According to Clemens and Wilby , the Pacific Chub mackerel is similar enough to the Atlantic spanish mackerel that they consider them the same species. The only difference is in the swim bladder, but they said the similarities are close enough to be called the same.
My wife and I kept 7 mackerel from an Alberni Inlet trip the other day.
She wanted to smoke some which she did, using a wet brine recipe from Luhr-Jensen's smoker manual.
Now when we caught them, I did not bleed or gut them (didn't know any better), I just put them on ice and they stayed there til we got home.
Smoked them in a "Little Chief".
Results:- the taste itself was not bad at all as far as flavor goes.....seemed to have a "smoked oyster" affinity going for it.
But the one thing that turned me off:- the meat seemed to dissolve in my mouth like fish paste...and......once the initial flavor subsided there was a bit of a weird aftertaste.
Whether this had anything to do with not bleeding and gutting them I don't know.
However they did not taste like the European version to me.