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Feasibility of Using Mobile Hydroacoustic Surveys for Estimating Spawning Stock Size of Blueback Herring in Western Albemarle Sound, North Carolina

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Principal Investigator Name: Terry Pratt, Warren Mitchell, Chris Taylor, Jeffrey Buckel
Project #: 07-FEG-09
Funding Period Begin: 08/01/2007 End: 07/31/2009
Region: Northern
Primary Category: Fisheries Equipment & Gear
State Funding: $142916.00

Summary:

Recent landings from Albemarle Sound’s river herring (collectively blueback and alewife) fishery are dramatically lower than historical levels. A recent stock assessment for Chowan River blueback herring indicates that low abundance is due to a combination of recruitment failure and high exploitation rates. Chowan River harvest has dominated statewide landings by water body for many decades, and decline in this population is of great concern to citizens, fishers and fisheries managers. The N.C. Division of Marine Fisheries draft Fishery Management Plan (FMP) recommends that the N.C. Marine Fisheries Commission “approve a statewide moratorium, on any commercial or recreational harvest of river herring.”

The FMP further states that: “More complete data are needed on adults during the spawning migration run regardless of whether a fishing season is in place. Fishery-independent data are deficient to non-existent.” Existing gillnet and fishery dependent surveys provide indices of relative adult abundance but no current methods provide estimates of absolute abundance that can be used to ground-truth stock assessments and develop best possible management approaches. The stock assessment currently relies solely upon landings data. If a moratorium is established, there will not be a reliable estimate of stock size. Therefore, a reliable fishery-independent method to evaluate and monitor migratory river herring stocks is needed.

The purpose of this two-year project is to assess the feasibility of using mobile fisheries hydroacoustics to survey migratory river herring populations in western Albemarle Sound. This is a pilot study to investigate whether these methods are cost-effective and can be used to produce absolute abundance estimates of river herring.