Every spring, the Nemasket River welcomes thousands of migratory river herring that thrash and leap as they fight their way upstream from Mount Hope Bay. Of all non-domesticated animals, the river herring--or alewife--has arguably had the greatest impact on the towns along the river in southeastern Massachusetts. The area was called Nemasket, or place of fish, by Native Americans, and its earliest English colonists were dependent on river herring...