Posted by: The ocean update | November 4, 2015

Study: Spill affects dolphins’ reproduction (Gulf of Mexico, USA)

Louisiana Department of Wildlife and Fisheries photo shows one of the stranded dead dolphins that came ashore in 2012 along the Louisiana coast that was being photographed for study in this July 30, 2012 photo released on May 20, 2015. REUTERS/LOUISIANA DEPARTMENT OF WILDLIFE AND FISHERIES/HANDOUT

Louisiana Department of Wildlife and Fisheries photo shows one of the stranded dead dolphins that came ashore in 2012 along the Louisiana coast that was being photographed for study in this July 30, 2012 photo released on May 20, 2015. REUTERS/LOUISIANA DEPARTMENT OF WILDLIFE AND FISHERIES/HANDOUT

November 4th, 2015. NEW ORLEANS – Dolphins living in a Louisiana bay polluted by BP’s massive 2010 offshore oil spill have had a very difficult time giving birth long after their bay was covered in slicks, a study shows.

The government study is the latest by a team of scientists that has tracked the health of a population of bottlenose dolphins in Barataria Bay, an estuary south of New Orleans covered in heavy slicks after BP’s April 2010 oil spill off the coast of Louisiana.

The researchers tracked 10 pregnant dolphins for nearly four years and found that only two of the dolphins gave birth.

The study was published Tuesday in the Proceedings of the Royal Academy of Sciences in Britain.

BP PLC’s blown-out well killed 11 workers aboard the Deepwater Horizon drilling rig and spewed more than 130 million gallons of oil into the Gulf of Mexico in 2010.

After the spill, researchers found dolphins in Barataria suffering from lung diseases and abnormalities they associated with exposure to oil contamination. Since then, the dolphins have become a focus of work to assess the effects from the oil spill.

In August 2011, about a year after oil stopped leaking from BP’s blown-out well, researchers tagged 32 dolphins and followed them to see what happened.

The new study found they’ve suffered from a high mortality rate and chronic diseases that have hurt the animals’ ability to reproduce. The study said the effects of the spill “have been long-lasting.”

“The take-home message is that this dolphin population, as well as other dolphin and whale populations that were exposed to the Deepwater Horizon oil, will take a long time to recover,” said Lori Schwacke, a wildlife epidemiologist with the National Oceanic and Atmospheric Administration. She was the lead researcher.

Schwacke said data on 2013 and 2014 reproduction rates show continuing problems. Those data were not included in the new paper.

Dolphins are slow to reach reproductive maturity, and once they do it takes about a year for them to give birth. They only give birth to a single calf every three to five years. In a recent report on restoring the Gulf, government scientists say it could take decades for mammal populations to recover from the spill.

BP declined to comment on the study Tuesday.

Cynthia Smith, the executive director of the National Marine Mammal Foundation and a researcher in the study, said the dolphins are most likely suffering lingering health problems from when they swam in the oil slicks covering Barataria.

“Those health effects can last a long time,” Smith said. “It’s not just fleeting.”

Researchers estimated that there were about 2,300 dolphins living in Barataria at the time of the spill and that about 35 percent of them died because of the spill.

Citation : Reproductive outcome and survival of common bottlenose dolphins sampled in Barataria Bay, Louisiana, USA, following the Deepwater Horizon oil spill. S. M. Lane et al. Proc. R. Soc. B 2015 282 20151944; DOI: 10.1098/rspb.2015.1944. Published 4 November 2015

Source

Advertisements

Categories

%d bloggers like this: