When you think of jellyfish, you probably picture a translucent, bell-shaped creature with flowing, stinging tentacles that you would hate swimming into on your spring break or summer vacation. But that’s only its grown-up Medusa stage. Jellyfish increase their chances of survival by cloning themselves several times, and they go through an unusual “stack of pancakes” phase! To film ‘baby jellyfish’ doing their thing, I headed to San Francisco’s Aquarium of the Bay. Get a new perspective on jellyfish and their incredible reproductive strategy in this week’s video and newsletter. You’ll also find out more about how I filmed them.
Josh Cassidy, Deep Look lead producer and cinematographer
Watch Jellyfish Go Through Their “Stack of Pancakes” Phase
When grown-up jellyfish love each other very much, they make huge numbers of teeny-tiny potato-shaped larvae. Those larvae grow into little polyps that cling to rocks and catch prey with their stinging tentacles. But their best trick is when they clone themselves by morphing into a stack of squirming jellyfish pancakes.
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🌙🎐 Moon jellies are either male or female. Males release sperm into the water, which females collect to fertilize their eggs. Fertilized eggs grow into larvae called planulae that mom sends out into the world.
🦶 Each planula attaches to something solid – a rock or coral – and grows into a polyp that holds on with a sticky foot.
☠️ At the polyp stage, jellyfish have stinging tentacles, just like adults, which enable them to catch prey like tiny crustaceans.
🥞 As they feed and grow, polyps clone themselves. And when the waters cool, they go through a second round of cloning called strobilation, which looks like they turn into a stack of pancakes.
🌟 Each individual pancake, called an ephyra, is a clone that eventually works itself free from the stack and swims off to grow into an adult.
PLAY
Name That Critter!
The larva of this ocean animal looks like a tiny spaceship. It swims from the open ocean to the shoreline, where it attaches to a rock and grows into a familiar spiny creature. If it doesn't end up in a restaurant, this animal can live more than 100 years. What critter is it? Find the answer at the bottom of this newsletter.
DEEP EVENT
Deep Look at the International Ocean Film Festival
Join Deep Look at the International Ocean Film Festival, running April 11-13 at the Cowell Theater in San Francisco’s Fort Mason. Deep Look’s coral spawning episode will be screening on Friday, April 11, at 4 p.m., and our six-rayed sea stars episode will be screening on Sunday, April 13, at 4 p.m. The producers of both episodes, Rosa Tuirán and Josh Cassidy, will be at the screenings. Check out the full schedule and enjoy many other amazing ocean films.
Josh Cassidy films jellyfish polyps at the Aquarium of the Bay with senior marine biologist Mike McGill looking on.
“Adult moon jellies grow to be the size of dinner plates, but during their sedentary polyp stage, they’re smaller than sesame seeds. The real challenge with filming this story was catching the moment when the individual ephyrae (juvenile jellyfish) detach from their fellow clones to swim off and start the next stage of their lives as free swimmers. Filming wildlife takes a lot of patience and this story was a prime example of that,” says Josh.
Join Deep Look’s Patreon today for as little as $3 per month and help us to keep making incredible up-close videos about the tiny, unseen dramas playing out every day in the natural world. Plus, depending on your level of support, you’ll get more behind-the-scenes stories and exclusive swag, like T-shirts, stickers and more!
Sea Urchin! Conceived in the open sea, tiny sea urchin larvae search the vast ocean to find a home. After this incredible odyssey, they undergo one of the most remarkable transformations in nature.
