Alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis), two closely related species, are grouped under the common name of river herring. River herring are anadromous fish, meaning they spend most of their adult lives in the ocean then migrate into freshwater rivers and streams to spawn. Their annual spring migration typically takes place between April and June, when river herring ascend freshwater rivers and stream in large numbers. However, during the past ten years, river herring have experienced a coast wide decline.
To manage and restore these valued fish, we need an accurate record of how many adults pass upstream each spring. River herring are difficult to study because the time they migrate varies throughout the day and migration season. Consequently, a need exists for continuous monitoring, which is not possible using human counters. Video monitoring solves this problem.
The primary objective of this study is to develop the video monitoring technology necessary for successful monitoring of river herring migrations in different locations with different conditions. In this study, video cameras are placed above fish ladders, structures that allow fish to ascend dams. By using video cameras as a monitoring tool, a permanent record of a river herring migration can be obtained. The video can then be viewed and the number of river herring can be enumerated at a later time convenient for scientists and managers. Currently, our video monitoring stations are deployed in four river systems in coastal Massachusetts.
Town Brook click here to see video
Weymouth Back click here to see video
Monument River click here to see video
Massachusetts Department of Marine Fisheries (http://www.mass.gov/dfwele/dmf/)
Town of Plymouth, MA (http://www.plymouth-ma.gov)
Town of Weymouth, MA (http://www.weymouth.ma.us)
The Jenny Grist Mill (http://www.jenneygristmill.org)
Sasaki Associates (http://www.sasaki.com/)
Dr. John T. Finn (Graduate Committee and Co-investigator)
Dr. Robert M. Muth (Graduate Committee and Co-investigator)
Dr. John B. Kim (Graduate Committee and Co-investigator)