WILMA MCCORKINDALE IN DUNEDIN
An unknown scourge has been attacking the critically endangered species for the past three weeks, more than 50 found dead on Otago Peninsula.
DOC manager biodiversity David Agnew said the most likely scenario was that the penguins had been poisoned by toxins in algal bloom which formed in local seas during certain sea conditions.
Otago entered a period of unusually warm and humid weather conditions at the time penguins began dying.
However, toxin tests on the bodies of individual birds had returned negative results. No new penguin deaths had been reported during the past week, but the cause remained a mystery and needed to be explored, Agnew said.
Discovery of the cause of death was important for the future, he said. This was the second occurrence of its kind in the local population - the last such deaths were in 1990.
"It would be nice to know," Agnew said. "If it's something that is predictable then you could make some decisions because you know it's going to happen again."
Researching the cause, possibly comparing the weather and sea conditions during the two events, would be a good project for someone, he said. DOC, in conjunction with scientists, was now investigating the viability of carrying out more tests.
The deaths had been a major concern. The first dead birds were found on Peninsula beaches between January 21 and 23. Fifty-six yellow-eyed penguins have died.