Tag: hiking

February 2024

The Hillsborough River springs were about as different from the Econfina Creek springs as Florida springs could be. Whereas the Econfina Creek springs were somewhat wild and remote, the Hillsborough River springs were city springs with echoes of swimmers and picnickers past and whispers of visitors future. All three springs have exceedingly short runs that flow into the lower half of the Hillsborough River in the heart of Tampa.

The location of the three springs (Sulphur, Purity, and Ulele, right to left) in the Tampa metro area.

Sulphur Spring

I visited Sulphur Spring first, after securing a permit from some very nice people at Film Tampa Bay (I thought that process was funny because the group issues permits for companies making feature films and whatnot). The park hosts two large pools. One is a round pool of spring water that fills the run through a dam. The other looks like a regular swimming pool. From the round pool, after the water goes through the dam, it travels down a short run and into the Hillsborough River. The banks of the run are partially constrained by cement and metal walls and other park structures.

The spring issues from somewhere under the round pool and the water shoots through a huge dam, marked by a red arrow, into the run below, which enters the river at the yellow arrow.

The dam on Sulphur Spring.

The corroded retaining wall along the upper part of the run across from the large dam.

A bridge and gazebo about halfway down the run.

Because it was the off season, the park was locked up tight, so I put my boat in at the river just below the spring. As I launched, I noticed some crab carapaces among the rocks, which was encouraging as I was hoping to find salt-tolerant fish in the run. Fortunately, I was able to paddle up the run from the river, passing some manatees resting in the warm outflow in the early morning.

Manatees just visible in the spring’s outflow.

The water flowing over the dam produced a plunge pool of deeper water, but the remainder of the run was quite shallow. It appeared that exotic tilapia were nesting in deeper water of the pool. Male tilapia build nests by excavating sand with their mouths. They defend these nests during breeding season, waiting for females to come deposit their eggs. However, the nests that I saw in Sulphur Spring appeared to be empty.

A likely tilapia nest in the plunge pool.

Throughout this 2024 version of the project, I have been looking for differences in fish assemblages between springs that are proximal to salt water and springs that are not. All of the fish that I observed in this spring were either salt tolerant or exotic. Of the native freshwater fish that I observed, they were all either mosquitofish (Gambusia holbrooki), which can live nearly anywhere that is not full sea water, or rainwater killifish (Lucania parva), which tend to occur near coasts in water with higher conductivity (the freshwater version of measuring salinity). Rainwater killifish are fun because they can change hue with their background, appearing almost white over sand or mottled brown over leaves. Over the algal background in Sulphur Spring, they looked mottled, but not very dark.

Rainwater killifish chasing each other in territorial displays.

Sulphur Spring also hosted a fair number of salt tolerant fish, including striped mullet (Mugil cephalus), tidewater mojarra (Euchinostomus harengulus), and Atlantic needlefish (Strongylura marina).

Some mullet that I startled as they were coming up into the run.

Tidewater mojarra darting around with the rainwater killifish.

An Atlantic needlefish. The water clarity was a bit low, so it blends into the background.

This spring was my first experience with the dense exotic fish populations in the Tampa area. Having worked on exotic aquatic organisms for decades, I have looked at maps of exotic fish distributions on the USGS Nonindigenous Aquatic Species website. Even so, I was not prepared for the scale of the issue. If I were to evaluate the biomass (number of fish multiplied by the average weight of a fish) of native and exotic fish in Sulphur Spring, the exotic fish would far outweigh the native fish, I am quite sure. And in Sulphur Spring, they were all blackchin tilapia (Sarotherodon melanotheron).

A video of blackchin tilapia sped up 500 times.

The color patterns on the blackchin tilapia were highly variable. Some were almost all silver, some had golden sections on their sides, and some had spots in various places around their heads.

In addition to exotic fish, Sulphur Spring hosted loads of exotic snails: quilted melania (Tarebia granifera). These snails occur throughout Florida. No doubt other snails occur in the run as well, but their numbers would have been swamped by the hugely abundant quilted melania, I suspect.

Snails dotting the Sulphur Spring run (top) and a close up of the species: quilted melania (bottom).

On my way out of the spring, I stopped to take a look at the recreational area of the park.

The swimming pool features a large pink frog (?) and a yellow water slide.

Purity Spring

After finishing Sulphur Spring, I ventured over to Purity Spring, which was very small. The headspring was surrounded by a small cement wall, presumably to produce a pool for contemplation. It had a short, sandy run that flowed into the Hillsborough River through a culvert.

Purity headspring with its retaining wall.

The clear and sandy Purity Spring run.

Purity Spring outflow into the Hillsborough River.

