Sea NettlesSea nettles (Chrysaora quinquecirrha) are stinging jellyfish that normally proliferate in the saltier regions of Chesapeake Bay from late spring to fall. Their abundance seasonally is largely controlled by water temperature and salinity.
Indicator Details
Sea Nettles
Sea nettles appear early and disappear early in 2009
Sea nettles (Chrysaora quinquecirrha) are stinging jellyfish that normally proliferate in the saltier regions of Chesapeake Bay from late spring to fall. In 2009 the number of sea nettles at the Horn Point Laboratory monitoring station was higher than the last two years, but still within average range. There was a large peak in late August, right before the sea nettles disappeared altogether. Disappearance, which is thought to be related to water temperature, occurred earlier than expected this year. That is, they disappeared before the temperature dropped below the lower limit of their tolerance, an event that is similar to what was observed in 2007. Scientists have noticed a link between the nettles losing their oral arms (used to bring food to their mouth) and final disappearance. This year, the entire population was missing their oral arms and shrinking in diameter within a couple of weeks, and about two weeks after that, there were no nettles observed at Horn Point Lab. Researchers plan on doing data analysis and experiments to try to determine what environmental variables may trigger early disappearances.
Sea nettle now-casts are available online at http://155.206.18.162/seanettles/index.php. Below is an example of the daily maps generated by NOAA scientists. This now-cast map corresponds to the highest spike of sea nettle counts observed at Horn Point Lab (figure above). The high probability of encountering sea nettles in the Choptank River (red circle) corresponds with the high counts observed at the Lab.
Acknowledgements:
Webpage courtesy of Maggie Sexton (UMCES).
For more information, see Mapping sea nettles in the Chesapeake Bay.