Thursday, July 8, 2010

The Chesapeake Bay “Ouch” Forecast

Have you met Chrysaora quinquecirrha? If you’ve spent time in the Chesapeake Bay in the summertime, you probably have. His more familiar name is sea nettle, and he is not one of the most pleasant fellows you will ever meet. The sea nettle is a large sea jelly, a semi-transparent bell-shaped invertebrate with long stinging tentacles. Chrysaora quinquecirrha lives along the Atlantic Coast south of Cape Cod. Like many of us, he loves the Chesapeake Bay and its tributaries and can be seen in greater abundance here than anywhere else on the East Coast.
Getting tangled up with a sea nettle is not a fun experience. Those long tentacles contain thousands of microscopic nematocysts; upon contact the nematocysts fire a stinging filament into the victim. Sea nettle stings are not fatal but do cause a burning sensation and a painful rash. People often carry a bottle of meat tenderizer in their beach bags to counteract the sting, but plain vinegar works just as well. Vinegar prevents unfired nematocysts from firing thus preventing further discomfort.
Want to know how to avoid this unpleasant fellow? This summer NOAA is experimenting with sea nettle forecasting. Their website ( includes a map predicting the probability of encountering one, based primarily on water temperature and salinity. Sea nettles prefer water temperatures between 25° and 30°C (77° - 86°F) and salinity between 10 and 20 parts per thousand. Unfortunately for those of us who love it, the Chesapeake Bay is an ideal sea nettle habitat. So next time you head to the bay or the “Rivah” to swim or water ski, check out NOAA’s sea nettle prediction map. That way, you will know whether or not to pack the meat tenderizer.

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