Just south of where I dove a lot, the mouth of the Umpqua river, there have been quite a few Great White Shark attacks, though I've never seen anything other than tiny little sharks,.. I saw a grey whale pretty close once, while I was paddling along the surface.
When I go to a seafood market I don't say "I want a dozen crab." I say "I want a dozen crabs." The first time I ever heard them referred to as crab I'm the plural was on The Deadliest Catch.
When I lived in Maryland my buddy and I ran a crab line every summer Sunday morning. We ate well. Chesapeake Bay STEAMED Blue Crabs cannot be beat!