Three hundred endangered New Zealand sea lion pups in the Auckland Islands have died this season from a disease not yet identified , Conservation Minister Nick Smith says.
Results from autopsies on the pups were not yet known, so it could not be said if it was the Klebsiella pneumoniae bacteria that hit the population in the early 2000s, Dr Smith, who visited the islands last week, said yesterday.
While on the islands, he announced a threat management plan would be developed for sea lions.
There was an excessive focus on the fishing bycatch issue, he said.
''If we are serious about ensuring survival of the sea lions, we need to widen our area of interest.''
He believed more work needed to be done to test the efficacy of sea lion exclusion devices used in the fishery and to reduce accidental deaths in fishing nets, he said.
Speaking to the scientists and veterinary staff on the islands had highlighted the need for more work on the risk of disease and accidental death.
''A hard look needs to be taken at the opportunity to rid the main Auckland Island of pests, particularly pigs,'' Dr Smith said.
If the island was free of pigs, it would open up far larger areas for sea lions to breed in but it would require the largest island pest eradication programme New Zealand had attempted, Dr Smith said.
The largest island done so far had been Campbell Island's 11,000ha but the main Auckland Island covered 50,000ha and it would cost millions of dollars.
He has asked for a report on the logistical feasibility of such a programme.
This season's deaths showed the development of a vaccine or field treatment to prevent a disease from getting to epidemic level should also be researched.
Vets on the islands believed that sort of treatment was practical given sea lions did not get agitated by human approaches.
