Thursday May 10, 2012 @ 11 am
James J. Howard Marine Sciences Laboratory Conference Room

Jim Vasslides, Jennifer Barny, Nina Sassano
Barnegat Bay Partnership, Ocean County College, Toms River, NJ

Early results from the Barnegat Bay Sea Nettle Barrier Pilot Project

In recent years, Atlantic sea nettle (Chrysaora quinquecirrha) populations have been increasing in Barnegat Bay. Because little is known on how to reduce populations, we developed a project to test the effectiveness of a barrier net in protecting bathers from these stinging jellyfish. Two beaches were chosen for this pilot program: Windward Beach on the Metedeconk River in Brick, NJ, and Brooklyn Avenue Beach on Barnegat Bay in Lavallette, NJ. From June through September of 2011, a 1 ½-inch (38mm) square mesh gillnet was deployed twice a week at each beach, with the intent of preventing nettles from entering the beaches’ bathing areas. Once a week, we pulled a 50-foot bag seine both inside and outside the barrier at each beach to test the barrier’s efficacy at excluding nettles from the bathing areas. Peak jellyfish abundance occurred in the first two weeks of August, and coincided with the optimal water temperature range (26-30°C) established by researchers in the nearby Chesapeake Bay. However, we found peak abundance did not match the optimal salinity range established by previous research. In both Brick and Lavallette, peak abundance occurred when salinity was above the 16 psu threshold established in Chesapeake studies. Our results show a bell diameter distribution of 8-120mm, with a mean of 34.6mm in Brick and 44.5mm in Lavallette, and a mode of 30mm in Brick and 39mm in Lavallette. In general, the barrier was successful at excluding 59.9% of the jellyfish from the swim area in Brick, and 54.6% from the swim area in Lavallette. These seemingly wide ranges are likely a result of the different gillnet deployment methods utilized, as well as deteriorating barrier net conditions due to blue crabs. These preliminary results indicate that barrier nets may be useful at some bathing beaches in the Barnegat Bay with additional refinement of mesh size and other net properties.

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