Southern Bluefin tuna fishing

Southern Bluefin tuna fishing

A few weeks ago, I received an email enquiry from a small group of visiting anglers asking if I could help them catch southern bluefin tuna. These Gisborne anglers were due to fish off East Cape, where they hoped to target albacore, bluefin tuna and whatever else might be firing at the time.

Southern bluefin tuna have been eaten by humans for centuries. However, in the late 1970s the demand and price for bluefin sushi soared worldwide, particularly in Japan, with foreign commercial tuna long-line operations setting up shop throughout the Pacific, including the eastern and western coasts of New Zealand. Southern bluefin tuna are targeted in New Zealand by a small domestic long-line fleet, largely based out of Napier and Tauranga. By far the greatest proportion of the Total Allowable Commercial Catch (TACC) is taken by tuna long-line fishermen working the east coast area between Gisborne and White Island.

There is also a small number of commercial operators who target bluefin on hand-lines off Greymouth and Westport, but they are very few compared to the surface long-line fleet fishing around our EEZ almost year round.

The New Zealand bluefin tuna fishery was first developed by licenced Japanese tuna-fishing vessels in the early 1980s, almost at the same time as New Zealand tuna boats entered our fishery.

The Japanese caught a lot of pelagic fish that the majority of the New Zealand fleet hadn’t even seen before, let alone targeted. The bulk of the catch comprised: blue sharks (about 35%); albacore tuna (18%); southern bluefin tuna (12%); and bigeye tuna (2%). The rest of the longline shots caught anything from mako and porbeagle sharks, to lancetfish and oilfish, broadbill swordfish, moonfish, butterfly tuna, slender tuna, and so on.

Fishing for bluefin tuna in New Zealand waters in the early ‘80s threw up problems for the Japanese fleet, as they continuously found themselves operating in all weather and sea conditions to try and discover the different migratory routes undertaken by these tuna when entering and leaving New Zealand waters.

The Japanese first started fishing operations off the Otago Peninsula in the early 1980s, where much of their effort was focused on the early summer of 1981 off Timaru and towards the Canterbury Bight.

Although the Japanese knew the area had potential, the bluefin were too small and skinny for their liking. It wasn’t until the tuna started migrating north into the east coast fishery off the Wairarapa and Gisborne coasts that they really started to pile on condition and became a better commercial prospect.

The migratory patterns of southern bluefin into the East Cape fishery and on to the Bay of Plenty is an interesting one, especially due to the diversity of fisheries out there. Consequently, there are some really exciting fishing opportunities for big-game fishers wishing to pursue these fish; those anglers targeting bluefin off Waihau Bay and Whitianga in recent times are only just scratching the surface. There are also butterfly tuna between 20 and 30 kilos, broadbill swordfish, moonfish, some rather large squid, winter-run albacore of anywhere between 20 and 30 kilos and, of course, bluefin tuna, which can be fished for through to the end of August.

Little has been written about the movements of southern bluefin tuna in New Zealand waters, and often what is published seems contradictory. Whilst the bulk of the Total Allowable Commercial Catch (TACC) is captured by the northern domestic long-line fleet off Gisborne and Tauranga, bluefin also feature in long-line captures off Great Barrier and Cuvier Islands, out wide off Whitanga and, to some degree, up and down the whole western coastline of New Zealand.

While speaking with an old friend of mine, ‘Ding’, who was the engineer on the Nelson-based tuna long-liner The Daniel Solander, he told me they used to catch tuna as far south as the Auckland Islands, 300 nautical miles south of Bluff. They also took southern bluefin from the Challenger Plateau and off the Viti Canyons, which is southwest of New Plymouth. From there, they used to follow the bluefin tuna north, west of Raglan and the Kaipara Harbour, and then fish their way towards Lord Howe Island, and up into the Coral Sea off Australia.

