Far more young endangered sea turtles were likely exposed to toxic oil from BP’s Deepwater Horizon explosion five years ago than previously thought, according to a new study from University of Miami researchers published this week.
The number may be as high as 320,000 because previous counts failed to account for nesting turtle moms and hatchlings from across the Atlantic, researchers said.
“There is a perception that the spills’ impacts were largely contained to the northern Gulf of Mexico, because that is where the oil remained,” said lead author Nathan Putman, a researcher at the Cooperative Institute for Marine and Atmospheric Studies at UM’s Rosenstiel School.
But using a model to backtrack oil from the explosion that dumped 210 million gallons over 87 days, Putnam’s team calculated the probability of young turtles being in the Gulf. The model factored in population sizes, survival rates and other information from 35 major nesting beaches and came up with more than 320,000 turtles including green, loggerhead and Kemp’s ridley species.
More than 95 percent of the turtles likely migrated from the Caribbean, northern South America, western Africa, the Gulf of Mexico and places outside the U.S, suggesting the need to look at turtles beyond the Gulf.
Our findings give new geopolitical context to the scope of the spill.
University of Miami researcher Nathan Putman
“Our findings give new geopolitical context to the scope of the spill, placing its impacts far beyond the present focus on the northern Gulf of Mexico,” Putnam said in a statement.
While the study did not look into what damage the oil may have caused to young turtles, previous UM research has documented harm to the hearts and swimming ability of juvenile tuna and mahi mahi. Researchers have long worried that the oil could have long-lasting effects by causing hidden problems in young marine life that might survive the initial spill. At the time of the spill, mahi had just begun their spring spawning in the region. And tuna are already in trouble: in the last 40 years, their numbers have dropped 75 percent.
The population of sea turtles has also plummeted. Of the seven species worldwide, four are endangered and two are considered threatened.
In addition to tracking turtles, researchers said the model used in the research could help document threats to other marine life from oil exploration as well as military operations.