[DenisM]

I just scanned the article, it seems correct now in its use of shark/fish/whale/etc designators.

It's a confusing situation with both belugas (who are whales, and therefore mammals, and not fish despite their appearance) and whale-sharks (who are sharks, and therefore fish, but not related to whales despite their name). Add to that things like fish-tanks and so on, and you got a lot of room for confusion, so it pays to double-check everything!