Wed, 02 Sep 2009 12:00a.m.
Necropsy (fish autopsy) tests on the dolphins to date indicated that the deaths were not related to brodifacoum
Toxicology tests will be carried out on the dolphins that died recently in the Hauraki Gulf.
In the face of growing public concern the Department of Conservation has commissioned the tests to determine how the dolphins died.
Necropsy (fish autopsy) tests on the dolphins to date indicated that the deaths were not related to the rat poison, brodifacoum, used by DOC in its recent restoration programme on Rangitoto and Motutapu islands.
DOC Auckland area manager Brett Butland said today Massey University held samples from the dead dolphins and DOC was working with Massey marine biologist Karen Stockin on testing to identify the cause of the deaths.
"While we are confident that brodifacoum has been ruled out as a cause of death, we are conscious of the level of public concern surrounding this issue.
"As a result, we have commissioned further chemical tests on the dolphin, penguin and pilchard samples that will specifically look for brodifacoum poisoning," Mr Butland said.
Independent toxicology tests that DOC commissioned on vomit from one of the dogs that died at Narrow Neck beach had already proved negative for brodifacoum.
Tests done by the Cawthron Institute have identified the toxin found in the vomit of a dog that died after visiting Narrow Neck Beach as tetrodotoxin, Mr Butland said.
Tetrodotoxin is a naturally occurring substance, found in tropical puffer fish, and has also been found in sea slugs taken from the beach.
Penguin deaths have been reported in the Far North, Rodney, Auckland, Coromandel and Bay of Plenty regions. Penguin deaths in winter, particularly following winter storms, are not uncommon for this time of year, he said.
The New Zealand Centre for Conservation Medicine had conducted post-mortems on six penguins to date, and had found that the birds were in poor body condition and that starvation was the likely cause of death.
Post-mortems on the penguins showed that none of the birds showed "any sign of a haemorrhagic effusion consistent with rodenticide poisoning".
"Each of the birds was very thin and their stomachs were empty, consistent with starvation being the cause of death."
NZPA
