Red Tide is back in southwest Florida

For 14 months, a Red Tide toxic algae bloom plagued Florida, killing thousands of fish and other marine creatures, chasing away tourists and harming the economy of coastal towns. Finally it faded away in February.

Now Red Tide is back along the state’s southwestern coast, according to scientists at St. Petersburg’s Florida Fish and Wildlife Research Instituate.

The biologists at the state’s marine science laboratory reported Friday that the samples they took from the waters of Collier County found “background to high concentrations” of the algae, and there were multiple reports of fish kills.

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The last big Red Tide bloom started the same way in November 2017, and at its peak last fall it was touching all three of the state’s coasts -- the Panhandle, the southern gulf coast and the Atlantic coast.

Small, scattered colonies of microscopic Red Tide algae live in the Gulf of Mexico all year long. Usually their numbers are so tiny that no one notices. But every now and then, usually in the late summer or fall, the algae population 10 to 40 miles offshore explodes into something called a bloom.

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During a bloom the algae multiply rapidly and spread across the water’s surface, staining it a rusty color that gives the phenomenon its name. Then winds and currents carry it toward shore, where it can be fed and prolonged by pollution from fertilizer, sewage spills and leaky septic tanks.

The 14-month Red Tide bloom was the longest lasting Red Tide this decade. The longest on record lasted for 17 months from 2004 to 2006.

At this point it is hard to predict how long this bloom will last or where the bloom will go next. State scientists say that over the next four days, they expect “net northwestern transport of surface waters and southeastern net movement of subsurface waters in most areas.” Their next report is due next Friday.