Aloha from Kaua'i!
One of our endangered sea critters here is the green sea turtle - also known by its Hawaiian name - "honu".
These turtles are highly endangered and many times will pull themselves up on a beach in order to sleep after feeding. If they are scared, etc. by people getting too close, touching them (or worse!) - they will go back into the water where they then become easy prey for their natural predator - the sharks.
Here is a good article on the efforts of some people to educate visitors about these turtles and how apparently some will not only go up and touch them, but straddle them for a picture!