Vibrio & MRSA in Hawaiʻi Ocean Water

Vibrio vulnificus — The Facts

Vibrio vulnificus is a naturally occurring bacterium found in warm coastal and brackish waters worldwide. In Hawaiʻi, ocean temperatures consistently exceed 75°F, creating favorable conditions for Vibrio year-round. The bacteria is found in higher concentrations near estuaries, canal outlets, and areas where freshwater mixes with saltwater.

For the majority of healthy people, Vibrio exposure causes mild gastrointestinal symptoms at most. The danger is primarily to two groups: immunocompromised individuals (especially those with liver disease) who face life-threatening bloodstream infections, and anyone with open wounds exposed to contaminated water who may develop rapidly progressive wound infections.

MRSA in Hawaiʻi's Coastal Waters

Hawaiʻi has among the highest community-acquired MRSA (methicillin-resistant Staphylococcus aureus) rates in the United States. Studies have detected MRSA in nearshore waters, particularly in areas impacted by sewage contamination from cesspools and aging sewer infrastructure.

The Ala Wai Canal on Oʻahu is a focal point. This canal collects stormwater from a large urban watershed and frequently contains extremely high bacteria levels. When it overflows or discharges into the ocean near Waikiki, it delivers concentrated bacterial contamination to the nearshore waters. Surfers at spots near the canal outlet face elevated MRSA exposure, particularly after rain events.

The Ala Wai Canal Connection

The Ala Wai Canal was built in the 1920s to drain the wetlands that became Waikiki. Today it serves as the primary stormwater drainage channel for one of the most densely developed areas in Hawaiʻi. The canal collects runoff from roads, parking lots, golf courses, and residential areas — including areas with aging sewer lines and cesspools.

In 2006, a man died from Vibrio-related septicemia after falling into the Ala Wai Canal. The incident highlighted the extreme contamination levels in the canal and the risk that this contamination poses to ocean water quality when the canal discharges into the ocean.

After heavy rain, the canal overflows and discharges contaminated water directly into the nearshore ocean. This is the primary reason that Waikiki beaches receive brown water advisories after storms and why bacteria levels near the canal outlet are consistently higher than at beaches farther from the discharge point.

Who Is at Highest Risk

Prevention for Surfers & Swimmers

• Cover all wounds — Waterproof bandages before every session
• Wear protective gear — Reef boots, rash guards, and board shorts reduce skin exposure
• Avoid post-rain surfing — Wait 72+ hours after heavy rain, longer near canal outlets
• Avoid surfing near stream mouths and canal outlets — Bacteria concentrations are highest at discharge points
• Exit immediately if cut — Leave the water, clean the wound thoroughly
• Shower after every session — Thorough soap and water rinse
• Monitor wounds for 48–72 hours — Watch for increasing pain, redness, or swelling
• Seek immediate care — Any wound that becomes rapidly worse within hours is a medical emergency