My experience in Japan is that salmon is still second class sushi even if it is more common now.
In the US, all fish intended for raw consumption must be frozen in one of two ways that kill any parasites.
In Japan, this is not required.
Salmon is extremely high compared to tuna in parasites. In fact if you eat it regularly cooked, you've almost certainly seen little white worms at some point (though you may have dismissed it as just fat or something). I've found them even in farm raised salmon.
So in an environment where there's no freezing of fish to kill parasites, it's not particularly surprising that fish that more frequently ends up with parasites isn't popular.
In fact, just read over this Wikipedia page, which hits everything from salmon being high in parasites to the impact on raw consumption:
https://en.m.wikipedia.org/wiki/Fish_disease_and_parasites
A choice quote: "A study in Seattle, Washington showed that 100% of wild salmon had roundworm larvae capable of infecting people."
Frankly parasites, I don't want parasites in any capacity. I don't want them dead I want them gone, no cadavers either.
Like other posters are saying, better to eat no fish.
I don't doubt this but who imports non-flash frozen fish? All the tuna and salmon I've seen at auction/market is flash frozen on the boat.
There is a wild / higher grade salmon available, even Japanese domestic salmon exists.
how do you do that? My expensive freezer only goes down to -30 when set to maximum cold (and then it becomes really loud!)
> Freezing and storing at an ambient temperature of -4°F (-20°C) or below for 7 days (total time), or freezing at an ambient temperature of -31°F (-35°C) or below until solid and storing at an ambient temperature of -31°F (-35°C) or below for 15 hours, or freezing at an ambient temperature of -31°F (-35°C) or below until solid and storing at an ambient temperature of -4°F (-20°C) or below for 24 hours are sufficient to kill parasites. Note that these conditions may not be suitable for freezing particularly large fish (e.g., thicker than 6 inches).
> Brining and pickling may reduce the parasite hazard in a fish, but they do not eliminate it, nor do they minimize it to an acceptable level. Nematode larvae have been shown to survive 28 days in an 80° salinometer brine (21% salt by weight). Fish that contain parasites in their flesh may also contain parasites within their egg sacs (skeins), but generally not within the eggs themselves. For this reason, eggs that have been removed from the sac and rinsed are not likely to contain parasites. Trimming away the belly flaps of fish or candling and physically removing parasites are effective methods for reducing the numbers of parasites. However, they do not completely eliminate the hazard, nor do they minimize it to an acceptable level.