According to a study, the 2010 oil spill caused chronic illness in female dolphins, which is thought to have led to an extremely high mortality rate among their offspring.
Many animal species are still paying the price for human recklessness and what was perhaps the worst environmental disaster in American history. We are talking about the Deepwater Horizon oil rig accident, owned by British Petroleum (Bp), which exploded in 2010 during the drilling of a well at a depth of 1,500 metres in the waters of the Gulf of Mexico. The accident killed eleven people and caused approximately 780 million litres of oil to spill into the sea.
That oil is still killing today, and "it will take years or even decades before we know the true environmental impact," reads the report by the National Wildlife Federation published in 2015. It is wildlife above all that is bearing the consequences of the accident — in particular, bottlenose dolphins and sea turtles are dying at an unprecedented rate.
Mortality among dolphin calves has increased exponentially in recent years in the Gulf of Mexico area. A study conducted by the United States federal agency Noaa (National Oceanic and Atmospheric Administration) and published last Tuesday links this phenomenon to the oil spill, which is said to have caused chronic illness in dolphins that is then passed on to their young. The researchers analysed dolphins that died between 2010 and 2014 in the coastal areas of Louisiana, Mississippi and Alabama.
The study highlights significant differences between the dolphin calves found dead within the area affected by the disaster and those that died elsewhere from other causes. The researchers found that the cetaceans discovered in the Gulf of Mexico that died in the womb or shortly after birth were significantly smaller than those found in other areas.
88 per cent of the animals found in the area where the oil spill occurred showed serious lung abnormalities; some specimens had partially or completely collapsed lungs. Among the dolphins found dead in other areas, only 15 per cent had malformations of this kind. According to scientists, the dolphin calves died in the mother's womb or shortly after birth, and their lungs never had the chance to develop fully.
"Our findings confirm those of previous scientific studies and demonstrate that exposure to oil-derived substances has severely compromised the reproductive health of dolphins living in the northern Gulf of Mexico," said Dr Teri Rowles, veterinarian and head of the Noaa marine mammal health programme.