Download Questions and Answers - Sarasota Dolphin Research Program

Questions and Answers
Barataria Bay Dolphin Findings
Provided by NOAA
March 32, 2012
Q: Why is NOAA studying dolphins in the Northern Gulf of Mexico now?
A: NOAA and its federal, state and local partners are working together on the Natural Resource Damage
Assessment and evaluating the long-term impacts of the DWH oil spill on dolphins in the Gulf as well
investigating an Unusual Mortality Event in the northern Gulf. An important goal of this cooperative
NRDA effort is to assess impacts of the DWH oil spill and response activities on the dolphins in the
northern Gulf of Mexico. NOAA is working closely with the Working Group for Marine Mammal
Unusual Mortality Events, a group of marine mammal health experts, and an investigative team to
determine causes or contributing factors of the UME and what role the DWH spill may have had.
Q: What is going on with dolphin strandings in the Gulf of Mexico?
A: Dolphin strandings have been elevated in the northern Gulf of Mexico since February 2010 and
strandings have remained elevated after the Deepwater Horizon oil spill occurred. These increased
dolphin 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. Dolphin strandings in Louisiana have been occurring at a much
higher rate throughout most of the last two years. 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 DWH 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 involved in this Unusual Mortality Event.
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 to this mortality
Event.
For more on the investigation into this Unusual Mortality Event go to:
http://www.nmfs.noaa.gov/pr/health/mmume/cetacean_gulfofmexico2010.htm
Q: Why did NOAA and its NRDA partners focus one study on the dolphins in Louisiana’s
Barataria Bay?
A: Barataria Bay was heavily oiled for a prolonged time during the DWH 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.
Q: What are the preliminary findings?
A: The Barataria dolphins are much sicker than other dolphins in other study areas. The Barataria results
are very different from what NOAA has seen in other examined populations. For example, these health
concerns were not observed in 27 dolphins sampled with the same methods in Sarasota Bay, Florida, in
May 2010 and May 2011.
Several dolphins sampled in Barataria Bay were severely underweight, anemic, hypoglycemic, and/or
showed symptoms of liver disease.
44% of the dolphins sampled in Barataria Bay had abnormally low levels of cortisol in their blood.
Cortisol is one of several hormones produced by the adrenal gland; cortisol is crucial for stress response
but also has an important role in other body functions such as metabolism and immune function.
In addition, many of the dolphins also had abnormally low levels of another adrenal hormone,
aldosterone. 35% of the dolphins evaluated in August had both low cortisol and aldosterone levels.
The low levels of both of these hormones provide evidence of adrenal insufficiency.
Adrenal insufficiency in mammals can lead to severe health problems, including hypoglycemia, weight
loss, low blood pressure, and eventually even kidney failure, heart failure and death.
On Jan. 31, 2012, one of these sick animals stranded dead on Grand Isle, Louisiana, extremely emaciated,
and NOAA performed a necropsy.
Q: Has this new information caused NOAA to change the way it is handling stranded dolphins in
Barataria Bay and other parts of the Gulf of Mexico?
A: The stranding network and the associated veterinarians have been informed of the health concerns in
Barataria Bay dolphins. This will inform their decisions when caring for live stranded dolphins and when
performing necropsies on dead animals. NOAA is advising stranding network veterinarians to obtain,
where appropriate, additional samples from live and dead stranded dolphins based on the health findings
from Barataria Bay.
Q: What can be done or what is NOAA doing to help the dolphins given that they seem
compromised?
A. NOAA is sharing the preliminary results of the Barataria Bay study with the Marine Mammal
Stranding Network and veterinary partners who are responsible for rescuing stranded dolphins so that
they can better care for live stranded dolphins and look for similar health conditions.
Q: What should Gulf residents do if they find stranded wildlife?
