Two issues that came up in February's Dark Mirror discussion thread
related to Commander Hwiii ih'iie-uUlak!ha', more commonly Hwiii, a delphine physicist. A Googling revealed an entry
for the character at the ErrantryWiki.
Hwiii sings a lot -- casually, while working -- and states during some work with Geordi LaForge in Engineering that singing "runs in his family": Geordi tells Captain Picard at one point that what Hwiii has been singing is "some kind of delphine opera... Or I may have misunderstood him: it was hard to tell whether Hwiii was describing theater or a ceremony of some kind -- or just live performances of some sort of passion play." Later, during an instance of distress (secondary to the Enterprise slipping unexpectedly into the Mirror universe), Hwiii breaks out into what Mr. Data describes as "part of the Song of the Twelve...a cetacean epic sung-poetic work...".
In a later conversation with Commander Riker, Hwiii very succinctly describes the Song to him, and tells Riker that he had a "partner" who once was considering singing "one of the fatal parts" in the Song - possibly that of the Silent Lord. The conversation sheds no light on the issue of whether Hwiii himself is a wizard. But it is interesting that several times in his conversation with Riker he uses the word "intervention", one of the words wizards routinely use to discuss or describe a certain class of spell (as well as other actions carried out with wizardly intent but not necessarily requiring that one do a wizardry).
The implication would seem to be that the universe of Star Trek: The Next Generation, being a distant "successor" to today's modern world, also includes wizards and wizardry -- but that the culture of 23rd-century Earth remains astahfrith. Hwiii's language to Riker regarding the Song has, to the reader who knows about wizardry, a rather circumspect sound to it; and Hwiii does not mention either wizardry, or the Song's specifically wizardly aspects.
The article goes on to mention that Duane wrote Hwiii into Dark Mirror
as a present to Rick Sternbach, who had apparently written cetacean crew into the TNG bible only to have them out.
I thought you'd all be amused.