Celebrating World Aquatic Animal Day: The Jellyfish
April 3 is World Aquatic Animal Day, a day to celebrate and learn about the importance of all the aquatic creatures in our waters. Aquatic animals (including fish, amphibians, marine mammals, crustaceans, reptiles, mollusks, birds, and insects) provide essential services, including water purification, flood control, and nutrient cycling. They are integral parts of complex food webs.
Climate change and human activities are two main threats harming aquatic animals. Warmer and more acidic waters and the increase in overfishing and plastic pollution are altering ecosystems and are threatening the health of many aquatic animals’ habitats.
One aquatic animal that has been found in our waters even before the dinosaurs roamed the earth is the jellyfish. Scientists have found that jellyfish have been bobbing along in our oceans for over 700 million years. Some of the oldest traces of jellyfish have been found in Utah in the United States. They date back to when the entire West of the US was under the Pacific Ocean. Jellyfish can be found in abundant numbers all over the world, in cold and warm water, deep in the sea, or near the surface.
Despite their name, the jellyfish aren’t actually fish. They are invertebrates or animals without a backbone. The jellyfish are 95% water. Their bodies comprise just three layers— the outer epidermis, a gelatinous middle layer, and the inner gastrodermis. They have tiny stinging cells in their tentacles, which are used to stun or paralyze their prey before they eat them. They have one opening inside their body, which they use to eat and discard waste.
The jellyfish can vary in size. The smallest jellyfish are genera Staurocladia and Eleutheria, which have bell disks from just 0.5 millimeters to a few millimeters in diameter. The largest jellyfish in weight is the Nomura jellyfish, which has a bell diameter of 6.5 feet and weighs as much as 440 pounds. The jellyfish with the longest tentacles is the lion’s mane jellyfish, which can extend its tentacles as far as 120 feet.
The jellyfish are important for the health and survival of our aquatic ecosystems. Nutrients such as nitrogen and phosphate, which the jellyfish release, enable the growth of phytoplankton, which form the base of marine and freshwater food webs. Jellyfish control species populations and maintain the balance of the ocean’s ecosystem simply by feeding on smaller creatures such as fish larvae and eggs. Jellyfish are also food for other aquatic animals and even for jellyfish.
Jellyfish also provide feeding opportunities for the young fish who snack on small organisms that are found on the jellyfish or any prey that has fallen victim to the jellyfish. Their tentacles also provide protection for various fish species to grow in safety.
World Aquatic Animal Day and every day is an opportunity to celebrate unique aquatic creatures like jellyfish and the hundreds of thousands of other species found in our waters. There are many ways to celebrate this day, including:
- Learning about the threats aquatic animals face
- Visiting a local aquarium or wildlife sanctuary to learn more about aquatic animals
- Watching a documentary about sea life, such as The Blue Planet, Mission Blue, and Life in the Blue)
- Researching ways to reduce your use of plastics and products using microbeads
- Signing a petition supporting a ban on single-use plastics or other practices that threaten aquatic animals.
- To keep aquatic animals off of your plate, try a plant-based diet instead.
- Donating to aquatic animal organizations.
However you choose to celebrate World Aquatic Animal Day will help bring awareness to the underwater world we love and depend on.
