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Welcome to the Jelly Jungle

Deep inside the Institute of Marine and Environmental Technology (IMET) building, the National Aquarium runs a little-known lab. Here we carry out the propagation of jellies, many of which later end up on exhibit in Jellies Invasion. Read on for a peek into the process!

Published November 04, 2019

Before learning about the propagation process, let’s be clear on what a jelly is. Jellies are animals, and while they don’t have brains or hearts, their cellular structure and other organs place them firmly in the kingdom of Animalia. They’ve been there awhile, too—jellies form the oldest multi-organ animal group, estimated to have existed for at least 500 million years.

There are more than 2,000 different species of jellies, and while they usually share the same general look and feel, many only share ancestors in the distant past. This means that despite looking almost the same, many species of jelly are only distantly related!

Jelly lab

With that in mind, let’s talk about moon jellies.

In their natural habitat, moon jellies “breed” in the millions. They follow a lifecycle somewhat similar to plants, with a polyp and medusa stage, which is roughly analogous to that of seedling and its flower. Polyps grow along the sea floor and bud immature jellies (called ephyra), which then grow into medusa-stage jellies—the typical jelly with a pulsating bell and tentacles that most are familiar with.

So when you see a medusa-stage moon jelly in the wild, you’re actually witnessing the tail-end of its life—the “flower” stage in which it sexually reproduces by releasing eggs and sperm.

In artificial habitats, jelly propagation can be challenging. The conditions created by the open ocean are difficult to recreate but are often necessary to jellies across their many life stages. So how do we do it?

Our aquarists have created a special jellies propagation lab, using specialized equipment, habitats and practices to help ensure a bumper crop of baby jellies—from moon jellies to flower hats!

Our aquarists propagate jellies from our own polyps, as well as polyps from wild-collected medusae and other aquariums and researchers to ensure genetic diversity.

By giving our polyps resting periods during which we carefully control water temperatures, our aquarists ensure that when the polyps are ready to produce medusa, their medusa are healthy! We then feed the resulting ephyra a home-grown diet of phytoplankton, zooplankton and even larval fish, depending on the species. As they reach the medusa stage, these jellies are kept in special circular nursery tanks called kreisels. These large, circle-shaped nurseries provide gentle water flow and smooth interiors that protect the infant jellies from injury.

Throughout the propagation process, jellies are continually moved to larger and larger nurseries, where their diet, light exposure, and water temperature are adjusted to mimic natural conditions.

Once the mature medusa stage is reached, the jellies are ready for exhibit!

Need a jelly fix? Check out our live jelly cam!

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