How to Catch the Tuna of Your Dreams

There are a few tricks to catching tuna, and a few more to maximising their excellent food qualities.

Tuna are very special fish. Evolved far beyond the capabilities of other fish, tuna are the Olympic athletes of the piscine world — in both the marathon and sprint divisions. The physiology of these exquisite fish is remarkable, with increased oxygen intake from a greatly enlarged gill system, a blood system incorporating a heat exchanger, a warm body that enhances muscle performance, and streamlining that surpasses even the best jet aircraft. 

A tuna’s firm body is torpedo-shaped and mostly muscle. In fact, their gut system is proportionally tiny, meaning they process their food quickly and need to keep eating regularly to fuel their high-speed swimming. Like other animals, tuna have different types of muscle for different purposes, but here again, tuna are different, even from other fish. 

EXTRAORDINARY MUSCLE

Located centrally, either side of the backbone, tuna have bands of what is known as ‘slow-twitch’ red muscle, which is what they use for most of the day, including regular swimming. This oxygen-saturated, dark-red muscle can keep going tirelessly, and is what the tuna use to power their long-distance migrations, frequently across the borders of multiple countries. However, surrounding this dark muscle, making up most of a tuna’s body bulk, is what is called ‘white muscle’, which in tuna is actually pink. 

The white muscle is a ‘fast twitch’ muscle that can work very hard and fast for short periods. This gives tuna their exceptional speed and power, used in bursts when chasing prey or swimming away from a threat. However, this muscle builds-up lactic acid when used for extended periods, which affects not only its taste but also the storage life and freezability of the flesh. Since this muscle is the part we eat, we need to take steps to counteract this — and a damaging build-up of heat — which I will discuss later in this article.

EXCEPTIONAL SPORTFISH

As well as providing tasty meals, a tuna’s athleticism makes them a supreme challenge for anglers wanting to test their skills. Their speed makes them incredibly exciting to catch, sending the reel spool into a blur, and making the ratchet scream like a banshee.

There are a number of different species of tuna found in various regions around the world, varying in maximum size from quite small to more than 600kg. The Game Fishing Association of Australia (GFAA) keeps records for nine species of tuna, including albacore, bigeye, dogtooth, kawa kawa (mackerel tuna), longtail, Pacific bluefin, southern bluefin, skipjack, and yellowfin. 

As shown by the GFAA records, the largest tuna species you are likely to find in Australian waters are southern bluefin (to at least 167kg), yellowfin (to at least 124kg), bigeye (to at least 120kg), and the rarely seen Pacific bluefin (to at least 282kg). However, the world’s largest tuna is the Atlantic bluefin, the record for which is Ken Fraser’s 678kg monster caught off Nova Scotia, Canada in 1979.

RECKLESS OR INCREDIBLY WARY

Schools of tuna are continually hunting to feed their need for energy, so their desire to race in and swallow prey before their brethren beat them usually makes them fairly reckless and easy to hook. However, at times they can be exceptionally wary. I have caught yellowfin that took a large hook and wire trace set for sharks, and yet at other times I have seen tuna repeatedly swallowing chunks of berley at the back of our drifting boat while refusing every bait set on a hook and leader. On one memorable instance when we had a school of 15kg yellowfin feeding at the back of the boat, I continually reduced the hook size and leader strength until I ended up with a 2/0 bream hook on 6kg line with no leader before one of them would take a bait.

Of course, it is a rare situation when you get to actually see a fish refusing your offering, so it always pays to keep stealth in mind when fishing for tuna — that way you have a good chance of catching the wary specimens as well as the ravenous school fish. 

Leader strength needs to be varied to suit the situation and the technique being used. However, a rough guide would be to use nylon monofilament leader strength approximately equal to the weight of the tuna expected — for example, 25kg leader for tuna up to 30kg in weight.

MATCH WHAT THEY’RE EATING

The largest of each species may be solitary hunters, or roam with small packs, but most tuna live in schools of up to thousands of fish. They migrate with the flow of major ocean currents, taking advantage of whatever prey species they come across. 

The prey most tuna favour includes squid and slender baitfish species such as sardines, redbait, herring, slimy mackerel, yellowtail, flying fish, and saury. However, at times they will feed on an abundance of odd species, including tiny copepods and even small oceanic pufferfish. 

Catching tuna can get tricky if a particular prey species is super abundant, as the tuna will often lock onto that prey and ignore everything else, even other species they would normally happily feed upon. For example, at times yellowfin will be seen feeding explosively at the surface chasing sauries and will prove almost impossible to catch on anything other than a saury-lookalike lure cast into the school, or a similar soft-plastic lure skipped across the surface beneath a fishing kite on the troll.

In most situations, as long as you keep your leader stealthy and your lure or livebait matches their local prey in size and shape, most schooling tuna are quite easy to hook. Once you find a school it is often possible to hook multiple fish at once.

TROLLING FOR TUNA

The easiest way to catch tuna is by trolling with lures. This technique enables you to troll a variety of different size, type, and colour of lures at the same time, which is very helpful until you determine what is around on that day, and which offering they are responding to. There certainly are consistent favourites, but tuna can be fickle and what they prefer one day can be totally different the following day.

For tuna up to around 10kg, a consistent producer is a bullet-headed skirted lure around 10–15cm in length, with a tail of either plastic strips (‘squid’ tail) or sparkly mylar strips. A similar but larger lure of 15–20cm produces well for tuna from 10–40kg in weight, but one of my favourites is a baitfish-shaped high-speed trolling minnow, such as the Halco ‘Laser Pro 160’ or the Rapala ‘CD14 Magnum’.

