Posts Tagged 'jellyfish'

Animal Update – April 18

national aquarium animal update

Spotted Lagoon Jellies in Jellies Invasion!

We have spotted lagoon jellies now on exhibit in Jellies Invasion: Oceans Out of Balance!

Did you know? Instead of a single mouth, this species of jelly has many small mouth openings on its oral arms, which capture plankton.

These jellies love the sunlight! It fuels the growth of symbiotic algae in their tissues, giving them a greenish-brown to blue color in the wild.

Spotted lagoon jellies can be found throughout the South Pacific!

Be sure to check back every Friday to find out what’s happening!

The Annual Resurgence of Urban Jellies!

national aquarium animal expert update

In late summer and early fall, Baltimore visitors and downtown workers are often startled when they glance down into the harbor and see large pulsing Atlantic sea nettles!

national aquarium atlantic sea nettle

Photo via Flickr user KTSeery.

The Atlantic sea nettle (Chrysaora quinquecirrha) is a jellyfish species native to the western Atlantic and the tributaries of the Chesapeake Bay. If we ever had a Maryland State jellyfish, it would be the notorious Atlantic sea nettle. While it’s true that most jellyfish species do make their homes in the ocean and are unable to tolerate fresher, “brackish” waters, this sturdy species can actually thrive in it!

Their umbrella-like bell is about the size and shape of grapefruit half. Long stinging tentacles trail from the margin of the bell and are used to capture food which includes plankton, other jellies and small fish. These jellies pulse up and down the water column, day and night, in search of food. During moving tides and windless days, large numbers of nettles may gather near the water’s surface.

national aquarium atlantic sea nettle

This jelly was spotted in the harbor water right outside of the Aquarium!

Jelly species survive the cold winter in a sedentary, polyp stage attached to hard surfaces like oyster shells, rocks and pier pilings. These polyps resemble tiny sea anemones and capture microscopic plankton with stinging tentacles. In late spring and early summer, when water temperatures start to rise, each polyp will start to produce and release tiny free-swimming sea nettles.

Feeding on the Bay’s abundant supply of plankton these nettles grow and reproduce rapidly. A single sea nettle may release up to 45,000 eggs daily. By July and August, sea nettle populations continue to expand and push north into the upper Bay. By the end of summer and early fall, the lack of rain allows the waters of the Inner Harbor to become saltier. This is usually when Atlantic sea nettles start arriving in decent numbers into the Inner Harbor.

jellyfish in the inner harbor

Photo via The Baltimore Sun.

The abundance of good food in these deep harbor waters usually results in some fairly massive nettles! And, just as our downtown sea nettle show starts to attract attention, it will soon come to an abrupt end. As the water temperatures begin to drop, the nettles die off and/or start shrinking rapidly. Though the jellies quickly disappear, it’s exciting to know that millions of tiny Atlantic sea nettle polyps are scattered throughout the Bay waiting for the warming waters of spring to start the annual cycle all over again!

national aquarium expert jack cover

Adventures in Jellyfish Collecting

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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

Animal Updates – September 13

Between our Baltimore and Washington, DC, venues, more than 17,500 animals representing 900 species call the National Aquarium home. There are constant changes, additions, and more going on behind the scenes that our guests may not notice during their visit. We want to share these fun updates with our community so we’re bringing them to you in our weekly Animal Update posts!

Check our blog every Friday to find out what’s going on… here’s what’s new this week!

Leidy’s comb jellies on exhibit! 

leidy's comb jelly

These amazing creatures can now be seen in  Jellies Invasion: Oceans out of Balance!

Did you know? Leidy’s comb jellies are bioluminescent, meaning they can make their own light (which they flash when disturbed).

leidy's comb jelly

This species looks different from other jellies because it’s not made up of a bell and tentacles. Instead, it is a translucent walnut-shaped body with wart-like bumps. For this reason, it’s sometimes called a sea walnut.

They make look “out-of-this-world,” but the natural range of this species is much closer than you think! They’re commonly found in the coastal waters of the Atlantic, from Cape Cod down to the Carolinas.

Be sure to check back every Friday to find out what’s happening!

A Blue View: Jellies – Oceans Out of Balance

A Blue View is a weekly perspective on the life aquatic, hosted by National Aquarium CEO John Racanelli.

From the smallest plants and animals invisible to the human eye to entire ecosystems, every living thing depends on and is intricately linked by water.

Tune in to 88.1 WYPR every Tuesday at 5:45 p.m. as John brings to the surface important issues and fascinating discoveries making waves in the world today.

August 14, 2013: Jellies – Oceans Out of Balance

A Blue View podcastClick here to listen to John discuss how the rapid increase in jellyfish
populations has 
negatively impacted the health of our oceans. 

Beautiful, eye-catching, and otherworldly, jellyfish are dazzling creatures to look at, though not something you want to run into at the beach.

Not technically fish, jellies have drifted through our seas for more than 500 million years. They range in size from that of a pinhead to more than 8 feet in diameter, with tentacles 130 feet long. Most species have tentacles that sting, even when they become detached from the jelly’s body. And, as many a beach-goer can attest, those stinging cells can make for some less than pleasant experiences when our paths accidentally cross.

Related to sea anemones and corals, jellies have no heart, brain, blood, or bones, and are 95 percent water. Contrary to popular myths, jellies are not out to get you. As ocean drifters, they are carried along on ocean currents. But their vast numbers in certain places have made them a menace, and their unique ability to thrive in less-than-ideal conditions has scientists keeping a close eye on these fascinating creatures.

Jellies seem less susceptible to algae blooms, pollution, warming waters, and reduced oxygen levels, meaning that the more the environment deteriorates, the better it is for jellies. In an alarming phenomenon dubbed “jellification” by some scientists, jellies in some areas of the world are literally taking over the seas.

The role of jellies in the ocean ecosystem and whether or not their increasing numbers are displacing other ocean inhabitants are both matters of active debate in the marine science community. There are several reasons attributed to the rise of jelly populations. In addition to their ability to thrive in inhospitable conditions, jellies benefit when the fish, turtles, and other species that normally eat them are overfished. Then, as jellies eat zooplankton, fish eggs, larvae, and even fish, they further impact the food chain, perpetuating an imbalance that’s difficult to correct.

An overabundance of jellies isn’t good for tourism around the globe, particularly when they wash up on beaches. Depending upon the species, a jellyfish sting can cause anything from mild discomfort to severe pain and in rare cases, like the box jellies of Australia, even death. Jellies also affect fisheries—and fisherman—when they collide with nets, sometimes even killing the catch with their toxins. Jellies can also cause power outages and equipment damage at power plants by clogging cooling intakes.

Considered a delicacy in China, some see dining on these unique creatures as a creative and efficient way to control the jellyfish population. The European Union has embarked on an international research program to evaluate the spread of jellies in the Mediterranean and other regions and develop a coastal management strategy accordingly.

For all the issues that jellyfish blooms can cause, they are essential and active participants in the ocean ecosystem. They belong there. The best way you can keep bays and oceans healthy is to make smart choices at home. One important place to start is in your yard. Avoid overfertilizing your lawn and garden. Excess fertilizer washes into our waterways, reduces oxygen, and contributes to harmful algae blooms—conditions that are great for jellies but terrible for fish populations. You might even consider opening your mind to a new delicacy when jellies show up on a restaurant menu near you.

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