In marine areas 2-1 and 2-2 you can fish with either a fresh water or saltwater license. Page 106 of the rules pamphlet at the bottom of the page for area 2. Get a freshwater license for all your needs in town and this area. Go surf fishing or fish outside the channel between the jetties at Westport and Ocean Shores you need a salt water license. Basicaly any fishing from aline drawn for the west ends of the jetties east is fresh or salt water license. Fish on the ocean side of the jetties and you need salt water license.

http://www.wdfw.wa.gov/publications/00957/wdfw00957.pdf
Cick on marine area rules and find area 2.

Don't know anything more about the derby than the dates. I don't play in them. And remember, if salmon is not listed on a body of water it is closed to fishing for salmon.