A historical assessment of Karenia brevis in the western Gulf of Mexico

This work examines the historical records of red tides in the western Gulf of Mexico (GOM) as they pertain to the toxic dinoflagellate Karenia brevis (Davis) G. Hansen and Moestrup. K. brevis commonly causes major fish kills, human respiratory distress, and significant economic disruption in the Gulf of Mexico. It can also lead to illness by consumption of contaminated shellfish. The nearly annual blooms that have occurred in Florida in the past several decades have focused most attention on the eastern Gulf of Mexico. There are few published chronological accounts of red tides in the western Gulf of Mexico despite a wealth of information on probable red tide blooms in Mexico during the 17th–19th century. Using these data and more modern records, we present a chronology of K. brevis in the western Gulf of Mexico. A 1879 report of red tide blooms in Veracruz, Mexico in the period 1853–1871 provides a clear description of concurrent fish kills and respiratory irritation, and provides the earliest verifiable account of K. brevis in the Gulf of Mexico. An analysis of the records suggests that Texas has experienced a notable increase in red tide frequency in the years 1996–2000. However, the record is too limited to assign any causes.