Golden Alga in Texas

Archived News Release

Nov. 25, 2002

International Conference Topics Include Algae Found in Texas

AUSTIN, Texas — The 10th International Conference about Harmful Algal Blooms was held recently in St. Petersburg, Fla. and discussion included work being done in Texas by universities and state agencies to better manage response to harmful algal blooms.

Harmful algal blooms in Texas are being addressed in a variety of forums. Scientists at the University of Texas Marine Science Institute and at Texas A&M University are conducting research about red tide and golden algae to better understand why they occur in Texas and what may be done to control bloom impacts. These researchers are working with the Texas Parks and Wildlife Department and the Texas Department of Health to develop tools to monitor blooms, conduct basic research on these algae, and improve communication about harmful algal blooms among scientists and the general public.

An interagency workgroup has been established to encourage communication and cooperative work about harmful algal blooms. Members of this workgroup represent Texas on the Harmful Algal Bloom Observing System pilot study designed to compile bloom data and provide detailed information about where red tides may occur and conditions that encourage bloom formation throughout the Gulf of Mexico.

Algae are microscopic plants living in water and when there are unusually high numbers of those algae in the water "blooms" occur. Harmful algal blooms occur when algae produce toxins that harm aquatic animals. These toxins may also harm humans, wildlife and livestock.

Harmful algal blooms have been known to occur in the Gulf of Mexico for hundreds of years. Spanish explorers reported massive fish kills that were probably red tides. Texas experiences three types of harmful algal blooms.

Red tides in the Gulf of Mexico are caused by a toxic alga called Karenia brevis. Red tide can kill large numbers of fish and cause respiratory irritation for beach goers. Blooms are reddish-brown in color and can actually make large areas of bays or the Gulf appear red. Red tide is important because the toxin can be concentrated in oysters making them unsafe to eat. The Texas Department of Health closely tracks toxin contamination of oysters to ensure consumers do not get sick from consuming contaminated shellfish.

Also discussed were golden algae blooms, which occur periodically in slightly salty waters of rivers and reservoirs in west Texas. Portions of the Pecos River, Colorado River system, Brazos River system and Red River system have experienced golden algal blooms since the 1960's. Golden algae, called Prymnesium parvum, release a toxin that kills fish and other animals that breathe through gills such as tadpoles. Golden algae do not pose a direct health threat to humans. Golden algal blooms turn the water a dark tea color. Although no one knows what causes golden algae to bloom, we know that conditions that make water salty such as drought, brine contamination from oil and gas production, intensive water use and some irrigation practices may contribute to conditions necessary for blooms.

Also discussed were blue-green algae, closely related to bacteria, that typically form blooms in freshwater ponds during late summer. Blue-green algae thrive in nutrient-rich waters and can create a scum layer on the water's surface that looks as if someone dumped blue-green paint on the water. Blue-green algae may cause fish kills but have also caused kills of domesticated animals such as cattle and dogs that drink the bloom water. High concentrations of blue-green algae cause taste and odor problems in some reservoirs used as drinking water supplies.

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Take Action
  • Report Kills - If you see a fish kill or suspect golden alga, contact TPWD's 24-hour communications centers at 512-389-4848 (Austin).
  • Get the Facts - TPWD has collaborated with the Texas Commission on Environmental Quality and other entities to produce a golden alga information card. Download a PDF from the TCEQ website or request a free hard copy from TPWD at