Deepwater Horizon-linked Gulf animal populations remained depleted through 2023
A study in the Proceedings of the National Academy of Sciences found that deep-water fish, large crustaceans and small cephalopods in the Gulf of Mexico were roughly 60–64% less abundant in surveys after 2011 than in that year's baseline. The researchers said the Deepwater Horizon spill and its response were the most plausible explanation, but the study does not establish a direct causal link or a recovery timetable.
Bottom line — By 2023, fish abundance was still 63.5% below the 2011 survey level.
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The researchers compared the 2011 sampling campaign with surveys from 2015 to 2023; the comparison does not measure losses from before the spill.
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Krill were 72.8% less abundant, bristlemouth fish 69.0% less abundant and lanternfish 62.9% less abundant, according to the study.
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Genetic tests found signs of reduced diversity in two of the three lanternfish species examined.
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The researchers said changes in temperature, oxygen and food supply did not explain the lower counts.
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The study identified the spill and its response as the most plausible explanation, while stopping short of proving causation.
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The sampled animals are prey for larger marine species and some carry carbon from surface waters into the deep ocean; the study did not measure effects on predators or carbon storage.