What is "planked shad"

Plank \Plank\, v. t. [imp. & p. p. Planked; p. pr. & vb. n. Planking.]

1. To cover or lay with planks; as, to plank a floor or a ship. ``Planked with pine.''
   --Dryden.

2. To lay down, as on a plank or table; to stake or pay cash; as, to plank money in a wager. [Colloq. U.S.]

3. To harden, as hat bodies, by felting.

4. (Wooden Manuf.) To splice together the ends of slivers of wool, for subsequent drawing.

   Planked shad, shad split open, fastened to a plank, and roasted before a wood fire.