Where is that place any way? The incredible part is that in foklore, there is a legend that describes that EXACT beast with the trident shaped tail and long snout with teeth (although from the footage I think it was a little exagerated) along the Florida and Georgia coast and inland waters. They show them attacking boats but I suspect it may have been from them getting a harpoon in the ribs.
Very Old(Think new world old) charts show them pictured off of the east Coast alot.
On a different note.
I heard of a sea monster off of the Texas city dike that tries to steal your laundry.They say it looks more like a Turtle than a manatee though.