Ten years later, BP oil spill continues to harm wildlife—especially dolphins (2023)

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Some species, such as brown pelicans, have rebounded, while long-lived species have been hindered for generations. Still, data is scarce.

ByJoan Meiners

Published April 17, 2020

14 min read

New Orleans, LouisianaOn April 20, 2010, an explosion at the BP Deepwater Horizon oil rig released over 130 million gallons of crude oil into the Gulf of Mexico. It was the biggest oil spill ever in U.S. waters and remains one of the worst environmental disasters in world history.

(Video) Full Impact Of BP Oil Spill 10 Years Later

Eleven rig workers lost their lives. So did untold millions of marine mammals, sea turtles, birds, and fish. While the world watched, helpless, oil gushed into one of the planet’s most biodiverse marine habitats for 87 long days.

A decade later, many species, such as deep-sea coral, common loons, and spotted sea trout, are still struggling, their populations lower than before. By contrast, a few Gulf inhabitants have shown a robust recovery—among them, menhaden fish and the brown pelican, Louisiana’s state bird. (Read how the Gulf oil spill has harmed dolphins and turtles.)

Scientists say it’s still too early to tell definitively what the impact has been for longer-lived species such as dolphins, whales, and sea turtles.

Even so, “based on our science to date, if you were a marine mammal alive in the Gulf at the time of the spill, it doesn’t look good for you,” says Cynthia Smith, a veterinarian at the National Marine Mammal Foundation. “Animals that weren’t born yet, those are the hope,” says Smith, a marine mammal expert who traveled to the spill.

Smith is one of many scientists whose careers pivoted after this event. Funds from the Gulf of Mexico Energy Security Act, the Gulf of Mexico Research Initiative—and more recently, the $16 billion settlement between BP and the U.S. federal and state governments—have enabled a legion of researchers to undertake long-term projects investigating how the spill affected Gulf wildlife.

Many species have been difficult to study. But after a decade of close monitoring, Smith feels that she and colleagues have a clear picture of what is going on with that most gregarious of cetaceans, the bottlenose dolphin—and it’s grim.

About a thousand dolphins died in the months following the spill, after they ingested toxins from the oil. Many others apparently have been sick ever since. (Read about a die-off of baby dolphins in the Gulf.)

Recent research, not yet published in a peer-reviewed journal, has revealed that only about 20 percent of pregnancies among the dolphins in Louisiana’s heavily oiled Barataria Bay are successful, compared with 83 percent in unoiled regions. This number remains unchanged from 2015 findings.

Ten years out, Smith is also seeing higher rates of reproductive failure, lung disease, heart issues, impaired stress response, and death in bottlenose dolphins.

Interestingly, says Smith, these symptoms mirror the most common health issues faced by another large mammal exposed to the oil spill: humans. Two recent studies, both published in 2018, found impaired lung and heart function and strained breathing, respectively, among cleanup workers and U.S. Coast Guard personnel who had been in contact with the oil.

“You don't necessarily think of a dolphin as being representative of yourself or a human being representative of a dolphin, but our lives overlap,” Smith says. “We're in this space together, and there's a lot to learn from that.”

(Video) 10 years later: Scientists learn long-term impact of Deepwater Horizon spill

Listening for life

Kaitlin Frasier remembers the day in 2010 that her Ph.D. adviser told her he thought she should focus her career on the recent Deepwater Horizon spill.

At the time, Frasier, couldn’t have imagined where that journey would take her. Today, she’s an assistant project scientist at the Scripps Institution of Oceanography at the University of California, San Diego, and has spent the past decade listening for signs of life in the Gulf—namely, the clicks and clacks of echolocating marine mammals.

“We can’t really see the seafloor, so we don’t really know how [the oil] has affected whales,” Frasier says. It’s hard to tell, she says, whether or not oil from sediments is getting resuspended into the water and affecting cetaceans’ food. (Here’s why “shocking” amounts of oil fell to the seafloor.)

The Gulf of Mexico is home to 21 species of marine mammal, most of which humans rarely see—so scientists have to listen. The sounds these animals emit can reveal which species are still active many years after the spill, and which have declined.

One species Frasier hears less and less these days is the pantropical spotted dolphin.

“It is a surprise in some ways,” Frasier says, “because they used to be so commonplace. The visual observers called them rats because they were crawling all over the Gulf. And now, we just get way fewer encounters on our acoustic data.”

For many species, results are not this clear. In part, that’s because scientists knew little about the habits of many deepwater marine mammals before the spill, so have trouble detecting changes from current data.

