Springs Outing: ONF Springs Fish Study

Dr. Steve Walsh, a research biologist with the U.S. Geological Survey, led 22 intrepid adventurers to the Ocala National Forest to observe fish up-close.  The Springs Outing began with everyone meeting at Salt Springs Recreation Area, where Dr. Walsh provided a brief introduction to fish identification for species typically seen in the north Florida springs.  Despite overcast skies on a chilly fall day, most everyone donned masks and snorkels and jumped into the 72-degree water to view and collect fish, where we had the opportunity to observe firsthand a variety of unusual fish.  After snorkeling in Salt Springs and eating lunch in the recreation area, we headed to Silver Glen springs to observe a second habitat.

Participants saw a variety of fish during the day, including both native and exotic species. The most common and visible were the “panfish” species, including Bluegill, Redear Sunfish, Spotted Sunfish, and Largemouth Bass. There were schools of White Mullet at Salt Springs, in contrast to only schools of Striped Mullet at Silver Glen Springs. A few Atlantic Stingrays were seen in both springs.  Since this specie of Stingray represents a resident freshwater population restricted to Lake George and other sections of the St. Johns River, it is unique.  Another species seen in Silver Glen and an iconic fish often photographed at this spring was the Striped Bass, which appeared to be in lower abundance than typically observed. Some of the more cryptic species were captured with small dipnets.  (The dipnets were required because of their small size, microhabitat occurrence, and secretive behavior.)  Included in this catch were Eastern Mosquitofish, Sailfin Mollies, Rainwater Killifish, Clown Gobies, and Naked Gobies.  The springs in the Ocala National Forest are unusual because the water originates from the salty layer of the Lower Floridan aquifer leading to high conductivity and chloride ion content of the water.  (Other springs in this category include Juniper and Alexander Springs.)  Thus, these springs harbor many species of fish (including the mullets, stingrays, and gobies)  more typically associated with a marine environment.

In addition to the native species, a large specimen of the nonindigenous Vermiculated Sailfin Catfish was captured at Salt Springs. Outing participants were fascinated with the rough texture of the skin of this armored catfish and observing its rasping mouthparts. This exotic species, with a native distribution in South America, has spread throughout large portions of Florida and is particularly abundant in spring environments because of its ability to survive in low-oxygen habitats.  Unlike the native species, this fish has the ability to gulp atmospheric air.  Unlike other species, this fish also is quite willing to feed on abundant filamentous algae. It is likely that establishment of this exotic species in Florida and elsewhere resulted from pet owners releasing fish that had outgrown home aquaria.

The condition of springs in the eastern portion of Ocala National Forest continues to be of concern. Despite being in a well-forested region with relatively little impact from urbanization or agriculture, algal growth is substantial and there appears to be a reduction of native aquatic plant cover. More scientific research is needed to better understand the ecology of these ecosystems.

All-in-all we enjoyed a great day at the springs learning firsthand about the fish and their habitat.  A couple of us even slipped off for a quick side trip to observe the “quicksand” boils at Silver Glen.  The ever-present black vultures enjoyed the visitors picnic lunches when they could.