large tropical predators, carry a small ciguatera risk, so locals tend to keep the mid-sizers. It smokes well and freezes acceptably portioned and vacuum-sealed, though it's best in the first day or two.
Perth Tips
Tantabiddi, the Muiron and Mackerel Islands, the Montebellos and the Pilbara reefs all hold shark mackerel in season, often mixed with Spanish and spotted mackerel. Bleed them instantly — it's the difference between a good feed and a smelly one. Run wire or expect bite-offs. They're a great light-tackle option when the bigger Spanish aren't playing.