Nav: Home

Climate change threat to dolphins' survival

April 01, 2019

An unprecedented marine heatwave had long-lasting negative impacts on both survival and birth rates on the iconic dolphin population in Shark Bay, Western Australia. Researchers at UZH have now documented that climate change may have more far-reaching consequences for the conservation of marine mammals than previously thought.

Shark Bay in Western Australia in early 2011: A heatwave causes the water temperatures to rise to more than four degrees above the annual average. The extended period caused a substantial loss of seagrass, which drives the Shark Bay ecosystem, in this coastal area, a UNESCO world heritage site.

Researchers from UZH have now investigated how this environmental damage has affected survival and reproduction of dolphins. They used long-term data on hundreds of animals collected over a ten-year period from 2007 to 2017. Their analyses revealed that the dolphins' survival rate had fallen by 12 percent following the heatwave of 2011. Moreover, female dolphins were giving birth to fewer calves - a phenomenon that lasted at least until 2017.

Negative influence of the heatwave is unprecedented

"The extent of the negative influence of the heatwave surprised us," says Sonja Wild, former PhD candidate at the University of Leeds and first author of the study. "It is particularly unusual that the reproductive success of females appears to have not returned to normal levels, even after six years." There are several possible explanations for this phenomenon, for instance neglect of calves, increased newborn mortality, delayed sexual maturity or a combination thereof, but researchers have not yet been able to investigate them in detail.

Tool-using dolphins are less affected

Interestingly, the heatwave did not have the same effect on all dolphin groups. Dolphins that use sponges as tools - a socially learned foraging technique that helps dolphins to locate food in deep water - were not as badly affected as those that do not use this technique. "Nevertheless, our work raises concerns that such sudden events might have quite negative long-term effects even in groups of marine mammals that are known to adapt usually well to novel environmental conditions," says Sonja Wild.

Dire news for entire oceanic ecosystems?

The UZH researchers show in their study for the first time that marine heatwaves not only affect or-ganisms at lower levels of the food chain, but also might have considerable long-term consequences for the animals at the top, such as dolphins. "Marine heatwaves are likely to occur more frequently in the future due to climate change," says study leader Michael Krützen, professor at the Department of Anthropology at UZH. "This is worrying not only for the long-term prospects of marine mammal populations, but also for the entire oceanic ecosystems."
-end-


University of Zurich

Related Climate Change Articles:

Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).
Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.
Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.
Could climate change cause infertility?
A number of plant and animal species could find it increasingly difficult to reproduce if climate change worsens and global temperatures become more extreme -- a stark warning highlighted by new scientific research.
Predicting climate change
Thomas Crowther, ETH Zurich identifies long-disappeared forests available for restoration across the world.
Historical climate important for soil responses to future climate change
Researchers at Lund University in Sweden, in collaboration with colleagues from the University of Amsterdam, examined how 18 years of drought affect the billions of vital bacteria that are hidden in the soil beneath our feet.
Can forests save us from climate change?
Additional climate benefits through sustainable forest management will be modest and local rather than global.
From crystals to climate: 'Gold standard' timeline links flood basalts to climate change
Princeton geologists used tiny zircon crystals found in volcanic ash to rewrite the timeline for the eruptions of the Columbia River flood basalts, a series of massive lava flows that coincided with an ancient global warming period 16 million years ago.
Think pink for a better view of climate change
A new study says pink noise may be the key to separating out natural climate variability from climate change that is influenced by human activity.
Climate taxes on agriculture could lead to more food insecurity than climate change itself
New IIASA-led research has found that a single climate mitigation scheme applied to all sectors, such as a global carbon tax, could have a serious impact on agriculture and result in far more widespread hunger and food insecurity than the direct impacts of climate change.
More Climate Change News and Climate Change Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Risk
Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#541 Wayfinding
These days when we want to know where we are or how to get where we want to go, most of us will pull out a smart phone with a built-in GPS and map app. Some of us old timers might still use an old school paper map from time to time. But we didn't always used to lean so heavily on maps and technology, and in some remote places of the world some people still navigate and wayfind their way without the aid of these tools... and in some cases do better without them. This week, host Rachelle Saunders...
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at Radiolab.org/donate.