Bay Nettles & Other Gelatinous Zoolpankton

Bay nettles (Chrysaora chesapeakei), a type of stinging jellyfish, are present in the waters of Barnegat Bay and other coastal waterways of New Jersey, especially in the warmer months.

The Barnegat Bay Partnership has been surveying the presence of bay nettles at popular bathing beaches in the Barnegat Bay since 2011, and our data does not show any significant increase or decrease in the population over that time.

Regardless, these nuisance species cause an irritating sting when they come into contact with humans and remain an unwelcomed part of most people's time trying to enjoy the bay.

A complicated Life cycle

Nettles (like many other jellyfish species) have a complicated life cycle. They can reproduce sexually through fertilization or asexually through budding. Check out this video to learn a little more about the life cycle of the nettle!

Note: This video was made before the bay nettle was identified as a species distinct from the sea nettle, Chrysaora quinquecirrha, but the life cycle remains the same.

How We Are Working to Understand Jellies

Population Surveys

The BBP has been interested in documenting population trends of the Atlantic Bay Nettle since 2011 when, in partnership with Conserve Wildlife Foundation, we launched the Sea Nettle Barrier Project. This project aimed to test a prototype net designed to reduce swimmer contact with stinging sea nettles. Installed at Lavallette’s bay beach and Brick’s Windward Beach, the net was deployed twice weekly, with researchers collecting data on jellyfish populations, water quality, and impacts on marine life.

Since then, the BBP has continued to sample the presence and abundance of bay nettles at fourteen sites/bathing beaches in the region. Teams haul the seine net throughout the summer season and count, measure, and identify all species caught.

In the summer of 2024, our team added a secondary net to the survey to determine the likelihood of a swimming being stung based on the number of jellyfish present. This data was applied to the over ten years of presence/absence data collected by the BBP to determine a sting likelihood index.

Our team is currently "crunching the numbers" and are hoping to publish those findings soon.

5 Potential factors contributing to the expansion of the bay nettle population in the Barnegat Bay estuary.

1. The “hardening” of shorelines throughout the bay (e.g., bulkheads, pilings, docks) provides habitat for jellyfish “polyps.” Each jellyfish polyp buds off many baby jellyfish.

2. Changes in the salinity in the bay can shift the distribution of jellies in the bay, as some jellies, including sea nettles, have a “narrow” salinity tolerance. Examples of factors that can cause large-scale changes in salinity include weather conditions, increased potable water use, and large offshore discharges of sewage effluent.

3. Increasing water temperature accelerates growth rates and maturation of bay nettles.

4. Fishing affects the abundance of jellies in the bay: different fish species may eat polyps, larvae, and adult jellies. Some fishes and other animals also compete with jellies for their microscopic food, such as copepods.

5. Eutrophication, an increase in the bay’s production due to nutrient loading (see a,b, and c, above), also may affect the abundance of jellies. Nutrients stimulate the production (growth) of phytoplankton, which leads to increases in small zooplankton (such as copepods) which are the favorite food of jellies. Phytoplankton production also makes the water more turbid, making it difficult for visually-feeding animals, such as fishes, to find food. Eutrophication may also reduce the oxygen in the water. Unlike fishes and most other invertebrates, most jellies are tolerant of low oxygen conditions.

Can we get rid of them?

Since jellyfish have always been a part of the bay’s ecosystem, the goal would be population control, not complete eradication. There have been a number of attempts to control jellyfish worldwide, but none have been particularly effective. Nets and bubble screens have been used to keep them away from swimming areas, but the jellyfish either clogged the mesh of the nets or the tentacles were broken into pieces that continued to sting. The bottom-living stage of their life was targeted with chemicals, but that also killed many other organisms. A combination of actions that target the potential reasons for their increase as outlined above may be the best long-term solution.

What should I do if I’m stung?

Prevention of stings through the use of lightweight protective clothing (lycra “rash guards” or panty hose), or petroleum jelly spread on unprotected skin, is recommended for areas with high concentrations of sea nettles. If you are stung, clean the affected area with salt water to remove any tentacles remaining on the skin (fresh water may cause more stings from any tentacles still on the skin). Apply shaving cream, or a paste of baking soda and salt water, and scrape it off to help remove any remaining stingers. Ice may help with pain and itching. Seek medical attention for any serious reactions.