Intensified by historic drought conditions, the Gulf of Mexico has been subjected to the invasive and life-threatening algal bloom known as red tide, which has killed 4.2 million fish since September.
Red tide is a brownish-red algae, known as phytoplankton or Karenia brevis, that produces a neurotoxin called brevetoxin — a compound that disrupts normal neurological processes. During drought conditions, the Gulf of Mexico is more susceptible to red tide because the algae favors warm, salty water.
As fish swim through the red tide, they ingest red tide cells, which attack their nervous system and paralyze the fish, causing them to suffocate. In oysters, the neurotoxin becomes a heat-stable compound that cannot be cleared by cooking the oyster. The Texas Department of State Health Services shut down oyster season, which was supposed to begin Nov. 1, in the Gulf of Mexico due to red tide.
Meridith Byrd, marine biologist for the Texas Parks and Wildlife Department, said that although it’s not safe to eat the oysters due to the neurotoxin, it is safe to eat fish, crab and shrimp.
“The reason why it’s safe to eat fish, crab and shrimp is because the neurotoxin affects the organs and not the meat,” Byrd said. “Since the cancellation of the oyster season in the Gulf of Mexico, it has affected the oystermen that rely on oysters as a source of income to feed their families. Businesses that rely on oysters that come from the Gulf of Mexico have to go to other states to obtain their oysters.”
Lisa Campbell, professor in the Texas A&M U. Department of Oceanography, said that red tides have occurred historically in the Gulf of Mexico and are a part of the natural cycle.
“To explain when and why red tide occurs, we have a number of active research projects that involve monitoring bloom abundance and developing predictive models,” Campbell said. “My research is funded by the NOAA (National Oceanic and Atmospheric Administration) and the Texas Sea Grant Program, which support training of graduate students in research on red tide.”
Byrd said that red tide can be harmful and fatal for pets and encourages people not to bring their pets to the beach.
“Since dogs have smaller bodies compared to humans, fighting off the neurotoxin would be much more difficult for a dog,” Byrd said. “Dogs can easily ingest the neurotoxin by licking their fur and grooming themselves. There have been documented dog and coyote deaths due to the red tide in the past.”
Campbell said the Gulf of Mexico obtains the red tide once every few years and the last red tide that occurred was in 2009.
“Although the current continuing algal bloom is not the most damaging to have occurred, the bloom is nonetheless affecting large areas of the Texas coast,” Campbell said.
The Texas Sea Grant’s mission is to develop a better understanding of Texas’ coastal resources through research, outreach and educational programs in support of sustainable use and conservation of resources for the benefit of the economy and environment. Jim Hiney, communications coordinator for the Texas Sea Grant College Program, said the grant provides about $800,000 annually in competitive research grants to scientists at a number of the state’s accredited universities.
The Imaging Flow Cytobot is a funded project from the Texas Sea Grant, developed by Campbell, which combines video and flow cytometric technology to capture high-resolution images. This instrument will be able to develop predictive indices for early warnings of harmful algal bloom events that occur in the Gulf of Mexico.