Sea lion survival rate causes trust concern

Sea lion Mum basks on Taieri Beach. Photo by ODT.
Sea lion Mum basks on Taieri Beach. Photo by ODT.

Only 36% of the descendants of the matriarch of Otago's New Zealand sea lion population are still known to be alive.

Calculations by the New Zealand Sea Lion Trust and the Department of Conservation showed of the 63 descendants of ''Mum'', 18 were known to have died, 22 had not been seen in the past two years and 23 had been, trust executive member Shaun McConkey said.

''It's not as high survival as we would like. We are a little concerned,'' he said at the trust's annual meeting this week.

Half of the 54 sea lion deaths Doc and the trust knew about had occurred in the past four years.

Most of those had been either necropsied (animal autopsy) or had samples taken from them.

These had shown they died from a variety of reasons, including different diseases and being crushed by males.

''If the trend continues, we will need to work with the university and Doc on this.''

Last summer, only three pups were born on Otago's coast and from the one before that only two survived.

Usually, five pups were born along the coast.

Mr McConkey said the recent disease and starvation deaths in yellow-eyed penguins, which shared similar habitats to the sea lion, added to the concerns.

Low numbers of sea lion pups being born in the Auckland Islands triggered the need earlier this year for a new threat management plan.

That plan was examining all threats to the sea lions and what could be done to mitigate effects on the population which might help shed some light on the challenges Otago's population faced, he said.

The trust was also working with Doc over having the trust's data analysed so avenues for further research could be identified, he said.

rebecca.fox@odt.co.nz

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