'Monster' shark sightings could be of same beast

A "monster" white shark in the Manukau Harbour could be the same one that has terrorised people along the Taranaki coast - but experts say it is impossible to tell.

The Department of Conservation has issued a warning to swimmers around New Plymouth after several sightings of a large great white shark. The last sighting was last Friday.

On Sunday three fishermen were forced to abandon a catch near the Manukau Heads in Auckland when they attracted the attentions of a "monster" which was longer than their 6m boat.

DoC marine scientist Clinton Duffy said it was easily possible that it was the same shark.

"With a cruising speed of four to seven km/h they move long distances pretty fast," Mr Clinton said.

But he said it was "equally possible" that there was more than one giant great white in New Zealand waters. "The average size we see here is about 3.5 metres and they are often much smaller, which implies it is one and the same, but there are sharks moving through and on the coast all the time."

In Taranaki, people fishing from a charter boat got a fright when a great white swam directly under their boat.

A few days earlier, two competitors in a yacht race off Port Taranaki watched in horror as the shark - its fin clearly out of the water - swam between their small craft.

DoC programme manager Bryan Williams said: "This makes sense, because our fur seal population has just finishing pupping - and no doubt the great white has scoffed quite a few of them."

The department has postponed a two-week dive survey programme after the sightings.

In Auckland, the three anglers had hooked a mako shark and were battling to bring it in when they realised a much bigger great white was circling. It began to nudge the boat, prompting the men to free the mako and make a swift exit.

"We've seen and caught sharks before, but never experienced or seen anything like it," fisherman Mark Lane told the Howick and Pakuranga Times newspaper. "It was a monster."

Mr Duffy said the white would have been attracted by the struggling mako.

But the rash of sightings was common during summer and not a sign of an influx of sharks, he said.

"It's a combination of them moving in to breed and eat, and many more people being out enjoying the water in the summer and spotting them.

"Every single year people say there are more sharks about, but it's complete rubbish," Mr Duffy said.

"If anything there's less because of the numbers caught in fishing."