Cyanobacteria (or blue-green algae) are ubiquitous in Florida's freshwater and brackish habitats (lakes, rivers, and estuaries). Like red tides, cyanobacteria can increase in concentration and form visibly obvious blooms or “scums.” These blooms or scums can lead to decreased oxygen levels and contribute to fish kills. Many of Florida's largest and most important aquatic systems, including Lake Okeechobee; the Harris chain of lakes (Apopka, Eustis, Griffin, and Harris); and the St. Johns, St. Lucie, and Caloosahatchee rivers and estuaries have been affected by persistent cyanobacteria blooms.

 

Some cyanobacteria are known to produce toxins that can contribute to environmental problems and affect public health and natural resources. Cyanobacterial toxins are divided into three main groups: hepatotoxins (which affect the liver), neurotoxins (which affect the nervous system), and dermatotoxins (which cause topical skin irritations). Different cyanobacteria species can produce more than one type of toxin.

 

The state legislature recognized the need to assess the status of toxic microalgae in Florida and in 1998 funded the Florida Harmful Algal Bloom Task Force (FLHABTF) to address potential concerns regarding microalgae, including cyanobacteria. Collaborative studies were initiated between the St. Johns River Water Management District, the Florida Fish and Wildlife Conservation Commission's (FWC) Fish and Wildlife Research Institute (FWRI), the Florida Department of Health (DOH), private laboratories, and Wright State University to investigate the distribution of toxic cyanobacteria and their toxins (cyanotoxins) in Florida waters. A total of $683,000 was expended for cyanobacteria monitoring and investigation and for a workshop on toxin detection and quantitation.

 

Microcystis aeruginosa Bloom in Coffee      Pot Bayou, St. Petersburg, Florida    Photo Credit: FWC

Several groups of toxic cyanobacteria have been detected in Florida’s aquatic systems. Among the groups, or genera, are Microcystis, Anabaena, and Cylindrospermopsis, and the toxins they produce (microcystins, anatoxin-a, and cylindrospermopsin, respectively) all occur in Florida freshwater systems and surface waters used for drinking water. If ingested, contaminated water can cause nausea, vomiting, and, in severe cases, acute liver failure. Although the presence of cyanobacterial toxins in reservoir systems used for drinking water is of potential concern in Florida, no illnesses directly related to drinking water containing these toxins have been documented. In other states and countries, incidences of skin irritation, swollen lips, eye irritation and redness, earaches, skin itchiness, sore throats, hay fever-like symptoms, and fatigue have been reported after swimming in highly affected lakes.

 

To report blooms with dead, diseased, or abnormally behaving fish, call the FWRI Fish Kill Hotline toll free at (800) 636-0511. The hotline's recorded message asks callers to leave contact information and a detailed report. A biologist will respond, usually the following workday, if more information is needed. This service is part of a federally funded project to survey fish-related diseases and mortalities. Fish kills may also be reported online; visit How to Report a Fish Kill for additional information and details. (Please note: The FWRI Fish Kill Hotline should NOT be called to request dead fish cleanup. Local authorities are responsible for dead fish cleanup—usually only on public beaches.)

 

To report dead, diseased, or abnormally behaving wildlife, call the FWC Wildlife Alert Hotline toll free at (888) 404-3922.