Southern Bluefin Tuna – Thunnus maccoyi – How to Catch – Video

Southern Bluefin Tuna – Thunnus maccoyi

by Allan Burgess

Southern Bluefin Tuna – Catches, Lures

The body of the southern bluefin tuna is almost round in cross-section. The first dorsal fin folds down into a groove on the back affording the fish an almost perfect bullet-like shape free of protrusions that would hinder forward swimming speed.

There is a caudal keel stabiliser at the base of the tail. There is also small finlets present between the second dorsal fin and the tail, and also between the anal fin and the tail. The pectoral fins are relatively short for a tuna. The body is covered with small scales.

Video: A group of Blenheim boys travel to the Bay of Plenty in New Zealand’s North Island for some magic Southern Bluefin Tuna action. The big tuna ranged in size from 70 to 120kg. Video courtesy of Nick Best.

The body colour is blue to black on the back and silver to white on the flanks and underside. Fish fresh from the water are a dark metallic blue. The finlets in the upper and lower surfaces near the rear of the body are yellow edged with black. The caudal keel is yellow on smaller fish and much darker on larger fish.

Southern bluefin from 70 – 120kg caught off Waihau Bay in the Bay of Plenty in July 2021. Photo courtesy of Nick Best.

The southern bluefin tuna is now classified as Critically Endangered on the IUCN Red List of Threatened species. Overfishing by commercial interests has greatly reduced their numbers to the extent that they are nowhere near as abundant as they were back in the 1970s.

This species can grow to a maximum length of 2.5m and weigh over 400kg. The southern bluefin is a large, fast-swimming migratory tuna found in southern oceans between 10 degrees South and 50 degrees South during the autumn and winter.

Its preferred temperature range is 10 to 22 deg C. The best New Zealand fishing grounds for bluefin tuna are off the West Coast of the South Island. During the summer months, schools are occasionally seen on the surface. These migratory schools usually contain fish of a similar size as they pursue squid, anchovies, sauries and pilchards.

The Solander Fishing Company, which operates in New Zealand, takes about 300 tonnes of southern bluefin tuna annually. The fish is carefully caught by long lines on the East and West Coast of New Zealand. The commercial season runs from March to September.

A bluefin tuna caught by Steve Smith off Fiordland, in New Zealand’s deep south. This is the fish species that every offshore angler would love to catch. Photo: Lex Coutts. Click on the image to enlarge. See also Cindy Hardy Fiordland Fishing Adventure.

Like other migratory tunas, the southern bluefin is able to maintain a body temperature up to 10 degrees C higher than the surrounding water temperature making it possible for them to make sudden extremely quick bursts of speed in pursuit of prey.

Big southern bluefin tuna have been taken off the West Coast of New Zealand’s South Island while drift fishing fillet baits in a burley trail. This method has proven successful as bluefin follows Hoki trawl nets to the surface.

Fishing Methods

Bluefin tuna are taken by anglers trolling Hexheads, Konaheads and Rapalas in offshore waters out from Westport and Greymouth. Strikes are more likely on tuna when lures are trolled on monofilament leaders instead of wire.

It also pays to keep the boat moving forward when a lure is struck as this often results in multiple strikes on other lures at the same time.

In general deep water ocean trolling for bluefin tuna is a somewhat “hit and miss” affair. The waters off the South Island’s West Coast are often rough, and there is almost always a considerable swell running. Look for surface activity signalled by the presence of mollymawk and shearwaters.

Expect bluefin to make a powerful surface run when first hooked that may take out several hundred meters of line. As the fish begins to tire it will most likely go deep and slug it out well beneath the boat circling in an anti-clockwise direction. On lighter lines, this battle can easily drag on for many hours.

The flesh of the southern bluefin tuna is excellent to eat and is much prized in Japan, particularly fish caught late in the season when the flesh has its highest fat content.

There is an article here about the possibility of farming southern bluefin tuna.

Bluefin Tuna Caught at the Entrance to Nancy Sound, Fiordland, on a Rapala Lure

Christchurch angler Paul Stewart with his big bluefin tuna taken at the entrance to Nancy Sound, Fiordland, New Zealand.

Christchurch angler Paul Stewart was fishing from a friend’s boat when he caught this monster bluefin at the entrance to Nancy Sound on Fiordland’s rugged coast back in 1995.

Rapala CD Magnum: Top 18cm Dorado, 14cm Blue Mackerel and 9cm Red Head.

