Wellington, Feb 5 - Scientists still have not identified the cause of the death of hundreds of rare New Zealand sea lions on the Auckland and Campbell Islands but the region was closed to tourists today as a precaution.
Conservation Minister Nick Smith said the sub-Antarctic islands, which were due to be visited by one domestic and two international tourist boats this month, would be reopened when the situation had returned to normal.
Thousands of sea lion pups have been found dead on and around the islands, which are breeding grounds for the threatened species.
Massey University scientist Per Madie said more results had been expected today but there had been ``hiccups'' in the testing.
Tissue samples had been cultured and a bacterial-agent found but it was not yet possible to say if it was the cause of the sea lion deaths.
A diverse array of tests would be carried out over the weekend and the earliest the results would be known was Monday afternoon.
Dr Smith said the islands had been closed because it was wise to be cautious. If the cause of death was bacterial, rather than a virus or biotoxin, there could be a risk to humans.
This would also reduce the risk of tourists spreading any disease.
Meanwhile, there has not yet been any link found between the sea lions deaths and the emergence of toxic algae in some coastal areas, although scientists say toxic algae cannot be ruled out as a cause.
John McCoy, director of fisheries research at the National Institute of Water and Atmospheric Research (NIWA), said today toxic algae had been implicated in marine mammal deaths in other parts of the world, but there was no strong evidence yet for that here.
However, a toxic algae has been confirmed as causing health problems such as sore throats and nose and eye irritations in beach goers in the Wairarapa region.
Officials have also against collecting shellfish in the area.
Public health officials have also closed the coasts of Great Barrier Island to shellfish gathering after detecting a poison which can cause paralysis.
And the Department of Conservation is investigating the significance of dead marine animals being washed up on Kaikoura's coast.
The El Nino weather pattern, blamed for a variety of ills, is one factor in the emergence of toxic algae in coastal areas.
MetService weather ambassador Bob McDavitt told NZPA today that there had been algae blooms in previous El Nino years.
``And we're going for the mother of all El Ninos this summer, so it wouldn't surprise us if it also produced algae blooms.''
But, he said, more resources needed to be allocated to investigate the connection.
Algal bloom occurred when there was a particular combination of nutrients, sea surface temperatures, sunshine, food and fish.
One factor would be cooler than normal waters -- or upwelling -- bringing nutrients found at the bottom of the sea to the surface.
Dr McCoy said the toxic algae at both Great Barrier Island and Wairarapa beaches were similar, but scientists did not know whether it was exactly the same species.
It couldn't simply be blamed on the warm weather.
Whether large areas of coastline were shut down for collecting shellfish would depend on the spread of the bloom, which was difficult to predict.
He said it was better not to eat any shellfish in the affected areas.
Dr McCoy told NZPA that NIWA was collecting water samples and samples from dead or dying animals on the Kaikoura coast today.
Further specimens had already been taken from the Wairarapa.
Work was also being done to identify the particular toxic algae poisoning shellfish at Great Barrier Island.
He said NIWA hoped to also get samples from the Auckland Islands to test for toxic algae although he said the remoteness of the area and fragility of the algae made this difficult.
Meanwhile, Greenpeace said today the Government should immediately close the squid fishery surrounding the Auckland Islands and not wait for further testing.
Spokesman Michael Szabo said in a statement today ``the worst case scenario could see virtually all the Auckland Islands sea lion pups wiped out by the end of the month if the mortalities continue at the present rate of 700 a week''.