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. 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.
Late last month 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 USFWS 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.
“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.
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. 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.
“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.