It's a sea monster. The guy who approached the company that makes the MonsterQuest series has taken video of the creature for the past few years.
Yeah I know what you mean about not finding anything. At least we got lots of video in this episode. Although, of course, it's not the best quality.
Previously I've edited the Beast of Exmoor episode as well as Squid Attack II.
The show is made by a company in Minneapolis, but they can't do everything so they farm out shows (both for shooting and editing) to companies like mine.