Given that the connection to the river was through a culvert, I almost did not film here. But I was already there, so I decided to go ahead. The wall around the headspring precluded easy fish movement, although fish from the run were present, and there were no plants in this little pool. However, downstream the run was filled with plants and leaves. Most of the fish in the run were mosquitofish (Gambusia holbrooki) and sailfin mollies (Poecilia latipinna).

Male sailfin molly showing off his blue and gold breeding colors on his tail. Some individuals can get quite extravagant with huge fins and bright colors.

As I watched the mosquitofish living their lives on the video, I was surprised to see three chanchita (Cichlasoma dimerus) timidly approach the camera. They jerk forward and stop as if they are ready to dart off at a moment’s notice.

Mosquitofish and chanchita in the Purity Springs run.

I was surprised again when I saw another exotic species new to me in the wild: the convict cichlid (Amatitlania nigrofasciata). I was starting to see a theme.

A stripy little convict cichlid darts through the foreground. Chanchita and mosquitofish mill around in the background.

This spring also hosted an exotic snail, a different melania: the red-rimmed melania (Melanoides tuberculata).

Red-rimmed melania dotting the sandy substrate of Purity Springs.

The spring itself had much lower salt concentration than the river, producing distortion as the spring water entered the river.

Visual distortion due to the difference in salinity of the water leaving the spring and the water of the river.

Ulele Spring

Ulele Spring, in Water Works Park, is in some ways a brand new spring. I have been told that the original spring was under the law building behind it and the water has been piped out from underneath the building through a culvert and into the restored run of the spring.

The law building in the background sits atop the source of Ulele Spring.

Like the spring, Water Works Park is brand new as well. It was a brownfield site that was completely reclaimed to produce a green space, a splash park, a dog park, restaurants, apartments… and Ulele Spring.

View of apartments (I think) and retail space from the spring.

View of the Ulele Run with Ulele Restaurant alongside. As I worked, people ate and relaxed on the patio.

Public art in the green space next to the Ulele Spring run.

A view looking down the spring at the bridge that spans the run. Just beyond the bridge is the Hillsborough River.

As I worked, a young boy and his dad stopped out of the stream of people walking late in the day. They asked me if I was fishing. After I told them what I was doing, they thanked me for my work. So nice.

When I began to review the footage that I collected at Ulele, I was stunned by two things: 1) the incredibly high density of fish and 2) the incredibly high density of large, exotic fish. I have never seen anything like it.

A very flashy male sailfin molly courting females with a huge dorsal fin and gold color in the foreground (top) and very pregnant female mollies (bottom) in Ulele Spring. Not only are there a lot of mollies and mosquitofish in the foreground, but there are lots of big cichlids milling around in the background. It is a lot of fish biomass.

Beyond the poeciliids (mosquitofish and mollies), there were only a few native, truly freshwater fish. I recorded a few killifish (bluefin, Lucania parva, and least, Heterandria formosa). In the upstream area, almost all of the other fish were exotic. I recorded more chanchita, convict cichlids, blackchin cichlids, but I also observed blue tilapia (Oreochromis aureus) and Mayan cichlids (Mayaheros urophthalmus). The exotic fish biomass was astounding.

A large blue tilapia with a very blue snout (top) and Mayan cichlids with blackchin cichlids in the background (bottom).

Downstream, below a small weir, I observed more marine fish: common snook (Centropomus undecimalis), striped mojarra (Eugerres plumieri), tidewater mojarra (Eucinostomus harengulus), and Atlantic needlefish (Strongylura marina).

Tidewater mojarra darting around the foreground with a snook cruising through the background.

Striped mojarra with blackchin tilapia in the background.

Even with all that fish biomass, a turtle ventured into the spring.

Mayan cichlid in the foreground with blackchin cichlids in the background and mosquitofish and mollies above and below. Shortly after the end of this clip, the Mayan was overrun by more Mayans and blackchins.

I have been looking for saltwater influences on springs and I definitely found them in two of the three of these springs. Purity was too small and disconnected to have salt tolerant fish roaming into and out of it, but the other two springs hosted a combination of freshwater, salt tolerant, and exotic fish. These mixtures of freshwater and salt tolerant fish were no surprise as the conductivity (something like the freshwater version of salinity) in Sulphur Spring (5.3 microS/cm) and in Ulele Spring below the weir (5-5.1 microS/cm) was 25-50 times the conductivity in most of the other springs that I have visited (Ulele conductivity above the weir = 0.7 microS/cm, Purity conductivity = 0.5 microS/cm). According to the eminent Florida journalist and writer, Craig Pittman, Sulphur Spring has experienced increases in salinity as underground connections have changed with landuse on the surface. In Ulele, the high conductivity water below the weir probably was river water.

