Deepwater Horizon Oil Spill-Longterm Effects on Marine Mammals, Sea Turtles – via Herp Digest

NOAA Home New, DEEPWATER HORIZON: EFFECT ON MARINE MAMMALS AND SEA TURTLES APRIL 20, 2017 (My apologies for the delay in posting this, but I just found it,. Still, though it’s almost 3 months old, I thought it is important enough to post. Go to https://oceanservice.noaa.gov/news/apr17/dwh-protected-species.html for some great photos that went with the article.)

A recent Endangered Species Research special issue (You will find the special issue at http://www.int-res.com/abstracts/esr/v33/  all articles cited are open access and links are provided)  summarizes some of the devastating longterm effects of the Deepwater Horizon (Here you will find a bibliography on NOAA articles on the spill and its aftermath at http://response.restoration.noaa.gov/deepwaterhorizon with links to the articles) oil spill on protected marine mammals and sea turtles. 

The issue compiles 20 scientific studies authored by NOAA scientists and partners covering more than five years' worth of data collection, analysis, and interpretation. The research indicates that populations of several marine mammal and sea turtle species will take decades to rebound. Significant habitat restoration in the region will also be needed.

NOAA scientists used a variety of cutting-edge research methods in these studies and many others as part of a Natural Resource Damage Assessment. This is the legal process where we investigate the type of injuries caused by the oil spill, quantify how many animals were harmed, develop a restoration plan to compensate for the natural resource injuries, and hold responsible parties liable to pay for the restoration.  

As the largest offshore oil spill in U.S. history, the Deepwater Horizon oil spill released 134 million gallons of oil into the Gulf of Mexico over a period of 87 days, fouling 1,300 miles of shoreline along five states. The scientists concluded that the Deepwater Horizon oil spill killed thousands of marine mammals and sea turtles, and contaminated their habitats.

The northern Gulf of Mexico is home to 22 species of marine mammals, including manatees in coastal seagrasses and dolphins and whales in estuarine, nearshore, and offshore habitats.

Five species of sea turtles live in the Gulf of Mexico: loggerhead, Kemp's ridley, green turtle, hawksbill, and leatherback. All of these species are protected under the Endangered Species Act. The Gulf of Mexico provides critically important habitats for sea turtle reproduction, feeding, migration, and refuge, including extensive Sargassum habitat in the open ocean that small juvenile turtles depend on for survival.

The scientists determined that four species of sea turtles (Kemp's ridley, loggerhead, green turtle, and hawksbill) and their habitats were exposed to Deepwater Horizon oil in the open ocean, across the continental shelf, and into nearshore and coastal areas, including beaches. A fifth species, the leatherback, was likely exposed to Deepwater Horizon oil, and some exposed leatherbacks likely died.

Deepwater Horizon oil contaminated every type of habitat that northern Gulf of Mexico marine mammals occupy.

To determine the types of injuries to whales and dolphins due to the spill, the scientists collected a variety of information, including field studies, stranded carcasses, historical data on marine mammal populations, and toxicity testing studies.

Marine mammals and sea turtles may have been exposed to the oil by inhalation, aspiration, ingesting contaminated sediment, water, or prey, or by absorbing contaminants through their skin.

Marine mammal researchers concluded that exposure to the oil caused a wide range of adverse health effects such as reproductive failure and organ damage, and that animals killed by these adverse effects contributed to the largest and longest marine mammal unusual mortality event ever recorded in the Gulf of Mexico.

Miring in oil and exposure to oiled surface habitat caused significant harm to sea turtles, including decreased mobility, exhaustion, dehydration, overheating, likely decreased ability to feed and evade predators, and death.

Examples of impacts to species included: up to 20 percent of all oceanic juvenile Kemp's Ridley sea turtles present during the Deepwater Horizon oil spill perished from oil exposure; and oil-associated health effects to Barataria Bay, Louisiana, bottlenosed dolphins reduced their survival and reproductive success in years following the spill, leading to a 50 percent decline in the population, according to NOAA scientists and partners.

Findings from these research studies, in addition to other studies on other parts of the ecosystem, formed the basis of the natural resources damage assessment settlement with BP for up to $8.8 billion for restoration projects.

Because marine mammals face a wide range of threats, a portfolio of restoration approaches include: decreasing and mitigating interactions with commercial and recreational fishing gear, characterizing and reducing impacts from noise, reducing illegal feeding and harassment, and increasing understanding of causes of marine mammal illness and death.

Specific activities for sea turtles could include reducing fisheries bycatch, enhancing sea turtle stranding response and mortality investigation, and improving nesting habitat by protecting nests and reducing artificial sources of light that can disorient hatchlings at night.

Turtle excluder devices on nets allow sea turtles to escape unharmed. Restoration activities could include promoting the use of such devices. 

