Cooperative Development and Testing of Sink Gillnet Modifications for Reducing Bycatch of Atlantic Sturgeon While Maintaining Target Species Catches

In 2012, five DPSs of Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) were listed under the ESA.  The preceding Status Review concluded that bycatch in sink-gillnets was a significant hurdle to Atlantic sturgeon recovery.  Over two field seasons (2010, 2011), we worked with commercial fishermen on sink gillnet modifications to achieve reductions in sturgeon bycatch while still achieving adequate catches of target species.  In 2010, we fished paired replicates of gillnets (12 meshes x 30.5cm stretch) with and without tie-downs and although Atlantic sturgeon bycatch did not differ significantly, target species catches were reduced in the no tie-down nets.  In 2011, we subjected two different tie-down configurations to the same experimental protocol.  Bycatch of Atlantic sturgeon was reduced in the short tie-down nets but landings of target species were minimally impacted.  Our findings suggest that the use of tie-downs is important for maintaining adequate catches of target species, and that certain tie-down configurations can reduce Atlantic sturgeon bycatch.  Additionally, experimental testing of gear developed by harvesters allows for the identification of gear configurations that both address conservation objectives and are realistic for use in commercial harvest.  This model of collaborative research may prove useful in the recovery of other imperiled sturgeons.