If I recall correctly, Sitchin further explained that Enki would wade ashore in the Persian Gulf, after either splashing down from a spacecraft or emerging from an underwater habitat, wearing an atmospheric suit crafted to resemble a fish. Given that he was known as the 'Lord of the Deep' I personally find the latter more likely.
Sitchin described his theory that the humans would see Enki lift the visor of the fish-helmet helmet into an upright position, creating a look that would resemble what came to be used as the bishops hats, inherited from the priests of Dagon.
Historic references paralleling this can be found in Hades, Greek God of the Underworld,
And in the anthropomorphic figures found in Egyptian Hieroglyphs depicting humanoid figures with animal heads such as those of Jackals, Egrets, Owls, Cats and Crocodiles