Take the little-studied dwarf sperm whale: It’s unclear how to interpret the short, high-pitched clicking sounds Frasier can associate with them now. Likewise, sperm whales, which emit longer, lower-frequency clicks, haven’t been detected recently near the spill site, but this may just mean they have moved.

Marine mammals are important indicators of the overall health of the ocean, so studying them can tell scientists a great deal about their environment.

“We have all these different pieces of the puzzle, but it’s hard to know how they fit together,” Frasier says.

The silent behemoths

Some of the longest-lived animals of all sit silent and sessile at the bottom of the sea.

Peter Etnoyer, a marine biologist at the National Oceanic and Atmospheric Administration’s (NOAA) Hollings Lab, studies deep-sea corals. Some were thriving very near Deepwater Horizon’s wellhead before the spill, according to seafloor surveys. After the spill, scientists found that half of those coral colonies—colorful, fan-shaped creatures called gorgonian octocoral—surveyed had been injured to some extent.

(Video) 10 Years Later: Understanding The Impact of The BP Oil Spill | NBC 6

“We don’t know how long it’s going to take these coral colonies to recover,” Etnoyer says. “They grow very, very slowly. The ones we found to be injured are on the order of decades to hundreds of years old.” (Learn how the Gulf oil spill was even bigger than thought.)

Corals are important habitat for species such as shrimp, crabs, grouper, and snapper. And because they exhibit growth rings like those of trees, corals act as “little environmental monitors, recording conditions over time,” Etnoyer says.

Now, his team is preparing for future disasters, mapping deep-sea corals and developing a coral database with more than 750,000 records so far. The team also has a seven-year plan to help coral rebound, which includes traveling to the seafloor using divers or a remotely operated vehicle and cloning or transplanting a few hundred coral from one spot to another.

“It’ll be the first time it has ever been attempted to transplant these specific corals at an industrial scale,” he says.

A setback for endangered turtles

The Gulf of Mexico is home to five species of sea turtle, all of which are protected under the Endangered Species Act.

Leatherbacks and Atlantic hawksbills roam offshore waters, while loggerhead, green, and Kemp’s ridley sea turtles frequent near-shore habitats. A 2017 study estimated that of at least 402,000 sea turtles exposed to oil during the spill, 51 percent were Kemp’s ridleys, the smallest and most critically endangered species.

Before the spill, the Kemp’s ridley population had been projected to grow at a rate of 19 percent per year. Instead, the number of nests on Gulf beaches—the species’ main nesting location—dropped 35 percent between 2009 and 2010, and plummeted again in 2013, according to a 2016 study. That research also suggested that Kemp’s ridley females have struggled to maintain the weight and health necessary to reproduce.

A new version of a federal recovery plan for the Kemp’s ridley was signed in 2014 in response to the spill. The move resulted in new protections for nesting beaches in Texas and Mexico, and requirements that shrimp fisheries in the Gulf use excluder devices to prevent the reptiles from being captured in trawls.

A bright spot for birds

Birds were among the hardest-hit animals immediately after the spill, says Erik Johnson, director of bird conservation for Audubon Louisiana.

“We know the number of birds affected was somewhere between 100,000 and one million. Unfortunately, we’ll never know the true number,” he says. (See photos of birds and other wildlife coated with oil.)

That statistic includes common loons, northern gannets, double-crested cormorants, royal terns, Wilson’s plovers, black skimmers, and seaside sparrows, to name a few. Also affected: Up to 32 percent of laughing gulls and up to a quarter of all brown pelicans. (Learn how nature can bounce back from an oil spill.)

Many birds that weren’t killed outright by the oil coating their feathers have since shown higher rates of oil-related cancers, reproductive issues, and a reduced ability to regulate their body temperatures due to feather damage, according to a 2020 study.

(Video) Deepwater Horizon In Their Own Words (Full Episode) | In Their Own Words

But just as birds overall were most devastated, in some cases they seem to be showing some of the strongest recovery. Settlement money was put to use restoring Louisiana’s Queen Bess Island as bird habitat. The project was completed this past February and is being hailed as a success for brown pelicans, with up to 20 percent of the state’s population already nesting there, along with great egrets, roseate spoonbills, royal terns, and tri-colored herons.

Oily fish

What was a bust for birds turned into a temporary boon for some fish: Scientists think that the lack of birds in the skies over the Gulf of Mexico is one reason some populations of fish exploded after the spill.

There were twice as many Gulf menhaden, for example, in the years following the spill as in four decades before, likely because so many fish-eating birds were absent.

