Chattanooga, Tenn. (Nov 28, 2016) – The fishes that live in headwater streams are like the scrappy underdogs of the aquatic world. They’ve adapted to hang tough in low-oxygen conditions and to make it through the occasional drought.
But even Rocky Balboa couldn’t go 15 rounds — let alone months at a stretch — without the occasional water break.
Thanks to a drought of historic proportions, the few creeks and tributaries on the Cumberland Plateau where the federally endangered Laurel Dace can still be found have all but dried up.
That’s a problem because, even though fishes in headwaters are survivors, they still need to breath, said Tennessee Aquarium Conservation Institute (TNACI) Aquatic Biologist Dr. Bernie Kuhajda.
“They can handle a lot, but they can’t handle no water,” Kuhajda said.
On Nov. 22, after monitoring slowly dwindling water levels in the handful of headwater streams that constitute the only known habitat for the bronze-bodied, orange-bellied minnow, representatives from TNACI and U.S. Fish and Wildlife mounted a rescue operation to recover as many as possible to keep in captivity until conditions improve.
“Not everyone will agree that the Laurel Dace is something special and worth saving, but it is important,” said USFW Aquatic Listing and Recovery Biologist Warren Stiles. “The Laurel Dace is found in just a few watersheds and nowhere else. That’s incredible, and it’s a part of this ecosystem and has been here for as far back as anyone has known.”
As the rescue operation made its winding way up Walden Ridge to visit Lick Branch, a tributary of Moccasin Creek in Bledsoe County, TN, Kuhajda was pessimistic about the Laurel Dace’s prospects.
Representatives from TNACI and USFW last surveyed that site in late July, when about two dozen pools of adequately deep water still remained. After months with no appreciable rainfall and questionable ground water influence, however, Kuhajda’s hopes weren’t high.
“I’m thinking the worst there,” he said. “There may be no water, and they may be all gone. We’re going to get the depressing stuff done first.”
On site, the stream was mostly dry, as predicted, but a few shallow pools dotted the dense blanket of fallen leaves covering the streambed. After hours of dragging fine-mesh seine nets dozens of times through these waters, the team recovered large numbers of crayfish, salamanders, tadpoles and the similar-looking Blacknose Dace, but only a single juvenile Laurel Dace.
Nevertheless, Kuhajda said even that result was better than anticipated.
“I thought they’d all be gone, so to get one was amazing,” he said.
The team’s efforts at a second recovery location on Bumbee Creek deep within a Rhea County logging site were both more and less successful.
Of the eight streams on Walden Ridge known to host Laurel Dace, Bumbee Creek has historically been home to the largest and healthiest population, but the Laurel Dace in Bumbee Creek hadn’t escaped the effects of the drought, which had drastically lowered its water levels.
On Sept. 15, TNACI and USFW representatives moved more than 145 Laurel Dace to a deep upstream pool after the pool they were living in showed signs of drying up. When they arrived on Nov. 22, however, rescuers found that the relocated Laurel Dace’s upstream home had been reduced to shallow, partially frozen pools.
After breaking through a quarter-inch layer of ice, nets hauled through the first of these pools failed to recover a single Laurel Dace. Work at another, deeper pool further upstream recovered a few Laurel Dace, but not as many as expected.
In all likelihood, Kuhajda said the population of Laurel Dace is a fraction of what it had been just two months ago.
“Now, we’re down to about 50 fish, total, out of two or three pools,” he said. “The population is way, way down.”
Between both recovery sites, TNACI and USFW returned home with 18 Laurel Dace — one from Lick Branch and nine adults and eight juveniles from Bumbee Creek. These will be kept as an ark population to safeguard against the Laurel Dace’s extinction should drought conditions further degrade their wild habitat, Kuhajda said.
If the Laurel Dace were to go extinct, he said, it probably would have minimal impact on humans, but its presence in streams indicates a robust aquatic ecosystem, which contributes to the clean drinking water society relies upon. The Laurel Dace and other small fishes also serve as prey to muskie, bass, catfish and other gamefish that anglers enjoy catching.
But ensuring its continued existence is about more than just these practical concerns.
“I think it’s morally the right thing to do,” Kuhajda said. “If we, as humans, can watch species that have been around for tens or hundreds of thousands of years go extinct on our watch and not care, that seems kind of amoral to me.”
[The following video contains footage from the Laurel Dace rescue and a discussion with Dr. Bernie Kuhajda.]