July 25, 2018

Jellyfish Barrier Nets – Do They Work?

by S-FX.com

sea nettle jellyfish barrier jim

A newly published peer-reviewed article in Ocean & Coastal Management reports the results of a BBP project studying the effectiveness of low-cost barriers in limiting interactions between bathers and stinging jellyfish. The BBP conducted the “Bay Nettle Barrier Pilot Project” during the 2011 and 2012 bathing season at two beaches, the Lavallette bay beach and Windward Beach in Brick. BBP scientists installed a prototype barrier net around each bathing area to study its effectiveness in limiting contact between bathers and any bay nettles that may have been present. Used twice a week at each location, weather permitting, the barrier net was set up in the morning and removed the same afternoon.

Sea Nettle Net Barrier 20113 Scaled

BBP researchers seined both within and outside the protected area before removing the net. They identified, counted, and measured any jellyfishes and fishes captured by seining or in the barrier net itself. They also recorded water quality data. This pilot project was designed to test the effectiveness of the barrier net in excluding bay nettles, gather information about any impacts the net may have had on other bay animals, and obtain data about bay nettle populations.

Highlights of the research findings include:

  • The presence of a net-style barrier reduced the mean number of bay nettles captured within the exclusion areas by 28% – 67% compared to immediately adjacent waters.
  • The mean size of the nettles (bell diameter) captured within the exclusion areas was also significantly smaller than that in the adjacent areas.
  • There were limited interactions with other local fauna.

The full paper can be viewed or downloaded here.

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UNKNOWN

There is limited data available to quantify Wetland and Riparian Buffer Preservation, or updated data to quantify Wetland Acreage. The BBP has obtained funding and will begin assessment efforts for both targets, in the next few years.

 

 Hard Clam abundance has not been updated since 2012. Recovery of the stock will be guided by the Fishery Management Plan for Hard Clams, which is under development with the NJDEP, BBP, and other organizations. Reclam the Bay and other partners have continued to plant clams for restoration purposes. Continued plantings in strategic locations which maximize survival and reproduction is one strategy to pursue in the coming years. This work can use a model developed by Rutgers with BBP funding which identified areas where planted clams could have the greatest dispersal of their larvae and thus potentially maximally contribute to the recovery of the stock.

 Water Withdrawals were over the target in the 2021 report; USGS has not yet completed its latest update, so a definitive determination of status is not available. However, additional NJDEP data show that it is likely that we continue to not meet the target. Per capita water use has gone down, demonstrating the effectiveness of water-saving appliances and practices, but that decrease has been offset by population gains. 


IN PROGRESS

New maps quantifying Submerged Aquatic Vegetation extent were developed, but poor image clarity resulted in a high degree of uncertainty in the total acreage. NJDEP and Rutgers are working to resolve the uncertainty of these maps, and improve the total acreage estimate. Funding has also been obtained for further research and restoration activities. Several groups are developing potential restoration actions.

The USGS has completed the first phase of its study to identify minimum ecological flows in select Barnegat Bay tributaries. USGS scientists compared streamflow statistics between historical and current time periods to better understand trends in watershed flow conditions. This work provides a foundation for developing ecological flow targets in the Barnegat Bay watershed.  Similar to SAV extent, funding (approximately $450K) has been obtained by the BBP to complete the remaining phases necessary for threshold determination.

 

TARGETS ACHIEVED

No targets can be considered “Achieved” at this time.

 

NOT ACHIEVING

Several Public Swimming Beaches exceeded their safe swimming standards more frequently than during their baseline time period (2016-2018).

While most beaches are routinely safe for swimming, several problematic areas such as Beachwood, Hancock, Windward, and several lake beaches need track-down studies and restoration to pinpoint and address sources of bacteria.

Acres of Approved Shellfish Waters decreased from the last report. While this decrease was small, it represents a loss of previously approved waters. Similar to public beaches, track-down studies and restoration work are needed to pinpoint and address sources of bacteria.

 

Jellyfish Barrier Nets – Do They Work?

A newly published peer-reviewed article in Ocean & Coastal Management reports the results of a BBP project studying the effectiveness of low-cost barriers in limiting interactions between bathers and stinging jellyfish. The BBP conducted the “Bay Nettle Barrier Pilot Project” during the 2011 and 2012 bathing season at two beaches, the Lavallette bay beach and Windward Beach in Brick. BBP scientists installed a prototype barrier net around each bathing area to study its effectiveness in limiting contact between bathers and any bay nettles that may have been present. Used twice a week at each location, weather permitting, the barrier net was set up in the morning and removed the same afternoon.

Sea Nettle Net Barrier 20113 Scaled

BBP researchers seined both within and outside the protected area before removing the net. They identified, counted, and measured any jellyfishes and fishes captured by seining or in the barrier net itself. They also recorded water quality data. This pilot project was designed to test the effectiveness of the barrier net in excluding bay nettles, gather information about any impacts the net may have had on other bay animals, and obtain data about bay nettle populations.

Highlights of the research findings include:

  • The presence of a net-style barrier reduced the mean number of bay nettles captured within the exclusion areas by 28% – 67% compared to immediately adjacent waters.
  • The mean size of the nettles (bell diameter) captured within the exclusion areas was also significantly smaller than that in the adjacent areas.
  • There were limited interactions with other local fauna.

The full paper can be viewed or downloaded here.

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sea nettle jellyfish barrier jim