When trolling for tuna larger than 40kg, you’re going to need fairly heavy tackle, so the hooks need to be substantial single hooks to deal with the pressure. Because of this, any diving/swimming lures — such as Halco’s excellent ‘Laser Pro 190’ or ‘Max 190’ — will need to be fitted with single hooks instead of treble hooks. Alternately, larger sizes of skirted trolling lures are the popular choice for many, with lure size matched to the expected baitfish in the area, typically ranging from 15–25cm in length. 

CASTING FOR TUNA

Casting lures into feeding tuna at the surface can be exceptionally thrilling. As the boat is positioned close to, but not in, the school, and the engine stopped, this stealthy approach can also be particularly effective. 

Casting slender metal lures works a treat for small schooling tuna, but you’ll need a reel with a very fast retrieve as the speed is one of the triggers that generate a strike. For tuna of 20kg to more than 100kg, the usual lures used are known as stickbaits and poppers, fitted with substantial single hooks rather than trebles. To handle such tuna on casting tackle will require braid line on premium-quality casting outfits.

Another technique, rapidly gaining popularity, is to jig for tuna using the same tackle as is used for casting stickbaits and poppers. For jigging, a slender metal lure — typically weighing 90–300gm — is dropped beneath the boat and then retrieved vertically at high speed. This works particularly well for bluefin, bigeye, albacore and yellowfin tuna when schools are seen on the sounder feeding on balls of baitfish well down below the surface.

NATURAL BAITS FOR TUNA

In most cases when trying to catch large predators, livebaits of the type they are hunting for will produce the best results. The downside is that to fish livebaits your search is going to cover very little ground. Whereas with trolled lures you can search over a wide area, with livebaits you need to know exactly where the fish are likely to be.

Livebaits can be fished on the drift, at anchor, or slow-trolled at perhaps one or two knots. However, the huge advantage of livebait is that it is far more appealing than an artificial lure, so they get results when lures are being ignored. They can also be fished at any depth, enabling you to prospect all layers of the water column, not just the surface, as is the case with trolled lures.

Another advantage of livebaits is that you can incorporate berley at the same time, attracting fish from the depths, and getting them actively feeding. One of the most successful berley strategies for albacore, yellowfin, and bluefin tuna is to take frozen blocks of pilchards (sardines), cut them into 3cm pieces, then drop them over the side in regular intervals of one chunk every 20 seconds or so. This creates a ‘staircase’ of chunks drifting down through the water column, staggered every 15–20m. Once a tuna intercepts a slowly descending chunk it will look for another, gradually climbing the ‘staircase’ until it reaches the boat or finds your set livebait.

A whole or half pilchard also makes an outstanding bait if rigged straight and natural-looking on a stealthy leader with the hook almost completely concealed within the bait. This bait is then lowered beneath the boat, pulling a metre of line off the reel every few seconds, so that it floats down unhindered along with the berley chunks. Immediately, a tuna takes the bait, the reel’s drag is engaged, hooking the fish.

TACKLE FOR TUNA

Tackle needs to be proportional to the size of tuna expected but can vary depending on how sporting — how challenged — the angler choses to be. 

For most anglers I suggest quality 10kg game fishing tackle for tuna up to 20kg, 15kg tackle for tuna up to 50kg, and 24kg or 37kg tackle together with the matching harness and rod bucket for the larger specimens. 

For trouble-free service, a reel used for trolling should be a top-shelf model with a lever-drag system, and hold between 600m and 1000m of line. 

ONCE YOU’VE CAUGHT YOUR TUNA

If you’re intending to eat your tuna, what you do in the minutes immediately after you’ve boated it will greatly affect its taste and storage qualities.

As mentioned at the beginning of this article, tuna have remarkable musculature that generates its own heat to enhance performance. They also have an iron-rich blood system to carry a large oxygen supply to the muscles. However, unless steps are taken immediately after capture, these features, especially their internal heat, rapidly deteriorate the eating qualities of your tuna.

Once boated, your tuna should be immediately killed. The most effective and humane way to do this is to pierce its brain with a spike, screwdriver, or knife — a technique known as ‘Ikijimi’. This is easy to do, by pushing your tool down through the middle of the top of its head, just behind the eyes.

To decrease the blood content, the fish should then be bled. This is done with a shallow cut on both sides of the tuna, through the slight ridge at the top of where the pectoral fin lies against the side of the fish. 

The next step is to remove the heat from the middle of the tuna before it starts to destroy the quality of the flesh. To do this, gut the fish and remove the gills, then place the tuna on its back and pack the body cavity with plenty of ice. Alternately, an even more successful technique is to put your bled and gutted/gilled tuna in a cooler or insulated fish storage bag and then add lots of ice and just sufficient seawater to create an ice slurry. An ice slurry is the best way to reduce internal heat and preserve premium-quality tuna meat for your future enjoyment.

For a short video on this, visit panaquatic.com/projects/fishing-for-tuna, and for more detailed videos and instructions on ikijimi, bleeding tuna, how to chill them, and how to fillet and prepare your tuna meat, visit the Tuna Champions website at: tunachampions.com.au

Now a parting thought — tuna are precious, so please harvest only one large fish per boat per day, and respect what you take. Carefully release the rest, preferably with a research tag, so there are plentiful stocks for the future.