Red tide detected off Manatee County coast

A Florida red tide (Karenia brevis) cell.

Updated April 5, 2019 – The April 5 FWC report shows background concentrations of red tide off Hillsborough and Sarasota counties, but none off Manatee County.

ANNA MARIA ISLAND – While swimmers enjoyed crystal clear water today at Anna Maria Island beaches, today’s Florida Fish and Wildlife Conservation Commission (FWC) report shows that background concentrations of red tide have returned to nearby waters about two miles southwest of Egmont Key.

Karenia brevis was observed at background concentrations last week in one sample collected offshore of Manatee County, one sample collected offshore of Charlotte County and one sample collected offshore of Lee County.

Respiratory irritation also was reported in Manatee and Sarasota counties over the past week, according to the FWC. NOAA’s latest report predicts no respiratory irritation locally.

No fish kills suspected to be related to red tide were reported this past week.

Background concentrations of the algae that causes Florida red tide, Karenia brevis, have no discernable effects on people or marine life. Higher concentrations of red tide cells emit a neurotoxin when they bloom that is deadly to marine life. It can make shellfish unfit to eat and can cause respiratory irritation in people, especially those with asthma, COPD or emphysema.

The last red tide bloom began in October 2017 in Southwest Florida. It appeared locally in August 2018, lasting until February 2019.

Scientists say that salinity, currents, temperature and light play a part in the formation of blooms, as do nutrients from Florida’s natural phosphate and limestone deposits, Caribbean seawater brought to Florida’s west coast on the Loop Current, the Mississippi River, Saharan dust blown across the Atlantic Ocean to Florida’s waters, and fertilizer and animal waste runoff.