Mark Bittman's piece in today's New York Times includes an interesting recipe for mackerel. Mr. Bittman states the following:
"Cook it with the skin on (it has no scales) and serve it over rice with some of the poaching liquid spooned over it."
I'd like to point out that mackerel does, indeed, have scales, albeit small ones. I was quite surprised to read Mr. Bittman's remarks, since mackerel is known to be a kosher fish (for fish to be considered kosher, it must have scales and fins).
Aside from this, the statement is quite absurd: when has a fish having scales prevented anyone from cooking it skin-on? Seems to me that scaling a fish is part of the process of cleaning said fish, no?