February 26, 2011 – By Robin Comita
This week, 24 baby dolphins washed ashore in Alabama and Mississippi along with at least 6 adults. So far, scientists have tallied a total of 67 dead dolphins along the coast. The number of dolphin carcasses appears to be growing hourly.
The majority of dolphin carcasses are babies and stillborn calves. Typically, only one or two dead baby dolphins wash ashore during the calving period. This year, many dolphins appear to have been born prematurely or died shortly after they were born. As this is the first calving season since the BP Oil Spill, scientists have noted the BP Oil Spill as a potential cause for the alarming number of deaths. However, they are not ruling anything out. Waters have been slightly colder than normal which could be a factor. Algal blooms can also increase mortality rates, but scientists have yet to find any indication of an algal bloom.
The dolphin carcasses are taken to labs where scientists take tissue samples and perform necropsies, but the majority have been too decayed to provide much information. Typically, any findings from these tests could be reported in about 3 weeks, but specialists say it could take months to release their findings. The BP spill is still a sensitive subject, and protocol delays processes and publication.
Thus far, there are few external signs of oil contamination on the dolphins. Many affected animals in the Gulf region, including birds and turtles, have turned up saturated with oil and visibly suffering from the explosion. Two dolphins were discovered with oil on their faces, but many signs point to unhealthy diet as a cause. Dolphins are at the top of the food chain, and if species further down the food chain are contaminated by oil then dolphins can ingest highly concentrated amounts of oil. The BP spill also coincided with the fetus gestation period, meaning unborn babies might have taken a lethal dose.
Greg Bossart, veterinary pathologist and dolphin expert for the Georgia Aquarium, told NPR that numerous ways the BP Oil Spill has affected the Gulf’s ecosystems are still unknown. “When those interactions become unbalanced from the oil, then you’re prone to seeing new diseases emerge, predator-prey relationships change, temperatures change, [and] chemistry of the ocean change. All those indirectly affect the health of organisms,” he explained.
An estimated 2,000-5,000 dolphins live in the Gulf region, and roughly 700 reports of stranded dolphins in the Southeast are reported each year. However, according to Moby Solangi of the Institute for Marine Mammal Studies, dolphin stranding season has yet to begin. Furthermore, it is highly unusual for such a large number of calves to be stranded. January of 2009 and 2010 reported zero stranded calves, denoting that in January 2011 the number of stranded calves increased 10 fold.
On February 20th, BBC News reported new findings by Samantha Joye, a professor at the University of Georgia. Joye has been studying the effects on the ocean floor surrounding where the BP oil well exploded and has found animals, plants, and corals devastated. In some places along the floor, oil, sludge, and dead animals are 4 inches thick. She predicts it will take a decade or more to determine the effects of the oil spill on the Gulf. When the filter-feeders and other smaller marine species die off or become deadly food, only time will tell the effects on mammals at the top of the food chain, like the dolphin. Claims made by BP’s compensation fund that the Gulf’s ecosystems will recover by the end of 2012 are false according to this data. There may be many more baby bottlenose dolphin carcasses to wash ashore in coming months.