Aquarium Biologists Decipher Complex Life Cycle of Flower Hat Jellies

Jul 02, 2014

Exhibits & Animals
Special Exhibitions

Marine biologists solve a puzzle that has baffled them for over a decade

Monterey Bay Aquarium is celebrating the success of its team of jelly biologists, which has mapped the elusive life cycle of Olindias formosus – the stunning flower hat jelly, whose multicolored, fluorescent-tipped tentacles are like a living fireworks show.

The flower hat jelly was originally described in Japan over 100 years ago, but its life cycle was a mystery. Biologists around the world have been eager to exhibit this gorgeous jelly, but were unable to culture it to adulthood. Now – after 12 years of research – the aquarium has solved the mystery, and the public can see these cool jellies in “The Jellies Experience” special exhibition.

“We’re thrilled to discover the life cycle of the flower hat jelly,” said Senior Aquarist Wyatt Patry. “Our team succeeded through collaboration, diligence and a bit of good luck.”

Patry is lead author of a paper describing the team’s achievement, which was published online June 24 in the Journal of the Marine Biological Association of the United Kingdom. The other authors are Aquarist II Thomas Knowles and Senior Aquarist Michael Howard of the aquarium, and Research Technician Lynne Christianson of the Monterey Bay Aquarium Research Institute (MBARI).

The discovery could lead to predicting dangerous jelly “blooms” in the wild. The flower hat jelly packs a powerful sting, enabling it to kill and eat fish – and harm humans. Blooms of hundreds or thousands of these jellies off Japan and Brazil have resulted in injuries to many beachgoers, and at least one death, Patry said.

Found in coastal waters off southern Japan, Brazil and Argentina, and in the Mediterranean, the flower hat jelly has brilliant tentacles trailing from its translucent, pinstriped bell. Another set of curly tentacles under its bell can quickly unfurl and grab prey. This nocturnal species swims in the water column at night and attaches itself to the seafloor during the day.

The aquarium’s work to understand the life cycle of this mysterious jelly began in 2002 during the “Jellies: Living Art” special exhibition, which ran from 2002 to 2008. That team was the first to successfully exhibit flower hat jellies in the United States, and culture fertilized eggs and larvae – another first.

Patry said the current team’s initial breakthrough occurred with a redesigned exhibit that let flower hat jellies capture and eat live fish and kept them away from debris on the bottom. Patry said the team hoped those conditions would encourage successful reproduction – and they did.

Special blue lighting in the exhibit was the next breakthrough. Flower hat jellies, which are fluorescent, are in a gallery that interprets three different types of “lights” in certain jellies – fluorescence, bioluminescence and diffraction. About six months after putting a batch of flower hat jellies on exhibit, Patry noticed two previously unseen stages of their life cycle – polyps and tiny baby jellies.

“I was only able to see them because they are fluorescent, like the adults,” Patry said. “From there we worked with the polyps to refine the ideal food and temperature requirements for them to produce more babies.”

Download this release as a PDF

The mission of the nonprofit Monterey Bay Aquarium is to inspire conservation of the ocean.