Dead fish, disoriented birds, and discolored water are signaling the Texas coast’s largest red tide bloom in a decade, with concentrations of the Karenia brevis organism appearing in patches from Galveston down to South Padre Island.
“We haven’t had a red tide affect this much of the coast since 2000,” said Meridith Byrd, a red tide biologist with Texas Parks and Wildlife. “This is a big one.”
Blooms of toxic algae occur around the world, but the Karenia brevis species, with its distinctive red nucleus, is unique to the Gulf of Mexico. It’s always present, but tends to thrive along shorelines in autumn, after months of hot, dry weather have increased salinity and nutrient levels. The blooms typically start offshore and are carried toward beaches by winds and currents.
The biggest concern for humans is the brevetoxin the algae release into the air, which can lead to itchy eyes, nose and throat, as well as coughing, wheezing and troubled breathing. The aerosol is most dangerous for asthmatics and others with respiratory problems — the 2009 bloom at South Padre Island led to an uptick of vacationers and island locals showing up at nearby emergency rooms.
The toxin can paralyze the nervous system of fish, making them unable to breathe. A coastwide bloom in 1986 caused millions to wash up on shore.
This year’s bloom, while extensive, is not expected to be nearly so severe, Byrd said.