A 6.2m (20ft) long whale has died after swimming up the Clyde and into a tributary of the river near Glasgow Airport.
The northern bottlenose whale would usually be found in the Atlantic where it hunts squid in deep-water canyons.
Volunteers from British Divers Marine Life Rescue (BDMLR) tried to save the animal on Monday before it died.
The whale was part of a pod BDMLR tried to "herd" to safety from Gare Loch using small boats earlier this month.
It is also the second of this group to die after stranding following a positive identification this week.
Scientists from Inverness-based Scottish Marine Animal Strandings Scheme are to examine the latest whale fatality.
The scheme's Dr Andrew Brownlow said BDMLR made "sterling efforts" to save the whale.
He said to find the deep-diving species so far inland was incredible. The location of the stranding is within the security boundary of the airport.
One theory as to how it ended up so far inland is that it may have mistaken a dredged shipping channel in the Clyde for a canyon.
BDMLR was aware of the whale in the Clyde at the weekend and had volunteers on standby in case it stranded.
Glasgow Airport staff raised the alarm on Monday morning after spotting the whale in Black Cart river just west of the northern end of the main runway.
Gavin Lemon, BDMLR's senior medic in the rescue effort, said the terrain in area where the animal stranded posed a challenge to rescuers.
He said: "Access to the water was tricky down a slippery embankment and once in the cold water it was found that there were hidden rocks and mud banks below the surface. This coupled with the estimate under current of six knots made the rescue attempt difficult and hazardous.
"It was only after the coastguard deployed their team to provide safety cover did the BDMLR medics enter the water and begin the rescue attempt."
Fourteen BDMLR medics and six coastguard volunteers spent almost five hours trying to save the whale but it died in the afternoon.
Mr Lemon said it was identified as one of six northern bottlenose whales BDMLR had been monitoring since August and had been part of the group seen in Gare Loch in Argyll and Bute.
The whales are capable of diving to depths of more than 1,400m (4,593ft) to find their prey.
The stranding near Glasgow Airport is the fourth this month involving northern bottlenose whales.
Two died after stranding on shores of the Firth of Clyde and another in the Western Isles.
One of the whales found in the Clyde had previously been seen in Gare Loch and was part of a pod rescuers attempted to "herd" to deeper water.