Monroe County is coordinating with state regulating agencies and local partners to publish guidance on the widespread influx of sargassum grass affecting oceanside shorelines and canals throughout the Florida Keys.
Sargassum grass is a naturally occurring seaweed found in the ocean that is essential to protecting habitat for a variety of marine life, including sea turtles, crabs, shrimp and other juvenile sea creatures. Influxes that wash ashore or into canals can become a nuisance, and as the sargassum decays, it produces a hydrogen sulfide gas. This year, the influx of sargassum grass is causing periodic inconveniences in some areas and contributing to fish kills.
The county has been coordinating with the Florida Department of Environmental Protection (DEP), which provided staff with an update on current conditions and regulatory guidance. According to DEP, this year’s sargassum bloom is widespread and extends throughout the Keys along the ocean side of the island chain and is expected to continue throughout the summer.
Sargassum grass is protected offshore and regulations govern its removal. Clearing sargassum from canals may provide temporary relief, but it is not a long-term solution. Additional blooms are anticipated, and removed material will likely be replaced by future influxes. While removal is not suggested, residents should be aware of the state regulations governing sargassum removal. These are at myfwc.com/research/about/ear/sargassum/.
Health considerations
The Florida Department of Health advises that decomposing sargassum can produce hydrogen sulfide gas, which has a strong odor similar to that of rotten eggs. While the gas is generally diluted outdoors, it may irritate the eyes, nose and throat and can affect individuals with asthma or other respiratory conditions more severely. Residents experiencing irritation are encouraged to limit exposure, avoid direct contact with decomposing seaweed, and seek medical advice if symptoms persist.
Monroe County Parks and Beaches crews are continuing onshore sargassum cleanup efforts at Harry Harris Park and other county-owned beaches using county equipment, including clamshell trucks.
Report fish kills and environmental concerns
Decomposing seaweed in canals can remove oxygen from the area, causing fish kills. Residents who observe fish kills can report them through the following state hotlines:
- FWC fish kill hotline: 1-800-636-0511
- DEP fish kill or fish disease reporting (Southeast Florida Action Network): 866-770-7335
Monroe County, DEP and partner agencies will continue to monitor conditions and provide updates as needed.
