Study: Fish Must Swim Faster & Travel Farther To Survive Climate Change

Fish and other sea creatures will have to travel large distances to survive climate change and avoid impending extinction, say marine scientists.

AsianScientist (Nov. 11, 2011) – An international team of marine scientists are warning that fish and other sea creatures will have to travel large distances to survive climate change and avoid impending extinction.

According to a new study published in the journal Science, the pressure to relocate or adapt has affected much sea life, particularly in the Indian Ocean, the Western and Eastern Pacific, and the subarctic oceans.

“Our research shows that species which cannot adapt to the increasingly warm waters they will encounter under climate change will have to swim farther and faster to find a new home,” says team member Professor John Pandolfi of the ARC Center of Excellence for Coral Reef Studies and The University of Queensland.

The researchers, using 50 years’ data of global temperature changes, analyzed the shifting climates and seasonal patterns on land and in the oceans to understand how this will affect life in both over the next century.

After examining the velocity of climate change (the geographic shifts of temperature bands over time) and the shift in seasonal temperatures for both land and sea, they found that both measures were higher for the ocean at certain latitudes than on land. This is despite the fact that oceans tend to warm more slowly than air over the land.

The team says that this finding has serious implications especially for marine biodiversity hotspots – such as the famous Coral Triangle and reefs that flourish in equatorial seas, and for life in polar seas, which will come under rising pressure from other species moving in.

“Unlike land-dwelling animals, which can just move up a mountain to find a cooler place to live, a sea creature may have to migrate several hundred kilometers to find a new home where the water temperature, seasonal conditions and food supply all suit it,” said Pandolfi.

Under current global warming, land animals and plants are migrating polewards at a rate of about six kilometers a decade – but sea creatures may have to move several times faster to keep in touch with the water temperature and conditions that best suit them.

The migration is likely to be particularly evident among marine species living at or near the sea surface, or subsisting on marine plants and plankton that require sunlight – and less so in the deep oceans.

The researchers are also concerned that no communities of organisms from even warmer regions exist to replace those moving out.

“Also, as seas around the equator warm more quickly and sea life migrates away – north or south – in search of cooler water, it isn’t clear what, if anything, will replace it,” he added.

Another detrimental effect of this migratory phenomenon would be that sea life living close to the poles could find themselves overwhelmed by marine migrants moving in from warmer regions, in search of cool water.

The team’s future research will focus on exactly how different ocean species respond to climate change. They are currently compiling a database on this for the Intergovernmental Panel on Climate Change (IPCC).

The article can be found at: Burrows MT et al. (2011) The Pace of Shifting Climate in Marine and Terrestrial Ecosystems.


Source: ARC Center of Excellence for Coral Reef Studies; Photo: Tom Weilenmann.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Sarah Chin is an animal management officer at the Singapore Zoo. She received a BA degree in natural sciences (zoology) from Cambridge University, UK. Besides caring for animals big and small, Sarah also enjoys wakeboarding and writing about nature and conservation.

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