10th and M is probably the #1 packer of seafood in ANC. It's a very popular place for out-of-staters who've gone fishing and want to ship or carry their catch home with them. I have no idea about the quality of stuff they sell retail, since I've never bought from them, though--I'm sure they're great, though.

Other options:

-Costco often has fresh stuff in every day in season and you can't beat the prices
-New Sagaya is known for the quality and prices of their seafood
-For the smoked variety of salmon (not my preferred style, but some people like it, and it is shelf-stable), you can get a good-priced gift pack at Costco. Alaska Sausage and Seafood has some as well: http://www.alaskasausage.com/Smoked-Salmon.aspx