What’s Killing Thousands of Dolphins in the Gulf?

Between February 2010 and April 1, 2012, 714 dolphins and other cetaceans — 95 percent of them dead — washed up on the northern shore of the Gulf of Mexico, from the border Louisiana and Texas share to Franklin County in Florida. The average number of dolphins who are stranded in a year is 74: What’s going on?

Now the National Oceanic and Atmospheric Administration (NOAA) is saying that those 714 animals found represent only a fraction of how many are actually perishing in what appears to be a massive die-off. Many of the dolphins sink, decompose or are eaten before they wash up to shore, notes Tim Wall at Discovery News. The NOAA has now declared the die-off an “Unusual Mortality Event,” according to the Marine Mammal Protection Act of 1972.

The frightening die-off does coincide with BP’s Deepwater Horizon oil spill and its aftermath. A recent study has found that exposure to oil leads to serious health problems for dolphins.

Could a Bacteria Be The Reason So Many Dolphins Dying?

But as Wall at Discovery News points out, the increase in dolphin deaths started happening two months before the April 20, 2010 explosion that led to a months-long oil spill. 112 dolphins were found to have died before the spill and the NOAA says that the Brucella bacteria could be the culprit.

The NOAA found Brucella in five stranded dolphins from Louisiana and its scientists have now been focusing on cases showing “pathological changes consistent with the fetal pneumonia or adult meningitis identified” in the original five cases. Infection with Brucella causes a disease, brucellosis, that, according to the NOAA, is “best known for its role in causing abortion in domestic livestock and undulant fever in people”; it can also cause infections im the brain, skin and bones. Scientists currently do not know how brucellosis is spread in dolphins. In domestic livestock, brucellosis spreads when animals consume the tissue and fluids left after delivery of a fetus and also via “inhalation, contact with a wound, and during nursing and breeding.”

However, dozens of the dolphins who have washed up show no sign of Brucella infection. NOAA scientists are continuing to investigate the possible role of the Deepwater Horizon oil spill in the Unusual Mortality Event, to figure out what is behind the shockingly high numbers of dolphins perishing in the Gulf of Mexico.

Related Care2 Coverage

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Save Dolphins From Fishing Nets


Photo by chaunceydavis818

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Duane B.
.2 years ago

Thank you for sharing.

David Sheridan
David Sheridan3 years ago

The die off may have started before the Deepwater Horizon blew up, but the oil has been leaking into the gulf since LONG before that. There are THOUSANDS of oil rigs in the Gulf of Mexico.

Carrie Anne Brown

hope they find the reason thanks for sharing

Howard C.
.3 years ago

This is dreadful - hopefully something is being done to identify the cause and hopefully come up with a solution.

Tricia Hamilton
Tricia Hamilton3 years ago

What a greedy B-----D!!

Debbie L.
Debbie Lim3 years ago

Very sad to hear.

mary l.
mary l.3 years ago

how sad

LMj Sunshine


Sofia Natsis
Sofia Natsis3 years ago

How horriffic! Humans are their own destruction.

Morgan Forrester
Past Member 3 years ago

....yeah,and we're supposed to trust our food sources!
When dolphins & the like are dying off,you know our waters are poisoned!!