Contrasting the Ecological Role of American Shad in Their Native and Introduced Range

American shad is an anadromous clupeid of increasing conservation concern on both the Atlantic and Pacific coasts of North America, but for very different reasons. The species historically supported valuable commercial in their native Atlantic coast range, but a suite of anthropogenic factors has resulted in dramatic rangewide declines in abundance and extirpations of spawning runs. Despite fishery closures and ongoing restoration efforts, native rangewide abundance has declined to historic low levels and shows few consistent signs of recovery. On the contrary, American shad in their introduced Pacific range have become prolific, and constitutes the single largest spawning run of any anadromous fish on the Columbia River. These opposing trends in population abundance provide an opportunity to examine the changing ecological role of anadromous clupeids in coastal watersheds, and to explore how these changes may have impacted important ecosystem dynamics, including the importation of marine derived nutrients. This synthesis will examine the changing role of American shad in altering connectivity between aquatic habitats and the marine realm.