Other fish species have shown evidence of having been harmed by oil, including nearly two thirds of all Gulf sturgeon, a threatened species. Studies of the economically valuable spotted seatrout and red drum found that fish in oiled areas showed reduced reproduction, and that even years after the spill, oil remaining in the environment is still toxic to fish larvae. (Read how some fish deformities have been linked to the spill.)

Recent research that tested 2,500 different fish across the Gulf found evidence of oil exposure in all 91 species sampled, suggesting that the impacts of the spill are widespread and ongoing.

Looking ahead

It could take decades to understand how oil affects the next generation of whales, coral, sea turtles, birds, fish, and more.

For Smith, Frasier, Etnoyer, and others involved in spill research, this event has become career-encompassing. Their research will be devoted to monitoring and understanding the Gulf for many years to come—particularly if these ecosystems remain vulnerable.

In May 2019, the U.S. Department of the Interior rolled back safety regulations to offshore drilling that were put in place to prevent a repeat of the Deepwater Horizon spill. At the same time, there have been proposed expansions of Gulf protected areas, like the Flower Garden Banks National Marine Sanctuary. (Is another deepwater disaster inevitable? Read our story from October 2010.)

Meanwhile, Kaitlin Frasier will remain at her desk, listening for the chirping sounds of Risso’s dolphins and the long, low vocalizations of sperm whales.

“If there was one thing I could do, it would be to take people out to the deep Gulf and show them all the wildlife that is out there,” Frasier says. “Most people never get the chance, but it’s the most amazing thing.”


How did the BP oil spill affect wildlife? ›

An estimated 4,900–7,600 large juvenile and adult sea turtles and between 56,000–166,000 small juvenile sea turtles were killed by the spill. Furthermore, an estimated 35,000 hatchlings were lost due to the effects of the spill and associated clean-up activities on sea turtle nesting beaches.

Are dolphins affected by oil spills? ›

Scientists looked at the long-term impact of the oil spill on bottlenose dolphins living in Barataria Bay, near New Orleans. The lagoon off the Louisiana coast was heavily polluted by oil, which killed scores of dolphins directly or within months, and their population is now slightly over half of what it was.

How many animals did the BP oil spill affect? ›

We found that the spill likely harmed or killed about 82,000 birds of 102 species; about 6,165 sea turtles; as many as 25,900 marine mammals; and a vast (but unknown) number of fish — from the great bluefin tuna to our nation's smallest seahorse — plus oysters, crabs, corals and other creatures.

How did the oil spill in 2010 affect the environment? ›

The scientists concluded that the Deepwater Horizon oil spill killed thousands of marine mammals and sea turtles, and contaminated their habitats.

How do oil spills affect humans and animals? ›

OIL SPILLS can harm wildlife in a number of ways. The toxic effects of inhaling vapors and ingesting oil when grooming or feeding can make animals sick. Oil can also coat an animal's fur or feathers, leading to hypothermia and a loss of buoyancy.

What animals were affected by the oil spill? ›

What Creatures Are Most Affected by Oil Spills? Since most oils float, the creatures most affected by oil are animals like sea otters and seabirds that are found on the sea surface or on shorelines if the oil comes ashore.

What is the main threat to dolphins? ›

Dolphins face many threats including entanglement in fishing gear, ocean pollution, habitat loss and climate change. Ocean noise pollution from human activity like commercial shipping and military sonar poses another serious threat to the beloved marine mammal.

What does oil do to dolphins? ›

Dolphins and whales can inhale oil, which can affect lungs, immune function and reproduction. Many birds and animals also ingest oil when they try to clean themselves, which can poison them.

What are the main causes of dolphins deaths? ›

As in any animal population, a variety of diseases and parasites can be responsible for dolphin deaths. Dolphins may suffer from viral, bacterial, and fungal infections. In addition, they may develop stomach ulcers, skin diseases, tumors, heart disease, urogenital disorders, and respiratory disorders.

How do oil spills affect humans? ›

Oil toxicity: Oil consists of many different toxic compounds. These toxic compounds can cause severe health problems like heart damage, stunted growth, immune system effects, and even death. Our understanding of oil toxicity has expanded by studying the effects of the 2010 Deepwater Horizon oil spill.

How could BP oil spill be prevented? ›

A culture of tighter safety and more experienced regulators might have prevented the BP Deepwater Horizon leak. But equipment modifications and new technology will be needed to minimize the risk of such deepwater oil leaks.

