KEY POINTS:
Warm ocean currents generated by La Nina have delivered a rare, colourful visitor to New Zealand waters.
A catch, understood to be a juvenile Pacific spotfin burrfish, was caught and photographed by Josh Worthington, Cole Whitehead and Blake Hardley on a spearfish trip to Bird Rock, near Cape Brett in Northland. The fish was spotted swimming along a blue water current line in a region where there were a large number of skipjack tuna.
Fishing enthusiast Craig Worthington, Josh's father, said he believed it was only the second sighting of the burrfish in New Zealand waters.
The fish can be identified by its blue tinge, dark spots, and short spines. It is inedible, as it has toxic internal organs which can be harmful, or even fatal, if consumed.
Josh Worthington said they managed to catch the burrfish because it swelled up in fright from the commotion the boys made in the water. Mr Hardley dived in when he saw the fish and captured it by hand.
Marine curator at Auckland Museum Tom Trnski said he was not surprised that the tropical fish was found in Northland waters.
"The spotfin burrfish has a long larval phase where it can be carried around in ocean currents. This phase can last for months, so it is not surprising it has carried this far, given the early arrival of warm currents."
Warm easterlies have blown on to the northeastern coast for much of summer, increasing the chances of tropical fish entering New Zealand's subtropical waters.
Mr Trnski said any tropical fish would struggle to survive in New Zealand waters once winter arrived.
Craig Worthington said game fishing enthusiasts reported larger numbers of blue marlin, mahimahi, and sailfish.
Large mahimahi are usually only found in the tropical Pacific.
