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| Earth on Apr 19, 2012

More jellyfish around the world, says study

Jellyfish are increasing in the majority of the world’s coastal ecosystems, according to a new study.

Jellyfish are increasing in the majority of the world’s coastal ecosystems, according to a new study.

Map of population trends of native and invasive species of jellyfish. Red: increase (high certainty); orange: increase (low certainty); green stable/variable; blue decrease, grey: no data. Circles represent jellyfish populations with relative sizes reflecting confidence in the data. Image credit: Brotz et al, Hydrobiologia

In a study published in the April 2012 edition of the journal Hydrobiologia, scientists from the University of British Columbia examined data for numerous species of jellyfish in ecosystems around the world. They found increasing jellyfish populations in 62 per cent of the regions they analyzed, including East Asia, the Black Sea, the Mediterranean, the Northeast U.S. Shelf, Hawaii, and Antarctica.

Lucas Brotz, lead author of the study, said:

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.

Giant jellyfish (Nemopilema nomurai) interfere with fishing in Japan. Photo credit: Niu Fisheries Cooperative.

Jellyfish sting swimmers, clog intakes of power plants, and interfere with fishing. Some species of jellyfish are now a food source in some parts of the world.

According to study co-author Daniel Pauly:

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.

A bloom of moon jellyfish (Aurelia sp.) near Denmark. Photo credit: Casper Tybjerg, http://www.ttf.dk.

Bottom line: In a study published in the April 2012 edition of the journal Hydrobiologia, scientists from the University of British Columbia say that jellyfish are increasing in the majority of the world’s coastal ecosystems.

Read more from the University of British Columbia