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Nemo the Climate Refugee

If you collected all the recent research on marine species and climate change, could you see a pattern of fish and marine species migration?

WHO: Elvira S. Poloczanska, Climate Adaptation Flagship, CSIRO Marine and Atmospheric Research, Brisbane, Queensland, Australia
Christopher J. Brown, Climate Adaptation Flagship, CSIRO Marine and Atmospheric Research, Brisbane, Queensland, Australia, School of Biological Sciences, The University of Queensland, Australia
William J. Sydeman, Sarah Ann Thompson, Farallon Institute for Advanced Ecosystem Research, Petaluma, California, USA
Wolfgang Kiessling, Museum für Naturkunde, Leibniz Institute for Research on Evolution and Biodiversity, Berlin, Germany, GeoZentrum Nordbayern, Paläoumwelt, Universität Erlangen-Nürnberg, Erlangen, Germany
David S. Schoeman, Faculty of Science, Health and Education, University of the Sunshine Coast, Maroochydore, Queensland, Australia, Department of Zoology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
Pippa J. Moore, Centre for Marine Ecosystems Research, Edith Cowan University, Perth, Western Australia, Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth UK
Keith Brander, DTU Aqua—Centre for Ocean Life, Technical University of Denmark, Charlottenlund Slot, Denmark
John F. Bruno, Lauren B. Buckley, Department of Biology, The University of North Carolina at Chapel Hill, North Carolina, USA
Michael T. Burrows, Scottish Association for Marine Science, Scottish Marine Institute, Oban, UK
Johnna Holding, Department of Global Change Research, IMEDEA (UIB-CSIC), Instituto Mediterráneo de Estudios Avanzados, Esporles, Mallorca, Spain
Carlos M. Duarte, Department of Global Change Research, IMEDEA (UIB-CSIC), Instituto Mediterráneo de Estudios Avanzados, Esporles, Mallorca, Spain, The UWA Oceans Institute, University of Western Australia,
Benjamin S. Halpern, Carrie V. Kappel, National Center for Ecological Analysis and Synthesis, Santa Barbara, California, USA
Mary I. O’Connor, University of British Columbia, Department of Zoology, Vancouver, Canada
John M. Pandolfi, Australian Research Council Centre of Excellence for Coral Reef Studies, School of Biological Sciences, The University of Queensland, Australia
Camille Parmesan, Integrative Biology, Patterson Laboratories 141, University of Texas, Austin, Texas Marine Institute, A425 Portland Square, Drake Circus, University of Plymouth, Plymouth, UK
Franklin Schwing, Office of Sustainable Fisheries, NOAA Fisheries Service, Maryland, USA
Anthony J. Richardson, Climate Adaptation Flagship, CSIRO Marine and Atmospheric Research, Brisbane, Queensland, Australia Centre for Applications in Natural Resource Mathematics (CARM), School of Mathematics and Physics, University of Queensland, Australia

WHAT: A review and synthesis of all available peer reviewed studies of marine species changing under climate change.
 
WHEN: 4 August 2013
 
WHERE: Nature Climate Change, August 2013
 
 
This paper, with its laundry list of collaborative authors must have had an awesome ‘we got published’ party. However, when you think about what they did – all that data would have taken forever to number crunch, so it’s a good thing it was all hands on deck.
 
So what were they looking at? They were trying to work out if you can see the fingerprint of climate change in the distribution changes of marine species. And to do that, they looked at all the available studies in the peer reviewed literature that were looking at expected changes for fish and other species in the ocean with climate change. Then, they lined up the predictions with the observed results to see what happened, and it turns out we’ve got some frequent travelling fish.
 
After getting all the studies together, the researchers had 1,735 different observations for everything from phytoplankton to zooplankton to fish and seabirds from 208 studies of 857 different species. They used all of the data they had which included the changes that lined up with climate change projections, the ones that had no changes and the ones that had unexpected changes.
 
Global marine migration (from paper)
Global marine migration (from paper)
 
Ocean currents make it easier for species to travel longer distances than plants and animals on land. There’s only so far a seed can travel from the tree with the wind, after all. However in this research they found that the average distance of expansion for marine species was 72km/decade (±13.5km). This doesn’t sound like a lot to a human, but it’s an order of magnitude further than land based migration averages, and it’s a long way for a mollusc or a starfish to go.
 
The species chalking up the most frequent flier points were phytoplankton which have been moving 469.9km/decade (±115km) followed by the fish who have been moving 227.5km/decade (±76.9km). Of the 1,735 observations, a whopping 1,092 were moving in the directions expected by climate change.
For each species migration, the researchers looked at what the expected decadal rates of ocean temperature change would have been in the area and found that some groups move early, some wait longer, others are falling behind.
 
For example, in the Bering Sea (where the Discovery Channel show ‘The Deadliest Catch’was set), many species rely on the really cold water that is less than 2oC and separates the Arctic and subarctic animals. This cold pool of water has been moving further north as the Arctic ice sheet melts, but the responses by species are varied. Some are at the leading edge and move early, others don’t. The researchers think this is related to issues around population size, ability to migrate, dependence on habitat (remember how Nemo’s dad didn’t want to leave the reef?), competition for food and others.
 
Clownfish (Wikimedia commons)
Clownfish (Wikimedia commons)
 
I guess it’s similar to when a natural disaster happens in a human area and some families leave, others rebuild and it’s for a whole complicated list of reasons like family, jobs, resources and more. Anyway, back to the fish.
 
The researchers tested their data for a climate change fingerprint globally. They used a binomial test against 0.5, which is the result you would get if these changes in location were random variability and from their test, 83% of the changes had climate change as a dominant driving force.
 
If they limited their data only to studies that were multi-species, there were still 81% of the changes that were driven by climate change. They ran the data to exclude every bias they could think of and still they concluded that it provided ‘convincing evidence that climate change is the primary driver behind the observed biological changes’.
 
Binomial test results – if you get 0.5 it’s a random occurrence – this migration is climate caused (from paper)
Binomial test results – if you get 0.5 it’s a random occurrence – this migration is climate caused (from paper)
 
So there you have it – climate refugees aren’t just land based. Nemo’s going to have to move too.

What do you think? Leave a comment below.

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