Giant sharks take a liking to NZ seas

By ROSALEEN MacBRAYNE

The whale shark - the common name for the world's largest fish - is being seen more often in New Zealand waters where it was once a rarity.

Considered to be a tropical species, the mighty sea-fish are becoming regular summer visitors to the northeast North Island, says Department of Conservation marine ecologist Clinton Duffy.

Only three to five sightings a year were reported in the mid to late 1990s. This year, 11 had been seen at Waiheke Island, Rangaunu Bay, the Bay of Islands, Tutukaka and the Western Bay of Plenty.

On January 28, Whangarei freelance photographer Pete Atkinson took the first known underwater photographs of a whale shark in the seas around New Zealand, off Tutukaka, in Northland.

In 28 years of photographing fish, he had never seen one before.

Mr Duffy, who has published a paper on whale shark sightings and would like more information, said the species had been seen from the Three Kings Islands to Te Kaha.

In the Eastern Bay of Plenty, the area off Whakatane between Rurima and Motuhora (Whale) Islands and White Island seemed to be a favoured location.

Several had been seen feeding on schools of anchovies there.

Those sighted in New Zealand ranged from 3.5m to 15m long. Most were between 6m and 9m. Whale sharks, which are harmless to humans, reach a maximum length of about 18m and can weigh more than 15 tonnes.

Most were spotted in February, but sightings ranged from November to April, said Mr Duffy, who is researching the presence of whale sharks around New Zealand to help develop a better understanding of them.

He would like anyone who sees one to let DoC know.

Divers were in a position to provide valuable information on the species, he said.

Details such as the estimated date, location, length, sex (males have a pair of elongated claspers on the inside of their pelvic fins), water temperature and behaviour were particularly useful.

Photographs of distinctively marked or scarred whale sharks could also be used to identify fish seen more than once around New Zealand or elsewhere in the Pacific.

Big eaters

* Whale sharks are filter feeders, sieving their tiny food through their large gills.

* As the shark swims with its mouth open, it takes in water filled with prey.

* After closing its mouth, the shark uses gills that filter the nourishment from the water. Anything that doesn't pass through the gills is eaten.

* The prey includes plankton, krill, small fish, and squid.

* The shark can process 6000 litres of water an hour.

* Contact Clinton Duffy.