‘Fin On Fly

Shane Mensforth | VOLUME 32, ISSUE 2
This is visual, adrenaline-charged fishing that’s hard to top
Southern bluefin tuna are on the comeback trail and anglers are trying different techniques to tackle these brutal sports fish.

For a fish that’s spent a fair slice of the last two decades on the globally endangered list, the southern bluefin tuna seems to have made a remarkable recovery. I can recall several consecutive seasons in the late 1990s and early 2000s when the annual bluefin migration through south-east Australian waters simply didn’t happen. It appeared that all the gloom and doom we were hearing about these iconic fish was true, and that it may already have been too late to arrest the decline.

However, as the new millennium unfolded, the bluefin schools gradually began to show again in late summer and early spring – first just a few fish, then considerably more the following year. By the end of the first decade in this millennium, the southern bluefin were back in the sort of numbers we had once been accustomed to, and this season that trend has certainly continued.

Along with the usual school-sized tuna of 12-20kg, we’ve also seen some huge fish of 100 kilos-plus – the so called ‘barrels’ that have injected new life into the heavy-tackle scene in Tasmania, Victoria and South Australia. It’s been a real bluefin renaissance, and one we trust will continue on its current trajectory.

In my home state of SA, we now expect the first ‘new season’ tuna to arrive pre-Christmas, and for numbers to build steadily through the summer before tapering off toward the middle of autumn. It’s been this way for several years now, with fish numbers and distribution influenced heavily by water temperature and baitfish aggregations. As a rule of thumb, the tuna appear off SA’s west coast first, then gradually push eastward around the bottom of Eyre Peninsula, passing Kangaroo Island and eventually settling in the State’s south-east. The vast schools are accessible to both commercial and recreational anglers from several ports, and they have become an extremely attractive target for all who pursue them.


I’ve been a ‘tuna tragic’ for as long as I can remember, catching them in many locations on many boats and at different sizes. I was fortunate to get into the barrel action a couple of years ago, boating one we weighed in at 108kg and tagging a couple of others of similar size. The vast majority of bluefin I’ve caught have been on lures trolled in the traditional manner, and there’s no doubt this is the most efficient way to go about it if you’re after a feed.

Just lately, however, I’ve opted to leave the trolling gear at home and approach the whole offshore bluefin scene from a different angle. Casting surface lures at feeding schools injects a whole lot more fun into the game, and particularly so with some of the brilliant threadline tackle that’s now available. There are few things more exciting than throwing a stickbait into a mob of surface-feeding tuna, cranking it back to the boat and watching in awe as a blue/silver missile homes in on the lure and smashes it just a few metres from the rod tip. This is visual, adrenaline-charged fishing that’s hard to top.

Always looking for a challenge out on the bluewater, however, tackling tuna on saltwater fly gear had long been in the back of my mind. Along with the traditional trout (and some spectacular Pacific salmon in Alaska), I had caught quite a few different saltwater species on fly, and it didn’t take much to get me thinking seriously about adding southern bluefin to the list. I already owned a high-end 12 weight outfit that would suit the job nicely, and all I had to do was a bit of homework on technique and tackle rigging before heading out to give it a try.

My first real opportunity came near Wedge Island, located at the bottom of SA’s Spencer Gulf and relatively accessible from the Yorke Peninsula township of Marion Bay. The school bluefin had been working in this area for several weeks, relentlessly pursuing vast pilchard schools that ride the warm currents. As usual, it had been a matter of ‘find the bait, find the tuna’, which seemed spot on for what I had in mind. The trolling and lure casting gear was loaded aboard as usual, but my primary focus would be hooking a southern blue on fly.

To that end, I had organised 20kg of fresh pilchards to be used as chum. Following the lead of professional tuna polers from way back, the plan was to burley the tuna to the boat with cut pilchards, then shoot a fly into the trail. I was confident that if there were plenty of tuna competing for the food source, hooking one shouldn’t be difficult. In theory at least, this all seemed pretty straightforward.

In practice, however, I quickly discovered that you have to have pretty much everything going right to succeed.


