In mid-August, a major red tide event started along the Texas Gulf coast, causing massive fish kills and respiratory irritation in humans. On August 12, fishermen reported seeing thousands of dead fish off Sabine Pass. An overflight contracted by Texas Parks and Wildlife Department (TPWD) indicated the presence of 100m x 1 km streaks of possible red tide extending into the Gulf of Mexico. Laboratory analysis of field samples confirmed the presence of the phytoplankton, Gymnodinium breve (G. breve). Within days, the bloom extended south to Galveston and Freeport and then to coastal waters off Mexico. The phytoplankton bloom dissipated after approximately 2 weeks, but within 5 days, the red tide reappeared near Galveston and has continued to plague the coast through the end of September. A historical sequence of updates on this event appears on the Texas Parks and Wildlife Web site: http://www.tpwd.state.tx.us/fish/recreat/redtide.html

The red tide photograph acquired off the jetties of Galveston Island shows a clear boundary of a red tide patch. Because of the extent of the Texas coast and the cost and availability of aircraft resources, it is impossible to map the extent of such large outbreaks using low flying aircraft. High concentrations of organisms like red tide cause associated extreme levels of chlorophyll that can be sensed by multispectral sensors on satellites, resulting in images such as the one above derived from data acquired by the SeaWiFS sensor on August 17. Although red tide is not the only source of high chlorophyll levels (shown as red in the above image), it was the primary cause of such levels on the Texas coast this fall because of low inflow from Texas rivers.