Weathering the storm

A few weeks ago, when Matthew and I were fishing for turtles out on Core Sound in North Carolina, this awe-inspiring squall line overtook us. None of us had ever seen a cloud formation quite like this one and fortunately, Matthew was able to take a picture of it. It has an ominous quality that makes it look like it could serve as a backdrop for the riders of the Apocalypse or some equally dread occurrence. As the squall hit, we tied off the boat to ride out the storm and during that time we had the chance to discuss the worst weather experiences we'd ever had. Going through my mental list - being in a trailer that was hit by lightning, witnessing a ball of lightning that burst through a friend's phone jack and briefly hovered in her living room, and excavating turtle nests on a beach as small funnel clouds occasionally appeared from the low clouds above and then were sucked back up - I started wondering how turtles (and, I guess, large aquatic animals in general) perceive such storm events. Can they sense the approach of a storm? Do they duck and cover when it hits, observing the light show from a secure location on or near the bottom? Or do they just continue to go about their turtle business, having their activities occasionally illuminated by flashes of lightning?