Why should we care about shad and river herring enough to restore them?

American shad (Alosa sapidissima), blueback herring (A. aestivalis), and alewife (A. pseudoharengus) are three of five anadromous alosines in North America.  Pre-20^th Century, American shad constituted one of the top U.S. fisheries, ranking second only after Atlantic cod.  The American Fisheries Society was founded, in no small part, to promote propagation of American shad.  In terms of sheer biomass, blueback herring and alewife (together termed “river herring”) likely outstripped shad, and in themselves formed the basis of important riverine, estuarine, and marine fisheries.  Today these species are highly depleted, due to a myriad of factors that include dams, other habitat alterations, overfishing and bycatch, and to some extent pollution.  The challenges to restoration are many, but the benefits of restoration are also great, and will be discussed in the context of ecosystem services and “full” vs. “empty” ecosystems.