Last winter’s amazing tuna run off Waihau Bay dominated social media and just about every fishing magazine covered it, but to see some 130 trailer boats and their crews get out of their comfort zone and head out wide off Waihau Bay during the middle of winter was still remarkable.
Seeing the majority of anglers working together to help each other find the tuna really is the stuff pioneering legends are made of.
Here in New Zealand, the southern bluefin tuna fishery seems to be getting bigger and stronger by the year, with a few oddball species thrown into the mix. As recreational fishers, we have only just scratched the surface.
These fisheries have been going on literally forever but have been the preserve of the surface longline fleet, largely based out of Gisborne and Tauranga.
This article explains a bit about the fishery with a wrap-up of last winter’s season and some idea as to what we might expect this year.
Marlin are definitely in our waters year-round. As proof, Andre Alexander, fishing from a local surface-longliner, captured a striped marlin whilst targeting broadbill swordfish and tuna last August, in the middle of winter.
Tutuaka-based recreational fisher Kyle Ridling will agree, having been involved in the capture of the first marlin of the NZ Sport Fishing Council’s season in early July for the past few seasons.
The reason we sportfishers are not capturing them in winter is simply that not enough of us are out there targeting them. Sure, there are obviously fewer of them in winter, but I wouldn’t be at all surprised to see striped marlin off the Three Kings Islands or North Cape on a regular basis during any month of the year – provided offshore currents are still pushing towards Northland.
A striped marlin was caught two years ago at the same location and the same time of the year as last year’s fish. It was caught out wide off Whitianga at the Double Knolls in 16.2-degree sea surface water temperature. There was another one caught off Mayor Island last year by another commercial operation in September.
What a lot of people don’t realise is that not all striped marlin head up to the Fiji Basin, but can actually be found swimming inside New Zealand’s exclusive economic zone (EEZ), which extends 200 nautical miles offshore.
As fellow commercial fisherman and tuna skipper Tony Walker (TK Offshore Fishing) rightly points out, “We do have striped marlin out here, yearround, but they swim around out wider on the offshore seamounts and knolls.”
I also recall chatting with Northland charter boat skipper Chris Brittain of Tagit fame and telling him about an August trip about 13 years ago off North Cape with Garry Coles on the Girl Isabell. On that trip, we released three striped marlin 17 miles from North Cape in 17-degree water!
The run of southern bluefin tuna (SBT) off East Cape and Waihau Bay last year took everyone by surprise. It proves, though, that there really is a solid game fishing option for the winter.
Whilst both the commercial and recreational fishers were cashing in on the SBT run, the month before saw a by-catch of some very large albacore tuna. Caught by a surface longline vessel, some of these albacore exceeded 30kg with one going 40kg. They were taken in the same area that recreational game fishers were catching southern bluefin tuna in July.
Just to show you how close recreational anglers were to catching these albacore, by the time the first recreational anglers showed up off Waihau Bay they had missed out on that run of big fish by just one week! By the time everyone else dropped what they were doing and headed for Waihau Bay, that first run of really big albacore had already passed through the East Cape region; the second wave of fish had smaller 20-25kg albacore thrown into the mix.
The biggest albacore I have heard of, caught by a tuna longliner, was a 52kg model in the early 2000s, but that was captured a long way out, north of White Island.
From about mid-May and right through June, the surface longline fleet usually gets into some seriously big butterfly tuna. I don’t know of many game fishers who have actually targeted these tuna, but they readily take lures. I’d say it’d be a real buzz to catch one, as these tuna average 25-30 kilos with a few bigger fish thrown into the mix.
Butterfly tuna are definitely fantastic eating, yet you don’t see them in the fresh fish markets as they are worth absolutely nothing to commercial operators. There’s actually a bit of a story here, which involves an ex-commercial tuna skipper friend of mine back in the early days.
He thought he had hit the motherlode of all jackpots when he caught a bunch of the damn things and he actually got his crew to trunk and dress the lot, ready for export to Japan, only to have the whole boatload rejected at the wharf in Tauranga!
When I worked as a crewman in my earlier days, butterfly tuna were a regular by-catch when targeting southern bluefin tuna and they were often in the company of both albacore and moonfish. They are found throughout the southern hemisphere and definitely prefer cooler water temperatures.
Apart from the southern bluefin tuna, the tuna fishery receives very little attention from the recreational fleet, perhaps because of its distance from ports, or the weather, or a combination of both.
This year, if anglers get out there just a little bit earlier, they may well get a good opportunity to target these big albacore and butterfly tuna, because the fish are always present, often alongside the southern bluefin tuna run.
