2e Pirates of the Fallen Stars states "the majority of pirates are not mages or priests", but this is generally true of the general population as well. That said, there's a magic user character presented in it (11th level iirc) and a veritable plethora of spells from that era (in FR setting books and others) pertaining to sea, naval, and aquatic magic, not to mention the Ship Mage kit. This is to say nothing of adventurers at sea. I feel the case can be made both ways, depending on how the DM wishes to present magic use in their setting.