UT's Energy, Environment
and Resources Center Presents
Smoky Mountain
Resource Issues in Great Smoky Mountains National Park
SIGHTLINE
SPRING/SUMMER 2003
Vol. 4 No. 1
SITE LOCATOR MAPFOR GSMNP STORIES
HUMAN INTERACTION Elkmont in the Balance
***
Editor: David Brill; Assistant Editor: Constance Griffith; Writers: Kris Christen, Lisa Byerley Gary, Elise LeQuire, Dennis McCarthy, and Becky Nichols. Graphic Designer: Lisa Byerley Gary.
SIGHTLINE is published on behalf of
Great Smoky Mountains National
Park
by the
Energy, Environment and Resources
Center (EERC)
at the
University of Tennessee.
EERC conducts research designed to promote real-world solutions to problems in the fields of energy, environment, technology, and economic development.
For additional information, write EERC, 311 Conference Center Building, The University of Tennessee, Knoxville, TN 37996-4134, call 865-974-4251, or visit our Web site at http://eerc.ra.utk.edu.
SIGHTLINE is sponsored by:
and
Rebirth
of a StreamFifteen years of stocking and more than a
decade of streambank improvements have allowed rare native fish to return to Abrams Creek.BY ELISE LEQUIRE
In
1957, with the blessing of the Game and Fish Commission of Tennessee and
the National Park Service, workers fanned out along Abrams Creek, from
Abrams Falls all the way down to its juncture with the Little Tennessee
River, and poisoned the waters with the piscicide Rotenone. The operation
was timed to coincide with the closing of Chilhowee Dam to create a lake
that would provide electricity to ALCOA aluminum company and excellent
trout fishing to anglers.
This massive fish kill was part of a management scheme designed, says David Etnier, to improve rainbow trout populations, an introduced species prized by anglers. Etnier is an emeritus professor of ecology and evolutionary biology at the University of Tennessee (UT) who remains active in monitoring the diversity of aquatic species in Great Smoky Mountains National Park. At the time, managing for fishing basically meant killing everything and restocking the streams with sport fish. "This was the philosophy of the day. If I had been there, I would have never said a word about it," Etnier says.
Prior to the kill, biologists conducted a baseline survey of the creek and accounted for nearly 60 different species of fish. Only about half of these recovered on their own by recolonizing from tributaries that were not treated with Rotenone. Among the extirpated species were smoky madtoms and yellowfin madtoms—small members of the catfish family—duskytail darters, and spotfin chubs, all of which have since been listed as threatened or endangered under the Endangered Species Act. In fact, the smoky madtom was newly identified from specimens collected after the kill and thus declared extinct upon discovery. The yellowfin madtom was also considered extinct.
SPAWN OF A NEW ERA
The creation of Chilhowee Lake essentially fragmented the habitat of these small- to medium-size stream species, which thrive in free-flowing waters. In the1970s and 1980s, however, biologists found remnant populations of the smoky madtom, yellowfin madtom, and the duskytail darter in a small tributary of the Little Tennessee, Citico Creek in Cherokee National Forest, and spotfin chubs in the Little Tennessee River above the reservoirs in North Carolina. Etnier identified these species as good candidates for a project to restore the native fish fauna to Abrams Creek.
Since the remnant populations of these species were so small, however, captive breeding of these fish was determined to be the preferred method of obtaining stock. Under Etnier’s tutelage, the first attempts at captive breeding were undertaken by UT graduate students Patrick Rakes, J.R. Shute, and Peggy Shute.
When Rakes and J.R. Shute left the university, they founded Conservation Fisheries, Inc. (CFI) as a nonprofit organization to continue the captive propagation program with the help of the Tennessee Wildlife Resources Agency and the U.S. Fish and Wildlife Service.
