KEY POINTS:
Spear fishermen stalking bluefin tuna around trawlers in the deep Hokitika Trench off the West Coast have been warned they could be risking death.
The new adventure thrill occurring about 55km out to sea is reportedly even attracting people from overseas, says Maritime New Zealand spokesman Steve Corbett.
The tuna, worth $30,000 to $40,000 each in the Tokyo markets, weigh up to 300kg.
They are being speared by fishermen as they chase hoki being caught by trawlers.
"These adventurers head out from Greymouth and take their boats to the trench area and the large factory trawlers," Mr Corbett said.
"When they get there they go into the water with spearguns and try to catch bluefins feeding around the trawl nets being hauled aboard."
But Marine NZ has a serious warning for spearfishers.
"It's not illegal and we can't stop you, but it's bloody dangerous," Mr Corbett said.
Spear fishermen risked entanglement in nets as well as the more obvious hazards posed by trawler propellers.
"Divers should stay clear of the trawlers at least until the entire trawl net is on the surface.
"Skippers should be aware that the trawler may turn, speed up or slow down or re-deploy the net at any time, so they must ensure that someone is always keeping a good watch."
Mr Corbett said the challenge of catching tuna was apparently considered a great thrill and the latest adventure.
Maritime NZ first heard of what was going on from trawler skippers and other industry sources late last year.
Fishermen from other parts of New Zealand were apparently going to Greymouth to get in on the act.
It was normally impossible to spear bluefin tuna, because they did not visit shallow coastal waters.
But their presence around fishing fleets gave fishers the opportunity to catch the big fish.
Recreational fishers could catch the tuna, but they could not sell them despite their high value on the Japanese and other markets, Mr Corbett said.
"That would be totally illegal."
He said Maritime NZ urged people taking part in the tuna fishing to wear and use the right equipment - and be very careful.
- NZPA
