WASHINGTON — In a deep, dark part of the Gulf of Mexico, the number of marine animals plummeted by about 60% in the years following the 2010 Deepwater Horizon explosion , a new study found.
And those populations haven’t come close to recovering, the study found. In a crucial part of the Gulf between the light surface and the darkest depths, where the BP-operated well failed and dumped 134 million gallons of oil , the number of fish found dropped by 63.5% from the year after the spill to 2015. Crustaceans, including shrimp and krill, a key food for whales, went down 62%, and larger animals like squid and octopuses fell 59.7%, according to a study published Monday in the journal PNAS. Yet little is known about this gigantic ecosystem, and this region of the Gulf had not been studied before the 2010 spill, said study lead author Tracey Sutton, a biological oceanographer at Nova Southeastern University. A 2011 post-spill exploration cited in the research, which used six sets of nets at different depths and acoustic sonar, gave scientists a good sense of how much sea life was in the area between the surface and 5,000 feet deep . They returned to the same place with the same equipment three-and-a-half years later and found sea life was between one-third and one-quarter of what it was in 2011. Frasier, who wasn’t part of the study released Monday, published a post-spill study in 2024 looking at Gulf of Mexico whales and dolphins, finding population drops as high as 83%.
Because of inbreeding, sutton’s team documented the population declines with three different lines of evidence: what they caught in the nets, what their acoustic sonar found and genetic studies showing the species losing genetic diversity.
Researchers focused on the ocean’s “twilight zone,” a vast area above the seafloor, where much of the surface marine life, including dolphins and whales, feast on creatures. “It’s shocking how a single failure in a drilling rig can have this vast and sustained impact over thousands of square kilometers, with little visible recovery over 13 years after the spill,” said Dalhousie University marine scientist Boris Worm, who wasn’t part of the study. “It is important that we see this, because for the longest time these consequences were completely out of sight and out of mind.”
