Gulf Dolphins Questions & Answers
- Why is NOAA studying dolphins in the Northern Gulf of Mexico now?
- What is going on with dolphin strandings in the Gulf of Mexico?
- Why did NOAA and its NRDA partners focus one study on the dolphins in Louisiana’s Barataria Bay?
- How many dolphins, and what kinds, are in the Gulf of Mexico?
- How many dolphins are in Barataria Bay?
- If oil is the cause of these health problems, how could it make the dolphins so sick?
- If the dolphins are sick, are humans at risk?
- Is Gulf seafood safe to eat?
- What should Gulf residents do if they find stranded wildlife?
Why is NOAA studying dolphins in the Northern Gulf of Mexico now?
NOAA and its federal, state and local partners are working together on the Natural Resource Damage Assessment, investigating an Unusual Mortality Event and evaluating the long term impacts of the Deepwater Horizon oil spill on dolphins in the Gulf. An important goal of this cooperative effort is to assess the impact of the Deepwater Horizon oil spill and response activities on the dolphins in the northern Gulf of Mexico.
What is going on with dolphin strandings in the Gulf of Mexico?
Dolphin strandings have been high in the northern Gulf of Mexico, beginning February 2010, and continued to be elevated after the Deepwater Horizon oil spill. These increased strandings are part of an Unusual Mortality Event for the entire northern Gulf which includes all dolphin and whale strandings between the Panhandle of Florida and the Louisiana/Texas border. Alabama, Mississippi and Louisiana stranding rates have been higher than historic levels since the spill occurred and continue to be high in 2012.
The average annual number of dolphin strandings in Louisiana from 2002-2009 was 20. For the entire year in 2010, there were 139 strandings in Louisiana, including 48 strandings prior to the Deepwater Horizon oil spill. Although the stranding rate fluctuated across months, the overall rate has remained elevated and there were more strandings in 2011 than in 2010 (2011 had 159 strandings in Louisiana, almost 8 times the 2002-2009 historical average).
Dolphin strandings have also remained elevated in Mississippi and Alabama in 2010 and 2011. Strandings in 2011 for Mississippi and Alabama were 5 times and 4 times the 2002-2009 historical average respectively.
This magnitude of strandings in the northern Gulf is unprecedented. Further, there is no evidence that two of the most common causes of previous dolphin die-offs in the Gulf, morbillivirus and marine biotoxins, are the cause of this UME. NOAA is working with a team of marine mammal health experts to investigate the cause of death for as many of the dolphins as possible and to understand the potential contributing factors.
For more on the investigation into this Unusual Mortality Event visit www.nmfs.noaa.gov/pr/health/mmume/cetacean_gulfofmexico2010.htm.
Why did NOAA and its NRDA partners focus one study on the dolphins in Louisiana’s Barataria Bay?
Barataria Bay was heavily oiled for a prolonged time during the Deepwater Horizon spill. Scientists sampled dolphins there, and in an area that was not heavily oiled, Sarasota Bay in Florida. The Barataria Bay dolphins have severe health problems that are not showing up in dolphins from the un-oiled area and have not been seen in previous studies of dolphins from other sites along the Atlantic coast or the Gulf of Mexico.
The Barataria Bay dolphins that have been examined are underweight, have low hormone levels, low blood sugar, and some show signs of liver damage. Scientists from NOAA and its partners are working to figure out the cause. The dolphins’ symptoms are consistent with those seen in other mammals exposed to oil, but the study is not yet complete. Assessment efforts continue in Barataria Bay and in other coastal areas of Louisiana and Mississippi. A final report of study results for the Barataria Bay dolphins is expected in the next six months. Final results for other areas will take longer, because new samples are still being collected.
How many dolphins, and what kinds, are in the Gulf of Mexico?
There are nine different species of dolphins in the Gulf of Mexico as well as Bryde’s whales, which is a baleen whale, sperm whales, killer whales and several other kinds of smaller toothed whales. The bottlenose dolphin is the only species found in all Gulf coastal habitats. There are an estimated 10,000 bottlenose dolphins in these coastal waters although the exact number is unknown. In most cases, the other species live far from land in deep Gulf of Mexico waters.
- Inhaling vapors at the water’s surface.
- Ingesting oil from the sediment or water while feeding.
- Eating whole fish, including internal organs and fluids, such as liver and bile, which can harbor chemical contaminants.
- Absorption through their skin.
If the dolphins are sick, are humans at risk?
The EPA, FDA, NIH and CDC are aware of concerns about oil in the Gulf of Mexico and possible human health issues and will act swiftly to advise the public of any cause for concern. Nothing has indicated a risk to human health so far.
The NRDA trustees are conducting studies to better understand the potential routes of oil exposure for the dolphins. There are multiple ways that dolphins could have been exposed to the oil—they might have inhaled vapors at the water’s surface, incidentally ingested oil from sediments or water while feeding, or have been exposed by eating whole fish, including internal organs and fluids such as liver and bile, which can harbor chemical contaminants. These are not likely routes of exposure for most people. Most recreational activities like swimming and scuba diving are safe.
The National Institutes of Health also is conducting research into the potential health effects of the oil spill. For more information, please visit www.niehs.nih.gov/gulfstudy.
Is Gulf seafood safe to eat?
Seafood safety testing is generally conducted by states. NOAA currently only tests seafood when contracted to do so by seafood suppliers. BP funded a seafood safety testing program, which was conducted by the federal government during and immediately following the Deepwater Horizon spill. When that program ended, there were no indications of lingering oil or dispersants in Gulf seafood. The federal testing program began operation on April 28, 2010, and ran through June 2011. The testing conducted from April 2011 (when the last federal fishery closures ended) to June 2011 was surveillance of re-opened areas. State testing in Louisiana has been ongoing since April 28, 2010, and includes a broad set of sample types and locations each month. About 3,000 seafood, water and sediment samples have been tested in Louisiana since the start of the spill.
During the NOAA testing program’s existence, sensory and chemical testing methods were used to measure polycyclic aromatic hydrocarbons (PAH) and dispersants in more than 8,000 seafood specimens collected in federal waters of the Gulf of Mexico. In federal waters, 0.16% (6 of 3,810) seafood samples failed sensory testing. Overall (100 \% of samples analyzed), individual PAHs and the dispersant component dioctyl sodium sulfosuccinate were found in low concentrations or below the limits of quantitation using analytical chemical methods. When detected, the PAH concentrations were at least two orders of magnitude lower than the corresponding FDA level of concern for each PAH.
The federal and state governments agree on the seafood testing protocols. Since the 2010 oil spill, the federal government and the Gulf Coast states have used an identical test for seafood safety to ensure that it is safe for consumption. NOAA re-opened federal waters to fishing after extensive testing. The Gulf states continue to use the testing protocol to routinely test finfish and shellfish that are caught in state waters. While the majority of state waters are open, some areas remain closed to commercial fishing. For example, Louisiana has closed areas of the Barataria Bay Basin. Maps of areas closed to fishing in Louisiana are available at www.wlf.louisiana.gov/oilspill.
For additional information about seafood safety, please visit www.gulfsource.org and www.fda.gov/Food/FoodSafety/Product-SpecificInformation/Seafood/ucm210970.htm.
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