Rescuers trying to herd a pod of whales out to sea ahead of a major military exercise are assessing the situation from the shore after attempts to move them were unsuccessful.
Boats were used on Thursday to try and shepherd the mammals out of Loch Long in an operation involving British Divers Marine Life Rescue (BDMLR), the Ministry of Defence and local volunteers.
The operation was stood down at around 6.30pm due to the loss of light, with between three and five northern bottlenose whales remaining in the loch.
Rescuers are keen to move the creatures amid concerns over the impact that Exercise Joint Warrior, due to start on Sunday, could have on them.
Europe’s largest military exercise, it involves warships, aircraft and troops from the UK, Nato and allied forces.
BDMLR said the whales appear to be splitting into two groups and they will continue to be observed from the shore on Friday.
Rescuers will then decide whether to make another attempt to herd the whales using boats, which could take place next week.
Julia Cable, of BDMLR, said: “We know there are five around but they are split up so we cannot be sure how many are in the area.
“We will try and match up individuals and will be looking through images to try and piece together which have been where and when.
“They seem to be splitting into two groups so we will try and identify which are part of which group.”
Experts from BDMLR have monitored the pod for the last month in and around the River Clyde.
A pair of whales first seen in Loch Goil were spotted at the mouth of the Clyde near Millport on the Isle of Cumbrae some weeks ago.
Since then five whales have been spotted in separate locations in Loch Long, with some entering smaller lochs nearby.
Northern bottlenose whales are a deep-diving species normally found off the edge of the continental shelf to the west of the UK and Ireland.
An MoD spokesman said: “The Royal Navy takes its environmental responsibilities very seriously and continues to work with the relevant UK authorities to ensure all practical measures required to reduce environmental risk and comply with legislation are taken.
“A necessary series of safety checks is observed and an environmental risk assessment is carried out before any underwater task is undertaken by MoD, to minimise any potential risk to marine life.”