A recent drawdown at Stormwater Treatment Area 1 West in South Florida gave biologists an unusually clear look at the ecological state of the wetlands. When water levels were lowered for routine maintenance, the exposed marsh revealed a larger presence of invasive fish than researchers had anticipated. Among the native largemouth bass and bluegill, teams found significant pockets of armored catfish, a species known for burrowing into banks and disrupting the natural structure of the marsh.
Armored catfish are protected by hard, bony plates that make them difficult for predators to target. Their burrowing behavior damages the banks of wetlands and interferes with the growth of native plants. Prior to the drawdown, the extent of their population had been largely unknown because the water concealed their tunnels. The sighting was described by the team as one of the most notable findings in years, indicating that current control efforts remain insufficient.
The event offered a direct view of how invasive species have integrated into the ecosystem. It also highlighted the broader challenge of managing the Everglades, which has been altered by over a century of drainage and development. In the 1880s, Hamilton Disston led early efforts to drain the area for agriculture. Later, in 1948, the federal government initiated the Central and Southern Florida Project, constructing a network of canals and pumps to control flooding and supply water. Those projects reduced the original wetlands by more than half.
Stormwater treatment areas, like the one where the drawdown occurred, were created later to filter water before it reaches protected zones. These man-made wetlands span roughly 57,000 acres. When they are drained for maintenance, the exposed soil can contain phosphorus and other residues from historical agricultural use. Each drawdown provides researchers with an opportunity to assess whether restoration efforts are producing measurable results.
One of the more significant discoveries during low-water surveys occurred in the Picayune Strand, part of a larger restoration initiative. Crews clearing old canals found burrows belonging to Burmese pythons, which can grow to 20 feet in length. The snakes are difficult to locate in high water, but the drawdown exposed their dens, allowing removal teams to capture dozens more than usual. The pythons have contributed to a documented decline in small mammal populations, including rabbits and raccoons.
Low water levels also created conditions known as a predator pit, where large numbers of alligators concentrated in shrinking pools alongside trapped fish. This made it easier for biologists to observe territorial behavior that is normally hidden. Wading birds such as wood storks and great egrets gathered in the area as well.
The chemistry of drained wetlands is another concern. When soil is exposed to air, it can release phosphorus, a nutrient that flows into the region from agricultural fertilizer. If phosphorus re-enters the water system, it can fuel algal blooms downstream. These blooms can reduce oxygen levels and harm fish populations. In 2021, a release of contaminated water from the Piney Point facility contributed to a prolonged red tide event. Surveys after the water receded found extensive areas of dead shells and sediment affected by the release.
Invasive apple snails have also spread further into protected areas than previously documented. During drawdowns, researchers have found large numbers of their pink egg clusters attached to dead vegetation. These snails can carry rat lungworm, a parasite that poses a risk to humans.
Despite the challenges documented during recent drawdowns, restoration efforts have shown some positive results. In 2023, scientists reported that controlled drawdowns, which mimic natural dry seasons, helped reduce invasive plant cover by roughly 40 percent. In some cases, native vegetation regenerated on its own from seed banks in the soil once invasive fish were removed and the mud had dried. Researchers also observed the return of native crayfish and grass shrimp, which form the base of the food web in the region.
Biologists are using data from these events to map where invasive species are concentrated when water levels drop. This information is intended to guide future water management decisions and reduce accidental fish die-offs during maintenance operations. The findings are part of an ongoing, long-term effort to restore parts of the Everglades, a process that requires sustained funding and coordination across agencies.
Each drawdown offers researchers a brief opportunity to examine conditions that are otherwise hidden beneath the surface. The information gathered helps refine management strategies, though the scale of the challenge remains substantial. The recent discoveries have reinforced that effective restoration depends on understanding what lives in the mud as much as what swims in the water.
