Gulf Deep-Sea Species Declined 60%-85% After Spill

A long-term study published in PNAS found that marine life in the Gulf of Mexico’s deep-water ecosystem fell sharply after the 2010 Deepwater Horizon oil spill, with some species groups declining by roughly 60% to 85% between 2011 and 2015. Researchers used net samples, acoustic surveys and genetic analyses to document losses among fish, crustaceans and squid, and found that populations have not substantially recovered in subsequent years. Because measured conditions such as temperature, oxygen and food availability did not explain the decline, the researchers say the oil spill is the most likely cause, while noting the ecosystem’s scale and limited baseline data make it difficult to fully understand the damage. The findings also raise concern that losses in genetic diversity could weaken species’ ability to adapt to future environmental change.