yellowtail \yel"lowtail`\, n. zool.
   a any one of several species of marine carangoid fishes of
       the genus seriola; especially, the large california
       species seriola dorsalis which sometimes weighs
       thirty or forty pounds, and is highly esteemed as a food
       fish; -- called also cavasina, and white salmon.
   b the mademoiselle, or silver perch.
   c the menhaden.
   d the runner, 12.
   e a california rockfish sebastodes flavidus.
   f the sailor's choice diplodus rhomboides.
       1913 webster

   note: several other fishes are also locally called
         yellowtail.
         1913 webster
see also:
seriola seriola dorsalis cavasina white salmon sebastodes flavidus diplodus rhomboides