The mammal was pictured in the River Clyde on Tuesday
A rescue operation is under way in Glasgow following confirmed sightings of what is thought to be a northern bottlenose whale in the River Clyde.
The mammal is thought to be 5m long and has been seen in the area of the Clyde Arc Bridge, just over a mile from the city centre.
British Divers Marine Life Rescue (BDMLR) said it was waiting to confirm the animal was a northern bottlenose.
BDMLR vet Cameron McPherson said he was worried the animal was unwell.
Mr McPherson said: "The glimpses of it I've had myself have been very fleeting, but the concern I do have is that it appears to have some muscle wastage across its back muscles, which would indicate it is in a negative energy balance and that it hasn't been eating well for quite some time, which again doesn't bode well."
The vet said he was sure the stricken creature was a northern bottlenose, which is the same type of whale which was found in the River Thames in London a couple of years ago.
Mr McPherson said: "The reasons why they might do this are fairly numerous, but the end result for this type of species is not usually great, unfortunately, because they don't tend to cope well with the stranding process.
"They are an offshore species, they live in the deep Atlantic and to be in River Clyde is obviously not its natural environment."