What are the 5 effects of oil spills? ›

The main oil spill effects include a variety of diseases, negative economic impact, pollution with crude oil or petroleum products (distillates such as: gasoline, diesel products, jet fuels, kerosene, fuel oil, as well as heavy distillates like hydraulic and lubricating oils) and the aesthetic issues that affect the ...

How does oil spill affect humans and the environment? ›

Studies of biomarkers have uncovered irreparable harm to humans exposed to oil and gas from spills. These effects can be grouped into respiratory damage, liver damage, decreased immunity, increased cancer risk, reproductive damage and higher levels of some toxics (hydrocarbons and heavy metals).

How did the 2010 oil spill affect humans? ›

A similar study found that citizens on the Gulf Coast had increased levels of anxiety, depression, and respiratory issues that lasted for several years after the catastrophe. Other coastal residents had similar symptoms including skin rashes, muscle cramps, pneumonia, migraines, and much more.

What is oil spill and its effects? ›

An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially the marine ecosystem, due to human activity, and is a form of pollution. The term is usually given to marine oil spills, where oil is released into the ocean or coastal waters, but spills may also occur on land.

Do animals survive oil spills? ›

Dr. Adamski: Depending on the extent of an animal's injuries and how quickly they receive help, animals do survive after treatment. There is significant research that animals injured in an oil spill no longer reproduce.

How are oil spills cleaned? ›

Dispersants and booms and skimmers are the most frequently used methods to clean up ocean oil spills. All methods have advantages and disadvantages. The effectiveness depends on the situation – the amount and type of oil, the ocean currents and tides and the weather.

What are oil spill solutions? ›

1. Shoreline Flushing/Washing: Water hoses can rinse oil from the shoreline into the water, where it can be more easily collected. 2. Booms: Long, floating, interconnected barriers are used to minimize the spread of spilled oil.

How are wildlife cleaned after covered in oil? ›

The animals are warmed, fed, hydrated and rested for a period of around 48 hours before they are washed in a series of tubs filled with a mixture of diluted cleaning agent and hot, softened water. The cleaned animals are then placed in outdoor pools, or other appropriate housing.

Why should we protect dolphins? ›

Without dolphins, the animals they prey on would increase in number, and their predators wouldn't have as much to eat. This would disrupt the natural balance in the food chain and could negatively affect other wildlife and the health of the ocean environment.

How do humans help dolphins? ›

In general, implementing the 3 Rs: Reduce, Reuse and Recycle; diminishes water pollution. Participate in coastal cleaning programs. Avoid going to Dolphinariums could help to reduce the capture of wild dolphins since some have unpleasant experiences when caught to end their life in captivity. Do not feed wild dolphins.

How do dolphins solve problems? ›

“This study clearly shows that dolphins use vocal communication to jointly solve problems”, says Torres. “The results point toward the possibility of a dolphin language that enables team problem solving.”

Do dolphins help save humans? ›

In reality, dolphins have saved humans on many occasions. In two (sort of) similar incidents, one in 2004 and one in 2007, pods of dolphins circled imperiled surfers for over thirty minutes in order to ward off aggressive great white sharks.

Do dolphins mourn death? ›

Studies suggest that a variety of dolphins and whale species grieve for their dead. These species can range from a small spinner dolphin to larger animals such as pilot whales and sperm whales.

Are dolphins aware of death? ›

Orcas and bottlenose dolphins may try to keep dead calves at the surface of the sea, as if giving them a chance to breathe. Quite possibly, none of these behaviors means that the animal is “aware” of death. A dolphin trying to keep a dead baby afloat may even suggest a lack of such awareness.

What do dolphins do when one dies? ›

In some observations, the dolphins maintained constant physical contact with dead individuals. They swam around the dead body, sometimes nudging and attempting to push it underwater. If observers approached the scene too closely, they would even carry the carcass away, as if reluctant to let go.

Why should we stop oil spills? ›

The cost of a spill

A significant oil spill could cost the state an average of $10.8 billion (based on 2006 estimates) and adversely affect 165,000 jobs. It would disrupt maritime shipping, port activities, recreation, and tourism, and cause significant harm to fish, shellfish, and wildlife resources.

What will happen if people spill a lot of oil in water? ›

When oil is spilled into an aquatic environment, it can harm organisms that live on or around the water surface and those that live under water. Spilled oil can also damage parts of the food chain, including human food resources.

How is oil harmful to the environment? ›

Oil and gas drilling has a serious impact on our wildlands and communities. Drilling projects operate around the clock generating pollution, fueling climate change, disrupting wildlife and damaging public lands that were set aside to benefit all people.

