VIMS

River Herring Monitoring

River herring, including alewife (Alosa psudoharengus) and blueback herring (Alosa aestivalis), once supported one of the oldest and most valuable fisheries in Virginia. Since the 1970's a substantial decline in the stocks of river herring coast wide was noted. Commercial landings for both species have declined dramatically from historic highs. This resulted in the Atlantic States Marine Fisheries Commission(ASMFC) to require moratoria on fisheries unless stocks within a jurisdiction were shown to be sustainable. The most recent stock assessment for river herring concluded that stocks coast wide are severely depleted(ASMFC 2012). Due in part to lack of available fishery-independent data to address the question of sustainability, the Virginia Marine Resources Commission(VMRC) implemented a ban on the possession of alewife and blueback herring to begin January 1, 2012. The current regulation states, in part that "It shall be unlawful for any person to catch and retain possession of any river herring from Virginia tidal waters." (VMRC Regulation 4 VAC-20-1260-30).

Fishery-independent monitoring programs of the adult spawning stock and juvenile abundance were initiated on the Chickahominy River in 2014. Drift gill nets were used in the spring to monitor adult river herring spawning runs. An index of abundance of juvenile river herring and American shad is obtained through the annual VIMS Juvenile Striped Bass Seine Survey on the James, York and Rappahannock rivers. Catches from different years are standardized by calculating a juvenile index of abundance (JAI) and the geometric mean catch per tow, which allows for a relative comparison of catches among years and between rivers. A nighttime trawl survey was initiated in the summer and fall of 2014 on the Chickahominy River as an additional measure of juvenile abundance of river herring and American shad. In 2015 an anchor gill net survey was initiated on the Chickahominy River to determine its effectiveness for monitoring river herring in a major tributary of the James River. Samples of adult river herring were also collected from pound net fishers with special collection permits from the Chesapeake Bay and Rappahannock River; to be examined for biological data.

The primary objectives of the monitoring program:

  1. Survey for river herring in the Chickahominy River using drift and anchor gill nets and monitor the catch rates of river herring during the spawning run.

  2. Describe the biological attributes (size, age composition, sex ratio, spawning history and reproductive status) of the catch of river herring.

  3. Provide information useful for management of river herring including:

    1. spawning stock strength and composition
    2. Calculation of instantaneous mortality (Z)
  4. Survey juvenile alosines using nighttime surface trawls to calculate a juvenile abundance index and determine patterns of downstream migrations.

This work is federally-mandated and provides critical information for stock assessment of a fishery under moratorium. Assessment of these data will provide fisheries managers with the ability to monitor recovery levels and set restoration goals for these stocks, in the hopes that stocks will recover to a level that will support a full fishery.