At CFI’s facilities in Knoxville, Tennessee, stock taken from the wild is raised in tanks in a laboratory where the light is manipulated to mimic natural conditions. The tanks’ water temperature is adjusted to provide the seasonal variation the fish will experience when they are released. Slabs of tile, gravel, sand, pebbles and stones, and even nests of yarn, provide artificial habitat similar to the cobble sands, slab rocks, flat rocks, and aquatic vegetation where the wild fish thrive.
After more than15 years of work, the restoration project in Abrams Creek is nearly completed. "In the past two years, we have seen a lot of wild reproduction in three of the species," says Rakes. Snorkeling surveys reveal that the madtoms are successfully reproducing. "Last year, we saw more young smoky madtoms than in all earlier years combined," Rakes says. And since 1995, CFI has found signs of wild reproduction of duskytail darters, including nests and young spawned fry. "That fish is doing well," he says. "We could walk away and consider it established." A few spotfin chubs have also spawned in Abrams Creek.
Stocking occurs at sites upstream from Abrams Creek Campground, downstream near the mouth of Abrams Creek above Chilhowee Lake, and in waters that flow through the campground. "The Abrams Creek campground area is ideal," Rakes says, though he has seen evidence of serious habitat alteration, as visitors playing in the creek construct dams out of cobbles and slab rocks. "These species are almost gone from the Earth," Rakes says. "We need to make a concerted effort to tiptoe around them."
RESTORING HABITAT
Abrams Creek was considered ideal for restoring these native fish because the pH is close to neutral—thanks to the limestone substrate of Cades Cove—and Abrams’ warmer waters are more conducive to spawning than are higher elevation streams. Abrams Creek also has a variety of special habitat niches each of the species prefers and an abundance of their preferred food—midges, gnat larvae, and the larval stages of aquatic insects such as mayflies, stoneflies, and caddisflies.
Some portions of the creek, however, have in the past suffered from high levels of sedimentation and eroded streambanks, especially in Cades Cove, where cattle had been allowed access to the creek. Field surveys in 1991 and 1992 revealed that stream bank erosion and loss of vegetative cover in Maples Branch—also where cattle were allowed access to water—were resulting in heavy sediment loads downstream in Abrams Creek. In 1993, the Park Service, with the help of volunteers from Trout Unlimited, began fencing stream banks and limiting cattle access to a small number of crossings.
About the same time, a UT graduate student began an in-depth baseline study of aquatic insects along the length of Abrams Creek. For two years, Stephen Fraley, in a cooperative agreement with UT and the National Park Service, compiled an exhaustive inventory of the creek’s macroinverterbrate richness and community structure. Fraley evaluated the abundance and variety of aquatic insects as an indicator of overall stream health.
Fraley sampled seven sites scattered throughout the 88 square miles of the watershed and found 340 taxa from 90 families. "We took massive amounts of qualitative samples, tens of thousands of organisms," says Fraley, who is now a non-game aquatic biologist with the North Carolina Wildlife Resources Commission in western North Carolina.
Though the overall condition of the creek was very good to excellent, Fraley found evidence of effects from streambank erosion, nutrient enrichment, and lack of habitat diversity. This study lent support to the Park Service’s plans to exclude cattle from the creek, build and repair fences along the streams, contain eroded streambanks, and reseed with native grasses.
In 1999, the cattle were removed when the last leaseholder in Cades Cove, Kermit Caughron, died. Since the streambank improvements and removal of the cattle, turbidity, which is measured by collecting stream samples after big storm events, has dropped dramatically.
"Abrams Creek naturally carries more sediment than other streams because it is in an alluvial plain, and it meanders and cuts the banks more than other streams," says Steve Moore, fisheries biologist with the Park. "When the cows were fenced off away from the streambanks, all the real fine mud, the fine sediment, washed out. Since they have been removed, the amount of sediment is close to natural," Moore says.
For more information, contact Bob Miller, Great Smoky Mountains National Park, 107 Park Headquarters Road, Gatlinburg, TN 37738, or call 865-436-1207.