Oban Bay sperm whale swims back out to sea Published duration 9 April 2013

image caption It is "highly unusual" to see sperm whales in Scottish shallow waters

A sperm whale which has been in the shallow waters of Oban bay for almost nine days has swum back out to sea.

David Scott, of the British Divers Marine Life Rescue, said the male swam off on Monday afternoon.

He told the BBC Scotland news website it had provided whale experts with valuable information.

"Nobody has observed an animal of that kind so close to shore, in shallow water, for such a prolonged time," he said.

"We don't know why he came into the bay but whales will seek shelter from time to time.

"We had established he was able to swim in and out of the harbour at will and went of his own accord which is so important.

"The moral of the story is 'leave whale alone'."

media caption The BBC's James Cook talks to people who have travelled for miles to catch a glimpse of the whale

Mr Scott said the whale was aged between 11 and 14 and was about 11.9 metres long, weighing about 20 tonnes.

Mr Scott thanked boat owners, the police and the Scottish SPCA for their assistance, along with Caledonian MacBrayne, which had re-routed its ferries to avoid colliding with the whale.

"Normally these whales are in the Atlantic, in water thousands of metres deep," he said. "They are not used to things like tidal streams and there was a risk of him panicking and stranding.

"He has been banging up against boats and barges so has picked up the odd battle scar but we would like to thank boat owners in the area for allowing the whale to be about the bay."

World whale experts are currently gathered in Portugal for the European Cetacean Society conference, and Mr Scott said the BDMLR had been able to pass valuable information on to them.

"It is highly unusual to see something like this," he said. "If it happens again we have the knowledge to build on."