As someone who used to live in Japan I can say that Chilean salmon is much more common than Norwegian while it is also cheaper. The higher price of the Norwegian salmon and its packaging which has the character for fresh used before it ( 生 - as opposed to cured with salt) is made to give the impression that it is superior. I don't have the data for this but I think Sushi sold in stores is mostly Chilean too, unless being explicitly tagged as Atlantic in which case again it would be more expensive.