Well, where ever they get it seeing salmon you catch that isn't pale pink but grey is disturbing and not something which would occur naturally.
I fly fished wild salmon since I was in my early teens and they were always pink. We stole enough fish from the fishfarms to see a difference (either grey or insanely over coloured) ;)
I think maybe Pacific salmon are different to the kind we get in Scotland though? Ours only spawn once and they don't eat when they're back in freshwater (as a consequence the tail end of the fishing season is horrible; black skinny things that fall apart when you touch em)
Only Atlantic salmon are farmed in the United States and Europe. There's some farming of Pacific salmon in Chile and New Zealand, but overall it's a rounding error compared to the amount of farmed Atlantic salmon.
Most salmon (Atlantic or Pacific) only spawn once and then die, but occasionally an Atlantic salmon will survive to make another trip.
There's really no hard and fast distinction between what's called a "salmon" and what's called a "trout", other than salmon typically spending time at sea. For example, Oncorhynchus mykiss is called a "rainbow trout" if it remains in freshwater its entire life. It naturally has pale flesh (though farmed rainbow is often given the same pigments as the farmed salmon). If it spends time at sea, the exact same fish is called a "steelhead" (occasionally, a "steelhead salmon") and has red or pink flesh.
A near-relative, Oncorhynchus nerka, is called the "red salmon" or "sockeye salmon"if it spends time at sea, but "kokanee", "kokanee trout" or "silver trout" if it remains landlocked.
Grey flesh or skin can be the result of either applying too much carotenes to the diet; or maybe (I'm speculating in this second point) because its diet was high in vegetable protein contents (using soy as replacement for marine proteins is cheaper).
I fly fished wild salmon since I was in my early teens and they were always pink. We stole enough fish from the fishfarms to see a difference (either grey or insanely over coloured) ;)
I think maybe Pacific salmon are different to the kind we get in Scotland though? Ours only spawn once and they don't eat when they're back in freshwater (as a consequence the tail end of the fishing season is horrible; black skinny things that fall apart when you touch em)