The Collaborative International Dictionary of English v.0.48:

Jewfish \Jew"fish`\, n. (Zool.)
   1. A very large serranoid fish (Promicrops itaiara) of
      Florida and the Gulf of Mexico. It often reaches the
      weight of five hundred pounds. Its color is olivaceous or
      yellowish, with numerous brown spots. Called also guasa,
      and warsaw.
      [1913 Webster]

   2. A similar gigantic fish (Stereolepis gigas) of Southern
      California, valued as a food fish.
      [1913 Webster]

   3. The black grouper of Florida and Texas.
      [1913 Webster]

   4. A large herringlike fish; the tarpum.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Tarpum \Tar"pum\, n. (Zool.)
   A very large marine fish (Megapolis Atlanticus) of the
   Southern United States and the West Indies. It often becomes
   six or more feet in length, and has large silvery scales. The
   scales are a staple article of trade, and are used in
   fancywork. Called also tarpon, sabalo, savanilla,
   silverfish, and jewfish.
   [1913 Webster]

WordNet (r) 3.0 (2006):

jewfish
    n 1: large important food fish of Australia; almost
         indistinguishable from the maigre [syn: mulloway,
         jewfish, Sciaena antarctica]
    2: large dark grouper with a thick head and rough scales [syn:
       jewfish, Mycteroperca bonaci]