Wellington, Feb 25 NZPA - Scientists told today of their ``deep distress'' at discovering huge numbers of dead sea lion pups on the Auckland Islands.
Department of Conservation (DOC) marine mammal scientist Simon Childerhouse and veterinarian Nick Gales, working on contract for DOC, were studying the threatened New Zealand sea lion population when they discovered the mass pup deaths on Dundas and Enderby Islands a month ago.
Back in Wellington today after six weeks on the islands , the two could shed no new light on the cause of the deaths.
Tissue and blood samples they had retrieved were being studied in laboratories in New Zealand and as far afield as New York and Rotterdam. ``It's now up to the labs,'' Mr Childerhouse said.
Mr Gales said it had been ``deeply distressing'' being down on the Auckland Island beaches, picking up dead pups every day and putting them on huge piles of other rotting pups.
Mr Childerhouse said the smell of the dead sea lions was ``awful'' and they had to wear full protective gear while handling them.
Mr Gales said there was little they could do to help the sea lions while they were there -- even if they had known what the disease was and had a vaccine, moving among the animals would have stressed them, separated mothers and pups and caused even more deaths.
All they had been able to do was pile up the dead bodies away from the live pups and fence off the piles.
He said if a virus were identified and a vaccine created, it might be possible to vaccinate colonies that hadn't been affected by the disease yet.
Causes of the deaths could be complex -- algal bloom, viruses and bacteria are all under suspicious with the complicating factor of the El Nino pattern, with changing sea currents capable of upsetting food sources.
Mr Gales said the pup deaths started while they were there, killing some 60 percent of the entire pup population for the year. By the time they left, the deaths seemed to have halted.
An unknown number of adults also died, though an absolute minimum of 74 dead females and 11 dead males had been counted. The total loss of adults would not be known until three years of pup production had been monitored.
Once the deaths started, the DOC team put aside their planned monitoring work to deal with the catastrophe that faced them, count dead animals and take samples.
They said sea lions at all the breeding sites on the Auckland Islands had been affected by the mystery ailment and animals on Campbell Island, further south, were also showing effects of the disease.
Mr Childerhouse said about 1600 pups had died, along with an unknown number of adults, which meant a minimum of 10 percent of the threatened sea lion population had been wiped out.
Mr Gales said nothing conclusive had come back from the Erasmus University in Rotterdam, Netherlands, where samples had been tested for morbillivirus (seal distemper) which had caused massive sea lion deaths in Europe, and that laboratory would now look for other viruses.
Ministry of Agriculture and Massey University scientists were also studying samples and DOC has received offers of help from other overseas laboratories and scientists which it was following up.
Auckland University was studying the genetics of the samples -- if the gene pool of the New Zealand sea lions was too narrow, due to inbreeding, the species would not be able to resist disease well, he said.
DOC staff who monitor the sea lions' breeding season on the islands every year will go south again next summer, with special preparations in case similar mortalities occur again.