It's an Atlantic white-sided dolphin. We ran into a big pod of them on Stellwagen during a whale watch last year. They were all playing in the wake of the boat. Definitely one of the coolest things I've ever seen.
Location: Recently relocated to the shores of Rhode Island - East Bay!
Posts: 505
It did not go unnoticed by anyone on the beach that day and received plenty of attention from some concerned people. I gotta believe that someone called some sort of authority. My buddy was there the next day and it was gone.