Question: is the gulf of mexico salt water or fresh water

title: Gulf of Mexico
text: The Gulf contains a hypoxic dead zone that runs east - west along the Texas - Louisiana coastline . In July 2008 , researchers reported that between 1985 and 2008 , the area roughly doubled in size and now stretches from near Galveston , Texas , to near Venice , Louisiana . It is now about 8,000 square miles ( 21,000 km ) , nearly the record . Poor agricultural practices in the northern portion of the Gulf of Mexico have led to a tremendous increase of nitrogen and phosphorus in neighboring marine ecosystems , which has resulted in algae blooms and a lack of available oxygen . Occurrences of masculinization and estrogen suppression were observed as a result . An October 2007 study of the Atlantic croaker found a disproportioned sex ratio of 61 % males to 39 % females in hypoxic Gulf sites . This was compared with a 52 % to 48 % male - female ratio found in reference sites , showing an impairment of reproductive output for fish populations inhabiting hypoxic coastal zones .