Found on snopes.com today:
Urban Legends Reference Pages: Critters (Saved the Whale):
Claim: Newspaper article describes an ensnared whale who seemingly thanked her rescuers.
Status: True.
Example: [Collected via e-mail, 2006]
“If you read the front page story of the SF Chronicle on Thursday, Dec 14, 2005, you would have read about a female humpback whale who had become entangled in a spider web of crab traps and lines. She was weighted down by hundreds of pounds of traps that caused her to struggle to stay afloat.…”