Wellington, Feb 12 - The deaths of New Zealand sea lion pups on the sub-Antarctic Auckland Islands appeared to have peaked, the Department of Conservation (DOC) said today.
About 48 percent of this season's pups had died, DOC vet Nick Gales said in a statement.
The main cause of death now was starvation, not the mystery disease.
Hundreds of the rare New Zealand sea lion pups, previously known as hooker's sea lions, have been found dead, mostly on Dundas Island in the Auckland Islands group, a breeding ground for the sea lions.
Mr Gales said the total loss of adult sea lions was not yet known, although 45 dead females and nine dead males had been counted on beaches.
Massey University's cetacean investigation centre is examining samples brought back from the islands, in conjunction with the Ministry of Fisheries (MFish), to establish the cause of the deaths.
Samples have also been sent to Holland's Erasmus University in Rotterdam.
DOC marine mammal expert Mike Donoghue said the cause of the deaths was still unknown, although a virus, bacteria, biotoxin, or combination of these, was considered most likely.
``We hope to hear by next week whether virologists in the Netherlands have managed to isolate a virus from the samples that were sent last Friday.
``If no traces of a virus are found, the search for a causative agent will then be narrowed down to bacteria and/or biotoxins.''
A meeting was held on Tuesday between DOC, MFish, the Ministry of Health, the Ministry for the Environment, Massey University and fishing industry representatives to discuss the issue and exchange information.
Meanwhile, the Forest and Bird Protection Society has welcomed the Government's decision to review the maximum number of sea lions able to be killed by the squid fishing industry.
The maximum allowable level of fishing-related mortalities is 79 for the current fishing season and the Government has been under pressure from environmental groups to close the squid fishery around the Auckland Islands.
``Reviewing the by-catch level is a responsible and precautionary approach,'' Fisheries Minister John Luxton and Conservation Minister Nick Smith said yesterday.
``Our squid industry is very important for exports and jobs. We need to work through this complex issue carefully.''
They said the Department of Conservation would develop proposals for a new catch limit based on a revised estimate of the sea lion population in the sub-Antarctic islands.
But Forest and Bird conservation director Kevin Smith said the only ecologically responsible decision would be to set the limit at zero.
``The species is now critically threatened and the fishing industry cannot be allowed to kill any of the surviving sea lions,'' Mr Smith said in a statement.
``The short-term economic interests of the squid fishery cannot come ahead of the survival of the world's most endangered sea lion.''
The squid-fishing season around the Auckland and Campbell islands started last week and to date there had been little fishing activity in the area.