In my 15 years of fishing, I have also seen my fair share of bluefin tuna. My first experience was as a crewman on a tuna long-line vessel in 2001. We would plan our trips well in advance, taking into account the weather conditions and the moon phase, before finally checking out the latest Sea Surface Temperature charts (SSTs) from NIWA. This allowed us to look for the various temperature breaks and current convergences, in conjunction with their chlorophyll charts, which were available to us at the time. (I will explain more about this, and a whole lot more about how to read these charts from a tuna fisherman’s point of view in a future edition of this magazine.)

In those early years, New Zealand’s domestic fleet would head well out wide, visiting the offshore seamounts and knolls off Tauranga and Whitianga. Many of the tuna encountered were big ones well in excess of 100 kilos, and at the time they were certainly within the range of recreational game fishers, providing they had a big enough boat to safely cope with the ever-changing weather conditions.

It wasn’t just the tuna which caught my imagination at the time though; I was also fascinated by the by-catch comprising the species mentioned earlier. Again, we used to catch many of these fish much closer to shore than most people would believe.

One season we were landing bigeye tuna off Whitianga in October, and not one recreational vessel was out there chasing them. I also recall the time we had a big run of winter albacore on the Papamoa Knolls in early September, which were all between 20 and 30 kilos, not far from Mayor Island. It’s another example of what can be out there if you put in some time and effort.

For those of you who might have the chance to get out wide over the next month, I have profiled four locations that should be well worth a look, both now and later during the more traditional game-fishing season. And if you can’t make it happen right now, plan ahead for next year around late June through into August.

Where to start looking

Area 1: The Colville Knoll

GPS position: 36’ 10.4’S 176’ 47.8’E

Location: 48.8 nautical miles NNE of Red Mercury Island

Located 48 miles northeast of the Mercs, this offshore knoll has the biggest and best reputation for southern bluefin tuna – period.

From my experience, the best months to fish the area tend to be from mid-June till late July, with productive fishing continuing well into August some years. In 2001 we captured a northern bluefin in the area that went well over 200 kilos in February.

Apart from commercial long-liners, this area receives very little attention from recreational game fishers because of its distance from shore.

Bigeye tuna can also be found here and on the Colville Canyon, which is only a few miles to the north, and big swordfish are a real possibility as the year progresses.

This area is really the domain of the bigger launches; it’s a 2.5-hour run out to the grounds steaming from Red Mercury Island at 18 knots, and it can cut up rough out here quite quickly. However, again, this area really does have potential.

Area 2: The Mercury Knoll

GPS position: 36’31.8’ S 176’30.9’ E

Location: 28.5 nautical miles Northeast of Red Mercury Island

I have caught broadbill out here in the Alderman Trough, and have also encountered bluefin tuna jumping and feeding here.

To the southeast is the Alderman Knoll, where we have caught bluenose and broadbill swordfish deep down, as well as around the Alderman Rise area.

Area 3: West Ngatoro Knoll

GPS position: 36’58.0’S 176’ 51.6’E

Location: 33.2 nautical miles off Mayor Island

If we are fortunate enough to get a weather window, the fishing gods will send us down a good winter run of big albacore tuna. Potentially in excess of 25 kilos, these albacore are a true sporting proposition for any serious angler.

Over the years, Tauranga Sportsfishing Club members have captured them in close off Mayor Island and on the Alderman Rise in September, with some specimens close to 25 kilos in weight.

However, commercial fishermen have captured them even bigger out on the Ngatoro Knolls.

It’s roughly a 33-mile run out there from Mayor Island, and bigeye tuna can be found swimming around in this area from about mid-November.

With a flotilla of boats present here, some interest should be generated shortly, as the bluefin are due to pass through at any time now.

Area 4: East Ngatoro Knoll

GPS: 37’4.8’S 177’5.6’E

Location: 41.1 nautical miles E-NE of Mayor Island

With bluefin tuna being caught by recreational game fishers off East Cape in late June, it should be a happening thing at East Ngatoro Knolls until the end of July/early August.

This is another top spot to catch bigeye tuna in November, and we caught broadbill here, too.

The knoll itself rises from a depth of 1250 metres to around 626 metres at the top.

   This article is reproduced with permission of   
New Zealand Fishing News

August 2017 - Ben Carey
Re-publishing elsewhere is prohibited

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