Ride tide is drifting along the Florida coast. What to know about changing conditions

A red tide bloom that arrived on Southwest Florida shores last fall continues to drift up and down the Gulf Coast.

But conditions improved for many local beaches this week as a more concentrated area of the bloom moved into offshore waters near the mouth of Tampa Bay.

Reports of breathing irritation and dead fish stopped around most of Anna Maria Island this week, including in Bradenton Beach and Holmes Beach. An exception was the very north end of the island in Anna Maria, where a bloom concentration of red tide algae was detected at the Rod and Reel Pier on Monday.

Gulf beaches in Pinellas and Sarasota counties have also been enjoying a reprieve from the worst of the bloom, though very low to low levels of algae were detected near the shore in several spots this week, according to water samples collected by the Florida Fish and Wildlife Conservation Commission and partners.

For now, the worst of the bloom for the Tampa Bay region appears to be concentrated near the mouth of the bay in waters offshore of Manatee and Pinellas.

Karenia brevis, the organism that causes red tide, was detected at bloom levels in three samples around the Sunshine Skyway Bridge, one west of Terra Ceia Preserve State Park and one west of Port Manatee.

The algae also popped back onto the radar farther south, where it was detected in offshore samples at medium strength off of Charlotte County, medium to high strength off of Collier and medium off Monroe.

In all, red tide algae was detected in 72 samples around Southwest Florida this week, up from 67 last week.

When will red tide end?

Red tide blooms are naturally occurring in the Gulf of Mexico; they can last for days, weeks or months depending on many environmental factors that help or hinder their growth. Human nutrient pollution can make the blooms more intense when they approach shore, research has found.

Due to the many complex factors at play, it is difficult to predict whether the current red tide event will wind down soon, University of South Florida’s Ocean Circulation Lab director Yonggang Liu said in an email. But one important factor could help make this season’s red tide less severe.

Scientists have pinpointed the Loop Current in the Gulf of Mexico as a major factor in the formation, length and intensity of red tide blooms.

According to Liu, the Loop Current is currently interacting with a “pressure point” near the Dry Tortugas which causes a strong upwelling current along much of the the west Florida shelf; the upwelling has a flushing effect on waters near shore and should help reduce the presence of K. brevis in the long term.

For now, Liu predicts a southward movement of the bloom in the next few days thanks to an incoming cold front.

The Loop Current’s effect, combined with further flushing from the cold front, could also slightly reduce red tide concentrations over the next week, Liu said — provided that no new red tide cells from deeper, offshore waters are brought to the surface during the exchange.

Red tide forecast

The National Oceanic and Atmospheric Administration forecasts the respiratory threat from red tide. On Thursday, NOAA warned of a moderate to high risk of respiratory irritation on some beaches in Manatee and Pinellas counties over the next 36 hours, as well as a possible risk in Sarasota, Charlotte, Collier and Monroe counties.

In Manatee County, the highest chance of breathing irritation was forecast for the north end of Anna Maria Island.

Red tide respiratory risk is most likely when winds are blowing on or along the shore.

University of South Florida’s red-tide-tracking forecast predicts an overall southward drift of the red tide algae over the coming days, and that medium levels of the algae will continue to hover around the mouth of Tampa Bay into this weekend. Medium levels could also persist along mainland Manatee County, the forecast shows. The algae’s effects are expected to be minimal around most of Anna Maria Island.

The forecast predicts very low to low levels of red tide algae around Pinellas County over the next several days. On Sarasota County’s coast, very low to medium amounts of red tide could be present, forecast maps show.

Red tide safety tips

The Florida Department of Health in Manatee County offers the following safety tips for when red tide is present:

• Look for informational signage posted at most beaches.

• Stay away from the water.

• Do not swim in waters with dead fish.

• Those with chronic respiratory problems should be especially cautious and stay away from these locations as red tide can affect your breathing.

• Do not harvest or eat molluscan shellfish or distressed or dead fish from these locations. If caught live and healthy, finfish are safe to eat as long as they are filleted and the guts are discarded. Rinse fillets with tap or bottled water.

• Wash your skin and clothing with soap and fresh water if you have had recent contact with red tide.

• Keep pets and livestock away and out of the water, sea foam and dead sea life. If your pet swims in waters with red tide, wash your pet as soon as possible.

• Residents living in beach areas are advised to close windows and run the air conditioner, making sure that the A/C filter is maintained according to manufacturer’s specifications.

• If outdoors near an affected location, residents may choose to wear masks, especially if onshore winds are blowing.