What is "osmerus eperlans"

Smelt \Smelt\, n. [AS. smelt, smylt; akin to Dan. smelt.]

1. (Zo["o]l.) Any one of numerous species of small silvery salmonoid fishes of the genus Osmerus and allied genera, which ascend rivers to spawn, and sometimes become landlocked in lakes. They are esteemed as food, and have a peculiar odor and taste.

   Note: The most important species are the European smelt ( Osmerus eperlans) (called also eperlan, sparling, and spirling), the Eastern American smelt ( O. mordax), the California smelt ( O. thalichthys), and the surf smelt ( Hypomesus olidus). The name is loosely applied to various other small fishes, as the lant, the California tomcod, the spawn eater, the silverside.

2. Fig.: A gull; a simpleton. [Obs.]
   --Beau. & Fl.

   Sand smelt (Zo["o]l.), the silverside.