Jellyfish Blooms Don't Necessarily Mean What You Think

Recurrent jellyfish blooms are a consequence of global oscillations

Authors:

1. Robert H. Condon (a,*)

2. Carlos M. Duarte (b,c)

3. Kylie A. Pitt (d)

4. Kelly L. Robinson (a,e)

5. Cathy H. Lucas (f)

6. Kelly R. Sutherland (g)

7. Hermes W. Mianzan (h)

8. Molly Bogeberg (a)

9. Jennifer E. Purcell (i)

10. Mary Beth Decker (j)

11. Shin-ichi Uye (k)

12. Laurence P. Madin (l)

13. Richard D. Brodeur (m)

14. Steven H. D. Haddock (n)

15. Alenka Malej (o)

16. Gregory D. Parry (p)

17. Elena Eriksen (q)

18. Javier Quiñones (r)

19. Marcelo Acha (h)

20. Michel Harvey (s)

21. James M. Arthur (d)

22. William M. Graham (t)

Author Affiliations:

a. Dauphin Island Sea Laboratory, Marine Environmental Sciences Consortium, Dauphin Island, AL 36528;

b. University of Western Australia Oceans Institute, University of Western Australia, Crawley, WA 6009, Australia;

c. Department of Global Change Research, Instituto Mediterráneo de Estudios Avanzados, Universidad de las Islas Baleares y el Consejo Superior de Investigaciones Científicas, 01790 Esporles, Spain;

d. Australian Rivers Institute and Griffith School of Environment, Griffith University, Gold Coast Campus, QLD 4111, Australia;

e. Department of Marine Sciences, University of South Alabama, Mobile, AL 36688;

f. National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom;

g. Department of Biology, University of Oregon, Eugene, OR 97403;

h. Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Instituto Nacional de Investigación y Desarrollo Pesquero, Mar del Plata B7602HSA, Argentina;

i. Shannon Point Marine Center, Western Washington University, Anacortes, WA 98221;

j. Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520;

k. Department of Environmental Dynamics and Management, Hiroshima University, Higashi-Hiroshima 739-8528, Japan;

l. Woods Hole Oceanographic Institution, Woods Hole, MA 02543;

m. Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration Fisheries, Newport, OR 97365;

n. Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039;

o. Marine Biology Station Piran, National Institute of Biology, 6330 Piran, Slovenia;

p. Department of Primary Industries, Victorian Fisheries, Queenscliff 3225, VIC, Australia;

q. Institute of Marine Research, 5817 Bergen, Norway;

r. Laboratorio Costero de Pisco, Instituto del Mar del Perú, Paracas, 11550 Ica, Peru;

s. Direction des sciences océaniques et de l'environnement, Institut Maurice-Lamontagne, Pêches et Océans Canada, Mont-Joli, QC, Canada G5H 3Z4;

t. Department of Marine Science, University of Southern Mississippi, Stennis Space Center, MS 39529

Abstract:

A perceived recent increase in global jellyfish abundance has been portrayed as a symptom of degraded oceans. This perception is based primarily on a few case studies and anecdotal evidence, but a formal analysis of global temporal trends in jellyfish populations has been missing. Here, we analyze all available long-term datasets on changes in jellyfish abundance across multiple coastal stations, using linear and logistic mixed models and effect-size analysis to show that there is no robust evidence for a global increase in jellyfish. Although there has been a small linear increase in jellyfish since the 1970s, this trend was unsubstantiated by effect-size analysis that showed no difference in the proportion of increasing vs. decreasing jellyfish populations over all time periods examined. Rather, the strongest nonrandom trend indicated jellyfish populations undergo larger, worldwide oscillations with an approximate 20-y periodicity, including a rising phase during the 1990s that contributed to the perception of a global increase in jellyfish abundance. Sustained monitoring is required over the next decade to elucidate with statistical confidence whether the weak increasing linear trend in jellyfish after 1970 is an actual shift in the baseline or part of an oscillation. Irrespective of the nature of increase, given the potential damage posed by jellyfish blooms to fisheries, tourism, and other human industries, our findings foretell recurrent phases of rise and fall in jellyfish populations that society should be prepared to face.

Now THAT'S an author list!