I believe that is a video camera... Could you imagine being "hit" by a dolphin and then having the dart go into your leg (or some other part of your body)??? And THEN cranked in like a fish on a hook by the guys in the boat?
from what i can determine ... all those "high-profile" special ops types who we have always called Navy SEALS are just a cover for the truly secret Navy Seals ... a group of Seals that are trained to wreak havoc behind enemy lines - their major benefit is that we only have to feed them fish. They're able to distract evil tyrants with their hypnotic beach-ball-balanced-on-the-nose trick.