Hear the Sea

Your ears are keenly attuned to faraway sounds in the water.
You gain a +2 bonus to your passive Perception when you are in water, and on hearing based Perception checks in all situations.
You reduce the distance penalty on hearing-based Perception checks to -1 per 30 feet at the water's surface and -1 per 60 feet underwater. In addition, you can detect the location of creatures moving creatures in the water within 5 feet (or within 20 feet for creatures lacking a swim speed) as if you had tremorsense.