Red tide still around Captiva, Marco Island

Chad Gillis | The News-Press

Show Caption Hide Caption An introduction to red tide Red tide is a harmful algal bloom that can sicken or even kill local wildlife. It also causes respiratory issues in humans and other animals.

Lee and Collier county waters have lower red tide counts this week, although the outbreak is still killing fish and marine creatures.

The Florida Fish and Wildlife Conservation Commission released its latest red tide report Tuesday.

Counts last week measured anywhere from not present to 1 million cells or more per liter from Sarasota to Collier counties.

This week local counts were more in the medium range, 100,000 to 1 million cells per liter.

But the bloom may be working its way to the south, toward Lee and Collier counties.

"On Captiva there weren’t any beaches without red tide and it was over 1 million cells per liter at two spots," said Rick Bartleson, a water quality scientist with the Sanibel-Captiva Conservation Foundation. "It looked like it was coming this way because we saw it on the north end of Captiva last week and it’s extending at least to Bowman's Beach. We’ve had fish kills to just south of Blind Pass."

The organism that causes red tide (Karenia brevis) is found naturally in the Gulf of Mexico but can bloom to deadly levels when conditions are right.

Respiratory irritation has been reported this week from Sarasota beaches and at Boca Grande in Lee County.

"We’ve got it from Captiva up to Lido (Key)," said Tracy Fanara, a red tide expert with Mote Marine in Sarasota. "But there have been no (respiratory) reports at other beaches. The red tide is really patchy so that makes sense."

Fanara said cell counts were as high as 24 million cells per liter at some Sarasota beaches.

Respiratory issues and fish kills can start once levels reach 10,000 cells per liter, according to the FWC.

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Several sea turtles and untold numbers of fish washed up on Charlotte, north Lee and Marco Island beaches in the past few weeks.

"It moved north a little bit," said local fishing guide Chris O'Neill. "We’ve got a massive kill in Lemon Bay. I’ve seen dolphin, thousands of fish but the thing that concerns me the most are the dozen turtles they’re seeing on the beach. That’s another level of catastrophe."

O'Neill has been documenting the bloom in recent weeks, posting his findings on social media.

He said the respiratory irritation was so bad that he needed to wear a breathing filter to stay out on the water.

"I had to wear a mask," O'Neill said. "I’ve been around it so much in the past week it’s really gotten to me. I’ve been stopped up for over a week."

The University of South Florida's College of Marine Science predicts that the red tide will move to the southwest over the next three days.

The red tide bloom started last November and has lingered off the coast since.

Although red tides have been documented in this area since the 1800s, many researchers say the events are more intense and longer-lasting these days because of human activities like farming and fertilizing lawns.

Fanara said it's the longest-lived bloom that she knows of in more than a decade, since the mid-2000s saw an 18-month long bloom.

"There may be a historical record of a bloom that has gone on this long but I do not know of it," Fanara said.

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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