The shark was spotted by a lifeguard at Lyall Bay on Thursday afternoon and swimmers were told to get out of the water. File photo Photo: RNZ / Rebekah Parsons-King
A scientist tracking the movements of great whites says New Zealanders are showing interest in the prevalence of sharks.
On Thursday afternoon, a popular Wellington swimming beach was closed for two hours when a large shark made an appearance.
Wellington Council said the shark was spotted by a lifeguard at Lyall Bay about 1pm and swimmers were told to get out of the water.
Tauranga shark scientist Dr Riley Elliott said the length of a "large" shark depends on the species and who you talk to.
"That spreading of warm water down here may have redistributed some of that population" - Shark scientist Dr Riley Elliott
But experts believe a large great white, for example, could be 5-7 metres long.
"The closing of the beach is out of respect that there's a predator in the water but 99 percent of the time, these predators are eating fish and stingrays and just trying to catch a wave like us," Elliott said.
Conservation efforts was one of the reasons why sharks were more prevalent in areas not seen before, he said.
"We protected them for three decades, it makes sense they should come back in areas they once were and their population should increase."
Another reason was warming waters and changing ocean conditions were redistributing populations, he said.
"Southeast Australia is a stronghold for great whites of the south Pacific, and especially juveniles, so that spreading of warm water down here may have redistributed some of that population."
New Zealanders were showing interest in the prevalence of great whites, he said.
Elliott is part of The Great White Project which tracks the movements of great white sharks - one of his recent ones, Mananui, travelled from Tauranga Harbour and up near Doubtless Bay as of Friday morning.
It was a way to give us a better idea of their habitat range and long-term behaviour, he said.
"I used to get up in the morning and listen to you guys," he told Morning Report. "But now the first thing I do is look at my app and see where the great whites are because ... it's very addictive and fun and you learn every day."