Quantcast

Marine Heat Waves Could Threaten Dolphin Survival, Study Suggests

Popular
The survival rates of Indo Pacific bottlenose dolphins like this one were reduced following a marine heat wave in Australia. Graeme Snow

Climate change could have a deadly impact on dolphins and other marine mammals.


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.

Read More Show Less
Line of soldiers walking. Pexels

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.

Read More Show Less
Sponsored
People take part in a ceremony to mark the 'death' of the Pizol glacier on Sept. 22. FABRICE COFFRINI / AFP / Getty Images

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.

Read More Show Less
Luis Alfonso de Alba Gongora, the UN secretary-general's special envoy for the climate summit speaks at The World Economic Forum holds the Sustainable Development Impact Summit 2018 in New York on Sept. 24, 2018. Ben Hider / World Economic Forum

By Howard LaFranchi

When United Nations Secretary-General Antonio Guterres decided to hold a high-level climate summit in conjunction with this year's General Assembly kicking off next week, he was well aware of the paradox of his initiative.

Read More Show Less
Acting U.S. Homeland Security Secretary Kevin McAleenan meets with Guatemalan farmers on May 29 in Santa Rosa, Guatemala. John Moore / Getty Images

The Trump administration ignored its own evidence on how climate change is impacting migration and food security when setting new policies for cutting aid to Central America, NBC reports.

Read More Show Less
Sponsored
Mike Pence brought the first motorcade to Mackinac Island on Saturday. Cars have been banned on the island since 1898. 13 ON YOUR SIDE / YouTube screenshot

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.

Read More Show Less
Inhaling from an electronic cigarette. 6okean / iStock / Getty Images Plus

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.
The number of vaping-related illnesses has grown to 530 cases in 38 states and 1 U.S. territory, federal health officials reported.
Read More Show Less
Activist Greta Thunberg leads the Youth Climate Strike on Sept. 20, 2019 in New York City. Roy Rochlin / WireImage / Getty Images

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.

Read More Show Less