WELLINGTON, Jan. 9 (Xinhua) -- Six pilot whales have died and another 15 re-stranded following a mass stranding at Farewell Spit in New Zealand's South Island on Friday.
Volunteers and Department of Conservation (DOC) staff worked overnight to refloat the pod of 55 long-finned pilot whales after Thursday's initial stranding, with 34 successfully returning to sea.
Marine rescue group Project Jonah said rescuers were battling to save those who returned to shore.
Farewell Spit, located at the top of the South Island, is a naturally occurring "whale trap" along a migratory route for long-finned pilot whales in New Zealand, said a DOC statement.
Whales may be easily deceived and caught out by the gently sloping tidal flats and a rapidly falling tide, it said.
"Pilot whales have strong social bonds and if one whale heads into shallow water, the rest of the pod will follow due to their natural instinct to look after one another," it added. ■