The Ribbed Mussel is a cousin to the edible Blue Mussel. The main difference is that Blue Mussels are found out in the clean ocean, while Ribbed Mussels are found in smelly marshy places. And the ribs. So you wouldn't want to eat a Ribbed Mussel. Actually, I don't care for Blue Mussels either, but back in my diving days I used to collect them because back at the dock you could trade them with the fishing boats for tuna steaks and all kinds of good stuff. Like trading gravel for gold. Blue Mussels form a thick layer over almost anything solid, and the ones I got were much bigger and better than anything I ever saw in the store, where they are also very expensive.