Adventures in Jellyfish Collecting


When planning what species to display in Jellies Invasion: Oceans out of Balance, we knew it would be important to include species found in local waters. To keep our exhibits full of jellies, National Aquarium staff venture out to the Chesapeake Bay throughout the year to collect the following local species: Atlantic sea nettles (Chrysaora quinquecirrha), Leidy’s comb jellies (Mnemiopis leidyi) and Lion’s mane jellies (Cyanea capillata).

Our most frequented spot for jellyfish collecting is on the Eastern Bay, off the southeast end of Kent Island. This past weekend, we launched from my family’s waterfront property located in the southeastern region of the island. My nephew, Joe Cover, Jr., a resident of Kent Island and an avid fisherman, is my unofficial jellyfish monitor/assistant. He keeps me posted on when and where he is seeing groups of jellies.

Ideal jelly-collecting conditions include a moving tide (to raise jellies to the water’s surface), little to no wind and a cloudless sky (the mostly transparent Leidy’s comb jelly is almost impossible to spot when the sky is overcast). There are times when you believe the conditions are ideal, yet few or no jellies are found at the surface. When this happens, my standard line is, “You know, we have just been outsmarted by an animal that has no brain.”

jellies collecting trip 2013

We were glad to see calm waters and no clouds this past Saturday!

Equipped with collecting bags, five-gallon buckets, glass beakers and special plastic jelly-collecting nets, we motored out to the middle of Eastern Bay. The water was a bit choppy, but I stopped the boat as soon as I saw a “slick,” a narrow band or area of still water among the light waves. Natural slicks are sometimes formed when concentrations of microscopic diatoms gather at the surface and release natural oils that change the surface water’s density and retard the formation of ripples and small waves.

As we slowly drifted along with the wind and tide, we started to see Atlantic sea nettles and large Leidy’s comb jellies (a whopping 3 to 4 inches long) pulsing along the surface. We were in the right place at the right time! Upon further examination of the water’s surface, we saw thousands of tiny copepods (zooplankton) gathered – another great sign! Jellies continued to surface to feed on the copepods and, in some cases, each other. Yes, some jellyfish (like Atlantic sea nettles) include other jelly species (Leidy’s combs) in their diets.

I started filling collecting bags placed in five-gallon buckets with Bay water.

jellies collecting trip 2013

Jellyfish have no bones and little body structure. In fact, 96 percent of a jellyfish’s body is water! A delicate jelly can easily be injured if it is removed from the water or rubs against any abrasive surface. To avoid injuring our specimens, we used smooth-sided beakers to corral the jellies. The jelly is then moved, in water, to one of the water-filled plastic bags in a bucket. The beaker is submersed into the bucket and tilted to gently release the jelly.

jellies collecting trip 2013

Care must be taken to prevent the creation of air bubbles, which can get trapped in the jelly’s tissues and injure it. This is why beakers containing jellies are not poured in from above the water’s surface. Leidy’s comb jellies are especially fragile and must be transported with extra care.

In addition to their delicate body structures, quick temperature changes can be detrimental to jellyfish. It was relatively cool on this sunny afternoon, and the water in the buckets was staying close to the temperature of the Bay water. In a relatively short period of time, we filled six five-gallon buckets to capacity with jellies.

We headed back to the dock to prepare the buckets for transport to the Aquarium’s Jellies Lab. Prior to loading the buckets into the car, air is removed from each bag, which is then sealed with a rubber band. After loading up the car, I headed back over the Bay Bridge to the Aquarium. The car’s air-conditioning kept the jellies at their preferred temperature.

Once at the lab, the buckets of jellies are unloaded and the rubber bands are removed to allow gas exchange to the water.

The final leg of the jelly-collecting process is to slowly acclimate these jellies to the water in an exhibit or holding tank. I hand this part of the journey off to the Jellies staff. All incoming jellies need to be slowly acclimated to both the temperature and the salinity of our exhibit water. This process can take several hours or several days depending on how the salinity of the Bay and our exhibit waters compare.

Jellyfish continue to fascinate and amaze our visitors. We’re glad to provide our jellyfish gallery as a wonderful resource to connect people with our local jellies!

Jack Cover

5 Responses to “Adventures in Jellyfish Collecting”

  1. 1 Ann Cornett September 24, 2013 at 10:36 am

    did you ever get stung by a jellyfish? if so what did you do for the pain or to take out the sting?

    • 2 National Aquarium September 24, 2013 at 5:19 pm

      From Jack:

      Growing up in Maryland and vacationing with my family on Kent Island I received my share of stings from Atlantic sea nettles. The worse sting I received was as a teenager swimming just off a Kent Island beach, near Matapeake pier, in the main stem of the Chesapeake. I had the misfortune of swimming in murky water face first into the sting tentacles of a very large Atlantic sea nettle. Thousands of tiny sting cells nematocysts injected me with venom when the tentacles contacted my skin. I was stung across my face, arms, neck and chest. A typical sting causes slight pain and a skin rash that itches. The amount of venom that this large sea nettle injected resulted in systemic symptoms- nausea and vomiting. My Mom applied the home remedy of meat tenderizer. After about an hour’s time I the symptoms largely disappeared. What a hands on lesson in biochemistry that was!

      A dermatologist at the University of Maryland, Dr. Joseph Burnett, conducted lots of research on jellyfish stings( primarily Atlantic sea nettles) several years ago and found that most of the home remedies and recommended First Aid treatments for jellyfish stings were completely ineffective. Applying vinegar, meat tenderizer, rubbing alcohol and urine did not neutralize the venom as it was already injected into the victim’s body. Luckily the stings of our local jellies are not life threatening. Stings from tropical species like the Portuguese man-of- war are more serious and require immediate emergency medical attention. A typical recommended treatment for an Atlantic sea nettle sting includes rinsing the sting site with freshwater (showering) and taking an over –the- counter oral antihistamine like Benedryl. If symptoms are more severe than minor pain and itching it would be best to seek medical attention.

      I do occasionally brush up against the stinging tentacles of Atlantic sea nettles while collecting but the stinging nematocysts cannot penetrate through the thick calloused skin on my hands. However I do feel the sting when a tentacle contacts the more tender areas of my arms.

  2. 3 Barry Kidd September 26, 2013 at 10:22 pm

    Hi there Jack and thank you for sharing.

    Though I only live a few miles north of Baltimore hadn’t seen the “Jellies Invasion: Oceans out of Balance” except till just this past weekend. I still haven’t gotten over what how amazing these creatures are.

    Since then I’ve been reading quite a bit about them. Though I’m by no means the all seeing and all knowing jellyfish guy I do find them not only beautiful but very interesting.

    Have a happy day,


    • 4 National Aquarium September 27, 2013 at 9:20 am

      Thanks for the note, Barry!

      We’re so glad you were able to come down and check out our Jellies exhibit! If you have any questions for our jellyfish guy, Jack would be more than happy to try and answer them!

      • 5 Barry Kidd September 27, 2013 at 12:41 pm

        Thank you. In truth the only thing that keeps crossing my mind is that I would love to photograph them in the wild. I’m sure to get a decent shot however that you would need to light them from the side rather than direct flash from the camera. Perhaps not, but it just seems that way to me. Their so translucent that direct flash just wouldn’t work.

        Unfortunately I’m not really setup for that type of work. Either way it would be a great experiment worth trying someday.

        Last, I’m sorry for the typos in hieroglyphic message above. Rule #1. Never send a message to anyone other than your wife when you’re in the either zone and can barely keep your eyes open!

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