Seasonal low oxygen content worsened by red tide in Mississippi Sound
Officials are blaming a combination of two natural factors, a large area of low dissolved oxygen exacerbated by a “red tide,” for a fish kill this week that littered Mississippi’s beaches with dead fish.
“The Mississippi Department of Marine Resources began getting calls early Monday morning about fish and other marine life washing up on the beach,” said Melissa Scallan, a DMR public information officer. “There were sting rays, crabs, flounder and mullet, as well as some shrimp, from the Beau Rivage in Biloxi to Long Beach in Harrison County. There also were dead fish found on the beaches in Hancock County and on Cat Island.”
Officials from DMR and Mississippi’s Department of Environmental Quality responded, and tests Monday first pointed to a large area of reduced dissolved oxygen.
“We found widespread areas of low dissolved oxygen,” said Dr. Kelly Lucas, chief scientific officer for MDMR, adding that oxygen levels are lower in warm water. “In two of the 14 sampling areas, we found high concentrations of a microscopic algae that causes blooms, also known as red tide. This particular species is non-toxic; however it can clog the gills of fish.”
Tuesday, Scallan said, more tests showed the area affected by the red tide was larger than expected. Officials are evaluating results.
Summer months often produce reduced oxygen levels in the Mississippi Sound, Scallan said, adding that when algae blooms in the water, the resulting red tide further reduces the oxygen content fish can use.
“While it is hard to tell exactly how long the fish kill will last, scientists say these events usually are short-lived, a few days,” Scallan said Tuesday. “There were a few dead fish on the beaches early Tuesday morning, and there could be some Wednesday also.”
DMR, DEQ and scientists with the University of Southern Mississippi’s Gulf Coast Research Lab will continue to monitor the event.
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