Rahway River migrations. Fish ladders are inundated structures with small underwater steps that allow fish to navigate around a dam and continue their migration. Other approaches include removing obstructions that are inoperative or no longer serve their purpose, or improving water quality and reducing debris that obstructs passage. The fish targeted for upstream passage at the Rahway River Water Supply Dam are alewife (Alosa pseudoharengus), blueback herring (Alosa aestivalis), gizzard shad (Dorosoma cepedianum), white perch (Morone Americana) and the endangered American eel (Anguilla rostrate). Alewife and blueback herring are collectively referred to as river herring due to their similarity in appearance, range,
Coonamesset River cranberry bogs that run to the rivers edge. Long ago nearly the entire river may have been bordered by red maple or white cedar swamp when the Wampanoag fished for herring. After European settlers arrived in 1660, the river was initially known as the Five Mile River. Philip Dexter located Falmouth's first grist mill at its mouth around 1700, and by 1795 there were three mills along the river with a corresponding decline in fisheries. A "herring war" began in 1798 with a bylaw giving an elected committee the right to remove any obstructions to allow fish free passage from