Report on a biochemical red tide repressive agent.

Organisms were isolated from the November 1973 red tide outbreak in a search for a naturally occurring predator organism. Two organisms were found which look promising as a means of biocontrol: a Tintinnideae spp., ciliate and Gomphosphaeria aponina Kutzing, a blue-green algae. This report characterizes a blue-green algal toxin found to be lethal to the Florida red tide organism Gymnodinium breve Davis.