The long-term viability of the Gulf’s bottlenose dolphin population is in jeopardy. Two more dead dolphins – juveniles, under a year in age – washed up on the beach in Gulfport, Mississippi, over the Thanksgiving holiday weekend. That pushed the body count to five in just the last week on Mississippi and Alabama beaches hit hard by last year’s colossal oil spill.
From Margaret Baker’s Nov. 27 Sun Herald report:
Two more dead dolphins washed ashore in a 24-hour period ending Sunday, said Mobi Solangi, director of the Institute for Marine Mammal Studies.
Both of the dolphins were under the age of a year old.
One was a female dolphin that washed ashore on the beach in Gulfport around the area of Lewis Avenue, with the other, a male, washing ashore on the beach in Pass Christian about 500 yards west of Henderson Avenue.
“They were under a year old and about 5 feet long,” Solangi said. “It is unusual to find them this time of year. And if we have these two, there are probably others we might see.”
The “Unusual Mortality Event” (UME) – which coincides with BP’s 200-million-gallon oil spill – has claimed up to 10 times the normal number of dead dolphins in any given month since spring of last year. Some of the carcasses have shown visible signs of oil. From an Oct. 12 Mobile Press-Register report:
“We should be seeing one (death) a month at this time of year,” said Ruth Carmichael, a Dauphin Island Sea Lab scientist tasked with responding to reports of dead dolphins. “We’re getting one or more a week. It’s just never slowed down.”
An examination of the Gulfwide death toll, broken down by month, reveals that dolphins continue to die at rates four to 10 times higher than normal. For instance, 23 dolphins were found dead in August, compared to a monthly average of less than 3 each August between 2002 and 2009.
Three sets of data have experts deeply concerned about the long-term health of the Gulf’s dolphin population: (1) the unprecedented death rate; (2) the abnormal length of the UME (21 months); and (3) the types, or ages, of the dead dolphins washing shore. It is the third set that most troubles Dr. Ed Cake, a Gulf Coast biological oceanographer:
…we’re still losing this year’s cohort of young dolphins to some “unusual mortality event” that permeates the coastal region and that nobody seems to be able to identify. First the still-borne fetuses washed ashore; then the dead neonates washed ashore; and now the juvenile dolphins are dying and stranding on our beaches. Will any of the young generation of dolphins survive the BP oil spill and its aftermath? So far the evidence is not favorable if you are bottlenose dolphins trying to “live” in the “Gulf of Oil.”
The dying off of the “young generation” of dolphins could potentially thin out the population exponentially as there will be far fewer dolphins procreating. It’s important to remember that the number of dead dolphins washing ashore doesn’t account for the dolphins that die at sea and are never recovered. Consider the numbers from my March 31, 2011, post:
The French newswire service AFP quotes a researcher from the University of British Columbia pointing out why U.S. officials keep saying the spill was not all that bad: “…this is because reports have implied that the number of carcasses recovered, 101 (as of November 2010), equals the number of animals killed by the spill.”
Looking at other studies, including a handful conducted after the Exxon Valdez spill in 1989, researchers came up with a formula that suggests up to 50 times more sea mammals die than are found, or recovered, on the beach.
This UME has claimed more than 540 dolphins. Using the established “50 times” formula, that comes to 27,000 dolphins that will not be reproducing. That translates into a dramatic thinning of the dolphin population – a dropoff from which the Gulf may never fully recover.
The most frustrating part of this entire event is that our federal government may prevent the public from ever definitively knowing what killed all the dolphins. Consider this from an April 16 Reuters report entitled “Federal practices hamper study of Gulf dolphin deaths”:
…wildlife biologists contracted by the National Marine Fisheries Service to document spikes in dolphin mortality and to collect specimens and tissue samples for the NOAA were quietly ordered in late February to keep their findings confidential.
“Scientists try to get to the truth of the matter when the government is worried about political ramifications,” said Dr. Mark Peterson of the College of Marine Sciences at the University of Southern Mississippi.
Dr. Cake couldn’t agree more, and he fears that even if information is released, we won’t be able to trust its veracity:
…it will probably be a cold day in hell before the federales release any of the forensic dolphin data that they or others have collected from the hundreds of dead dolphins that they examined during this “UME.” And even then, those forensic data will be distrusted by the public and the scientific community because of NOAA’s lack of transparency and failure to permit independent analyses thereof.
So it goes in the Gulf: Our cherished marine life continues to die off in startling numbers while our federal government looks the other way.
Read the Sun Herald report here: http://www.sunherald.com/2011/11/27/3598746/two-more-dead-dolphins-found.html#storylink=misearch#ixzz1f06IDN7w
Read the full Reuters report: http://www.reuters.com/article/2011/04/16/us-dolphin-strandings-idUSTRE73F2XW20110416
Read my post on how many dolphins have really died in the Gulf: http://www.stuarthsmith.com/while-a-new-study-finds-bps-oil-spill-may-have-killed-more-than-5000-dolphins-noaa-confirms-sea-turtle-deaths-also-on-the-rise
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