Sea Nettle Probability of Encounters
***Forecasts resumed on July 22, 2015 after a salinity adjustment was made based on CBIBS buoys. The salinity had drifted about 4 psu too high over the Summer and is being monitored and adjusted with a new correction every 2 weeks.***
The jellyfish often encountered in the Chesapeake Bay in the summer is the sea nettle Chrysaora quinquecirrha. Knowing where and when
to expect this biotic nuisance may help to alleviate an unpleasant encounter.
Chrysaora quinquecirrha is white and occurs most abundantly in the tributaries of the middle Bay, where salinities range from 10 to 20
parts per thousand (ppt). In the southern Bay, it often has red/maroon markings on the long central tentacles and on the swimming bell. C. quinquecirrha
occurs from Cape Cod south along the U.S. East Coast, Caribbean, and Gulf of Mexico; it abounds in the Chesapeake Bay in numbers unequaled elsewhere.
The maps are experimental and depict the probability of encountering sea nettles (jellyfish) in the Chesapeake
Bay and its tributaries. They are generated for the Chesapeake Bay Office of NOAA's Fisheries Service by
the National Centers for Environmental Prediction and the National Ocean Service. These
maps are numerical model guidance only; they are not fully validated and may not reflect actual conditions.
Additional sea nettle information, including the method to calculate encounter rate of sea nettles in the Bay, is available from
the NOAA Chesapeake Bay Office sea nettle forecasting web site. Contact
NOAA with any comments or inquiries.
(Mouseover and click the desired area to view the Sea Nettle Probability Guidance (Current Day and Day 2 Forecasts from latest model run)
(To see the full Chesapeake Bay click outside of the regional boxes.)