Study Reveals Major Decline in Deepwater Marine Life in Gulf of Mexico

Study Reveals Major Decline in Deepwater Marine Life in Gulf of Mexico

SoMAS professor Joseph Warren part of a national investigative team; findings published as a cover article in PNAS

STONY BROOK, NY, November 12, 2026 - A study that assessed marine life in one of the largest deep-pelagic (open waters) zones in North America found that animal abundances declined some 60-to-85 percent between 2011 and 2015. The study results by a national team of marine scientists including Joseph D. Warren, PhD, of Stony Brook University, conducting research in the Gulf of Mexico, bring rising concerns on the health of ocean ecosystems and deepwater habitats. Their findings are detailed in a paper published in PNAS.

This net tow used from a boat on one of the sampling cruises captured organisms that live in the deep sea of the Gulf of Mexico. It can be lowered down to depths of more than 1,000 meters, more than a mile deep, then hauled back. On the net is Tracey Sutton of the national research team and lead author of the paper.
Credit: Joseph Warren, SoMAS

The deep-pelagic habitat of the Gulf of Mexico comprises 90.4 percent of its volume and houses and exceptionally diverse deep pelagic animal community that provides numerous ecosystem services, including carbon sequestration and prey provisioning for ocean predators. This research team reports on sudden, severe, and unprecedented declines in the abundance of deep-pelagic fishes, crustaceans, and cephalopods (i.e., squid, octopuses) that have persisted for over a decade. Their work encompassed a 13-year period of research through May 2023.

"Investigating the deep ocean and its creatures is strangely similar to work in space, as it is an extremely large environment, harsh, difficult to attain samples, and we are still discovering new information about fish and other animals that live there," says Warren, co-author and a Professor in the School of Marine and Atmospheric Sciences (SoMAS) at Stony Brook University. "We documented very clear decreases in abundance in multiple types of animals, regardless of what investigative tools we used during the research period."

The team used net tows, acoustic sensing and genetic analyses, all of which found declines in multiple species. Genetic analyses indicated reductions in genetic diversity among dominant taxa, which appeared to be both a corroboration and consequence of the decline.

According to the authors, the animal groups with the steepest declines over the period included euphausiids and lanternfishes, which are foundational to the entire Gulf of Mexico ecosystem. The decline in these and other deepwater species parallels those of protected marine species, such as beaked whales and Rice's whale, both of which are dependent on deepwater prey.

An important aspect to the findings and future research for Warren and the team, including lead author Tracey T. Sutton, PhD, of Nova Southeastern University, is to better understand exactly why these marine life declines are happening in the Gulf.

The authors reported no evidence that natural factors like changes in water temperature, oxygen levels, or food supply are responsible for the decline. This, they write, suggests an anthropogenic cause. They note that the decline occurred after the Deepwater Horizon massive oil spill of 2010, which suggests this event was a causative factor in the decline.

Sutton et al write that the magnitude of the ecosystem decline is greater than any observed in more than 60 years in comparable datasets from the California Current. This finding illustrates that the animal decline in the Gulf may be the greatest recorded ever in a deepwater ecosystem.

Warren says that continued research remains necessary to determine the full cause and true extent of marine life decline in the Gulf. He cautions that applying their findings to other deep-pelagic regions around the world may or may not be relevant. The waters around New York (and the Northeast) have its own nearby deep-sea ecosystem. In the New York Bight for example, Warren's research group collects some of the same deep-sea creatures. But these creatures are typically much further offshore (80 to 100 miles) or in the Hudson Canyon.

The authors conclude that the deep-pelagic biome is vulnerable to human-induced disturbances and possesses limited resilience to facilitate recovery. Yet, while they deem this as an immense issue, it is not immutable.