What's the difference between an underwater archaelogist and a salvager?

Dr. dig responds:

Archaeologists are interested in the things of the past for the stories they tell about people; they are not interested in things for what they are worth, although sometimes archaeologists do find valuable stuff. Archaeologists study artifacts to learn about the human past; they do not keep what they find, and they certainly do not sell their finds for their own benefit.

People who dive for 'treasure' and take artifacts from shipwrecks to sell are called salvagers. If they take artifacts or destroy a site without permission from the property owner, or if they do this sort of thing on public property, then they are called looters. In addition, their activities are illegal. The Titanic was not excavated by archaeologists -- it was explored by salvagers who removed artifacts for public display.