After Deepwater Horizon spill: Which animals weathered the disaster

Scientists construct a food web of heavily oiled marshes in Barataria Bay, Louisiana

Date: March 13, 2017

Source: Rutgers University

A new study from a Coastal Waters Consortium team of researchers led by Rutgers University postdoctoral researcher, Michael McCann, has found which birds, fish, insects and other animals affected by the Deepwater Horizon explosion should be given top priority for conservation, protection and research.

Until now scientists didn't know which kinds of animals were most affected and what impact their collective fates had on the food chain after the offshore oil rig Deepwater Horizon exploded in 2010 and dumped 4.9 million barrels of oil into Louisiana's salt marshes.

"There were lots of studies about who eats whom, and about what species are sensitive to oil," says Olaf Jensen, professor of marine and coastal sciences in the School of Environmental and Biological Sciences, and co-author of the study. "We put those together and asked, 'Who is both important in the food web and really sensitive to oil?'" These are the species most in need of protection because their loss can have ripple effects throughout the food chain, said Jensen.

The study, published this month in Frontiers in Ecology and the Environment, in which the team of scientists from Rutgers University, Louisiana State University, Louisiana Universities Marine Consortium, University of North Carolina, East Carolina University, and Stony Brook University constructed a marsh food web for Barataria Bay, Louisiana. The study found that killifish played a key role in the food web and fared relatively well in the wake of the spill.

The researchers determined that terns, gulls and wading birds, such as herons, were both sensitive to oil and so extensively connected to other animals as prey and predator that their loss would impact other species in the food chain. Some studies indicate that the mortality among terns and gulls in Barataria Bay was as high as 32 percent.

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Turtles' Wayward Travels May Mean BP Oil Spill's Impact Was Global

by Stephanie Pappas, Live Science Contributor | December 28, 2015 09:05am ET

The far-flung journeys of juvenile sea turtles could mean that the impact of 2010's Deepwater Horizon oil spill was global.

More than 300,000 sea turtles were likely in the region of the Gulf of Mexico affected by the oil spill, according to a new computer simulation. About three-quarters of these marine animals probably came from Mexican nesting populations, the research found. Others hailed from South America, Costa Rica and as far away as western Africa.

As a result, efforts to rehabilitate the environment after the spill should likely reach far beyond the Gulf Coast of the United States, said study researcher Nathan Putman, a biologist at the University of Miami.

Continued ...

Deepwater Horizon oil spill contributed to high number of Gulf dolphin deaths

Date: May 20, 2015

Source: NOAA Headquarters

Summary: As part of an unusual mortality event investigation, a team of scientists has discovered that dead bottlenose dolphins stranded in the northern Gulf of Mexico since the start of the Deepwater Horizon oil spill have lung and adrenal lesions consistent with petroleum product exposure according to a paper published today in the peer-reviewed online journal PLOS ONE.

These findings support those of a 2011 health assessment of live dolphins in Barataria Bay, Louisiana, a heavily oiled area during the spill which showed those resident dolphins had poor health, adrenal disease, and lung disease.

The timing, location, and nature of the detected lesions support that contaminants from the Deepwater Horizon oil spill caused these lesions and contributed to the high numbers of dolphin deaths within this oil spill's footprint. Increased dolphin deaths following the oil spill are part of the northern Gulf of Mexico unusual mortality event investigation.

Continued ...

Five years after Deepwater Horizon, wildlife still struggling dolphins dying in high numbers; sea turtles failing to nest

Date:

March 31, 2015

Source:

National Wildlife Federation

Summary:

As the five-year anniversary of the explosion of the Deepwater Horizon oil rig approaches, a new report looks at how twenty species of wildlife are faring in the aftermath of the disaster.

Continued ...

Four Years Later, Marine Life Still Feeling Significant Impacts From Deepwater Horizon Oil Spill

April 18, 2014

Lawrence LeBlond for redOrbit.com – Your Universe Online

As the fourth anniversary of the Deepwater Horizon accident in the Gulf of Mexico approaches, much of the region’s environment and marine life are still feeling the effects of the largest accidental oil spill in US history.

Despite the continued impact on the environment and wildlife, BP – formerly British Petroleum – said in a statement on Tuesday that it has ended its “active cleanup” of Louisiana’s coast. This follows last year’s end of active cleanup in Florida, Alabama and Mississippi.

BP’s announcement also follows a directive issued by the US Coast Guard transitioning the active cleanup phase to a new response phase in which crews and equipment will be pre-positioned for future response to cleanup if new reports of oil surface.

“Our response posture has evolved to target re-oiling events on coastline segments that were previously cleaned,” said Coast Guard Capt. Thomas Sparks, who serves as federal on-scene coordinator for the BP response to the spill. “But let me be absolutely clear: This response is not over – not by a long shot. The transition to the Middle Response process does not end clean-up operations, and we continue to hold the responsible party accountable for Deepwater Horizon cleanup costs.

“We are absolutely committed to continuing the clean-up of Deepwater Horizon oil along the Gulf – for as long as it takes, and to surge as necessary and as the situation dictates,” Sparks said, as cited by Manuel Torres of The Times-Picayune.

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