Orange slick turns up on top beaches

By ELIZABETH BINNING on the Coromandel

A bright orange algal bloom has appeared at some of Coromandel's most popular beaches but experts say there is no need for holidaymakers to flee the water yet.

The highly visible orange mass, believed to be a non-toxic algal bloom, surfaced at Grays Beach, just north of Whitianga, as a large blob yesterday morning.

As dozens of people enjoyed the sun, surf and sand, the conspicuous mass, accompanied by several smaller blobs, bobbed on the surface of the water about 25m from shore.

They attracted some attention from local residents but they did not wash up on the sand or cause problems for swimmers.

However, further along the coast the mass attracted more attention from curious onlookers.

Rings Beach resident Pene Fox, who has holidayed in the area since she was a child, said the orange mass appeared about 11am.

She and her brother-in-law, Craig Steiner, used an inflatable boat to investigate the substance, which had settled in a line of about 100m by 5m, just out from the shore, near the popular tourist spot of Matarangi.

The couple returned with a bucketful of the thick murky liquid.

Environment Waikato water scientist Bill Vant said it seemed to be an algal bloom and was appearing in various parts of the eastern Coromandel coast.

A week before Christmas a Whangapoua resident notified Environment Waikato of a mass of orange, roughly the size of several cars, floating in the water.

In that case photographs were taken but no samples were gathered.

Based on those photographs and a description of yesterday's sightings, Mr Vant said the mass appeared to be a dinoflagellate alga called Noctiluca scintillans.

"I am reasonably confident that it is an algal bloom."

He said that such blooms, which occurred when the algal mass cells produced at a rapid rate, were not known to be harmful to humans and there was no need for concern.

But the cells did release toxins when they died, which could kill fish.

Mr Vant said such blooms were not uncommon at this time of the year, but many residents and holidaymakers said they had not seen anything like it in the region before.

Whitianga fisheries officer Gary McAneny said several boaties had reported seeing the orange mass floating out at sea.

One skipper said he had seen the blooms floating around the coast for about a week.

Coromandel bloom

The problem: Orange slick off beaches near Whitianga.

Suspected cause: Noctiluca scintillans, an algal bloom.

Likely effect: Harmless for humans but its toxins can kill fish.