Over the past few years, jellyfish sunk a Japanese fishing vessel, forced a nuclear power plant to shut down in Sweden, and caused several other nuisances around the planet. You’ve probably heard by now that ‘jellyfish are taking over’ and that a ‘jellyfish apocalypse’ looms, but many scientists are saying there’s not enough evidence to support this worry, and that current population growth is likely part of normal fluctuation patterns, according to the Woods Hole Oceanographic Institution.
To help understand jellyfish trends, researchers from several universities developed the world’s first scientifically-coordinated jellyfish database, known as the Jellyfish Database Initiative, or JeDI. It maps jellyfish biomass across the upper 200 meters of the world’s oceans, and is filled with more than 476,000 data items on jellyfish and similar species.
“People say that jellyfish are increasing globally, but up until recently, we had never even done a global analysis. The whole issue is based on speculation, and really when scientists say ‘climate change and overfishing are driving jellyfish blooms,’ that’s still speculation because no one has done the analyses or identified the true mechanisms that link environmental drivers with jellyfish rising and falling,” says Rob Condon, a JeDI manager and assistant professor at the University of North Carolina Wilmington. “That’s what we’re doing now, and the research is ongoing.”
The comprehensive data in JeDI fills a long-withstanding knowledge gap about future trends of jellyfish populations, ecological and societal impacts of jellyfish blooms, and distribution patterns, according to a University of Southampton press release. For example, Dr. Condon is currently using JeDI to research whether sea turtles are migrating to areas of heavy jellyfish congregation. And further down the road, JeDI could be useful for climate reports, since blooms are often linked with climate change and degraded oceans, explains Condon.
“There are potentially ways to use this for management and conservation – and maybe there is a way that this could be used in tourism as a socio-economic,” says Condon. The researchers are also looking into creating a JeDI phone app so that beachgoers and citizen scientists can report sightings.
The database’s establishment compliments several recent studies on jellyfish. A University of Southampton study found that jellies and other zooplankton maintain a presence throughout the world’s oceans, but are most concentrated in the mid-latitudes of the Northern Hemisphere, according to the University of Southampton press release. Another study, led by Condon, found that global populations fluctuated over multiple-decade time scales. JeDI involved collaboration by multiple universities and groups, including the National Center for Ecological Analysis and Synthesis, the University of North Carolina Wilmington, the University of Southampton, the University of Mississippi and others.