Red tide taking out larger fish, lingering in Lee

More dead fish are washing up on local beaches as a persistent red tide bloom festers in coastal Lee County waters.

Recent measurements have shown some areas here have 1 million or more cells per liter of red tide (Karenia brevis). That's more than enough red tide cells to cause fish, marine mammal and sea turtle kills and for the bloom to be detectable from space.

John Cassani, with Calusa Waterkeeper, said his group ran into several dead fish in different areas of south Lee over the weekend.

"(Some of our members) were out in Estero Bay (Sunday) and saw eight adult black drum, floaters, somewhere near San Carlos Pass," Cassani said. "Another reported them behind Junkanoo (on the Beach) restaurant. And we had a report of 25 miles offshore, seeing black drum and red drum. And we got one (report) about six or eight dead grouper on Fort Myers Beach, so something is going on."

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Florida Fish and Wildlife Conservation Commission records show red tide levels of between 100,000 and 1 million cells per liter in Lee waters.

Fish kills have also been reported in Pine Island and Bunche Beach, according to FWC records.

And it's killing big fish, not schools of mullet and baitfish.

"I haven’t seen too many fish here but there are reports of big old red fish washing up," said Rick Bartleson, a water quality scientist for the Sanibel Captiva-Conservation Foundation. "Those big ones were spawners and were definitely from offshore. I haven’t been seeing any schools of mullet washing ashore. With mullet you can tell if they’re close in if they’re fresh. They look fine except for the eyes that the birds eat, and that means the bloom is right there."

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The toxin can become airborne and is problematic for humans and other animals.

Bartleson said he could feel respiratory irritation when he collected samples on Tarpon Beach on Sanibel Island.

Respiratory irritation has been reported on Fort Myers Beach, the causeway islands and Lovers Key State Park, according to Mote Marine Laboratory records over the weekend and on Monday.

Red tide typically starts in the fall off the coast of Sarasota. It's a naturally occurring organism that becomes deadly when concentrations explode.

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This year, though, the bloom seems to have started in Lee waters, and it's stayed here to some degree for the past four months.

"We haven’t had any reports from Sarasota county, so it seems to be Estero (Bay) and in other areas of Lee County," Tracy Fanara, a scientist with Mote, said. "That's where it started and that’s where it’s been since the season began back in mid-October."

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