Florida's Indian River Lagoon Sees Seagrass Surge Back by 7,000 Hectares
New monitoring from the St. Johns River Water Management District shows seagrass in Florida's Indian River Lagoon grew from 9,924 hectares in 2023 to 17,042 hectares in 2025 — a 72% increase. Drier weather and canal-diversion restoration projects helped the recovery, though coverage remains well below historic levels.
EnvironmentGNGV Editorial Team5 min readLast reviewed September 28, 2026
For years, Florida's Indian River Lagoon — one of the most biodiverse estuaries in North America — was a symbol of ecological decline, its seagrass meadows decimated by algae blooms fed by pollution and runoff. The loss of those underwater grasses, which feed manatees and shelter fish and crabs, triggered manatee starvation events that alarmed the nation. Now there is genuine, measurable hope. According to monitoring reported on May 18, 2026, seagrass coverage climbed from 9,924 hectares in 2023 to 17,042 hectares in 2025, an increase of more than 7,000 hectares, or 72%.
The grasses are not only spreading but thickening. Data from the St. Johns River Water Management District show the mean transect length rose from 84 meters in 2023 to 124 meters in 2025, while average transect cover jumped from 3.95% to 10.77%. In practical terms, the lagoon's underwater meadows are both wider and denser — a sign the ecosystem is rebuilding its foundation.
Scientists attribute the turnaround to two factors. Drier weather reduced the freshwater runoff that washes nutrients and pollution into the lagoon, easing the algae blooms that block sunlight. And canal-diversion restoration projects — including the C-54, Fellsmere Main, C-1, and Crane Creek/M-1 Flow Restoration projects — redirected water back toward the St. Johns River, helping restore the lagoon's natural hydrology.
The researchers are careful not to overstate the win. "We've seen a 72% increase. That's absolutely fantastic, but we are still 47% behind that historical coverage," said Dr. Lorae Simpson, who noted that real success means returning to the lagoon's 2007–2009 coverage. Gains were strongest in the northern lagoon and Banana River, while the central lagoon continues to lag with recent declines, and a return of wetter weather could reverse progress. Still, the rebound shows that when nutrient pollution eases and natural water flows are restored, even badly degraded estuaries can begin to heal.
Why it matters
Seagrass feeds manatees and shelters fish and crabs, and its loss in the lagoon led to manatee starvation events. A 72% rebound since 2023 shows that easing nutrient pollution and restoring water flows can help, though coverage is still 47% below historic levels.
Sources
What you can do
Follow the St. Johns River Water Management District’s seagrass monitoring. Check whether your area has a programme to reduce nutrient runoff into local waters.
