Mysterious mass deaths of Gulf Coast dolphins (UPDATED: Also in Peru)

Thousands of Dolphins Dying in Gulf Waters

The dolphins in the Gulf of Mexico are in the midst of a massive die-off. The reasons why remain a complicated and mysterious mix of oil, bacteria, and the unknown.

Normally an average of 74 dolphins are stranded on the northern shore of the Gulf of Mexico each year, especially during the spring birthing season. But between February 2010 and April 1, 2012, 714 dolphins and other cetaceans have been reported as washed up on the coast from the Louisiana/Texas border through Franklin County, Florida, reported the National Oceanic and Atmospheric Administration (NOAA). 95 percent of the mammals were dead.

Think it’s the gulf oil spill? Not so fast…

Tip: Strange Times

This is known as a Unusual Mortality Event (UME), where there is a higher than anticipated dieoff of creatures. Right now, there is no complete answer. And, since not all the dolphins that died will wash up on shore to be counted, we must assume that the counts they do have represent a small portion. A bit frightening and sad.

Here is the official link from NOAA:

2010-2012 Cetacean Unusual Mortality Event in Northern Gulf of Mexico

In addition to investigating all other potential causes, scientists are investigating what role Brucella [bacteria] may have in the Unusual Mortality Event.

Since our original finding of Brucella in 5 stranded dolphins from LA, scientists have been concentrating testing on cases that show pathological changes consistent with the fetal pneumonia or adult meningitis identified in the first 5 cases.

And here is their FAQ about the Gulf oil spill that shows this episode began before the oil spill occurred.

March 2010
The WGMMUME was consulted regarding an increase in strandings in Lake Pontchartrain, Louisiana. As this consultation proceeded an increase in strandings in the wider northern Gulf was also noted that appeared to start in February 2010 but accelerated in March 2010.

April 20, 2010
The WGMMUME was in the process of receiving and reviewing information on elevated strandings in the northern Gulf and providing advice on the overall stranding increase when the Deepwater Horizon fire and oil spill occurred.

UPDATE(6-Apr-2012): More on dolphin deaths in Peru Massive Dolphin Die-Off in Peru May Remain a Mystery

Now, the death toll could be as high as 2,800, based on volunteers’ counts. Peru’s massive dolphin die-off is among the largest ever reported worldwide.

All of the 20 or so animals Yaipén has examined showed middle-ear hemorrhage and fracture of the ear’s periotic bone, lung lesions and bubbles in the blood. To him, that suggests that a major acoustic impact caused injury, but not immediate death. Most of the dolphins apparently were alive when they beached, or had died very recently.