Finding current water quality data on springs in Florida can be a challenge as it has been collected somewhat spottily, if at all. Nitrogen data for Sulphur Springs suggest that the nitrate concentrations have not been particularly high, but the phosphate concentrations have been an order of magnitude higher than background. High nutrient concentrations could contribute to the abundant algae that I observed in the run, although there is likely more to that story. My data suggest that all three of these springs were particularly warm for Florida springs (25-26C). As for oxygen, for all but the walled-off headspring of Purity Springs, the oxygen concentrations were high for Florida springs (Sulphur: 5.4-9.1 mg/L, Purity: 1.6-4.7 mg/L, Ulele: 6.7-7.9 mg/L). However, I cannot know the oxygen concentrations at the sources of Sulphur and Ulele as I was sampling water that had gone through a dam at Sulphur and through a conduit at Ulele.

February, 2024

Pitt (above), Sylvan, and Williford springs are just upstream of the Gainer springs group on Econfina Creek. The region around Pitt and Sylvan Recreation Area hosts a cluster of springs that contribute to Econfina Creek, which flows into Deerpoint Lake and eventually St. Andrews Bay at Panama City. The region is agricultural to the east, water management area to the west, and a mixture of both upstream.

Map of the landscape around Pitt, Sylvan, and Williford springs (top) with a closer version showing some of the many springs in the vicinity (bottom).

Pitt Spring has a parking area adjacent to it, but walking trails connect with the other two spring systems. I raced to visit these springs before I ran out of light for the day. Because I had to use a boat to get there, I visited the Sylvan Spring system first. In my haste, I only found the spring system by the clear water flowing out into the flooding Econfina River. I paddled up the short run to a flat, sandy underwater plain that was largely covered with dead algae. Near the bank at the end of this plain, I saw a tell-tail sign of spring vents: circular rippling on the surface.

The three Sylvan vents at the surface.

Underwater, the vents were obvious by the live, bright green algae waving in the flow.

Sylvan Spring vents underwater. Notice the fluttering green algae.

The dead algae-covered sand plain near the Sylvan vents.

The fish density was quite low in this spring system and virtually all of the fish that I observed were sunfish of one species or another. I only observed larger numbers of fish, interestingly, at a spot where the water was murky with suspended material. Here, the bluegills were undoubtedly eating invertebrates from the decaying algae.

A spotted (Lepomis punctatus) and a longear sunfish (Lepomis megalotis) in clear water and bluegill (Lepomis macrochirus) in the murkier water.

Near the confluence, there were lots of snails covering fallen log, although I sadly did not pick any up to identify them. Next time.

Snails dotted all over a fallen log with a lone sunfish in the background.

The river was running fast due to the flooding and I flew back to the canoe launch.

Floating down the Econfina River to the canoe launch from Sylvan Spring.

Once I pulled the boat out of the water, I visited Pitt Spring on foot as the confluence with the river was blocked. Pitt Spring was a contrast to the Sylvan system: lovely, clear and blue, with a large, round vent and almost no run. However, the fish diversity was low there as well. I thought that there were only shiners and sunfish, mostly bluegills (Lepomis macrochirus), but when I scanned through the extra footage, I discovered a fish new to me: a lovely little russetfin topminnow (Fundulus escambiae).

Shiners (top), bluegill (middle), and a russetfin topminnow (bottom) at the Pitt headspring.

After filming at Pitt Spring, I hurried up to Williford Spring by car. A trail leads to the spring from the Pitt/Sylvan parking lot, but I was running out of daylight. Had I had more time, I could have paddled up to it, but it was a bit of a trek, so I filmed on foot only.

The Williford Spring vent at sunset.

The fish density in Williford Spring also was low. I only observed mosquitofish (Gambusia holbrooki) and a few bluefish killifish (Lucania parva). I was rewarded, however, with a tiny juvenile musk turtle in one of the videos. I have seen an adult musk turtle (Sternotherus sp.) mistaken for a juvenile snapping turtle because they are so small; the juvenile musk turtle is barely bigger than a quarter.

Underwater views on either side of the Williford vent, with mosquitofish at the surface and a tiny juvenile musk turtle in the lower left hand corner of the bottom photo.

All three of these springs benefited from restoration projects between 2012 and 2015. Projects included bank stabilization and stormwater runoff reduction. I could not find specific water quality information for the springs, but nutrient concentrations for Econfina Creek have been generally low for the period of 2009-2020 (https://protectingfloridatogether.gov/water-quality-status-dashboard). Most data points have been in the ~0.2 mg/L range with periodic measurements up to 0.6 mg/L and a few high spikes up to 1.4+ mg/L (that would be considered quite high) during the period of the restoration. Phosphorus has exhibited similar trends with most points quite low (~0.01 mg/L), virtually all points below 0.03 mg/L and just a few points in the 0.035-0.045 mg/L range. My oxygen measurements were low for the headspring of each system (0.45-1.95 mg/L) and the measurements for the Sylvan run only reached as high as 4.72 mg/L for one sample. The conductivity was low 1330-1400 microS/cm for all samples.