Clupea aestivalis

Blueback Blue"back`, n. (Zo["o]l.) (a) A trout ({Salmo oquassa}) inhabiting some of the lakes of Maine. (b) A salmon ({Oncorhynchus nerka}) of the Columbia River and northward. (c) An American river herring ({Clupea [ae]stivalis}), closely allied to the alewife. [1913 Webster]