Dolphin tagging 'low risk'

By JULIET ROWAN

Satellite tagging of Hector's dolphins is not bad for them, a preliminary report has found.

Three of the endangered South Island dolphins were captured and tagged in a three-month trial this year.

Opponents of the trial feared the tags would harm the dolphins.

But the preliminary report, released to the Herald yesterday, said the short-term risk from capture, handling and tagging appeared to be low.

It said the long-term risks also appeared acceptable, although further assessment of the dolphins involved in the trial would be needed in the next year.

The Department of Conservation (DoC) conducted the trial to find out if the technology could be used on the Hector's dolphin's close relation, the North Island Maui's dolphin.

Hector's dolphins are thought to number between 3000 and 4000, while Maui's are estimated at between 80 and 150 animals, making them one of the rarest dolphins in the world.

The three Hector's dolphins were caught and tagged in March. Two 7mm holes were drilled in their dorsal fins and the tags were attached with pins and nuts designed to corrode in sea water after three months.

The tags sent data via satellite on the dolphins' movements.

The report found the procedure was achieved with minimal bleeding and the dolphins showed no distress.

The report was compiled by experts from DoC; Auckland, Massey, and Victoria universities; the New England Aquarium; and Denmark's National Environmental Research Institute.

Auckland DoC head Rob McCallum said satellite tagging revealed more about the dolphin's behaviour than had been learned in the past 20 years.

But Otago University marine biologist Dr Liz Slooten, who has studied Hector's dolphins since 1984, said in June that the initial satellite data revealed nothing new.

Dr Slooten, the Royal Forest and Bird Protection Society and the Green Party opposed the tagging, fearing it could leave the dolphins vulnerable to infection.