A. If you find an oiled, injured or dead marine mammal, sea turtle or bird, please contact:
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Dolphins and Whales
1-877-WHALEHELP (1-877-942-5343)
Manatees
FL: 1-888-404-FWCC (1-888-404-3922)
LA, MS, and AL: 1-904-731-3079
Sea Turtles
TX: 1-866-TURTLE5 (1-866-887-8535)
LA: 1-337-962-7092
MS: 1-888-SOS-DOLPHIN (1-888-767-3657)
AL: 1-866-SEA-TURT (1-866-732-8878)
FL: 1-888-404-FWCC (1-888-404-3922)
Q: When do you expect final results from the Barataria Bay study?
A: We are still analyzing results from the health assessment of Barataria Bay dolphins, but we hope to
have a final report completed within the next six months. Other assessment efforts, which include remote
biopsy and photo-identification surveys, are ongoing in Barataria Bay as well as other coastal areas of
Louisiana and Mississippi. Because this sampling is still happening, final results from these studies will
take longer to complete.
Q: What is the status of investigations on other dolphins in the Gulf? Is this linked to the Unusual
Mortality Event? Is what’s happening in Barataria Bay an Unusual Mortality Event?
A. In addition to the Natural Resource Damage Assessment studies, scientists continue to investigate a
dolphin Unusual Mortality Event in the northern Gulf of Mexico (Franklin County, Florida to the
Texas/Louisiana border). Since February 2010, unusually high numbers of cetaceans have stranded along
the U.S. northern Gulf coast. Historically, stranding rates in this area typically peak between February and
April. As of March 11 , 2012, the Unusual Mortality Event involved 685 cetacean strandings in the Gulf
of Mexico; 5% of these animals stranded alive while 95% were dead. In addition, we are continuing to
work with our stranding network members in Florida and Texas to monitor strandings outside of the
UME area. Current evidence supports that this Unusual Mortality Event is not due to marine biotoxins or
morbillivirus, common causes of previous dolphin mortality events.
Brucella, a bacterium, has been the only common infectious pathogen identified among some dolphin
mortalities in this event. Prior to this event, Brucella has not been associated with Unusual Mortality
Events in marine mammals in the United States and is considered a common marine microbe. While
brucellosis has been detected in some Unusual Mortality Event dolphins, the cause of death among most
dolphins, especially subadult and adult dolphins, has not been confirmed. The role of the Deepwater
Horizon oil spill on stranding rates, diseases, and the death of dolphins during this Unusual Mortality
Event continues to be investigated.
Q: What are you seeing in offshore animals?
A. We continue to monitor offshore populations through visual and acoustic surveys. We have also
collected remote biopsy samples from some offshore species, but we do not yet have analysis results from
these samples. It is not logistically feasible to conduct health assessments on offshore species as we have
conducted for the inshore dolphins. But, we are conducting analyses and modeling to understand the
likely exposure of offshore species to oil and associated chemicals and we will use this information to
estimate their likely health impacts. While most offshore cetaceans that die will not wash ashore, those
that do are thoroughly sampled by the stranding network .
Q: How were the animals in Barataria Bay exposed? Was it the fish they ate? What kinds of fish do
they eat, and do we eat the same fish? (Seafood safety)
A. We 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, they might have incidentally ingested oil from sediments or water while
feeding, or they might 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. Dolphins consume a number of different fish species, but they consume whole fish,
including liver and bile which may harbor chemical contaminants. This is different than what a person
would consume.
Q: Are the health concerns in Barataria Bay dolphins related to the Deepwater Horizon oil spill?
A. Although we cannot yet definitively say that the health issues were caused by the Deepwater Horizon
oil exposure, they are consistent with adverse health effects that have been seen in experimental studies of
another mammal (mink) exposed to oil. We continue to investigate the potential connection between the
Barataria dolphins’ health issues and their exposure to Deepwater Horizon oil.
Q: What is adrenal insufficiency?
A. In mammals, the adrenal glands are part of the body that sit next to the kidneys and release several
different types of hormones. These hormones control a number of important functions in the body such
as:
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Managing blood sugar levels
Working with the kidneys to regulate the balance of salt and water in the body
Controlling the body’s response to stress (usually involves increasing blood sugar and
suppressing immune function so the body can more effectively respond to a stress event)
Adrenal insufficiency occurs when the adrenal glands do not produce enough of these hormones.
