Are freshwater fish recovering in Florida's Everglades thanks to restoration of the River of Grass?/Audubon Florida

Editor's note: This article is part of a partnership series by Audubon Florida, connecting National Parks Traveler readers with conservation stories from the Sunshine State's national park sites.

This year has witnessed the completion of landmark Everglades restoration initiatives. The Tamiami Roadbed removal finished six months ahead of schedule, and with the historic road gone, billions of gallons of water now flow into the Everglades once more.

The Kissimmee River Restoration – decades in the making – returns the river back to its meandering path after a disastrous attempt at channelization in the 1960s and early 1970s. Forty miles of river and floodplain have been restored, returning almost 25,000 acres to wetlands. Other projects are still in the development, from the EAA Reservoir to a new water management schedule for Lake Okeechobee. But how will we know if they are improving the health of the Everglades?

Freshwater fish.

Fish are a critical indicator of Everglades' health up and down the ecosystem. The Kissimmee River, for example, once harbored 39 species of fish.

“The Kissimmee River channelization changed the face of the fisheries the once-winding river supported,” explains Kelly Cox, Esq, Director of Everglades Policy for Audubon Florida. “The miles-wide floodplain dried out and remaining oxbow lakes and channels quickly became depleted of oxygen and were no longer able to support the once robust largemouth bass and pan fish fisheries,” she continues.  “Lacking fish communities, formerly abundant wading birds all but vanished.”

“Instead, gar and bowfin began to move in due to their tolerance for low oxygen environments. However, with the restoration of this river and floodplain, the freshwater sport fisheries have rebounded. Largemouth bass and pan fish, such as bluegill,  continue to colonize and the river is viewed as a fishing destination again.”

Now that the de-channelization project is complete, monitoring fish populations, and in turn birds, become critical metrics of restoration success.

In South Florida, when the Everglades receives enough water, freshwater fish species should thrive. If not, an influx of brackish or saltwater species results.

Audubon’s Everglades Science Center team regularly monitors fish species in Taylor Slough, where the Everglades meets northeast Florida Bay. In good news, during the sampling year from June 2020 through April 2021, 14.2 percent of fish captured were freshwater species. Center staff recorded very few species that depended on moderate salinity and virtually no high salinity species.

An increase in the number of fish species that thrive in low salinity conditions show that the community could be moving back towards one dominated by freshwater species, which would mean a greater abundance of fish available to predators such as the Roseate Spoonbill – an indicator that we may be seeing the intended benefits of Everglades restoration.

By comparison, the three-year average annual percent of freshwater species captured prior to this year was 6.1 percent. On a positive note, this year, Bluefin Killifish made up a significant portion of the catch. This species takes a relatively long time to recolonize habitat once it has been too salty, so an increase in their numbers points to freshening of water in this basin.

Although these findings show a tremendous improvement over the last three years, it still falls well short of the target of having freshwater species make up more than 40 percent of the catch. To complicate matters, the Spotted Tilapia — an invasive species — dominated the freshwater recorded this year.

Ongoing fish monitoring projects are critical canaries in the coal mine for Everglades success and resilience, and help agencies and land managers adapt to changing conditions and a changing climate. With dozens of restoration projects in the queue, we can only hope to see freshwater fisheries rebound even further over the next ten years.