SAN FRANCISCO -- Crews towed the rotting carcass of a massive dead whale, discovered wedged underneath Pier 27 on San Francisco's waterfront, out to sea Friday afternoon.

The dead cetacean was towed 40 miles out to sea and cut loose so that let nature could take its course.

People standing in the area of Pier 27 Thursday evening couldn't see the dead whale, but they could certainly smell it.

The 25-to-30 foot long whale was trapped among the pillars underneath the pier. People who work at the pier told KTVU they thought the pungent odor was coming from a dirty bathroom nearby or dead rats. No one realized there was a whale decomposing underneath their warehouse.

"It's smelly," said Pier 27 worker Youmei Hou. When asked how long the smell had been noticeable in the area, she indicated the odor had been present "many days."

Frank Rescino has been running his family's commercial fishing vessel the Lovely Martha for almost four decades, but he also says a large part of his business is conducting whale watching tours for visitors at Fisherman's Wharf.

"The whale is beautiful. They come right up during the whale watching tours. This is just sad," said Rescino

Rescino says removing the dead whale would be an intricate operation and was likely to cost of the Port of San Francisco thousands of dollars.

"It's going to take a couple of divers to tie a line to it, a couple of small boats to pull it and a larger boat to take it out past the Farallon Islands," explained Rescino.

Exactly two weeks ago, there were whale sightings in San Francisco Bay near Crissy Field. And it wasn't clear then whether there were one or two whales in the bay.