Patapsco River Bloede's Dam leaves Daniels Dam, upstream, as the last remaining dam along the mainstem Patapsco River. Removal of Bloede's Dam in September, 2018 opened up of the Patapsco River watershed which will potentially restore spawning runs of at least six species of native anadromous fish: alewife ("Alosa pseudoharengus"), blueback herring ("Alosa aestivalis"), American shad ("Alosa sapidissima"), hickory shad ("Alosa mediocris"), striped bass ("Morone saxatilis"), sea lamprey ("Petromyzon marinus"), as only one species, sea lamprey, were found using the Bloede's Dam fish ladder in 2012. One catadromous species would likely also benefit, the American eel ("Anguilla rostrata"), a fish species which
Alosa sources, predators, etc. Since many adult "Alosa" species die after spawning, the young generally have to migrate to the sea from the spawning grounds. Duration of migration varies among fish, but it can greatly affect survival. Reproduction varies by species. Studies done on "Alosa" in Iranian waters have shown that spawning varies in time, place, and temperature of the waters they inhabit. Fecundity may also vary. Species are known to spawn as early as April or as late as August. Temperatures range from about 11 to 27 °C. Fecundity can range from 20,000 to 312,000 eggs. Eggs are pelagic. The