[riku_iki]

that's likely larger and more mature presorted units. Salmon can eat smaller ones. You can tell from the price that those cost more than actual salmon.

I am not expert, I am just speculating that if you dig into details, picture can be very different.

[ClumsyPilot]

This outright silly, salmon tastes better and thats why people eat it. There isn't some great mystery about small fish being less edible.

I regularly go to the fish market, small seafood like anchovi and shrimp can be bought 4 times cheaper than salmon.