Jellyfish in Barnegat Bay (Sea Nettles)

Overview

Sea nettles (Chrysaora quinquecirrha) have in recent years become more abundant in estuaries of the Mid-Atlantic region.  These stinging jellyfish are a serious nuisance on bathing beaches because of their large size and numerous stinging cells (nematocysts).  Although the species ranges from Cape Cod south to the Gulf of Mexico, it reaches greatest numbers in Chesapeake Bay.  Peak numbers occur in mid to late summer when water temperatures exceed 77 ºF.

Adult sea nettles are free-floating forms that have a well-developed, bell-shaped cap (> 10 cm in diameter) from which an array of tentacles extend downward toward the seafloor.  The tentacles, which can be more than 1 m in length, contain numerous nematocysts that pose a threat to pelagic organisms and a hazard to unsuspecting swimmers.  The unusual anatomy of sea nettles and other jellyfish species enables them to be transported considerable distances by estuarine and nearshore ocean currents.

Sea Nettles in Barnegat Bay

Sea nettles have only recently become a serious problem for human use of New Jersey’s coastal bays.  Prior to 2000, sea nettles were not present in the coastal bays in elevated numbers.  However, between 2000 and 2004 periodic blooms of the jellyfish occurred in various areas, most notably the lower salinity waters of the Barnegat Bay-Little Egg Harbor Estuary.  The summer of 2004 was particularly problematic.  Mid-summer abundance maxima were recorded then, with highest concentrations found north of the Toms River in embayments from Silverton to the Metedeconk River.  A serious eruption of sea nettles has occurred in the estuary during the summer of 2006.

The Barnegat Bay-Little Egg Harbor Estuary is a highly eutrophic system, meaning that its waters are over-enriched with nutrients (notably nitrogen) and excess organic carbon loading.  Research scientists at the University of Maryland, who have studied sea nettle problems in Chesapeake Bay, indicate that the jellyfish blooms are coupled to elevated nutrient levels associated with fertilizer runoff and other watershed waste inputs.  Therefore, the co-occurrence of sea nettle blooms and high nutrient inputs (>1 million kilograms per year of nitrogen to Barnegat Bay) infers a direct link to human activities in coastal watershed areas.  A similar relationship has been established in Chesapeake Bay and its watersheds.

What causes the abundance of Sea Nettles?

Many scientists believe that excess nonpoint source (NPS) pollution leading to elevated levels of nutrient levels is attributed to elevated jellyfish.  NPS pollution is caused by rainfall or snowmelt moving over and through the ground. As the runoff moves, it picks up and carries away natural and human-made pollutants, finally depositing them into lakes, rivers, wetlands, coastal waters, and even our underground sources of drinking water. Now, more than 60 percent of water pollution comes from NPS such as cars leaking oil, fertilizers from lawns and gardens, and failing septic tanks.  Visit our NPS pollution page for more information on what you can do to help!

Global warming may be another factor in the northward expansion of jellyfish blooms in U.S. estuaries.  Sea nettles thrive at temperatures above 77 ºF, and the warmer summer temperatures during the past two decades have probably fostered this expansion.  Increasing nitrification of bay waters, together with rising water temperatures, spells trouble for susceptible estuarine environments.

Solutions

There are no quick solutions.  Remedial actions that involve physical removal of sea nettles from estuarine waters are rarely successful once the jellyfish take up residence.  Attempts to net and remove jellyfish may actually increase their distribution and abundance.  The jellyfish larvae occur as cysts in parent tissue that then can be released by physical destruction of the jellyfish body by netting or other damaging shots to the body of the organism. The larvae can then be dispersed by currents while developing into later life stages.

Probably the best approach is to reduce pollution inputs and eutrophic conditions in the estuarine waterbody.  Water quality alteration must also be minimized by improving pollution controls at the watershed source and by instituting best-available stormwater controls.  In addition, greater enforcement of environmental regulations is necessary, as is the establishment of nutrient criteria (which currently do not exist) for coastal waters.  Therefore, the long-term solution to the sea nettle problems in New Jersey’s coastal bays requires more effective administrative/management intervention.

Treatment for stings

According to Maryland Marine Notes, "there are several things that you can do if you get stung. If bits or pieces of tentacles are still on the skin, pour alcohol or baby powder on the area. Alcohol will stabilize the nematocyst so that it will not be triggered. Powders do the same by drying the cells out. Without such treatment, tentacles which are disturbed may release additional nematocysts, causing additional irritation and swelling.

Next, apply diluted ammonia, sodium bicarbonate, vinegar or meat tenderizer to the area to relieve pain. Meat tenderizer is one of the best sources of relief from stings. Add a small amount of water to the meat tenderizer to make a paste and smear it on the inflamed area. Meat tenderizer is an enzyme which breaks down proteins. Jellyfish venom is made of protein and is consequently destroyed by the meat tenderizer."

A special thanks to Dr. Michael Kennish from the Institute of Marine and Coastal Sciences, Rutgers University for providing information for this page to the BBNEP.