Dr Malcom Francis, a fisheries scientist at NIWA, is recognised as one of New Zealand’s foremost experts on sharks and their behaviour. In the wake of the fatal shark attack at Muriwai Beach, he answered questions from the public as part of the New Zealand Herald’s Ask an Expert series. He will also be taking part in a live Q&A on the Stuff.co.nz website.
Excerpts from the NZ Herald:
As a keen scuba diver/spear fisher, what is the best action to take when coming across a shark in NZ while diving?
Sharks are rarely seen underwater by divers but they can be attracted to dead or struggling fish.
If you are spear fishing, remove dead fish from the water immediately and get out yourself. Sharks will key in on the sounds and smells of dead fish, and the latter linger long after the fish is removed from the water.
If you find yourself in the water with a shark and can’t readily get out, face the shark and keep your eye on it – sharks often use surprise in their attacks on prey and if they know they’ve been seen they may not think it’s worth an attack (because their prey are often more agile and can escape easily) or may realise you aren’t their normal prey.
Stay calm, don’t splash or swim fast, and try and get something between you and the shark – a rock, a speargun, camera, or anything else you can use to fend it off. If you are attacked, try and hit the shark on the sensitive snout or gills.
Is the reason why sharks come to places they do not usually go due to decreasing number of fish in the sea? Is the overfishing from the fishing industry part of the cause for this? (Kazuhide Shaun Okuda)
Sharks of various species occur throughout NZ waters. The larger species are mobile and continually cruise around looking for food, and hope to surprise their prey. So there aren’t many places where they don’t usually go.
During summer, sharks often come close inshore because their prey (often schooling fish) may aggregate in shallow coastal waters. There is no evidence that sharks have difficulty finding prey because of low fish abundance.