There’s been one species that has captured the imagination of many Kiwi anglers over the past few months – the yellowfin tuna. It started with whisperings of commercial boats catching in mid-spring north of the Bay of Islands. By the end of November, the recreational fleet was getting stuck in with tales of busting tuna and multiple hookups. By mid-summer, there were all sorts of crazy stories involving topwater explosions next to the rocks, kayaks, jetskis, and landbased anglers. And of course, social media feeds have been inundated with the inevitable ‘food porn’ updates of yellowfin sashimi, ceviche, and poke bowls.
So, what’s behind this season’s bumper crop of yellowfin tuna? There’s plenty of speculation out there, including reduced commercial fishing pressure in the Pacific Ocean during the COVID-19 pandemic.
When we asked Blue Water Marine Research’s Director John Holdsworth, a fisheries scientist with decades of experience working on highly migratory gamefish species, he suggested there was nothing concrete to point to, although he kindly gave some insights.
“This season there’s been a nice mix of sizes, which isn’t typical. To have larger ones here at the same time as the smaller grades is encouraging.
“In La Niña years, the warm pool in the Western Central Pacific warms up and some tropical tuna move further to the east. That’s potentially one factor – it’s not a strong La Niña, but it’s likely to continue until April. There’s clearly lots of food for them here, too.
“There’s a large commercial yellowfin catch in the Western Central Pacific. The tagging studies conducted – mostly around Nauru, Indonesia, and New Caledonia – have shown that few tagged fish move down to our waters from those big purse seine fisheries.”
John has a theory that most of the yellowfin that arrive on our shores come from international waters to the north of New Zealand, such as the Fiji Basin, where commercial fishing is largely unregulated and the use of commercial Fish Aggregating Devices (FADs) tends to increase the catch of juvenile yellowfin and bigeye tuna.
“Although there’s not much tagging data from the Fiji Basin, when the catch went way up in that area that’s when we saw the big decline. Heavily fished species suffer range contraction – you see that locally with hāpuku, which are rarely caught in shallow water anymore.
“You have to remember that yellowfin used to be the most frequently caught gamefish in New Zealand in the early ‘90s.
“The smaller yellowfin we’re seeing probably came from good recruitment – they mature at two or three years old, and can spawn year-round in the tropics when the water is over 26°C. Perhaps there’s been favourable conditions north of New Zealand over the last few years, and the fish have taken advantage of that.”
Eminent ex-charter skipper and salty gentleman Rick Pollock says New Zealand is experiencing “the best yellowfin fishing in living memory.”
That’s quite a statement from a man who spent the bulk of his life at sea and fished the halcyon ‘meatball’ yellowfin tuna days off Whakatane decades ago.
“During the golden years of meatball action out from Whakatane, we could catch as many fish between 25-40kg as you’d like. However, a 50kg fish was considered a trophy. This season, we’re seeing almost daily social media updates of 60-80kg fish being landed.”
- Nick Jones
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