In the 19th century, Francis Henry Salvin and Gage Earle Freeman wrote Falconry: Its Claims, History, and Practice, a book which is perhaps most memorable for its addendum, subtitled To which are added remarks on training the Otter and Cormorant, by Capt. Salvin. It's always struck me as a very, well, 19th-century mishmash; it's hard to imagine a contemporary how-to book on falconry devoting space to such esoterica.
On the other hand, that hasn't prevented me from idly daydreaming about training double-crested cormorants (Phalacrocorax auritus) for fishing. Yes, they're protected under the Migratory Bird Treaty Act, and there are no provisions I'm aware of for possession of live cormorants, but on the other hand they're sometimes killed under depredation permit when they make themselves at home on fish farms. It seems like something could easily be worked out.
Here's a video from the BBC showing how it's done in southern China. (These are probably great cormorants, P. garbo.) The narrator's claim that "the birds are, in effect, slaves" is overstated, but otherwise the video is excellent. The underwater sequences make the parallel to falconry less far-fetched than I once supposed, and have me daydreaming again.
Come on, FWS, what do you say?...