Researchers have documented a dramatic and persistent decline in marine populations within the Gulf of Mexico’s “twilight zone,” the deep waters between the surface and the seafloor. The study, published in the journal PNAS, reports that fish numbers fell 63.5% from the year after the 2010 Deepwater Horizon explosion to 2015, while crustaceans such as shrimp and krill dropped 62% and larger species like squid and octopus fell 59.7%.
Methodology and findings
Lead author Tracey Sutton, a biological oceanographer at Nova Southeastern University, explained that the team used six sets of nets at varying depths and acoustic sonar to assess the abundance of marine life from the surface down to 5,000 feet (1,500 meters). A follow‑up survey conducted three and a half years later showed that overall sea‑life density was only one‑third to one‑quarter of the 2011 baseline.
“We saw this big decline,” Sutton said. “The question was then why? None of the natural variables we examined—temperature, oxygen, food—correlated with the drop. The event that did was the oil spill, so we think that’s the most likely cause.”
Limited recovery
Continued sampling through 2023 indicates that populations have remained low, with only a slight, statistically insignificant rise in 2022‑2023. Genetic analyses also revealed reduced diversity, suggesting inbreeding among the surviving organisms.
Key species have suffered severe losses: krill numbers fell 72%, lanternfish are now about one‑third of their former abundance, and iconic deep‑sea predators such as dragonfish have experienced major declines.
Implications and expert commentary
Scientists stress that these foundational species support the broader Gulf ecosystem, and their reduction has ripple effects up the food chain, affecting larger fish, dolphins and whales.
“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 after 13 years,” said marine scientist Boris Worm of Dalhousie University.
Former National Science Foundation director Rita Colwell added that future spill responses should prioritize agents that boost oil‑degrading microbes rather than chemical dispersants, which can increase exposure for deep‑water organisms.
Industry response
BP spokesperson Paul Takahashi acknowledged that the disaster “forever changed” the company and noted that BP has implemented many changes intended to prevent a repeat of such an event.
The study underscores the long‑term environmental costs of deep‑water drilling accidents and highlights the need for careful consideration of future offshore oil activities.
Original reporting: WPBF West Palm Beach — read the source article.
