The new resident “dolphins” of one riverside town have now been caught on camera putting on a display in the water. Photographer Jason Arthur managed to snap a few playful shots and videos of the marine mammals riding the waves of the Thames in Gravesend, by the town pier. However, this isn’t the first time he’s been able to take pictures of the majestic animals. He first saw them on Sunday, June 9, and told KentOnline at the time that there were around three in the river and were thought to have been there for a few days. It is not known yet if they’re dolphins or porpoises – both of which ha…