Scientists recently measured Gulf of Mexico's dead zone – an area with low oxygen water – at 5,052 square miles, the National Oceanic and Atmospheric Administration reports.
EPA and NOAA scientists say the size of the dead zone is smaller than it was last year but still greater than the target of less than 1,900 square miles, according to the report. It is about the size of Connecticut.
"Dead zones," also called hypoxia areas, are caused by nutrient runoff from agricultural and other human activities in the watershed and are highly affected by river discharge. These nutrients stimulate an overgrowth of algae that sinks, decomposes, and consumes the oxygen needed to support life in the Gulf.
The largest Gulf dead zone ever recorded occurred in 2002, encompassing 8,481 square miles. The smallest recorded dead zone measured 15 square miles in 1988. The average size of the dead zone over the past five years has been about 5,500 square miles.
The hypoxic zone off the coast of Louisiana and Texas forms each summer threatening the ecosystem that supports valuable commercial and recreational Gulf fisheries. NOAA-funded research in the past decade shows hypoxia results in habit loss, displacement of fish (including shrimp and croaker) from their preferred areas, and a decline in reproductive ability in some species.