Blue-green algae toxins showing up in Caloosahatchee River Published: May 13, 2021 6:03 PM EDT Updated: May 14, 2021 9:24 AM EDT Recommended New images of the Caloosahatchee River show blue-green algae surrounding the boat basin near the State Road 31 bridge. Streaks of green goo are also on the surface of the Franklin Lock, so much so that the Florida Department of Health in Lee County issued a health alert for algae toxins found by the ramp. Water advocates say the blue-green algae is a sign of what’s coming next. Experts say there is about 500 square miles of cyanobacteria in Lake Okeechobee and with the wet season starting soon, the lake level won’t get any lower.