The Collaborative International Dictionary of English v.0.48:

Surmullet \Sur*mul"let\, n. [F. surmulet; saur, saure, brownish
   yellow, red + mulet a mullet. See Sorrel, a., and
   Mullet.] (Zool.)
   Any one of various species of mullets of the family
   Millidae, esp. the European species (Millus surmulletus),
   which is highly prized as a food fish. See Mullet.
   [1913 Webster]