As salmon fishermen will tell you, they'd rather have a piece of frozen salmon that was wild caught with a gill net, bled immediately (which slows down decomposition), and frozen that day than a "fresh" piece of salmon from a fish that was poorly caught, or not bled, or that sat on ice for days before being frozen. That's why it's so important to now where your salmon comes from.
Ask your fishmonger where and how the salmon was caught. Better yet, buy salmon directly from a fisherman or co-ops, that way you'll know exactly when and how it was caught. Many salmon fishermen in Alaska and Washington state are set up to sell their wild-caught Pacific salmon directly to consumers.
Learn more about salmon here. And once you have delicious fresh or frozen salmon on hand? Try throwing in on the grill - it's definitely my favorite way to cook salmon. Looking for something else? Find other ways to cook salmon here.