Dolphin Deaths Deserve More Answers Than Questions

Bottle-nose Dolphins

A pod of Bottle-nosed Dolphins (Tursiops truncata) off the Alabama coast in late December 2010, a month before the death

This is “normally” dead dolphin season along the Gulf Coast, but 2011 has a haunting, downstream-impact feeling about it; fueled by a “higher than average” number of still-born and baby dolphins washing ashore in the marshes and on the beaches along 200 miles of the Gulf Coast. Exactly why? Connecting the dots, or dolphins, can be a tricky business, and any good scientist, or journalist, worth their salt would be hesitant to venture too far from the facts and into the murky waters of opinion.

Without much sleuthing facts are surfacing.  The Institute for Marine Mammal Studies (IMMS) issued this February 25, 2011 media release:

The Institute for Marine Mammal Studies would like to confirm that further dolphin strandings have been reported since our last press release on Wednesday, February 23, 2011. The total count for the year now stands at 34 strandings, with 27 of these involving calves. This brings the total number of strandings for the year in Mississippi to 18 with 12 of these involving calves. Alabama’s total now stands at 16 with 15 of the strandings involving calves.

We are continuing to collect samples from the animals where possible to conduct tissue analysis for age and genetics as well as toxicology, histopathology, virology and parisitology. These samples are sent to laboratories outside of the IMMS and due to the extensive processes involved and the high number of samples to be tested, we do not expect any immediate results.

What’s unusual about this dead dolphin season is the number and kind, babies, making a few scientists deviate cautiously into those murky, possibly oily, waters of opinion.  The message posted on the Institute for Marine Mammal Studies (IMMS) reinforces the seriousness of the events:

Dead baby dolphin strandings are occurring in significantly higher than average numbers in Mississippi and Alabama. This has caused NOAA to declare an Unusual Mortality Event in the area. The dolphin calves are being examined by staff and volunteers from the Institute for Marine Mammal Studies in Gulfport. If you see a stranded marine mammal in Mississippi or Alabama please call the IMMS stranding hotline 1-888-SOS- DOLPHIN (1-888-767-3657).

This is the first post-BP oil disaster calving season for the up to 5,000 bottle-nosed dolphins that call the Gulf of Mexico home.  In fact this spring brings forth births of all kinds, pelicans, terns, black skimmers and other sea and shore birds, sea turtles, fishes, shrimp, crabs, oysters and a bevy of benthos creatures the shapes and names of which are closer to patrons of a Star Wars bar than Earthlings most of us recognize.

Despite the silence in the media there are a number of scientists from across the Gulf – not bound by the BP non-disclosure gag order – that are looking carefully and hard at what this coming season will portend; not just for the first year after the BP disaster, but for many years to come.  This comes as independent administrator Kenneth Feinberg announced this week, “The Gulf of Mexico should recover from the massive BP oil spill by the end of 2012.″

The death toll, known and reported, from the previous ten months, post- the greatest human-caused environmental disaster, is small, or “manageable” as I was told: about 7,000 various seabirds, 600 sea turtles, and millions of other creatures too small to register on the human conscience scale.  But will the death toll rise?  And what epitaph will be inscribed – collateral damage or direct death?

The remains of 77 animals – nearly all bottlenose dolphins – have been discovered on islands, in marshes and on beaches along 200 miles of coastline. This figure is more than 10 times the number normally found washed up around this time of year, which is calving season for some 2,000 to 5,000 dolphins in the region. Another seven dead animals were reported yesterday, [Feb 21, 2011] although the finds have not yet been confirmed by the US National Oceanic and Atmospheric Administration (NOAA).

One of the more disturbing aspects of the deaths is that nearly half – 36 animals so far – have been newborn or stillborn dolphin calves. In January 2009 and 2010, there were no reports of stranded calves, and because this is the first calving season since the BP disaster, scientists are concerned that the spill may be a cause.

“The number of baby dolphins washing ashore now is new and something we are very concerned about,” NOAA spokeswoman Blair Mase said. She said that the agency had declared the alarming cluster of deaths “an unusual mortality event”, adding: “Because of this declaration, many resources are expected to be allocated to investigating this.”

Bottlenose dolphins, like Gulf Coast resident humans, sit atop the Gulf food chain.  During the BP oil disaster their surface air-breathing world was toxified.  Every breath they took was laden with off-gasing oil and Corexit (dispersant), and every fish on which they fed was likewise compromised.  That air and nutrition was on an expressway to the gestating fetus.  (The Bottlenose gestation period averages 12 months.)

Preferring to travel a cautionary road, scientists at the independent Dauphin Island Sea Lab in Alabama suggested last week (Feb 16) that unusually chilly water temperatures in the Gulf may be a key factor. They were quoted by Reuters:

“Everyone wants to blame toxicity due to the oil spill, said Monty Graham, a senior scientist at the Dauphin Island lab. “The oil spill … very well could have been the cause of the dolphin deaths. But the cold weather could have been the last straw for these animals.”

He noted that water temperatures abruptly plunged from the upper 50s into the 40s off Dauphin Island in January, just before the first two stillborn calves found there were recovered. He said a second wave of dolphin carcasses washed ashore after temperatures dipped again.

Fellow Dauphin Island scientist Ruth Carmichael called the arrival of the cold snap “incredibly compelling.”

“The timing of the cold water may have been important because the dolphins were late in their pregnancies, about one to two months from giving birth. That might render them more vulnerable to temperature shocks,” she said.

But NOAA officials discounted the significance of chilly weather, saying a similar cold snap in February 2010, months before the oil spill, was accompanied by higher-than-normal mortality among a range of wildlife, including fish and sea turtles. They also cited research showing bottlenose dolphins tend to swim away from extremely cool waters.

“These animals have the ability to move away from cold. They don’t stay around in cold water,” said Moby Solangi, director of the Institute for Marine Mammal Studies in Gulfport, Mississippi.

Food chains do not surrender their secrets easily.  They are complex, intricate and filled with pathways we humans rarely if ever travel.  It is understandable that the journey will be filled with dead ends and circuitous paths, but our scientists have to be brave enough venture into the unknown. Clearly products of the BP disaster are present and still poisoning the wind and waters of the Gulf.   To believe that is not the case is not cautionary science it is cowardly science.

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