Kiwi fish are causing a stink overseas.
At the heart of the scandal is the snoek - thyrsites atun - known here as barracouta.
South Africa's City Press newspaper reported Kiwi barracouta was being sold in that country as snoek.
Associate Professor Mafaniso Hara from the University of the Western Cape told the Herald on Sunday there were growing concerns over a lack of transparency. Hara said fish processors were buying the barracouta but just how much was unclear.
"One of the things that we've been grappling with is actually how much 'snoek' is coming from New Zealand."
City Press said New Zealand exported more than five million kilos of barracouta to South Africa in 2010.
Hara, a snoek expert, said the issue had prompted calls for South Africa's government to ban barracouta being traded as snoek. Hara's colleague Dr Moeniba Isaacs told City Press that snoek should be trademarked as a culturally important name used only for fish caught locally, much the same as Champagne meant sparkling wine exclusively from the French region of Champagne.
Adventure Fishing Charters owner Phil Scott, of Waiheke Island, said barracouta were not a popular eating fish in New Zealand.
Globules of fat and parasitic worms put people off. But Scott was aware of snoek popularity overseas. "I've had South Africans out with me and they talk about it all the time."
Scott said exported barracouta would be worm-free.
"I'm not surprised somebody has found a way of making money out of this because it is a very lucrative (business). They're making money out of our unwanted fish."
The Ministry of Primary Industries referred questions on barracouta exports to Seafood New Zealand, which did not return calls. Snoek and barracouta are a different species from barracuda.