At first Paul thought he had caught a yellowfin tuna. He had caught yellowfin before out off Tonga and was sure that the fish was this species of tuna. It would be rare indeed to take a yellowfin this far south.

As the crew had not long left Milford at the start of a six-day trip the fish could not be kept whole. It was estimated to weigh at least 100 lb. The big tuna had been gutted for the photo and Paul could only just lift it.

The fish was taken on the line dividing the dirty brown water coming out of the Sound and the blue water beyond. It crashed the blue Rapala CD18 and put up a great fight before being boated.

Paul relates that the only way to tell if the fish was a bluefin or a yellowfin would have been to keep a liver sample for later identification. According to Paul, it made excellent eating. Congratulations Paul – what is a magnificent fish!

This magnificent 110kg southern bluefin tuna was taken on a Pakula lure by angler Ron Grant, off Fiordland in April 1997. Photograph courtesy of Sam Mossman.

Southern Bluefin Tuna – Thunnus maccoyi – with Gary Wilson


Exquisitely coloured blue-black above with silvery-white belly. The first dorsal fin is grey with a yellowish tinge, with 2nd dorsal a reddy brown and the anal fin silver. All other finlets are bright yellow with tinges of black. By far and away the largest of the tuna species present in South Island waters. The average size of this tuna species is 40cm to 1.5m and the average weight is 20 – 50kg although large specimens can reach lengths of over 2 meters and top a massive 180kg in weight.


The southern bluefin is a very large and powerful migratory tuna capable of swimming vast distances during the course of a year. This species has a broad distribution in the southern hemisphere and can be found in waters off the coasts of Australia, South Africa and New Zealand although – like most of our tuna its migration patterns and growth rates are poorly understood.

We know that the stocks present in New Zealand waters breed in the waters south of Java in the Indian Ocean and the juveniles migrate along the west and southern coasts of Australia and then on around Tasmania and into the Tasman Sea. By the time they arrive on New Zealand’s shores they have reached adulthood. Along the way, they have also been susceptible to heavy commercial pressure from both Japanese and Australian sources.

From here it is believed that the bluefin retraces its steps again making its way back to the tropics to breed.

Here in New Zealand, the bluefin is relativity common in South Island waters with it being present off both coasts for at least several months of the year. The primetime to locate southern bluefin tuna in West Coast waters is between the months of February and May. Whilst anglers searching for the less available East Coast stocks have to target the brief period between April and July, this is when a small run of fish make their way up the East Coast to around Kaikoura. This run appears to be fairly small and each year only a few fish are extracted from it. 

One year on the East Coast just four fish were taken – all of which were caught commercially. Testimony to the existence of this run is the mounted bluefin on the wall of the Cheviot garage. This fish was taken, as most are, on a long line, quite some years ago.

Chasing bluefin in the south of the country is an altogether different proposition. Here greater numbers of fish over the last few seasons have allowed the recreational angler the chance to tangle with one of these exquisite gamefish with a more than reasonable chance of success. ln fact over the last couple of years the norm has been for the average days fishing to produce not one but several shots of landing a fish and a good day could quite easily see 2 or 3 fish boated, which by anyone’s standards has to be great fishing, especially considering that only a short few years ago these fish were nearly non-existent off our coasts.

Chasing bluefin in the south of the country is an altogether different proposition. Here greater numbers of fish over the last few seasons have allowed the recreational angler the chance to tangle with one of these exquisite gamefish with a more than reasonable chance of success.

ln fact over the last couple of years the norm has been for the average days fishing to produce not one but several shots of landing a fish and a good day could quite easily see 2 or 3 fish boated, which by anyone’s standards has to be great fishing, especially considering that only a short few years ago these fish were nearly non-existent off our coasts.

The primary area for targeting bluefin in the deep south is in the wild and rugged waters off the Fiordland coast here the angler has the choice of chartering one of the local operators, or if they are really keen, trailering their own rig into either Milford or Doubtful Sounds, and motoring the 20 or so km out to the heads each morning before setting their gear. The drawback with the latter system is two-fold.

First, the weather which traditionally is extremely wet and wild and can lay the angler up in port for days at a time. The second problem is the need to be almost totally self-sufficient in every area. Food, fuel and tackle are not readily available so virtually everything required for the trip has to be brought in with you. It can be quite a logistical challenge getting fuel for a week’s fishing in such a remote area but the results are defiantly worthwhile. To tangle with one of these massive fish with our own gear has to be one of the ultimates in South Island angling.

