Coastal Services Center

When a harmful algal bloom was detected in September 2011 in Texas waterways, state coastal resource managers called in the Red Tide Rangers. This band of about 30 volunteers—which has its own theme song and a secret handshake—does the sampling, cell counting, and site monitoring that state researchers neither have the time nor resources to do.

When the bloom turned into one of the largest and longest-lasting red tides in documented Texas history, state biologists relied on the Red Tide Rangers as “an invaluable part” of their red tide monitoring program.

“They’re out there giving us daily data,” says Meridith Byrd, the harmful algal bloom response coordinator at the Texas Parks and Wildlife Department. “There’s no other network like them along the Texas coast. Without them, we wouldn’t be getting the kind of data we need.”

The data the rangers provide are used by resource managers to issue warnings to citizens, ground-truth NOAA satellite imagery, and document the effects on resources and fisheries.

“I can’t say enough about them,” Byrd says. “Texas has a very long coastline. We just have painfully few biologists who can go out and collect data and come back and analyze it so that we can put it in a format that will be helpful to people.”

Red Tides

While there are thousands of species of microscopic algae in our nation’s coastal waters, only about a dozen cause harmful algal blooms that can result in massive fish kills, contamination of shellfish beds, and human illness.

These species are often called “red tides” because a bloom can turn the surrounding water red. But the name can be a little misleading since water can also be other colors or not have any color, and nontoxic species can also color the water.

The small photosynthetic plant Karenia brevis is an ever-present inhabitant of the Gulf of Mexico, but usually in extremely small numbers of cells per milliliter of water.

“Finding one cell here and there is not enough to cause a panic, but finding even a handful of cells can spur us into stepping up our monitoring to determine if the counts will continue to grow over time into a full-blown bloom,” Byrd says.

Side Effects

Karenia itself is not harmful. The danger comes from a potent poison called brevetoxin that the alga carries, which can be released when the fragile cells break in waves.

When broken, the cells release their brevetoxin into the water, where it mixes with the salt spray to form an aerosol that irritates eyes and respiratory systems. Healthy people suffer little more than discomfort, but the aerosol can pose much greater danger to asthmatics and others who suffer from respiratory conditions.

Brevetoxin is also dangerous if it is ingested through eating tainted seafood, including oysters, leading to neurotoxic shellfish poisoning. Animals, particularly dogs and coyotes, have died from eating contaminated fish.

A harmful algal bloom can require the closure of oyster harvesting, creating significant economic impacts for local fisheries.

First Sign

The state’s most recent bloom, which lasted five months, was first detected near the City of South Padre Island by a Texas Parks and Wildlife Department staff member who noticed fish swimming erratically and gulping for air near the water’s surface.

Tony Reisinger, a county extension agent for coastal and marine resources at Texas Sea Grant, soon confirmed the presence of Karenia cells.

He immediately called in the squad of volunteers.

Calling In Reinforcements

Reisinger formed the Red Tide Rangers along with Don Hockaday, director at the University of Texas-Pan American’s Coastal Studies Laboratory, during a 1996 harmful algal bloom.

Coastal managers had already been through a bloom in 1986 that spanned the whole Texas coast, killed 22 million fish, and is still considered the largest and worst in state records, as well as several smaller blooms in the early 1990s.

Knowing they couldn’t collect and analyze the number of samples needed to adequately monitor a bloom, Reisinger and Hockaday decided to train volunteers to collect water samples from locations around South Padre Island suspected of having red tide.

Reisinger dubbed the initial class of about 20 volunteers the Red Tide Rangers.

Too Much of a Good Thing

The volunteers did such a good job that they soon overwhelmed Reisinger and Hockaday with more samples than they could analyze in a timely manner. The solution, says Reisinger, was to train the volunteers to identify and count Karenia cells.

The volunteers also note the number of dead fish, if any, and gauge the severity of the irritating aerosol created when red tide cells break apart in the surf.

Ranger training is held every summer, and a secondary volunteer program was created called the Texas Coastal Naturalists to engage the rangers between red tides.

Big but Not So Bad

In terms of geographical size, the latest red tide was on par with the 1986 bloom, but it was much less severe in terms of fish mortality, only killing about 4.5 million fish.

While it was an inconvenience at times to coastal residents, it devastated the state’s oyster industry, which was closed along most of the coast through February 2012, costing oyster fishermen about $7 million.

Byrd says most of the information she uses to track red tide in the South Padre Island area comes from the Red Tide Rangers. The raw data they provide not only help state and federal agencies monitor and predict blooms, but also aid officials in determining fisheries closures and in updating the public so people can better judge health risks.

“When a red tide hits, you pretty much just have to drop everything,” Byrd says. “Having trained volunteers who can give us accurate data helps us do our jobs.”

She adds, “It’s really amazing to have something in place like this that works so well. I’m very confident in them.”

For more information on the Red Tide Rangers, contact Tony Reisinger at (956) 493-8129 or e-reisinger@tamu.edu. For more information on the state’s harmful algal bloom response, contact Meridith Byrd at (361) 575-6306 or meridith.byrd@tpwd.state.tx.us.