Anisakis is a nasty nematode that can occur in salmon/steelhead in the salt or freshwater. I used to eat a ton of raw salmon and gravlax and never had a problem, but after reading up on Anisakis I gave that up. Even if I did eat some myself, I wouldn't want to serve it to someone else and make them sick. Most home freezers don't get cold enough to kill the parasites in salmon, so be careful.

http://www.parasitesinhumans.org/anisakis.html