The Collaborative International Dictionary of English v.0.48:

Mattowacca \Mat`to*wac"ca\, n. [Indian name.] (Zool.)
   An American clupeoid fish (Clupea mediocris), similar to
   the shad in habits and appearance, but smaller and less
   esteemed for food; -- called also hickory shad, tailor
   shad, fall herring, and shad herring.
   [1913 Webster]