As this edition of the magazine hits the shelves, the tuna longline fleet will be well on its way to catching its southern bluefin quota out wide off Napier and Gisborne.
In New Zealand, southern bluefin tuna nearly always arrive in waves – separate schools of tuna swimming up behind one another. In general, they arrive first off Greymouth in February and March, after making a long journey across the Great Australian Bight, around Tasmania, across the Tasman Sea and on to New Zealand.
They then follow the coastline south, cruising past Fiordland and Milford Sound, where they feed up large on hoki and squid, before heading around the bottom and up the South Islands’ east coast. They feed for a while off the Canterbury Bight before entering the Hawkes Bay fishery in May.
This year southern bluefin started arriving off Greymouth in late January, where the local albacore commercial trolling boats were catching smallish 25-30kg fish.
To give you an idea of the scale of the tuna migration, a southern bluefin tuna tagged and released by Ben Croughan at the Saunders Bank in South Australia on February 7, 2015, was later recaptured off Hawkes Bay by a commercial tuna longliner on June 6, 2017. This tuna – 18kg and 100cm long when it was tagged – had been at liberty for 850 days and covered a total distance of 1894 nautical miles. It had travelled east-southeast from South Australia and was recaptured off the North Island’s east coast weighing in at 35kg and 118cm in length.
This is the third fish I know of from the New South Wales gamefish tagging program that was recaptured in or near the East Cape fishery, showing that these southern bluefin really are covering the miles and definitely following the trans-Tasman route.
Where the southern Bluefin tuna head next is anyone’s guess.
Two years ago, the surface longline fleet was catching bluefin tuna out a lot deeper and wider off East Cape in an area known as the ‘Hot Patch’. This is a nice body of water between East Cape and Waihau Bay, about 35 miles offshore, where cold water currents from the south meet warm water currents from the north. It is fairly much out of range for the trailer-boat fleet, but last season all of the stars aligned, and a phenomenal run of tuna came in much closer to shore, off Cape Runaway and Waihau Bay in 1500 metres of water.
Once the southern bluefin start arriving off Cape Runaway, the general trend is for them to swim west into the Bay of Plenty off White Island, around the East Ngatoro Knoll. Then they head north, up past the Colville Knolls.
Last year, sportfishing club members from Tauranga and Mt Maunganui were still catching southern bluefin tuna at East Ngatoro knoll at the end of July. They are more usually there in June and July, on most the offshore knolls in the Bay Of Plenty, after swimming around Cape Runaway. At this stage, the schools are scattered and the fish not as concentrated, so boats out on the water are what’s required to find them.
Last year, the first three weeks in July was definitely a wild ride for the Waihau Bay Sportsfishing Club, with the power of social media drawing anglers from all over the country seeking to catch their first bluefin tuna. If we have fish concentrated this year like we did last, there are a lot of anglers who can expect to catch their first southern bluefin tuna. But then again, who’s to say these tuna won’t run 40 miles further to the north, like they have done so many times in the past, well out of the reach of most recreational fishers. The southern bluefin tuna schools are fickle like that and no year is the same as the last.
If you are like me and plan on targeting southern bluefin tuna this June and July, here are a few pointers to set you off in the right direction.
Being highly temperature sensitive, bluefin tuna swim around our waters trying to find the perfect combination of two or more things. One is current convergence, and another is a specific water temperature range. Bluefin tuna prefer cooler water – anywhere between 16 and 16.4 degrees C.
If you can match the ideal water temperature with areas of current convergence, it can really help you find tuna schools, as it’s these highways they travel on.
If you haven’t got access to a sea surface temperature chart, find someone who does! A current convergence zone is basically an area where two currents collide – where a stronger current meets a weaker one, for instance.
If the SBT swim out wide this year, I would definitely recommend looking at your SST and watching areas where two opposing currents bank up to create current convergence zones. This is where warm, low salinity water from the north and cooler, higher salinity water meet and mix. This is likely where chlorophyll will also start forming, so keep an eye on your sea surface temperature charts checking for temperature breaks as well as the presence and concentration of chlorophyll blooms.
As I write in late April 2018, the commercial fleet has caught very few bluefin tuna. A few have been taken off Hawkes Bay, but as yet not in great numbers. We have yet to see the first waves of fish move through.
As the season gets underway, be sure to check out the NZ Fishing News and Fishing.net. nz Facebook page for area happenings, and reports on the southern bluefin as they come in.
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