First up, approaching a surface-feeding school of bluefin has to be done quickly and without spooking them with the boat. You’ve then got to attract their interest sufficiently with chum to drag them away from the natural baitfish school. Finally, you have to convince them that the fur and feathers you’re casting at them is real enough to at least have a crack at. Individually, these three facets of the game aren’t that hard to achieve, but combining them is often far from easy.

You can forget fly fishing for tuna in anything but perfect conditions. You need to be able to watch the fish from a reasonable distance and figure out quickly which way they are headed. Having worked out a point at which you should be able to intercept them, it’s then vital to start laying down the chum trail so that any prevailing current will carry the cut pillies right to their noses. Provided the tuna pick up your chum trail and start tracking its source, you’re more than halfway there.

Setting up that trail correctly and maintaining it for what can be several minutes demands some thought. It’s not simply a matter of dumping handfuls of pilchard halves indiscriminately and hoping the fish will stumble into them. The more effective way to go is to start off with a handful of burley, then cut back to half a pilchard every 10 seconds or so – sort of like the Hansel and Gretel scenario, in which a breadcrumb dropped regularly was enough to lead their father to where that nasty old witch was holding them in preparation for the oven.

Providing the tuna have discovered the chum trail and become visible behind the boat, getting one to eat your fly is the final and most significant part of the deal. Despite their compulsion to feed, southern bluefin can be downright fussy at times, and it’s always wise to offer them a fly that replicates a pilchard as closely as possible. I’ve found a blue and white deceiver or garfish imitation around 12cm long is usually perfect for the average school tuna of 20kg or less, but it has to be tied on a strong hook and look as natural as you can manage.

Getting a bite is nearly always easier if you have a dozen or more bluefin zapping around at the back of the boat than if there are just two or three. Competition for food will invariably cause less caution from the fish involved, but it doesn’t always ensure an instant response.


Harking back to my maiden fly expedition to Wedge Island, I can vividly recall watching several tuna rocket through the burley trail, inhaling virtually every pilchard piece in the water. It was with incredible anticipation that I made the first cast with the 12 weight rod. A dozen casts later that anticipation had all but evaporated. The fish were scoffing those pillies without hesitation, but ignoring my fly completely.

I tried putting the rod between my legs and stripping the fly back with both hands to increase retrieve speed, then slowed it down incrementally, but nothing seemed to work. I let the fly and 20 feet of line sink well out of sight before retrieving, I tried whipping it back across the surface and I tried just about every combination of depth and retrieve speed possible – all with no result. Obviously, these fish were smarter than your average pelagic!

More out of desperation than anything else, I chucked a handful of pilchards five metres behind the boat, flicked the fly to the spot the pillies had splashed down and merely allowed the fly to sink without stripping. I watched half a dozen bluefin devour the pilchards and then, with my fly barely visible, one of them turned around and sucked it in. Suddenly the penny dropped. They weren’t interested in chasing anything down; all they wanted was something that looked like a pilchard and was sinking at the same rate as the burley. That little revelation was definitely a ‘lightbulb moment’, and it’s proven to be one of the most significant fishing lessons I’ve learned in quite some time.

Fly tackle for school tuna needs to be robust without going over the top. I like my 12 weight Loomis outfit, as it allows me to cast relatively large flies the required distance, and also helps out when 20kg of bluefin is circling deep beneath the boat and needs some encouragement from above to throw in the towel. I can usually knock over a fish of this size in 20 minutes, although I have been known to spend an hour or more on particularly stubborn individuals.

I know a few experienced tuna devotees who prefer a 10 weight fly outfit, and there’s no doubt you could go this way if the fish were a tad smaller than average and you have plenty of patience. I like to use a sinking line with a straight-through, 2.5m leader of 60-80 pound fluorocarbon, which is supposedly harder for the fish to see and definitely provides some extra abrasion resistance from those little, but sharp tuna teeth.

One of the really nice things about fly fishing for these great sportfish is that you still get a fabulous feed at the end. Although, it doesn’t matter how you catch them – southern bluefin tuna are right up there with the best table fish available in south-eastern Australia. Long may their revival continue.