Red Tide, Bacterial Exposure & Surfing
Understanding harmful algal blooms, ocean bacteria, and infection risks for surfers
Many surfers continue surfing during red tide conditions — even when the water looks and smells terrible. But red tides are more than just unpleasant. They may expose surfers to harmful algal toxins, respiratory irritation, skin reactions, and increased bacterial risk.[1][2]
Red tides are caused by harmful algal blooms (HABs), most commonly involving the dinoflagellate Karenia brevis, which produces brevetoxins.[3]
At the same time, the warm nutrient-rich conditions associated with algal blooms may also favor the growth of pathogenic bacteria, including Vibrio species.[1][2]
For surfers who are prone to infections, sinus problems, skin breakdown, or respiratory issues, understanding these risks is important.
Common Symptoms During Red Tide Exposure
Respiratory Symptoms
Brevetoxins may become aerosolized through wind and wave action.
Common symptoms include:
coughing
throat irritation
sneezing
burning eyes
chest tightness
shortness of breath
Individuals with asthma or chronic respiratory conditions may experience significantly worse symptoms during active blooms.[3][4]
Some surfers develop:
itchy skin
rash
burning sensations
irritant dermatitis
Symptoms may occur shortly after ocean exposure.[5]
Open cuts and abrasions may also become more vulnerable to secondary bacterial infection.
Swallowing contaminated ocean water may contribute to:
nausea
vomiting
diarrhea
abdominal discomfort
Surfing after storms or runoff events may further increase gastrointestinal illness risk.[4]
Bacterial Risks for Surfers
Warm coastal waters and storm runoff may contain elevated levels of bacteria and pathogens.
Surfers may face increased risk for:
infected cuts and abrasions
ear infections
sinus infections
skin infections
gastrointestinal illness
Research has shown significantly increased infection rates among surfers exposed to wet-weather and stormwater conditions.[4]
Particular concern exists for Vibrio vulnificus, a potentially severe marine bacteria capable of causing rapidly progressive wound infections.[1]
Who Is at Higher Risk?
Higher-risk groups may include:
surfers with open wounds
immunocompromised individuals
people with liver disease
diabetics
surfers with chronic sinus or ear problems
individuals with asthma or respiratory disease
For these groups, avoiding red tide conditions and post-rain runoff may be especially important.
Prevention Strategies
Helpful precautions include:
avoiding surfing during active red tide blooms
avoiding surfing after heavy rainfall
staying out of visibly contaminated water
avoiding ocean exposure with open wounds
rinsing after surfing
monitoring local water quality reports
seeking care early for worsening infections
Surfers with respiratory conditions may notice symptoms even while standing on the beach during active blooms.
When to Seek Medical Care
Medical evaluation should be considered for:
worsening cough or shortness of breath
severe rash
fever after ocean exposure
spreading redness around wounds
drainage or pus
severe sinus or ear pain
blistering or rapidly worsening skin infection
Marine bacterial infections may occasionally progress rapidly and require urgent treatment.[1]
From a Surfer + Medical Perspective
As both a surfer and medical professional, red tide conditions are something I take seriously — even though many surfers still paddle out during blooms.
Surf culture often normalizes unpleasant ocean conditions, but repeated exposure to contaminated water, runoff, algal blooms, and bacterial exposure can significantly affect health.
For surfers prone to sinus infections, skin irritation, respiratory symptoms, or wound infections, these conditions can quickly become more than just “bad water.”
From a medical perspective, harmful algal blooms and warm-water bacterial exposure create a real combination of respiratory, dermatologic, and infectious risk.
From a surfer’s perspective, understanding the conditions, respecting environmental warnings, and knowing your personal risk tolerance can help protect long-term health while continuing to enjoy the ocean safely.
References
Semenza JC, Ko AI. Waterborne Diseases That Are Sensitive to Climate Variability and Climate Change. N Engl J Med. 2023;389(23):2175-2187.
Rosales D, Ellett A, Jacobs J, et al. Relationship Between Nutrients, Pathogenic Vibrios, and Harmful Algal Blooms. Appl Environ Microbiol. 2022;88(14):e00356-22.
Dahlin ME, O’Connor TE, Martinasek MP. A Scoping Review of the Respiratory Effects of Red Tide. Respir Care. 2024;69(12):1555-1563.
Arnold BF, Schiff KC, Ercumen A, et al. Acute Illness Among Surfers After Exposure to Seawater in Dry- and Wet-Weather Conditions. Am J Epidemiol. 2017;186(7):866-875.
Haddad V, Lupi O, Lonza JP, Tyring SK. Tropical Dermatology: Marine and Aquatic Dermatology. J Am Acad Dermatol. 2009;61(5):733-750.