Red tide spreads north to Pinellas

Red tide continues to plague Manatee and Sarasota beaches, and it has moved its way up to Pinellas County, according to the Florida Fish and Wildlife Conservation Commission.

According to the FWC red tide status page, through this past week, nine samples from Manatee County showed background to high levels of red tide cells per liter of water; 11 samples were collected in Pinellas County showing similar results; and Sarasota County collected 41 samples.

In a separate issue, a “No Swim” advisory that has been in place at Siesta and Longboat Key Beaches since Thursday was lifted Friday, according to the Florida Department of Health in Sarasota County.

Health officials in Sarasota received testing results Friday that were at a satisfactory level for enterococcus bacteria meeting both the U.S. Environmental Protection Agency and state recreational water standards, according to a release. Residents and visitors may return to swimming and other water sports at these beach sites.

The advisories at Turtle, Nokomis and North Jetty Beaches remain in effect.

Red tide is the toxic accumulation of Karenia brevis, a phytoplankton. Scientists don’t know much about how red tide occurs, but predictions are made through wind and water currents.

A collaborative study by University of South Florida’s Ocean Circulation Group and the FWC’s Collaboration for Prediction of Red Tides expects surface and bottom waters to move southward through Oct. 1 between southern Pinellas and Lee counties.

Dianne Shipley, public information and communication coordinator for the Department of Health in Sarasota, said that in addition to enterococcus bacteria sampling the county does for the Healthy Beaches Program, extra funding allows them to collect red tide samples to be sent to Mote and then to the FWC.

This story was originally published September 30, 2016 at 9:56 AM with the headline "Red tide spreads north to Pinellas."