Merrow

A mermaid, believed by Irish fishermen to forebode a coming storm. There are male merrows, but no word to designate them. (Irish, Muruadh or Murrûghach, from muir, the sea, and oigh, a maid.)

“It was rather annoying to Jack that though living in a place where the merrows were as plenty as lobsters, he never could get a right view of one.”—W.B. Yeates: Fairy and Folk Tales, p. 63.