Red tide exploding off Lee beaches

Chad Gillis
The News-Press

Rust-colored water creeping along some Lee County beaches can be seen from space. 

Red tide counts of 100 million cells per liter and higher have been measured on Sanibel beaches in recent days, and that's more than enough to be detected by satellites orbiting the Earth. 

"(Monday) when we were on the plane we got some photos along the shoreline from Boca Grande all the way to Fort Myers beach and you could see along the south and west side of Sanibel, the red tide was right up against the shoreline," said Rick Bartleson, a water quality scientist at the Sanibel-Captiva Conservation Foundation on Sanibel. "Fort Myers beach looked clear and the west side of Sanibel looked pretty clear."

Waters along a Sanibel beach are tinted brownish-red because of a red tide outbreak. Counts for the bloom have been as high as 1 million cells per liter, which is enough to make the bloom visible by satellite.

No large fish kills have been reported in Lee County but there are dead fish floating around in the Gulf of Mexico. Fish kills can occur when levels reach 10,000 cells per liter. 

"(Sunday) night there were mainly mullet, not very many," Bartleson said, "and some folks went out (Monday to pick up carcasses) and I don’t think they saw much in the way of fish."

Red tide can also sicken or even kill marine mammals like dolphins and manatees as well as sea turtles, and coastal birds can get sick and die from eating fish exposed to a bloom. 

Lingering red tide leads to more fish kills, manatee injuries

Several birds, mostly cormorants, have been treated in recent weeks for red tide poisoning at the Center for the Rehabilitation of Wildlife, or CROW, on Sanibel. 

Respiratory problems with beachgoers was reported recently in Sarasota County, which is somewhat odd since red tide counts there have been at background to low levels in recent weeks

Red tide blooms generally start off Sarasota and work their way south toward Fort Myers, Bonita Springs, Naples and Marco Island.

Rick Bartleson, of the Sanibel-Captiva Conservation Foundation, tests the salinity, chlorophyll and turbidity of the water at the Sanibel Causeway on Tuesday. Bartleson is looking for lyngbya, a cyanobacteria.

This latest outbreak is acting a little differently. 

"In Charlotte County we have some low counts but (red tide is) just in Lee County," said Tracy Fanara, a water quality scientist at Mote Marine Laboratory in Sarasota. "It’s crazy but it doesn’t seem to be crossing county lines."

Karenia brevis is the organism that causes red tide here, but it occurs naturally in this part of the Gulf of Mexico.

Blooms can be fed by excessive nutrients running off the Southwest Florida landscape. The nutrients don't cause Karenia brevis to form but can extend the frequency and duration of the harmful algal blooms.

Red tide lingering, aimed at Lee

High levels of nutrients and excess freshwater have been flowing into local bays and the Gulf of Mexico since August, when an unnamed system dumped several inches of rain just a few weeks before Hurricane Irma made landfall. 

Fanara said samples will be taken in the Sarasota area Monday and Tuesday and will be included in the Friday Florida Fish and Wildlife Conservation Commission report, a weekly look at red tide conditions along the west coast. 

The National Oceanic and Atmospheric Administration issues air quality advisories but has not issued one for the Southwest Florida region. 

East winds seem to be blowing the red tide offshore, which is where a University of South Florida's College of Marine Science website says the bloom is likely to move south over the next few days. 

Fanara said beachgoers will get a tickle in their throat and develop a cough if exposed to high levels of the neurotoxin. 

"Some people are really sensitive and others aren’t," Fanara said. "It almost feels like it’s very dry air that’s forcing you to cough. It’s a very strange sensation. It’s almost like an allergic reaction. Some people get itchy eyes and runny noses and uncontrollable coughing."

Connect with this reporter: Chad Gillis on Twitter. 

Red tide

Red Tide (Karenia brevis) in cells per liter:

0 to 1,000: background levels with no impact anticipated

1,000 to 10,000: possible respiratory irritation, shellfish harvesting closures

10,000 to 100,000: Respiratory issues, possible fish kills and bloom chlorophyll likely detectable by satellites at upper limits

100,000 to 1,000,000: All the above plus discoloration of water

Source: Florida Fish and Wildlife Conservation Commission