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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

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.


Partner Organizations

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. The initial leg of the 2021 survey is scheduled to begin on Sunday, June 13 and will survey the area from Pascagoula, Mississippi to the Texas coast, and then head back towards Pascagoula. The second leg will pick up where the initial leg leaves off on July 4 and make its way to the Florida Coast.

Due to COVID-19 restrictions, the Summer Groundfish Cruise did not sail in 2020.

Current Cruise Details

Last Update: April 16, 2021


The first leg of the 2021 Summer Groundfish Survey Cruise that was scheduled to sail June 13July 2 has been cancelled. The second leg will continue as planned for July 4July 21.

Leg 1: Cancelled
CTD Data AcquisitionPlanned Map Release
June 13–17 (Cancelled)N/A
June 18–22 (Cancelled)N/A
June 23–27 (Cancelled)N/A
June 28–July 2 (Cancelled)N/A
Leg 2: Pascagoula to Texas
CTD Data AcquisitionPlanned Map Release
July 4–8July 12
July 9–13July 16
July 14–17July 20
July 18–21July 25