River Herring is a collective term used to describe both anadromous alewives and blueback herring. The alewife is the more common of the two species in Maine. River herring are anadromous (sea-run) fish that spend the majority of their life at sea but return to freshwater to spawn. Both species are native to Maine rivers. Alewives and blueback herring have co-evolved and co-existed with other native fish and wildlife in Maine's streams, rivers, ponds and lakes for thousands of years. The historical distribution of this species is throughout the Atlantic seaboard, from Newfoundland to the St. Johns River, Florida.