Observations on the 1986-1987 Texas Red Tide (Ptychodiscus brevis)

From August 1986 thru January of 1987 a red tide caused by the unarmored dinoflagellate Ptychodiscus brevis impacted Texas coastal and Gulf of Mexico waters from Galveston to Port Isabel, TX and extended into Mexican waters. The red tide resulted in extensive fish kills, human respiratory and dermal irritation and closure of shellfish harvesting. This report documents the movement of and areas impacted by the red tide, through plankton and water chemistry samples and boat and aerial surveys. Water chemistry data from samples taken during the bloom were in agreement with those of other red tide studies but failed to correlate with cell densities. P. brevis densities ranged to an estimated high of 1.1 million cells/ml (Rockport Harbor). Vertebrate and invertebrates killed during the even were estimated at greater than 22.2 million.