The Florida Fish and Wildlife Conservation Commission put out its weekly red tide status report last Friday, September 25. For this stretch of coast the finding was the one you want to see: Karenia brevis, the organism behind Florida red tide, was present only at background concentrations in Charlotte and Lee counties. Background means 1,000 cells per liter or fewer, with no respiratory irritation and no fish kills expected. The next report goes out Friday, October 2.
I am writing this in a week when the news is good, on purpose. October is when this city starts booking waterfront parties again. The humidity breaks, the afternoon storm line stops setting up over the Cape every day at three, and the yards along the canals turn back into usable space. It is also the stretch of the year when blooms off this coast tend to get organized. Learn how the map works now, while it is clean, and you will not be trying to learn it on the Thursday before a Saturday party.
Half of Cape Coral is not saltwater
I survey lots in this city for a living, and the water question I get more than any other is some version of “is my canal the good kind.” People usually mean boat access. It turns out to be the same question that decides whether a red tide advisory has anything to do with your backyard.
Cape Coral has more than 400 miles of canals, which is more than Venice. What gets lost inside that number is that it is not one system. It is two. There is a freshwater system, landlocked, fed mostly by rainfall runoff and held at level by a set of city-operated weirs. And there is a saltwater system with Gulf access, which reaches open water by way of the Caloosahatchee River, Matlacha Pass, or the spreader canal. The city publishes a map of the split — look for the Fresh Water and Salt Water Canals map in the document hub at capecoral.gov. If you have never looked up your own address on it, that is two minutes well spent.
This matters because K. brevis is a marine organism. It does not live in a freshwater canal, and it cannot get into one, because the weirs that hold the freshwater system at level are the reason the system exists as something separate in the first place. If you are on a landlocked canal in the northwest Cape and a red tide advisory is running for Lee County beaches, that advisory is not describing the water behind your house. I have taken calls from homeowners trying to move a party for a bloom that physically could not reach them.
The freshwater side has its own water quality issue, and it is worth naming so you do not confuse the two. Blue-green algae — cyanobacteria — is a freshwater organism, it shows up in the Caloosahatchee and in freshwater canals, and it is tracked by the Florida Department of Environmental Protection rather than by FWC. Different organism, different agency, different map. A clean FWC red tide report says nothing at all about an algae mat in a freshwater canal, and the reverse is equally true.
A canal is not a beach, and that is the whole point
The reason red tide makes people cough on Fort Myers Beach is not the water. It is the air. Brevetoxins produced by the bloom get lofted into the air when waves break and the surf aerosolizes them. That is a surf-zone process. A canal behind a house several miles up the Caloosahatchee has no surf. Even during a real bloom out in the Gulf, the respiratory irritation that ruins an afternoon on Sanibel usually does not follow the water inland to a seawall on a residential canal.
What can follow it inland is dead fish. During a significant bloom, fish kill washes in on the tide and collects against seawalls and at the closed ends of dead-end canals, where there is nowhere for it to go and no current to move it along. That is an odor problem and a cleanup problem, and it is genuinely unpleasant to stand next to for three hours with forty people in your yard. It is not, however, a health advisory, and knowing the difference is what keeps you from moving a date you did not need to move.
The one Cape Coral address where the beach logic does apply is the Cape Coral Yacht Club, which has real open-water frontage on the Caloosahatchee and a small beach. If you are doing something on that side of the city, treat it like a beach rather than like a canal.
Reading the FWC numbers
FWC reports red tide as a cell concentration in cells per liter, sampled at specific stations on specific days. The categories are worth knowing because they map cleanly onto what you will actually experience standing outside:
| Category | Concentration | What FWC expects |
|---|---|---|
| Background | 1,000 cells/L or fewer | No irritation, no fish kills |
| Very low | Above 1,000 to 10,000 | Irritation possible, no fish kills |
| Low | Above 10,000 to 100,000 | Irritation expected, fish kills possible |
| Medium | Above 100,000 to 1,000,000 | Irritation expected, fish kills probable |
| High | More than 1,000,000 | Irritation expected, fish kills expected |
For an outdoor event the meaningful line sits between very low and low. Below it you are planning around nothing. At low and above, on a Gulf-facing address, it becomes a real conversation.
One caution about reading the map: these are point samples. A station showing background on Tuesday tells you about that one spot on that one Tuesday. Blooms are patchy and they move with wind and current, sometimes quickly. Check the map again a few days out rather than treating last week's reading as settled.
What I check before a waterfront booking
- The FWC status map. Go to myfwc.com/research/redtide/statewide for both the written status report and the interactive sample map by station. Reports come out Friday afternoons, with additional updates on Wednesdays when there is something to add.
- Mote Marine's Beach Conditions Reporting System. This is the useful complement to FWC, because it is people standing on named beaches reporting what they can see and smell — dead fish, water color, whether anyone is coughing — rather than a cell count from a lab. If FWC shows low and the beach observers report nothing, that gap is real information.
- leegov.com/waterqualityinfo. Lee County does not run its own count. The page gathers the FWC map, the FDEP bloom sampling results, and the NOAA red tide forecast in one place, which saves several tabs.
- The city canal map. Before any of the above, confirm the address is on saltwater at all. On a fair number of the calls I take, it is not.
If it lands on your date anyway
We do not move a party for background or very low readings. There is nothing there to move for, and the equipment does not care either way. A blower pulls ambient air, an inflatable is vinyl, and nothing about how a unit runs changes because there are cells in the water a mile away.
At low or above on a Gulf-access address, the first question is whether the setup needs to be on the water side at all. Cape Coral lot geometry is often forgiving here. The standard Cape lot leaves a strip of open grass between the swale and the front of the house that is frequently the flattest usable ground on the property, and we move units to the front yard regularly. It carries its own checklist — swale grade, driveway width, where guests park, and whether there is a marked burrowing owl burrow in the lawn — but it is usually workable, and it puts the house between your guests and the water.
The other honest answer is that some guests should not be outdoors near a moderate or strong bloom no matter where the inflatable sits. Anyone with asthma or COPD, and small children with reactive airways, will feel a bloom before the rest of the yard does. If that describes someone on your guest list and the numbers are bad that week, moving the date is a better call than moving the unit twenty feet.
Why this comes up in October
Blooms off this coast typically get going offshore in late summer and fall and then are carried inshore by wind and current, which is why October and November are the months people in Cape Coral remember. That timing overlaps almost exactly with the part of the year when the weather here finally cooperates and the calendar fills up: fall festivals, Halloween, the first snowbirds coming back, and every birthday party that spent the summer getting rained out. It is a frustrating overlap. It is also entirely manageable if you look at the map before you pick the date instead of after.
Right now the map is clean. Charlotte and Lee are sitting at background, which is as close to nothing as this measurement reports. If your address is on a Gulf-access canal and you are picking an October or November Saturday, say so when you call — (239) 212-0011 — and we will pull the current FWC samples for your stretch of water before you put anything down.
About the author
Christopher Johnson — Co-owner, SWFL Amusements LLC
Chris is co-owner of SWFL Amusements and a professional surveyor by day. He spends his working hours mapping Southwest Florida properties, which means he knows the canal-front quirks, the older Cape circuit grid, and which intersections back up during snowbird season. He proudly lives in Cape Coral, where he was born and raised.