Who caused the BP oil spill? ›

In September 2014, a United States District Court judge ruled that BP was primarily responsible for the oil spill because of its gross negligence and reckless conduct. In April 2016, BP agreed to pay $20.8 billion in fines which is the largest corporate settlement in United States history.

Who did BP blame for the oil spill? ›

Transocean (the rig's owner)

Transocean was responsible for the safety valve known as the blowout preventer. The report says six leaks were identified in its hydraulic system. While it was on the wellhead, the investigators say the preventer appeared to follow BP and Transocean's standards.

How was BP punished for the oil spill? ›

The Deepwater Horizon criminal case, also prosecuted under the Clean Water Act, resulted in the largest criminal penalty with a single entity in U.S. history. BP pled guilty in 2012 to 14 felony counts and was fined a record $4 billion–and half directly benefits the Gulf.

What negative effects can oil spills have on the water and beaches? ›

Because oil spills are localized, they can severely contaminate beaches and sediment, and cause serious harm to marine wildlife. Oil spills can suffocate fish, get caught in the feathers of birds and mammals and block light from photosynthetic plants in the water.

What is the main cause of oil spills? ›

Oil spills that happen in rivers, bays and the ocean most often are caused by accidents involving tankers, barges, pipelines, refineries, drilling rigs and storage facilities, but also occur from recreational boats and in marinas.

How do oil spills impact the economy? ›

Oil spills can lead to severe disruption for the tourist industry. Contamination of coastal areas with high amenity value is a common feature of many oil spills. In addition to costs incurred by clean-up activities, serious economic losses can be experienced by industries and individuals dependent on coastal resources.

Do oil spills affect climate change? ›

Oil 'spilled' by all of us into the air by combustion drives runaway climate change. Contingency planning and response are necessary tools but not sufficient everywhere. Spills were landmarks to the global warming crisis and the need for decarbonisation.

› Health Topics ›

Oil Spills

https://medlineplus.gov › Health Topics
https://medlineplus.gov › Health Topics
Oil spills often happen because of accidents, when people make mistakes or equipment breaks down. Other causes include natural disasters or deliberate acts. Oil...

Oil spills

https://www.noaa.gov › resource-collections › ocean-coasts
https://www.noaa.gov › resource-collections › ocean-coasts
Oil is an ancient fossil fuel that we use to heat our homes, generate electricity, and power large sectors of our economy. But when oil accidentally spills into...
Fire boat response crews battle the blazing remnants of the off shore oil rig Deepwater Horizon off the Louisiana coast Thursday. The oil drilling rig that had ...

What happened to wildlife during the Gulf oil spill? ›

Studies have determined that oil is particularly toxic for many species of larval fish, causing deformation and death. The federal study estimates that the disaster directly killed between two and five million larval fish.

How did the oil spill affect the birds? ›

When oil sticks to a bird's feathers, it causes them to mat and separate, impairing waterproofing and exposing the animal's sensitive skin to extremes in temperature. This can result in hypothermia, meaning the bird becomes cold, or hyperthermia, which results in overheating.

How can we help wildlife oil spills? ›

However, there are other ways ordinary people can help out, mostly by supporting organizations that care for wildlife that get caught in an oil slick or by volunteering for future beach cleanups. Wetlands & Wildlife Care Center, www.wwccoc.org, 21900 Pacific Coast Highway, Huntington Beach, CA 92646, 714-374-5587.

What methods are used to rescue wildlife after an oil spill? ›

The animals are warmed, fed, hydrated and rested for a period of around 48 hours before they are washed in a series of tubs filled with a mixture of diluted cleaning agent and hot, softened water. The cleaned animals are then placed in outdoor pools, or other appropriate housing.

How do oil spills affect humans? ›

Oil toxicity: Oil consists of many different toxic compounds. These toxic compounds can cause severe health problems like heart damage, stunted growth, immune system effects, and even death. Our understanding of oil toxicity has expanded by studying the effects of the 2010 Deepwater Horizon oil spill.

What are the effects of oil spills on animals? ›

Oil destroys the insulating ability of fur-bearing mammals, such as sea otters, and the water repellency of a bird's feathers, thus exposing these creatures to the harsh elements. Without the ability to repel water and insulate from the cold water, birds and mammals will die from hypothermia.

How is oil removed from birds? ›

Scientists and volunteer wildlife rescuers wash oiled birds with dishwashing soap. The dishwashing soap removes the oil, but it also removes the natural waterproofing oils from a bird's feathers. Birds that have been washed are able to fly and stay warm, but have difficulty flying when their feathers are wet.


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