Gulf of Mexico Dead Zone Attributed to Shark Attacks

For over 30 years, a dead zone, that extends from the mouth of the Mississippi River to the Texas border 250 miles west and covers more than 5,800 square miles, has been so devoid of oxygen that sea life cannot live in it. Marine experts believe that the dead zone has contributed indirectly to shark bites along the upper Texas coast, because it is closer to shore than usual this year. Fish and swimming crabs escape the dead zone," say Dr. Nancy Rabalais from the Louisiana Universities Marine Consortium. "Everything else dies." In the last 30 years, the dead zone has become an annual summer phenomenon, due to farmers in the Mississippi watershed using more nitrate-based fertilizers. The nitrates are carried into the Gulf's warm waters and feed the algae blooms that use up oxygen and kill the sea life in it. Three people have been bitten by sharks this year along the upper Texas coast, which is a high number, considering that the state has recorded only 18 shark attacks since 1980. Dr. Rabalais says the higher number of sharks in shallow waters is likely due to the low levels of oxygen being close to shore at the time of attacks. "The availability of habitat for sharks is definitely less when the low oxygen is so widespread," she said.