OIL SPILL ANIMAL VICTIMS

Bottlenose Dolphin


Photograph by Alex Brandon, AP



A bottlenose dolphin breaks the oily surface of Chandeleur Sound, Louisiana (see map), on May 6, 2010, two weeks after an explosion at the Deepwater Horizon oil rig sent crude gushing into the Gulf of Mexico.



Oil, gas, and chemical dispersants contaminated thousands of square miles of marine and coastal habitat. Many animals were killed or sickened outright, but on the one-year anniversary of the Gulf oil spill, scientists still don't know the extent of the spill's effects on most species.



(See: "Gulf Oil Spill Pictures: Ten Animals at Risk [May 2010.]")

Bottlenose dolphins have been dying in unusually high numbers in northern Gulf waters since February 2010, two months before the oil spill began, and the trend continues today. Since January, 68 premature, stillborn, or newborn calves have washed ashore.



The Gulf oil spill is certainly on the list of suspects in the recent dolphin deaths, but it's too early to say for sure, Blair Mase, coordinator of the Southeast Marine Mammal Stranding Network of the National Atmospheric and Oceanic Administration, told National Geographic News in March.



Only a handful of obviously oiled dolphins have been recovered. But a recent study from the University of British Columbia estimated that the actual number of dolphins and whales killed by the spill could be 50 times higher than official tallies suggest, putting the death toll in the thousands.

—Rebecca Kessler



Published April 19, 2011

Sea Turtle


Photograph by Bevil Knapp, European Pressphoto Agency



A rehabilitator checks an oiled Kemp's ridley sea turtle into a clinic in New Orleans, Louisiana, on June 24, 2010.



The oil spill posed a grave threat to the five species of sea turtle living in the Gulf of Mexico, all of which are on the U.S. endangered species list. (See sea turtle pictures.)



As of mid-February, the National Oceanic and Atmospheric Administration (NOAA) counted nearly 1,150 sea turtles that had been stranded or rescued at sea during the spill, more than half of them dead.



Very few of the stranded turtles showed visible signs of oil, yet their numbers were much higher than in previous years—suggesting a link. The agency is still trying to determine the overall effect of the Gulf oil spill on sea turtles, as well as to estimate how many died uncounted, according to NOAA spokesperson Monica Allen. (Get more Gulf oil spill anniversary news.)



To keep sea turtle hatchlings out of the oil's path, some 275 nests were moved from Gulf shores to Florida's eastern coast in July. By the end of summer, nearly 15,000 hatchlings from those nests made their way into the safer waters of the Atlantic.



(Watch video: "Gulf Turtle Eggs Relocated.")



Published April 19, 2011

Brown Pelican
Photograph by Joel Sartore, National Geographic

Three oil-coated brown pelican chicks sit on an island nest in Barataria Bay, Louisiana, in an undated picture.

The U.S. Fish and Wildlife Service has documented that more than 900 of the birds were harmed by the Gulf oil spill.

Images of brown pelicans drenched in oil were a common sight last summer. The species became the spill's "poster child" because it had been taken off the U.S. endangered species list just five months before the oil hit, said Melanie Driscoll, Gulf Coast director of bird conservation for the National Audubon Society.

This year, brown pelicans are returning to nest in areas that are still contaminated with oil, Driscoll said, and the extent of the damage to their food supply remains to be seen.

Published April 19, 2011

Wilson's Plover
Photograph by Bill Stripling

A Wilson's plover forages in the tide's wake on a beach in Fort Myers, Florida, in an undated picture.

Only about 6,000 of these little shorebirds exist, and they are extremely vulnerable to disturbance of their beachfront nesting habitat, experts say. (See more bird pictures.)

The U.S. Fish and Wildlife Service has tallied just two Wilson's plovers among some 8,000 birds affected by the spill. But many more undoubtedly perished unseen, in part because a number of cleanup responses were staged near nesting colonies, said the National Audubon Society's Driscoll.

"There were Humvees and ATVs and trucks running up and down the beach," Driscoll said.

(See "Gulf Oil Cleanup Crews Trample Nesting Birds.")

The threat from the spill continues today as tar balls wash up on Louisiana beaches and liquefy in the warm spring sun, she said.

Wilson's plovers and other birds are likely eating oil along with their prey, as well as getting it on their feet and feathers and bringing it back to their nests where it can coat sensitive eggs.

Published April 19, 2011

Seafloor Invertebrates
Photograph courtesy Lophelia II 2010 Expedition/NOAA-OER/BOEMRE

Oil has taken a heavy toll on invertebrates living on the seafloor near the wellhead.

In a series of submarine dives in December, a team led by University of Georgia marine scientist Samantha Joye documented what she has called an "invertebrate graveyard."

There were dead corals and brittle stars (similar to the living ones pictured here, clinging to a sea fan in the Gulf in 2010), as well as tube worms filled with oily slime. Sea cucumbers, typically numerous, were absent altogether. The few creatures left alive often looked sickly and behaved abnormally, Joye found.

She attributed the carnage to suffocation or poisoning by "slime streamers"—the waste of oil-eating microbes that have rained down on the seafloor since the Gulf oil spill began.

In many places, bottom sediment was blanketed with the slime, which does not appear to be degrading.

Published April 19, 2011

Florida Manatee
Photograph by Brian Skerry, National Geographic

A Florida manatee swims in a freshwater spring in Crystal River, Florida, in 2009.

The Gulf oil spill came at a terrible time for manatees, following on the heels of an unusually severe winter that killed off nearly 400 of the bulky marine mammals—a record number.

And the blowout occurred at a time of year when some intrepid manatees begin to strike out for the summer along the coasts of Louisiana, Mississippi, and Alabama—which was right into the spill zone.

Yet no animals were reported to be directly harmed by the oil, according to the Save The Manatee Club, a conservation group based in Maitland, Florida.

Still, as with most animals living in the Gulf of Mexico, the long-term effects of the Deepwater Horizon spill remain to be seen. Of particular concern is whether oil and chemical dispersants will persist in the environment or contaminate the manatees' main food supply of seagrass, according to the conservation group.

(See "Gulf Spill Dispersants Surprisingly Long-lasting.")

Published April 19, 2011

NATIONAL GOEGRAPHIC