FYI, the chances of having roundworm parasites latching on and in fecting humans is slim. If they do somehow get into your system, they usually just pass right through and if they dont then you do get sck, but it's not that bad
I have seen many roundworms in fish I catch in the fraser, if you bleed and clean them right away it is best as you rid any parasites living in the gut straight off the bat and dont allow them time to travel from the intestines into the meat.
This being said, I have eaten fish literally right out of the river - bonked, bled, and cut a piece off and eaten it on the spot. But to mow a whole bunch of sashimi I always freeze it for at least a week before defrosting and removing the brown meat before eating. I have never had any 'problems', knock on wood.
In response to your question, yes you can use fish from the fraser for sashimi. personally I would only eat sockeye raw as it is relatively firm, attractive and flavorful. Coho would be the next best but haven't tried. I wouldn't eat pinks raw personally, but thats personal preference as i would imagine it would have a tofu/mushy like consistency. but you wont get sick by eating it raw if frozen for a week.
let me know how it goes