November 18, 2022

On 11/16/22 Lake Okeechobee was at 16.25 feet, increasing by 0.31 feet in the past week. The weekly average flow at S-79 was 2,444 cfs (cubic feet per second) and flow from the Lake at S-77 was an average of 0 cfs. The 14-day average flow at S-79 was 1,967 cfs and has been in the optimal flow envelope (750-2,100cfs) for 22 days.

Water Quality Deteriorating After Ian and Nicole

Conditions around Sanibel Island deteriorated quickly after the passing of Tropical Storm Nicole with red tide blooming in very high concentrations causing large swaths of fish kills on the shores of Sanibel beaches and extreme respiratory irritation. After Hurricane Ian, red tide began blooming due to upwelling of nutrients from offshore and the substantial amounts of nutrient rich runoff from flooding and rainfall. Tropical Storm Nicole hit Florida 43 days later and brought with it strong onshore winds that pushed the blooming red tide onshore.

In addition to red tide, which is caused by microscopic phytoplankton called Karenia brevis, TS Nicole also pushed copious amounts of red seaweeds on shore. Red seaweed is not considered toxic, but it can be a nuisance when it is pushed onshore where it degrades and reintroduces nutrients back into the water which can exacerbate the red tide bloom. When dead fish decompose in seawater, they also release nutrients back into the water and rapid bacterial decomposition can create low oxygen zones, perpetuating the red tide bloom and causing additional stressors for marine life.

These natural, although devastating, phenomena were caused by two sequential storms that caused upwelling followed by onshore winds, and they were worsened by nutrient rich runoff. Although nutrients from Lake Okeechobee water releases are also known to contribute to feeding red tide, Lake releases during this period have been minimal with most of the water coming from our watershed.

No releases have been made from the Lake since TS Nicole hit, and flows to S-79 have been in the 14-day average optimal flow envelope (750 – 2,100 cfs) for 22 days since our recovery of high flows during Hurricane Ian. Lake Okeechobee levels are at their highest point this year (16.25ft) and the US Army Corps of Engineers is now considering making releases from the Lake to protect its ecology and manage it so that levels are low enough when the wet season begins next summer. SCCF has requested that the Corps keep releases to the Caloosahatchee Estuary within the lower end of the optimal flow envelope and consider other outlets from the lake for releases while the red tide bloom is raging off the coast adjacent to the mouth of the Caloosahatchee. This should help to minimize the nutrient loading to our area and give us some time to see how this red tide bloom unfolds.

Red Tide

Satellite imagery over the past week has detected high concentrations of chlorophyll of the coast of Southwest Florida.

On 10/28/22, the FWC reported that over the past week the red tide organism, Karenia brevis, was observed in 94 samples. Bloom concentrations (>100,000 cells/liter) were present in 40 samples: two in Manatee County, 26 in Sarasota County, 11 in and offshore of Charlotte County, and one in Lee County. In Southwest Florida over the past week, K. brevis was observed at background to low concentrations offshore of Hillsborough County, background to medium concentrations in Manatee County, background to high concentrations in Sarasota County, very low to high concentrations in and offshore of Charlotte County, very low to high concentrations in Lee County, and low concentrations offshore of Collier County.

On 11/13 - 11/14 SCCF staff observed 4 samples of K. brevis at bloom concentrations: Lighthouse Beach Park (920,000 cells/liter), Algiers Beach (5,500,000 cells/liter), Tarpon Bay Beach (1,940,000 cells/liter), and Bunche Beach (473,000 cells/liter).

The Clinic for the Rehabilitation of Wildlife (CROW) (currently displaced off island) received 1 bird with toxicosis symptoms (from red tide or blue-green algae) from 11/7/22 - 11/14/22.

Beach Conditions

 Fish kills were reported at Lighthouse Beach Park and Beach Access 6 on 11/14/22 and along the full length of Sanibel Beaches on 11/16/22 by SCCF staff. The fish kill at Beach Access 6 had abundant dead fish along the high tide line and scattered all over the beach. Respiratory issues were reported at west end beaches and the restoration crew at Lighthouse Beach Park reported respiratory issues as well. Respiratory issues were reported in North Matlacha near Jug Creek by Lee County staff. SCCF staff reported an abundance of red drift algae accumulation on Lighthouse Beach Park. 

Blue-Green Algae

On 11/14/22 sampling for cyanobacteria by the Lee County Environmental Lab reported no cyanobacteria in the Caloosahatchee Estuary.

Data from the FDEP blue-green algae dashboard reported 44 samples collected over the past 30 days for the 10 county area. No samples had toxins present.

On 9/21/22, satellite imagery from Lake Okeechobee showed no bloom potential in the lake.