Monitoring Spawning Runs of River Herring in Chesapeake Bay

River herring populations of the U.S. Atlantic coast (alewife Alosa pseudoharengus and blueback herring Alosa aestivalis) have declined precipitously in recent decades. A significant challenge to river herring conservation efforts in Chesapeake Bay is a poor understanding of stock status. The purposes of this project were to develop methods for and coordinate a Bay-wide monitoring network for river herring. DIDSON imaging sonar was evaluated as a method for conducting spawning run counts for river herring in two Chesapeake Bay tributaries from March to May in 2013 and 2014. Electrofishing and ichthyoplankton sampling were conducted at weekly intervals during DIDSON deployments to determine species composition, monitor spawning activity, and for evaluation as potential low-cost proxy methods for estimating run size. Spawner age distribution was determined from otoliths and the percent of repeat spawners was determined from spawning marks on scales. We are also coordinating a network of academic researchers, state and federal agencies, and conservation groups with the goal of coordinated, long-term monitoring of river herring spawning runs in Chesapeake Bay.