‘Dead zone’ off Texas coast poses threat to marine life

By Jack Doyglas, Jr.
Ft. Worth Star-Telegram; April 2, 2008


A dead zone of oxygen-depleted water has lurked off the Louisiana coast for years, but a Texas A&M scientist now says the same condition exists off Texas.
Although it was only publicly confirmed Tuesday, the dead zone has existed in Texas coastal waters for at least 23 years, said Steve DiMarco, associate professor of geosciences for Texas A&M University.
The condition is endangering the Gulf Coast shrimping industry, and more water-quality studies are needed, DiMarco said in a telephone interview.
The dead zone rises 6 feet from the ocean floor, stretches at least 20 miles from the shore and appears to exist along much of the state’s coast, spanning 377 miles from the Louisiana state line to Brownsville, he said.
While the dead zone’s existence and scope have just now been announced, the National Oceanic and Atmospheric Administration detected evidence last summer emanating from the mouth of the Brazos River, near Freeport, that covered 1,700 square miles, DiMarco said.
For years, experts have monitored the Louisiana coast, where the dead zone can cover 8,000 square miles — more than the land area of Massachusetts. Similar dead zones, where sewage and fertilizer run off into the ocean, have been found worldwide.
Despite that, "there are just not many people on the Texas coast that are looking at water quality," DiMarco said.
Texas’ coastline is the sixth-longest in the country, DiMarco said, "and it should be important to Texans to know what the health of their coastal environment is."
A lack of sufficient oxygen makes it difficult for marine bottom-dwellers, including many varieties of shrimp, to survive. Fish that stay near the water’s surface — full of oxygen from the air — are not affected, authorities say.
"It is a very serious problem," said Wilma Anderson, executive director of the Texas Shrimp Association, based in Aransas Pass.
The dead zone traps the shrimp during their early stages and prevents them from reaching deeper depths where they can grow to a larger and more valuable size, Anderson said.
She said she believes that the problem is drifting down from the Louisiana coast, fed by the Mississippi River, which carries pesticides and fertilizer from the nation’s Farm Belt.
But DiMarco said there has not yet been enough of a study to determine whether the Texas problem is man-made or the result of natural causes.
For Jimbo Barnes, owner of the Rusted Hook Guide Service in Port O’Connor, it is not a problem at all. "The fishing’s good," Barnes said Tuesday.
JACK DOUGLAS JR., 817-390-7700