Therefore, the functions mentioned above can be compromised.
The cause of the adrenal insufficiency can be a problem with the adrenal glands or it could be a problem
with another gland that helps to regulate the adrenal gland.
Q: Could adrenal insufficiency be a problem for other non-mammalian organisms such as fish or
turtles?
Fish (except for sculpins) do not have true adrenal glands. They do have cells that basically serve the
same purpose and secrete hormones similar to those secreted by adrenal glands in mammals, so it is
plausible that a similar effect could be seen in fish.
Turtles do have adrenal glands, so it is possible that similar effects could happen in turtles. But we do not
know for certain whether the mechanisms for adrenal toxicity would be the same between mammals, fish
and/or turtles.
Q: Are these findings about dolphins related to the lesions being reported on certain types of fish?
A. There is no known evidence suggesting a connection between the health concerns facing these
dolphins and the lesions documented on certain species of fish in limited areas of the Gulf of Mexico.
NOAA is engaged in several research efforts, both within and beyond the Natural Resource Damage
Assessment process, designed to better understand lesions on finfish. NOAA advises fishermen who catch
a finfish with lesions to release the fish with minimal handling, for example by using a de-hooking
device.
Q. Is Gulf seafood safe?
A. Consumers can be confident that the seafood from the Gulf of Mexico is safe to consume. Since the
2010 oil spill, the Food and Drug Administration, NOAA, and the Gulf Coast states have used an agreedupon protocol to test seafood and ensure that it is safe for consumption. NOAA opened federal waters to
fishing after extensive testing, and the Gulf states continue to use the protocol to routinely test finfish and
shellfish. As part of that protocol, Louisiana has closed areas of the Barataria Bay Basin to commercial
fishing, while the majority of state waters are open. 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.
With regards to the Brucella found in the dolphin Unusual Mortality Event study, there is little scientific
literature showing the presence of Brucella in fish. There have been only 3 cases globally linking
Brucella infection to consumption of raw seafood, and none were in the United States. There is little to no
risk of exposure to humans through the consumption of raw fish or other raw seafood. Cooking seafood
kills the Brucella bacterium. Learn more about Gulf seafood safety after the Deepwater Horizon oil spill.
Q. Is Brucella something humans can catch?
A. There is no evidence that the infections seen in the stranded dolphins are contagious to humans.
With regard to the Unusual Mortality Event dolphins found to have marine Brucella—cases of human
brucellosis in the United States are rare, and none have been due to contact with dolphins or other marine
mammals. Transmission of Brucella happens when humans come in contact with contaminated animals
(usually cows, goats, pigs, or dogs) or animal products such as unpasteurized milk or contaminated
cheese; however, with use of pasteurization, transmission is rare. Transmission can also occur by
inhalation of the Brucella organism or by direct contact with infected animal secretions.
Q. Why is NOAA releasing this information now?
A. Laboratory results on the Barataria Bay dolphins recently became available and NOAA is issuing new
guidance to the stranding network to assist in the investigation of dolphin illnesses and strandings. We
also understand that the public is eager to hear results of our assessment activities. NOAA is striving to be
timely and transparent in reporting our findings.
Q. Will this study of the dolphins continue (in the face of budget cuts)?
A. Continued monitoring of the Barataria dolphins as well as other marine mammals in the Gulf is
critical to fully understand the impacts from the Deepwater Horizon oil spill and to determine effective
restoration efforts. The ultimate impacts on marine mammal populations from the Deepwater Horizon
spill may not be fully apparent for years, as evidenced from long-term monitoring of killer whale
populations in Prince William Sound, Alaska after the Exxon Valdez oil spill. Long-term monitoring is
essential.
We can’t undo the damage that has been done. But we can look for ways to mitigate further impacts, and
we can try to mitigate impacts from other stressors (such as interactions with boats or fishing gear, or by
pursuing remediation of other significant pollutant sources). Long-term monitoring and restoration are the
highest priorities provided funding sources are available.