Boats monitoring the sperm whale - Pic copyright WDCS/Charlie Phillips
A large adult sperm whale which entered a bay in the Highlands could be suffering health problems, according to an expert.
The Whale and Dolphin Conservation Society (WDCS) has been monitoring the mammal. It has been swimming in circles around Avoch Bay, at the Black Isle.
Local officer Charlie Phillips told the BBC Scotland News website the whale swam under the boat he was on.
He said: "We got a good idea then what size it is - it must be about 45ft."
Conservationists hope it will be able to leave the bay and return to the Inner Moray Firth and, eventually, deeper waters.
A second whale was thought to have made out it to the firth.
Mr Phillips said: "The sperm whale does not look well and is going round in circles.
"It is a big adult male. We don't see many of them."
British Divers Marine Life Rescue (BDMLR) and the Maritime and Coastguard Agency (MCA) have also been notified.
BDMLR said said there was little they could do if it strands on the beach.
Trevor Weeks, of BDML, said they did not have the drugs or medical equipment available to put such a big animal to sleep.
He said: "We are very concerned for the whale."
The Whale and Dolphin Conservation Society (WDCS) has sent an expert out on to the water of the bay.
A spokeswoman said the species was deep diving and the whale in Avoch Bay was outside its normal habitat.
She said it was rare for such a whale to be so far inshore.