There’s something about old techniques that never really die. They just sit quietly in the background, waiting for the right moment to come back into play. Cubing for southern bluefin tuna is exactly that. It’s an approach that dates back decades, something that was almost standard practice through the 70s and 80s, before high-speed trolling and modern lure technology took over. But when the fish stop behaving how you want them to, when they sit mid-water and ignore everything you throw at them, cubing is still one of the most effective ways to turn a tough day into a memorable one.
When Tuna Won’t Play the Game
With the resurgence of southern bluefin numbers in recent seasons, particularly those solid medium-sized fish, more anglers are finding themselves in situations where tuna are present but not committing. You mark them clearly on the sounder, often sitting well up in the water column, but they won’t touch a spread of lures. That’s where cubing comes back into its own. On this particular day, the fish were easy to find. Sounder marks lit up at around 70 metres of water, with the bulk of the tuna holding at roughly 35 metres down. Classic mid-water behaviour. They weren’t busting up on the surface, and they weren’t pinned hard on the bottom either. Just cruising, relaxed, and not especially interested in chasing anything moving too quickly.
Rather than persist with lures and burn time, the decision was made early to switch tactics.
Building the Trail
Cubing is simple in theory, but the execution needs to be spot on. It starts with pilchards, and plenty of them. You’re not just feeding fish here, you’re building a consistent berley trail that mimics a natural food source sinking through the water column. The key is consistency. Same size cubes, same pace, and most importantly, no breaks in the trail.
Pilchards are cut into small, even cubes and fed into the water steadily. Not dumped in handfuls, not thrown sporadically, but introduced at a rhythm that matches their natural sink rate. As each cube disappears from view, another follows. Then another. Then another. It’s repetitive, almost hypnotic, but that consistency is what draws fish up through the water.
Once the trail is established, it becomes a conveyor belt of food drifting down-current. Tuna move into it, tracking the cubes as they fall, becoming more confident as the stream continues uninterrupted. And that’s the critical part. The trail must never stop.
A minimum of four 1kg blocks of pilchards is a good starting point, but realistically, you want more on board. If you’re not marking fish initially and you’re relying on cubing to bring them to you, you could easily go through ten blocks in a session. On this day, because the fish were already located on the sounder, less was needed, but the rule didn’t change. Once you start, you don’t stop.
Random cubing or letting the trail die off is one of the quickest ways to lose fish. They drift away just as easily as they come in.
Drawing Fish to the Boat
As the cubes sink and the fish begin to respond, you’ll often see a shift in behaviour. Initially, bites might come deeper, around that 35-metre mark where the tuna were first holding. But as the trail builds and confidence grows, the fish start to rise. Slowly at first, then more aggressively. Before long, they can be right behind the boat, sitting just out of sight, following the stream of cubes almost to the surface.
That’s when things get interesting.
Presenting the Perfect Bait
Fishing a whole pilchard among the cubes is the next step, and this is where restraint is important. There’s no need to overcomplicate it. Don’t bury the hook deep inside the bait or try to make it look unnatural. A simple, well-presented pilchard is all that’s required. It should sink at the same rate as the cubes around it, blending in perfectly with the trail.
Tackle plays a bigger role here than many realise. While braid has its place in many styles of fishing, cubing isn’t one of them. Braid is too buoyant. It doesn’t allow the bait to sink naturally, and that subtle difference is enough to turn wary tuna away. Monofilament, on the other hand, is close to neutral in the water. It sinks slowly and behaves far more like the cubes themselves.
Fishing 24kg line, often scale-tested closer to 8kg for consistency and sport, provides the right balance. It’s strong enough to handle powerful tuna, yet forgiving enough to allow a natural presentation.
Old School Gear That Still Works
Rods are another nod to the old school approach. Short-stroker fibreglass rods are ideal here. They’re soft, forgiving, and perfectly suited to the vertical nature of the fight that follows. When a big tuna circles deep under the boat, those rods come into their own, absorbing lunges and keeping constant pressure without pulling hooks.
In this case, the gear had serious history behind it. Custom-built 24kg Calstar rods, crafted back in 1989, still doing exactly what they were designed to do. There’s something fitting about using that kind of tackle for a technique like cubing. It connects you to the roots of the method, and proves that good gear, like good techniques, stands the test of time.
The Bite and the Fight
Deploying the bait is as important as preparing it. The reel is set to free spool, with the ratchet engaged. That way, when a fish takes the bait, you don’t risk overruns or backlash as line peels off under pressure. It’s a simple setup, but it works.
From there, it becomes a tactile process. Sitting on the gunwale, feeding line out by hand, feeling every movement as the bait sinks. Counting it down, metre by metre, staying in tune with where the fish are holding. It’s hands-on fishing in its purest form.
When the bite comes, it’s rarely subtle. The ratchet ticks, then screams. Line accelerates off the spool as the tuna commits, often at the same depth you’ve been marking them. At 35 metres early on, then progressively shallower as the session builds. There’s no need for a big strike with circle hooks. Let the fish load up, engage the drag smoothly, and the hook finds its place. From there, it’s a brutal, vertical contest. Big tuna hooked this way tend to fight differently to those taken on lures. There’s less of the high-speed surface run and more stubborn, dogged power. They circle deep, using their weight and strength to stay down. This is where the short-stroker rods shine. The softer action allows you to work the fish patiently, gaining line when you can, holding when you need to.
It’s physical, methodical fishing. Up and down. Lift and wind. No shortcuts.
Why Cubing Still Matters
And that’s part of the appeal.
Cubing isn’t just effective, it’s engaging. You’re constantly involved. Managing the trail, feeding cubes, monitoring the sounder, adjusting depth, and staying ready for the bite. It’s a far cry from setting a spread and waiting for a rod to go off. Every fish feels earned.
What stands out most is how adaptable the method is. Tuna habits change. Conditions vary. Some days they’ll climb all over lures, other days they won’t look at them. Being able to switch to a technique like cubing gives you options. It keeps you in the game when others might struggle.
It also brings a different kind of satisfaction. There’s something rewarding about out-thinking the fish, about going back to a technique that’s been proven over decades and making it work again in modern conditions.
For anglers used to lighter tackle, particularly those coming from a snapper background, cubing for tuna can feel like stepping up a level. The gear is heavier, the fish are stronger, and the fights are longer. But the principles remain familiar. Presentation, patience, and attention to detail.
In many ways, it’s just a scaled-up version of what we already do.
A Technique Worth Revisiting
The biggest takeaway is simple. Don’t overlook the old methods. Just because they’re not as widely talked about or don’t feature in the latest tackle catalogues doesn’t mean they’ve lost their effectiveness. If anything, they can be even more powerful now, precisely because fewer anglers are using them.
Cubing for southern bluefin tuna is a perfect example. It’s not flashy. It’s not fast-paced. But when the conditions line up and the fish aren’t cooperating, it can turn a frustrating session into one of the most rewarding styles of tuna fishing you’ll experience.
And once you’ve done it properly, sat there feeding a steady trail, watching fish rise on the sounder, and hearing that ratchet scream as a tuna commits, you’ll understand why it’s stood the test of time.
It’s simple. It’s effective. And it’s a hell of a lot of fun.
