Recent media reports have created a perception that jellyfish blooms may be increasing in the world's oceans, but a new international study suggests that there is no robust evidence for proof of a global increase in jellyfish over the past two centuries. Blooms, or proliferations, of jellyfish can show a substantial, visible impact on coastal populations –– clogged nets for fishermen, stinging waters for tourists, and choked cooling intake pipes for power plants. The key finding of this study, published in the Proceedings of the National Academy of Science, shows that global jellyfish populations undergo concurrent oscillations with successive decadal periods of rise and fall, including a rising phase in the 1990's and early 2000's that has contributed to the current perception of a global increase in jellyfish abundance.

Recurrent Jellyfish Blooms are a Consequence of Global Oscillations
Robert H. Condon, Carlos M. Duarte, Kylie A. Pitt,, Kelly L. Robinson, Cathy H. Lucas, Kelly R. Sutherland, Hermes W. Mianzan, Molly Bogeberg, Jennifer E. Purcell, Mary Beth Decker, Shin-ichi Uye, Laurence P. Madin, Richard D. Brodeur, Steven H. D. Haddock, Alenka Malej, Gregory D. Parry, Elena Eriksen, Javier Quiñones, Marcelo Acha, Michel Harvey, James M. Arthur, William M. Graham
Proceedings of the National Academy of Sciences, January 2013 (online)

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