As the weather heats up, many Bay residents and visitors consider taking a swim in the Chesapeake. Knowing where they might see the sea nettle Chrysaora quinquecirrha—commonly referred to as “jellyfish”—can help swimmers avoid a stinging encounter. To help people be aware of the chances of encountering sea nettles at buoy locations, new this year, CBIBS now provides “Sea Nettle Probability” as a parameter tracked at each of the buoys. Just click on the buoy you want the information for via the Locations section and scroll down to the data.
The buoys do not actually count sea nettles; instead, data observed at each buoy—water temperature and salinity—is fed into an equation that determines the likelihood that sea nettles are present at that point in the Bay. For several years, the NOAA Chesapeake Bay Office has hosted a sea nettle probability site, based on the same equation, which uses data obtained by NOAA satellites.
Chrysaora quinquecirrha ranges from Cape Cod south along the East Coast to the Caribbean and around to the Gulf of Mexico, but it abounds in the Chesapeake Bay in numbers unequaled elsewhere. Observations have shown that concentrations of these sea nettles are found within a relatively narrow, well-defined range of temperature (79-86° F) and salinity (10-16 PSU).