Wellington, April 14, NZPA - A technique to film the underwater world of rare New Zealand sea lions could help stop them getting trapped in squid nets.
New Scientist magazine reports that Australian vet Nick Gales, a marine mammal biologist, has been using ``crittercam'' -- video cameras that can be glued to marine mammals -- to find out what the sea lions get up to under the water.
Last month squid fishing around the sub-Antarctic Auckland and Campbell Islands was stopped for the season because of the number of sea lion deaths in squid nets.
Mr Gales, who has done contract work for the New Zealand Department of Conservation (DOC), has been studying the sea lions since 1994.
He now hopes to use the video technique to identify the sea lions' prey, study their hunting techniques and find out how they end up in squid nets.
``We don't know if sea lions get caught by chance as they go about their normal foraging or whether they actually pursue squid into the net and become trapped,'' Mr Gales said.
Previous film has shown the sea lions eating squid. Mr Gales hopes the new filming will show the mammals' interaction with nets.
Last year several video cameras were fitted to female sea lions.
``The New Zealand sea lion must be one of the worst candidates for this type of work as it dives to enormous dark depths and grubs around on the bottom,'' Mr Gales said.
The cameras were fitted with lights that illuminated an area two to three metres in front of the sea lions. The light didn't appear to disturb either the mammal or its prey.
``I was able to see the sea lions moving fast along the ocean bed, sweeping their heads left and right looking for prey. I could see them wedged into deep-sea caves trying to extricate prey from crevices.''
DOC said earlier this year about 1400 sea lion pups had been found dead in the Auckland Islands group, 320km south of New Zealand, because of a mystery ailment, and up to 1000 adults could also have died.
The ``crittercam'' technique came under fire last year when National Geographic Television applied for a permit to attach cameras to sperm whales using steel barbs.
Conservation Minister Nick Smith instead approved a 15-month permit to attach cameras to the whales using suction cups, off the Kaikoura coast.
New Zealand sea lions are among the rarest in the world. Numbers were estimated between 13,000 and 15,000 before the mystery disease hit the population.