The best of EcoWatch, right in your inbox. Sign up for our email newsletter!
Marine Heat Waves Could Threaten Dolphin Survival, Study Suggests
That's the saddening implication of a study published in Current Biology Monday. Researchers looked at what happened when a marine heat wave scorched waters off the coast of Western Australia in 2011. What they found was that the survival rate of dolphins in the area declined by 12 percent and that female dolphins gave birth to a smaller number of calves. The effects lasted up until 2017.
"The extent of the negative influence of the heat wave surprised us," lead study author and University of Leeds PhD student Sonja Wild in a statement reported by USA Today. "It is particularly unusual that the reproductive success of females appears to have not returned to normal levels, even after six years."
The researchers had been studying dolphins in an area known as Shark Bay, a World Heritage Site home to Indo-Pacific bottlenose dolphins. The 2011 heat wave, which raised ocean temperatures in the area as much as four degrees Celsius above average, killed off seagrass and fish in the iconic bay, a University of Bristol press release explained.
The researchers wanted to know if the seagrass die-off had impacted larger animals.
"It was serendipity really. We have been working in that part of Shark Bay since 2007, now as part of a large study," study author and Department of Anthropology at the University of Zurich Director Michael Krützen told CNN in an email.
The researchers reviewed more than 5,000 dolphin encounters between 2007 and 2017 and found that the heat wave had indeed had a lasting impact, according to the press release. Researchers thought that the loss of food and habitat meant that fish in the area could not recover quickly. This forced dolphins to spend more time hunting, making them less aware. This in turn increased the chances that sharks would prey on calves. In addition, the researchers thought that the lack of nutrition might have made it harder for both mothers and young dolphins to get enough to eat, leading to more calf deaths.
For the researchers, the findings were yet another example of the threat climate change poses to the oceans. A study published in March for example, found that the number of ocean heat wave days per year had increased by 50 percent between 1987 and 2016 and that they had the same destructive impact on marine ecosystems as wildfires on land.
"Given that marine heatwaves are occurring more often in association with climate change this raises serious concerns over the long-term prospects for the dolphin population, commercial fisheries and the ecosystem as a whole," senior study author and senior research associate at Bristol's School of Biological Sciences Dr. Simon Allen said in the press release.
The one silver lining from the study was that dolphins that used sponges to hunt were not as impacted as those who did not, but the researchers did not know if that advantage would hold for an extended period of time, CNN reported.
"It seems that extreme weather events appear to threaten marine mammal populations in their existence. If we want to conserve these populations, we have to think how the frequency of such events can be kept at a minimum," Krützen told CNN.
EcoWatch Daily Newsletter
A dire new report issued by the World Meteorological Organization (WMO) found that the climate crisis is on a worrying trajectory as the crisis's hallmarks — sea level rise, ice loss and extreme weather — all increased over the last five years, which will end as the warmest five-year period on record.
By Peter Gleick
War is a miserable thing. It kills and maims soldiers and civilians. It destroys infrastructure, cultures and communities. It worsens poverty and development challenges. And it damages and cripples vital ecological and environmental resources.
Hundreds of activists gathered in the Swiss Alps on Sunday to mourn the loss of Pizol, a glacier that has steadily retreated over the last decade as temperatures have warmed the mountain tops, according to CNN.
Vice President Mike Pence sparked outrage on social media Saturday when he traveled in the first-ever motorcade to drive down the streets of Michigan's car-free Mackinac Island, HuffPost reported.
By Shawn Radcliffe
- As illnesses and deaths linked to vaping continue to rise, health officials urge people to stop using e-cigarettes.
- Officials report 8 deaths have been linked to lung illnesses related to vaping.
- Vitamin E acetate is one compound officials are investigating as a potential cause for the outbreak.
By Julia Conley
As organizers behind Friday's Global Climate Strike reported that four million children and adults attended marches and rallies all over the world — making it the biggest climate protest ever — they assured leaders who have been reticent to take bold climate action that the campaigners' work is far from over.