River herring abundance in the Ipswich and Parker Rivers, Massachusetts, 1972 to present

This dataset summarizes abundance to assess the current status of alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis) in Massachusetts rivers.Data from 2011 and earlier is from Massachusetts Division of Marine Fisheries Technical Report TR-46. Catch data from 2012-2015 was provided by Ben Gahagan and John Sheppard from DMF. Visual counts are a mix of both fish species as they pass through a restriction in the river. Count data for three (Parker, Monument and Mattapoisett Rivers) of the five rivers used to estimate Massachusetts trends in passage and total run size indicated a precipitous decline in alewife abundance after 2000. Data for The Parker and Ipswich rivers are relavant to the Plum Island Ecosystems project.