American Shad of the Pacific Coast: A Benign Introduction or Harmful Invasive Species?

The Pacific coast of the United States has been subjected to non-native fish introductions since the 1800's.  The relative impacts of these introductions on Pacific coastal ecosystems remain largely unknown.  Many of these introductions were intentional and designed to benefit citizens by providing new fisheries.  Unanticipated negative impacts to native ecosystems have been documented from some of these introductions, and call into question their overall value and the appropriate management response.  Competing social values complicate management decisions to either promote or control the spread of non-native fishes.  Some non-native fishes have become well established and prolific, as in the case of American shad in the Columbia River, which in recent years have become more numerous than all Pacific salmon species combined.  Despite their presence on the Pacific coast for well over a century, non-native American shad have remained an ecologically overlooked and evolutionarily underappreciated species.  Whether or not this introduction has had a negative impact, positive influence or benign effect on Pacific coastal ecosystems remains equivocal.  This symposium would provide researchers and managers with the opportunity to share new information on the distribution, status, and trends in abundance, etc. of non-native American shad in Pacific coastal ecosystems, with particular focus on the Columbia River.