Southern Bluefin Tuna
Offshore / BluewaterSouthern bluefin tuna (SBT) are the south coast's blue-water prize — running off Albany, Esperance and Bremer Bay through the cooler months. Hard-fighting barrels, world-class sashimi, counted within the large-pelagic bag of 3.
Overview
Southern bluefin tuna are the south coast's marquee gamefish, running the deep water off Albany, Bremer Bay and Esperance from autumn into winter. The continental shelf swings close to shore along this coast, so SBT are reachable on a settled day from a trailer boat with the range and the weather window to match. Fish of 10–25kg are the staple, with bigger barrels a genuine chance. They feed hard along the shelf and the canyons, often with whales, dolphins and birds marking the bait. SBT are an internationally quota-managed stock that has been rebuilding for years — they fish better now than they have in a generation.
Identification
SBT, bluefin, barrels
Southern bluefin are the stocky one. Deep, heavy-shouldered body, short pectoral fins that don't reach past the front of the second dorsal, and short second dorsal and anal fins — not the long sickles of a yellowfin. The back is deep metallic blue-black, the flanks silver, and the giveaway is the caudal keel at the base of the tail, which is bright yellow on an SBT and dark on the other tunas. The finlets are yellow with dark edges. Yellowfin are slimmer with long trailing fins; longtail tuna are slimmer again with pale spots low on the flanks, and don't run in the cold southern water where SBT do.
How to Catch
Skipping garfish and pilchards in a trolling spread, live slimy mackerel where you can get them, cube trails of pilchard on the drift
Skirted trolling lures (Pakula, Richter) in a spread of 5–7, deep-diving minnows (Rapala X-Rap Magnum), chrome slugs cast at surface schools
Game gear — 15–24kg overhead outfits, or heavy spin (14000 reel, 65–80lb braid) for casting. 100–130lb fluorocarbon or mono leader, quality crimps, strong single hooks on the skirts. This is open-water southern-ocean fishing; gear failure costs you the fish of the trip.
Troll a skirt-and-diver spread along the shelf edge, the canyons and current lines off Albany and Esperance, watching the sounder for bait and the horizon for birds and whales. When schools surface, cast slugs or stickbaits ahead of them. A drifting cube trail will draw fish to the boat. Pick your weather — the south coast turns on fast, and the SBT grounds are no place to be caught out.
March through July is the south-coast window, with the cooler months the most consistent. Settled high-pressure weather between fronts is what makes the offshore grounds fishable.
Commonly 10–25kg 'barrels' off the south coast; larger fish possible
Autumn–winter (Mar–Jul) off the south coast
Size & Growth
The staple off the south coast is a 10–25kg fish — the 'barrels' of a good autumn run — with fish to 40kg and beyond a genuine possibility in a strong season. The species grows much larger again out in the Southern Ocean, but those aren't the fish a trailer boat out of Albany is meeting. Southern bluefin are slow-growing and long-lived by tuna standards, taking years to mature and living for decades, which is exactly why the stock is internationally quota-managed and has taken so long to rebuild. A big SBT is an old fish, and worth treating accordingly.
Diet & Habitat
Southern bluefin are cold-water open-ocean predators, feeding on pilchard, redbait, small pelagic fish, squid and krill, and they'll work a bait ball from the surface down. They hold along the continental shelf edge, the canyons, and the current and temperature breaks off the south coast, and their arrival is tied to water temperature and the bait moving through. In WA they run off Albany, Bremer Bay and Esperance from autumn into winter, where the shelf swings close enough to shore to put them within reach of a capable trailer boat on a settled day. Whales, dolphins and working birds along the shelf are the sign to look for.
WA Size & Bag Limits
| Minimum size | No minimum size |
|---|---|
| Bag limit | 3 — the statewide large pelagic finfish total mixed bag |
| Counts toward | Counts within WA's large pelagic finfish total mixed bag of 3 per fisher. A Recreational Fishing from Boat Licence is required from a powered boat. |
No minimum size. Southern bluefin tuna count within WA's large pelagic finfish TOTAL mixed bag of 3 per fisher (statewide). SBT are an internationally quota-managed, recovering stock — handle them carefully and keep only what you'll genuinely use. A Recreational Fishing from Boat Licence (RFBL) is required when fishing from a powered boat.
Eating Quality
Yes — southern bluefin is among the finest eating tuna in the world: rich, fatty, deep-red flesh that is prized for sashimi and sears superbly. Bleed, spike and ice the fish immediately — a brine slurry, not just a bag of ice — because that quality is the whole point of the trip. The belly flap (toro) is the prize cut, marbled and best raw or barely seared. Bigger, fatter fish are richer; a smaller one is leaner and closer to yellowfin in character. Serve it raw, seared rare or lightly grilled and stop well short of cooked through — heat destroys what makes it worth catching. Vacuum-sealed loins freeze better than most tuna thanks to the fat, though sashimi texture is a fresh proposition. Large tuna accumulate mercury, so treat it as an occasional meal.
Perth Tips
Albany, Bremer Bay and Esperance are the launch points — all need a capable boat and a genuine weather window. Watch for whales and bird activity, which mark the bait the tuna are working. Carry a brine slurry, not just ice; SBT are too good to waste through poor handling. Keep what you'll eat and release the rest carefully — the stock is still rebuilding.