Texas Parks and Wildlife Department officials believe isolated fish kills observed this week along the lower Texas coast can be attributed to red tide. “Our conclusion is that there is not a large red tide bloom along the South Texas coast,” says Dave Buzan, a scientist with TPWD Coastal Fisheries who heads the agency’s marine Kills and Spills Team. “Red tide is likely present but only in small patches and only causing intermittent relatively small fish kills. There is no evidence at this time that there will be a major bloom impacting Texas beaches. W

On Monday, Sept. 12, Tony Reisinger, Cameron County marine extension agent, discovered low levels of the microscopic algae Karenia brevis commonly called red tide in water samples collected along Boca Chica beach. Dead fish, mostly baitfish like menhaden and mullet, were discovered from Boca Chica beach to the south jetties at Brazos Santiago Pass. TPWD conducted an aerial reconnaissance of the area the following day and discovered two small patches of discolored water three miles offshore from the Texas coast, one halfway between the mouth of the Rio Grande and Brazos-Santiago Pass and the other about 13 miles up the coast from South Padre Island, but saw no evidence of additional fish kills. By Thursday, Sept. 15, red tide had moved closer to shore and red tide concentration levels had increased in water samples taken from Isla Blanca Park at the south end of the island. Residents of South Padre Island reported respiratory irritation consistent with the presence of red tide aerosol.

The red tide alga is a naturally-occurring organism that produces a toxin that affects the central nervous system of fish so they are paralyzed and cannot breathe. As a result, red tide blooms often result in dead fish washing up on Gulf beaches. When red tide algae reproduce in dense concentrations or “blooms,” they are visible as discolored patches of ocean water, often reddish in color.

Updated information on the current red tide situation in Texas, as well as background information on red tide and how it affects people and fish, is on the TPWD Web site.

The last red tide occurrence in Texas was in April 2002.