Massive dead basking shark makes return appearance in Boston Harbor

The carcass of a basking shark at least 24-feet long first seen stuck to the bow of a container ship in Boston Harbor more than two weeks ago has resurfaced.

A New England Aquarium spokesman says officials at first weren't sure what kind of marine creature was spotted Tuesday in an arm of the harbor known as the Reserved Channel.

Tony Lacasse says aquarium biologists who went to scene quickly determined it was a shark based on its cartilaginous fins.

It's unclear if the creature was killed by the ship strike or was already dead. It probably weighed three to five tons when alive.

Basking sharks, the world's second-largest sharks, feed on plankton and are generally harmless to humans. Because of their prominent dorsal fin they are often confused with great whites.