The Collaborative International Dictionary of English v.0.48:

Whitebait \White"bait`\, n. (Zool.)
   (a) The young of several species of herrings, especially of
       the common herring, esteemed a great delicacy by epicures
       in England.
   (b) A small translucent fish (Salanx Chinensis) abundant at
       certain seasons on the coasts of China and Japan, and
       used in the same manner as the European whitebait.
       [1913 Webster]