Are Global Jellyfish Populations Really Increasing?

Written by on January 3, 2013 in Jellyfish, Marine Life

Over the last few years, stories about jellyfish blooms and the threat of increasing jellyfish populations have become more popular. Now, some scientists are questioning whether jellyfish populations are actually on the rise.

Jellyfish bloom in Mar Menor, Spain.

Jellyfish bloom in Mar Menor, Spain. Photo credit: Stephanie Booth via photopin cc

A new multinational study found that there is no real evidence supporting the idea that global jellyfish populations are increasing.

The study determined that global jellyfish populations experience fluctuations–rising and falling every decade or so. The latest rising phases occurred in the 1990s and early 2000s, contributing to the idea that there are more jellyfish in our oceans. There was also a rising phase in the 1970s but due to lack of jellyfish research at the time, it went unnoticed.

The researchers found a slight increasing trend in jellyfish populations since 1970, but not large enough to support a global trend.

“Sustained monitoring is now required over the next decade to shed light with statistical confidence whether the weak increasing linear trend in jellyfish populations after 1970 is an actual shift in the baseline or part of a larger oscillation,” said lead co-author Dr. Cathy Lucas, a marine biologists at the University of Southampton.

“There are major consequences for getting the answer correct for tourism, fisheries and management decisions as they relate to climate change and changing ocean environments,” Dr. Lucas explained. “The important aspect about our work is that we have provided the long-term baseline backed with all data available to science, which will enable scientists to build on and eventually repeat these analyses in a decade or two from now to determine whether there has been a real increase in jellyfish.”

To learn more:


Jellyfish. Photo credit NOAA.

Check out some of the articles we’ve written about jellyfish and jellyfish blooms in the past:

Copyright © 2013 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .


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  1. Jonathan says:

    Rise of the jellies!

  2. MarineEnthusiast says:

    I’ve read that one way to correct this issue would be to make Jellyfish a delicacy and to start eating them. I’d love to hear a list of Jellyfish recipes if they exist!

  3. Emily says:

    But hopefully not rising for long….