Dramatic declines in diadromous fishes

 We examined the status of diadromous (marine-freshwater migrating) fishes within the North Atlantic basin, a region of pronounced declines in fisheries for many obligate marine species. Data are sparse for these 22 species except for a few high value forms. For most of these species, abundances have declined to 1 to 5 percent of historic levels. Many populations do persist but at sharply reduced levels. All species had suffered population extirpations and many are now classified as threatened or endangered.  Habitat loss (especially by damming), overfishing, pollution, and increasingly, climate change have all contributed to declines in this group. We show that where data exist, populations have decreased dramatically from original baselines.  We discuss the consequences of these losses in terms of lost ecosystem services.