Sharks fans of El Nino conditions

El Nino is bringing a shift in temperature to coastal waters this summer that is expected to draw out more fish life — including more sharks.

Marine scientist Riley Elliott said La Nina, in place over New Zealand for the past three summers, tended to warm the water, whereas El Nino conditions tended to cool it — by about 5C.

“It drags up water from our depths as it has the pull-up, like the conveyor belt, from New Zealand to Chile, and that creates upwelling of nutrientrich water that’s cold but creates a lot of [activity].”

At the beginning of summer there had not been nearly as many shark sightings as the same time last year, Elliott said. But where there were more fish, sharks would follow. However, that did not necessarily mean more shark attacks.

Sharks, especially those such as bronze whalers, do not pose a huge risk to people unless they overlap with fish — drowning statistics significantly outweigh shark attacks, he pointed out.

But there were things people could do to reduce the risk of an attack.

Swimmers should not swim where people are fishing and fishers should avoid throwing fish carcasses overboard.

Department of Conservation marine scientist Clinton Duffy said the most important thing to do with sharks was to stay calm.

“If you’re in the water, obviously you’re going to get out of the water as quickly and as quietly as possible. If you’re scuba diving, you should stay on the bottom, keep an eye on the animal and don’t attempt to leave the water until it has moved away.”