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Gulf of Mexico Hypoxia Watch

The Gulf of Mexico Hypoxia Watch maps near real-time bottom dissolved oxygen data to monitor hypoxic conditions in the Gulf of Mexico. Data is collected during the NOAA Fisheries annual Summer Groundfish Survey, which evaluates the population and health of commercially important shrimp, fish, and other marine organisms relative to environmental conditions in the Gulf as part of the Southeast Area Monitoring and Assessment Program (SEAMAP), a federal, state, and university cooperative. Oxygen data from the survey are used to generate products that provide updates on hypoxic conditions in the Gulf.

Interactive Map


Archived Data

Link to Interactive Map

What is Hypoxia?

Hypoxia occurs when oxygen levels in a body of water become too low to support marine life. Hypoxia can devastate aquatic ecosystems by driving away fish, invertebrates, and mammals, and killing or weakening organisms that can’t relocate quickly.  

The largest hypoxic zone in U.S. coastal waters—and second largest in the world—is located in the northern Gulf of Mexico on the Louisiana/Mississippi continental shelf, impacting an area about the size of the state of New Jersey. While hypoxia can occur naturally, there is strong evidence that nutrient pollution caused by runoff from industry and agriculture within the Mississippi River watershed significantly contribute to its presence in the Gulf.




About the Survey

This predetermined, stratified random survey samples fish and invertebrates using trawls or bongo and neuston nets, and deploys an environmental profiler to measure water temperature, conductivity, dissolved oxygen, fluorescence, and transmittance continuously from the surface to the sea floor. Samples and data are collected from stations located east of the Mississippi River and in the area between the 10 and 200 m isobaths from Brownsville, Texas eastward to the Florida Panhandle.

Due to COVID-19 restrictions, the Summer Groundfish Cruise did not sail in 2020.  In 2022, the Oregon II was not in operation.


Current Cruise Details

Last Update: May 23, 2023

Leg 1: Pascagoula, MS to Galveston, TX
CTD Data Acquisition Planned Map Release
June  3 - 6 June 7
June 7 - 11 June 12
June 12 - 16 June 19
Leg 2: Galveston, TX to Pascagoula, MS
CTD Data Acquisition Planned Map Release
June 19 - 22 June 23
June 23 - 26 June 27
June 27 - 29 June 30
June  30 – 2 July 3
Leg 3: Pascagoula, MS to Pascagoula, MS
CTD Data Acquisition Planned Map Release
July 6 - 9 July 10
July 10 - 13 July 14
July 14 - 16 July 17