Report: Jellyfish Increasing in Most of the World's Coastal Ecosystems

Posted on April 18, 2012

A study by University of British Columbia researchers has found that Jellyfish are increasing in number in the majority of the world's coastal ecosystem. The research, published here in Hydrobiologia, is the first global study of jellyfish abundance. In the photograph above, giant jellyfish (Nemopilema nomurai) interfere with fishing in Japan.

UBC scientists examined data for numerous species of jellyfish for 45 of the world's 66 Large Marine Ecosystems (LME). They found increasing jellyfish populations in 62% of the regions analyzed, including East Asia, the Black Sea, the Mediterranean, the Northeast U.S. Shelf, Hawaii, and Antarctica. The map above shows population trends of native and invasive species of jellyfish by LME. Here is what the colors on the map signify: Red = increase (high certainty); orange = increase (low certainty); green = stable/variable; blue = decrease, grey = no data. The circles represent jellyfish populations with relative sizes reflecting confidence in the data.

Lucas Brotz, a PhD student with the Sea Around Us Project at UBC and lead author of the study, says, "There has been anecdotal evidence that jellyfish were on the rise in recent decades, but there hasn't been a global study that gathered together all the existing data until now. Our study confirms these observations scientifically after analysis of available information from 1950 to the present for more than 138 different jellyfish populations around the world."

Daniel Pauly, principal investigator of the Sea Around Us Project and co-author of the study, says, "We can also see that the places where we see rising numbers of jellyfish are often areas heavily impacted by humans, through pollution, overfishing, and warming waters."

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