Tackle for Southern Bluefin Tuna

Soft plastic squid lure bodies are ideal for bluefin tuna. They run straight causing fewer problems than bibbed minnows. A lumo stick can also be placed inside the squid’s body.

Here as in other parts of the world the primary method for the capture of these fish is by trolling. Although at times they will respond to both live baiting and chumming, most of the angling for bluefin in Fiordland is done by dragging hex heads, soft-bodied squid lures, Rapalas and other small to medium-sized trolling lures around, out in the open ocean outside the mouths of the sounds.

Lures with proven track records are Rapala CD 18s – blue and silver and mackerel colours, Yo-Zuri soft-bodied squids – brown and natural (see below). As well as Pukula Pushers in a large selection of colours. These are usually mated to a strong reliable rod and reel combos with Shimano and Penn being the front-runners here and the reels are generally spooled to capacity with line classes in the heavier end of the range with 15, 24 and 37kg being the most popular. I like the Shimano TLD-2 Speed.

The fight of a bluefin, like all tunas, is characterised by long hard scorching surface runs and plenty of deep, tough, and draining circling, and is guaranteed to keep the angler busy for at least an hour or more. Just a word of warning here a good reliable drag is a must when tangling with these fish but the angler must be careful not to apply too much pressure as most tuna have fairly soft mouths and if too much pressure is applied throughout a prolonged fight could quite simply rip the hooks out resulting in the loss of a good fish. So as a rule of thumb go a little easier on the drag when fishing the heavier line classes.

The eating qualities of southern bluefin tuna are well known. These are the fish that the Japanese pay megabucks for in the Asian fish markets and that is the primary reason that they were nearly fished into extinction in local waters a few years ago.

Thankfully the last few years have seen an increase in their numbers off our coasts due mainly to a decrease in international fishing pressure but this recovery is again under threat as the Japanese again threaten to destroy the bluefin’s fragile comeback by exceeding the international quotas specifically laid down to allow the bluefin breeding stocks to recover by again sending up to an extra 50 boats into southern waters some years to yet again over fish this species. Hopefully, international pressure and common sense will prevent this from happening before the mighty southern bluefin tuna is once again fished to the brink of extinction.

These 25cm Yo-Zuri squid lures have been a favourite lure for southern bluefin tuna and broadbill swordfish in New Zealand waters.
Everything you need to make up these very natural-looking squid lures for bluefin tuna. Note the Cyalume light stick which is placed inside the lure so that it glows in the dark. The eyes are also luminous and glow after being charged with a torch or camera flash, as do the luminous hair and green-coloured beads.
The whole lure is designed first and foremost to be super strong so as to be able to survive a long drawn-out fight with a huge bluefin tuna.
The hooks should not have a gap larger than the diameter of the lure body.
These naturally coloured Yo-Zuri squid lures look like real squid when trolled behind a boat.
Photograph: Murray Whyte with a Southern Bluefin Tuna he caught fishing off Fiordland, New Zealand.

First Southern Bluefin from a Kayak February 2022 off Taranaki

With no tuna being caught on my first trip to Taranaki, I had to make a return journey to have another go at the extremely rare southern bluefin tuna run down the West Coast of New Zealand’s North Island. By the second day of this 3-day trip I was well and truly at breaking point (following 3 previous days of 50, 40 and 50km paddles), but somehow I found it in me to push on, and I’m glad I did – I landed the first ever southern bluefin tuna caught from a kayak in New Zealand. Another dream fish ticked off on my kayak fishing adventures! Can’t wait for the next one.

This post was last modified on 21/09/2023 4:19 am

Leave a Comment
Published by

Recent Posts

How to Catch Fish and Where

How to Catch Fish and Where - The Complete Kiwi Beginner's Guide By Mike Rendle…


Fishes of Aotearoa by Paul Caiger

Fishes of Aotearoa (includes both fresh and saltwater fishes) By Paul Caiger New Zealand has…


Fishing the Tongariro – A History of Our Greatest Trout River

Fishing the Tongariro - A History of Our Greatest Trout River By Grant Henderson  Since…


Porare – Girella tricuspidata

Porare - Girella tricuspidata - How and Where to Catch Porare By Allan Burgess Although…


Jack’s Sprat Trout Fly

Jack's Sprat Trout Fly - An old favourite for targeting rainbow trout in the lakes…


Counting on it – Fish & Game staff checking on wildlife numbers to manage species

Counting on it - Fish & Game staff checking on wildlife numbers to manage species…