when does fishing start in Washington?

Answer 1

Since you didn't state what type of fishing you were looking at, here's a link to the WDFW. The fishing regulations are on a link to the left of the page in pdf format. They are pretty big, so depending on your connection speed they may take a while.

http://wdfw.wa.gov/fishcorn.htm

Answer 2

the regulations change every year in may. in the seattle area, salmon season starts in june, but it's catch and release only. july 16, the retention of salmon is allowed.