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

Zero Waste Kitchen Essentials

Simple swaps that cut down on kitchen trash.

Sponsored

By Kayla Robbins

Along with the bathroom, the kitchen is one of the most daunting areas to try and make zero waste.

Read More Show Less
Protestors and police stand on ether side of railway tracks. dpa / picture-alliance

Police have cleared 250 climate activists who stayed overnight at the Garzweiler brown coal mine in western Germany, officials said Sunday.

Read More Show Less
Sponsored
Cecilie_Arcurs / E+ / Getty Images

By Megan Jones and Jennifer Solomon

The #MeToo movement has caused profound shake-ups at organizations across the U.S. in the last two years. So far, however, it has left many unresolved questions about how workplaces can be more inclusive and equitable for women and other diverse groups.

Read More Show Less
Cigarette butts are the most-littered item found at beach clean ups. John R. Platt

By Tara Lohan

By now it's no secret that plastic waste in our oceans is a global epidemic. When some of it washes ashore — plastic bottles, plastic bags, food wrappers — we get a stark reminder. And lately one part of this problem has been most glaring to volunteers who comb beaches picking up trash: cigarette butts.

Read More Show Less

Andrea Rodgers, second from the right, takes notes during a hearing in the Juliana v. U.S. case before the 9th Circuit Court of Appeals in Portland, Oregon on June 4. Colleague Elizabeth Brown sits to her left, while colleague Julia Olson sits on her right, with co-council Philip Gregory on Julia's right. Robin Loznak / Our Children's Trust

By Fran Korten

On June 4, Andrea Rodgers was in the front row of attorneys sitting before a three-judge panel of the 9th Circuit Court. The court session, held in Portland, Oregon, was to determine whether the climate change lawsuit (Juliana v. United States) brought by 21 young plaintiffs should be dismissed, as requested by the U.S. government, or go on to trial.

Read More Show Less
Sponsored
Seventy Extinction Rebellion protesters were arrested outside The New York Times building Saturday. SCOOTERCASTER / YouTube screenshot

Seventy Extinction Rebellion protesters were arrested outside The New York Times building Saturday as they demanded the paper improve its coverage of the climate crisis, Reuters reported.

Read More Show Less
Explosions and a blaze at the Philadelphia Energy Solutions Refining Complex on June 21. VOA News / YouTube screenshot

A fire broke out at a Philadelphia oil refinery Friday morning, starting with an explosion so massive it was felt as far away as South Jersey and Delaware County, Pennsylvania, CNN reported.

Read More Show Less
Pexels

By Alina Petre, MS, RD (CA)

Leeks belong to the same family as onions, shallots, scallions, chives and garlic.

Read More Show Less