Ivy the whale was spotted by Marine Discovery Penzance, a wildlife-watching tour, after it became stuck in lobster pot lines in Mount’s Bay, near the port of Newlyn at about 10am on Sunday.
Hannah Wilson, co-owner of the company, told the PA news agency that the whale was “stuck fast”.
“Stuck fast, motionless, breathing only every three to four minutes, which isn’t too bad.
“You know if they’re panting or breathing every minute that’s bad, but it’s breathing was fairly calm, but it was very stationary. So we don’t know how long it had been.”
The whale was “silent and still” she said.
She said her team felt “helpless” as they were under strict instructions not to intervene because of the choppy conditions.
“I think, well who knows what they’re thinking, but I think it may have had its struggle and was giving up,” she said.
However, the Royal National Lifeboat Institution (RNLI) were able to cut the whale free from the ropes.
“It’s incredible what the guy at helm achieved because it was properly rough,” she said.
“By then there was steep short chop, poor visibility, the whale started moving by this point.
“It was very impressive what he did. They cut the crucial rope, and the whale moved off, and that was that.”