NOAA says Gulf of Mexico dead zone is smaller this year

NOAA says Gulf of Mexico dead zone is smaller this year
by Lisa Hornung
Washington DC (UPI) Jul 31, 2025

The Gulf of Mexico "dead zone" -- an area deprived of oxygen -- is smaller than previous measurements and forecasts, scientists supported by the National Oceanic and Atmospheric Administration announced Thursday.

The dead zone in the gulf is 4,402 square miles, 21% smaller than estimates from June. It's the 15th smallest measurement on record.

That means that there are about 2.8 million acres of habitat in the gulf that is unavailable to fish and bottom-dwelling species. That's about 30% smaller than last year, according to a press release from NOAA.

Each summer, the dead zone develops off the coast of the Texas-Louisiana shelf when nutrient-laden fresh water spills into the gulf. The nutrients typically come from crops that need the nutrients to grow. Nutrients brought in from the river contribute to the formation of a low-oxygen area along parts of the gulf's seafloor. Mobile fish and marine mammals can swim away from the low-oxygen area. But weaker swimming organisms can be trapped and die.

Scientists at Louisiana State University and the Louisiana Universities Marine Consortium led the annual dead zone survey July 20-25 aboard LUMCON research vessel Pelican.

This annual measurement is an important metric that informs the collective efforts of the Mississippi River/Gulf of America Hypoxia Task Force, which has set a long-term goal of reducing the five-year average extent of the dead zone to fewer than 1,900 square miles by 2035.

President Donald Trump's administration refers to the gulf as the Gulf of America.

"This year's significant reduction in the Gulf of America's 'dead zone' is an encouraging sign for the future of this area," said Laura Grimm, acting administrator of NOAA, in a statement. "It highlights the dedication and impactful work of NOAA-supported scientists and partners, and serves as a testament to the effectiveness of collaborative efforts in supporting our U.S. fishermen, coastal communities, and vital marine ecosystems. We are proud of these achievements and remain committed to fostering the research and strategies that ensure the health and vitality of our oceans for generations to come."

In June, NOAA predicted an average-sized dead zone of 5,574 square miles, based mostly on Mississippi River discharge and nutrient runoff data from the U.S. Geological Survey. The measured size fell within the uncertainty range for NOAA's forecast.

While each NOAA-supported research survey offers a one-time snapshot of the dead zone, the five-year average captures the zone's changing nature over time. The five-year average size of the dead zone is now 4,755 square miles.

In June 2022, the Environmental Protection Agency established the Gulf Hypoxia Program to accelerate nutrient reduction actions by the Hypoxia Task Force and advance its Gulf Hypoxia Action Plan. As a result, the Hypoxia Task Force member states are scaling up their nutrient reduction strategies.

"The Gulf of America is a national treasure that supports energy dominance, commercial fishing, American industry, and the recreation economy," said Peggy Browne, acting assistant administrator of EPA's Office of Water, in a statement.