Goetia – S. L. MacGregor Mathers (1904) (quoted) 
The Forty-second Spirit is Vepar, or Vephar. He is a Duke Great and Strong and appeareth like a Mermaid. His office is to govern the Waters, and to guide Ships laden with Arms, Armour, and Ammunition, etc., thereon. And at the request of the Exorcist he can cause the seas to be right stormy and to appear full of ships. Also he maketh men to die in Three Days by Putrefying Wounds or Sores, and causing Worms to breed in them. He governeth 29 Legions of Spirits, and his Seal is this, etc.
Pseudomonarchia daemonum – Johann Wier (1583) (quoted)
Vepar, alias Separ, a great duke and a strong, he is like a mermaid, he is the guide of the waters, and of ships laden with armour; he bringeth to passe (at the commandement of his master) that the sea shalbe rough and stormie, and shall appeare full of shippes; he killeth men in three daies, with putrifieng their wounds, and producing maggots into them; howbeit, they maie be all healed with diligence, he ruleth nine and twentie legions.