Harmful Algal Blooms (HABs)

Harmful algal blooms include Golden Alga, Red Tide, and Other Harmful Algae.

Sightings of fish kills or suspected red tide can be reported to TPWD’s 24-hour communications centers at 512-389-4848 (Austin) or 281-842-8100 (LaPorte). For the status of shellfish harvesting areas, please contact the Texas Department of State Health Services at 1-800-685-0361.

Red Tide Status (Updated September 25, 2014)
Golden Alga Status (Updated September 25, 2014)
Brown Tide Status (Updated May 21, 2013)

Frequently Asked Questions

What are Harmful Algal Blooms?

Algae are microscopic plants that are usually aquatic, unicellular, and lack true stems, roots, and leaves. Algal blooms occur in both marine and freshwater environments when an algal species outcompetes other species and reproduces rapidly. An algal bloom can even discolor the water due to the large number of algal cells. A harmful algal bloom (HAB) is a bloom that produces toxins which are detrimental to plants and animals. (An algal bloom can still kill fish and other aquatic life by decreasing sunlight available to the water and by using up all of the available oxygen in the water, but a harmful algal bloom specifically produces harmful toxins.)

What causes blooms?

Blooms can be caused by several factors. An increase in nutrients can cause algae growth and reproduction to increase dramatically into a bloom just as fertilizing a lawn makes the grass grow faster. In other instances, something may change in the environment so that certain algae can out compete the other algae for food, which can result in a bloom of the algae with the advantage. This environmental change can be related to the water quality, temperature, nutrients, sunlight, or other factors.

How are Harmful Algal Blooms managed once they occur? By whom?

Different states and areas have different procedures. In Texas, Texas Parks and Wildlife Department (TPWD) has a Kills and Spills Team (KAST) of biologists that respond to an incident where fish or other animals have been harmed. These specially-trained biologists contact other agencies and personnel (including Texas Department of State Health Services if human health issues are suspected, Texas Commission on Environmental Quality for impacts to natural resources, and the governing authority that manages a particular area), collect water samples for analysis and confirmation of the alga, collect water quality and environmental data, and identify and count the number of dead wildlife, among other tasks. TPWD monitors on-going harmful algal blooms during the full span of the bloom and communicates to the public through their web site, email alerts, and 1-800-792-1112 information number. The authority in charge of a specific area (county, city, river authority, etc.) is responsible for the clean-up of the dead wildlife.

What should I do if I notice a fish kill?

If you see dead or dying fish and wildlife or pollution threatening fish and wildlife, call the 24 hour Communication Center for TPWD immediately at 1-512-389-4848. You may also contact your regional KAST biologist or your local game warden. For your safety, please do not touch, collect, or eat dead or dying fish or wildlife.

Are red tide and golden alga blooms the same?

No, both occurrences are caused by harmful algae species but the species are different. Species that cause red tide blooms belong to the group of algae called dinoflagellates. They are single celled algae with two whip-like flagella (one in a central groove and another placed vertically). The golden alga is a species in a different algal family called the Chrysophyta. It is a tiny single celled organism with yellow-green or golden-brown pigments. It has two whip-like flagella and a third appendage called a haptonema used to attach to other objects. Both types of organisms produce toxins but the toxins differ in their composition and mode of action.

Alga or Algae?

The term alga is used when only one species is being referenced. If the discussion is about several species (or a group of species) then the term algae is used.

top of page


Additional Resources :

Harmful Algae Page - Woods Hole Oceanographic Institution

Harmful Algal Bloom Project Bulletins - NOAA Coastal Services Center

Harmful Algal BloomS Observing System

ECOHAB - The Ecology and Oceanography of Harmful Algal Blooms

CDC Harmful Algal Blooms - National Center for Environmental Health

National Centers for Coastal Ocean Science - Harmful Algal Blooms

CBBEP - Coastal Bend Bays and Estuaries Program

Back to Top
Back to Top