Jellyfish on the rise

University of British Columbia: Jellyfish are increasing in the majority of the world’s coastal ecosystems, according to the first global study of jellyfish abundance by University of British Columbia researchers.

In a study published in this month’s edition of the journal Hydrobiologia, UBC scientists examined data for numerous species of jellyfish for 45 of the world’s 66 Large Marine Ecosystems. They found increasing jellyfish populations in 62 per cent of the regions analyzed, including East Asia, the Black Sea, the Mediterranean, the Northeast U.S. Shelf, Hawaii, and Antarctica.

“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,” says Lucas Brotz, a PhD student with the Sea Around Us Project at UBC and lead author of the study. “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.”

Jellyfish directly interfere with many human activities – by stinging swimmers, clogging intakes of power plants, and interfering with fishing. Some species of jellyfish are now a food source in some parts of the world....

Map of population trends of native and invasive species of jellyfish by LME. 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. (Brotz et al, Hydrobiologia). From the UBC website