This video from Scotland says about itself:
30 June 2015
Three juvenile dolphins in Northbay on the Isle of Barra. One of the dolphins was completely trapped in seaweed and shallow water. After a successful rescue the dolphin joined the other two for a fine display of thanks! Rescue was performed by a group from Clearwater Paddling.
See also here.
Marine animals can hear us swim, kayak and scuba dive. Humans make a lot of underwater noise because we generate and push bubble clouds underwater, which vibrate and send out acoustic waves: here.