DoC looked at delaying poison drop

The emails revealed fears that DoC could be seen as insensitive after a series of dog deaths on North Shore beaches. Photo / Greg Bowker

The head of the Department of Conservation told staff they should consider delaying rat poison drops on two Hauraki Gulf islands because of public worry about a link to dog deaths.

Emails released to the Herald under the Official Information Act reveal Director-General of Conservation Al Morrison asked his North Island manager to "seriously consider" postponing the third and final helicopter drop of Brodifacoum on Rangitoto and Motutapu islands, after learning that dogs, fish and marine animals had died in the harbour.

"It [the drop] will likely attract attention and look incredibly insensitive," said the email to Northern manager of operations Barbara Browne on August 5.

Mr Morrison said yesterday that, while he was worried about public perceptions, he was always confident that there was no link between the operation to rid the islands of predators and the dog deaths.

The drop went ahead with his blessing the day after the email was sent, after the Medical Officer of Health, Ministry of Agriculture and Forestry and Auckland Regional Council said they had no concerns about it proceeding.

The dog-killing toxin was eventually found to be tetrodotoxin - a naturally occurring substance found in sea slugs taken from North Shore beaches.

Councils and government departments ruled out Brodifacoum early on, however the timing of the deaths during the same weeks as the bait drops led to speculation the bait was involved.

An email from Auckland Conservator Sean Goddard reveals he, too, initially thought the drop should be delayed.

But after discussing it with other agencies he was "more confident than ever" there was no link and that the drop should go ahead.

Results of tests on the stomach contents of a beagle that died after walking on a North Shore beach, supplied to the Herald, found no traces of Brodifacoum.

Tests on dolphins that died in the Hauraki Gulf during the same weeks are still being done, however the scientist that did the autopsies has said there was no evidence of internal bleeding - the tell-tale sign of Brodifacoum.

The aim of the drops was to blitz introduced predators and create a safe haven for native birds on the popular islands, 9km from downtown Auckland.

In an email to Mr Goddard the day after the final drop, Mr Morrison congratulated staff on a "monster achievement and a world-class operation".

An early feasibility study said the project to clear stoats, cats, hedgehogs, rats, mice, and rabbits from the 3842ha islands was the most challenging and complex attempted by DoC.

Mr Morrison told the Herald he had no concerns about the technical aspects of the operation, "however I was concerned by attempts to link the deaths to the operation, and the possibility that going ahead at that time would create further confusion".