Sharks heading to our shores

Many different species are attracted to warmer waters to deliver pups. Photo / Supplied

If you go down to the beach today, you might be in for a toothy surprise.

Shark experts say a "myriad" of species are heading for our beaches and harbours as the weather heats up.

Rig, school, sevengill, thresher, bronze whaler and even great white sharks are moving closer to shore to drop their pups.

But unlike Queensland beachgoers, who are being warned of a "monster shark" lurking in the waters, swimmers here are likely to be safe because sharks generally don't feed when dropping pups.

Department of Conservation marine biologist Clinton Duffy said after pupping most sharks disappeared out to sea.

But over summer they will be feeding close to shore on smaller sharks and fish.

"As spring and summer progress there will be more sightings of larger sharks like bronze whalers and hammerheads," Duffy said. "Most hammerheads seen are juveniles about 1.5m long and they are no risk to people at all."

Thresher sharks, not dangerous to humans, would also make an appearance. "They have really tiny mouths, specifically to feed on small schooling fish.

"They are spectacular-looking animals though,"

But mako sharks could be a danger to boaties, Duffy said.

"Mako are particularly aggressive. They'll steal fish off lines and chase fish right to the boat. They are also known for their jumping ability.

"They are a popular game fish and they have incredible stamina. They can jump several times their own body length over and over and over. They could actually jump into a boat.

"Large mako are in excess of 3.5m and 450kg and they generally feed in deeper water well offshore."

Duffy said great whites were also lurking in our waters, but were not often seen by anyone other than researchers.

Last year there were no sightings by members of the public but researchers had a "bumper" season at Stewart Island. Thirty-two great whites were spotted in 11 days last year - almost double the number from the year before.

Duffy said paua divers in the Chatham Islands had regular encounters with "quite large" great whites. "Last year there was a report of a small great white in the Waitemata Harbour, substantiated by bite marks on a mooring buoy at Beach Haven," Duffy said.

"There are a reasonable number of juvenile great whites seen in the Manukau Harbour. They can be there at almost any time of the year. They come in to feed."

Duffy said school and rig sharks often frequented harbours around Auckland and Northland.

Hammerheads up to 1.5m long were known to inhabit waters around Northland and up to 3m long in the Firth of Thames and the Eastern Bay of Plenty.

Mako and blue sharks tend to stay off shore more than 100m deep, unlike bronze whalers which are regularly spotted around Matakana, the Coromandel and Tauranga.

Most sharks sightings reported to DoC turned out to be bronze whalers.

"They account for 90 per cent of shark alerts around New Zealand. But there has never been an attack associated with a bronze whaler.