The red tide organism, Karenia brevis, was detected in Southwest Florida during the week ending March 12.
The Florida Fish and Wildlife Conservation Commission reported K. brevis at very low to medium concentrations in Manatee County, very low to high concentrations in Pinellas County and background to high concentrations in Sarasota County.
There were reports of fish kills and respiratory irritation from Manatee County suspected of being related to red tide.
The toxin becomes airborne in high surf and windy conditions, which can exasperate impacts to people.
Red tide, which is naturally occurring, is patchy. People might experience respiratory irritation at one location but not another just blocks away.
For more information, go online to myfwc.com/research/redtide/statewide/.