Sailors get close look at a giant of the deep

An Auckland man and his friends thought they had spotted a whale when they glimpsed what turned out to be a giant manta ray.

Tim Allen, 24, was sailing between the Mokohinaus Islands and Great Barrier Island when he spotted the creature about 10m away from his boat.

The English language teacher grabbed his camera to video the ray, which was about 4m wide.

It was near the surface and doing loops in the water within a cloud of plankton, Mr Allen said.

"It was just cruising along the surface in the sun ... we thought it was a whale, it was that big. It was amazing," Mr Allen said.

Department of Conservation marine scientist Clinton Duffy said most New Zealanders were not aware that manta rays were regular visitors to New Zealand waters.

While they were here, they were a protected species.

"There have been a few sightings already this year," Mr Duffy said. "Game fishermen are the people most familiar with them, because they tend to be found further out to sea."

Timothy Allen filmed the giant manta ray feeding on the surface only 10m from his boat. Photo / Greg Bowker

The looping action Mr Allen had seen was common when the manta ray was feeding.

"They hit a patch of zooplankton, and then they keep circling back on themselves to stay in that patch."

The largest reported giant manta ray were 9m across, Mr Duffy said.

"Four metres is an average size for one sighted in New Zealand.

"They have been reported at up to 7m in the Bay of Plenty and out off Great Barrier Island."

Giant manta ray

*Average life span of 20 years.
*Close relatives of the shark and also closely related to the stingray, but doesn't have a stinger.
*Grows up to 9m across - surpassed in size in the marine world only by sharks and whales.
*Regularly migrate to New Zealand waters, where they are protected under the Wildlife Act.