Yellowfin madtom

Yellowfin madtom
Conservation status
Vulnerable (IUCN 2.3)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Siluriformes
Family:	Ictaluridae
Genus:	Noturus
Species:	N. flavipinnis
Binomial name
Noturus flavipinnis Taylor, 1969

The yellowfin madtom (Noturus flavipinnis) is a species of fish in the Ictaluridae family. It is endemic to the United States.

Abstract

Noturus flavipinnis, better known as the yellowfin madtom, is a federally threatened species of the Ictaluridae family. This page is being expanded in order to raise awareness of the severely low populations of the yellowfin madtom and to help facilitate the monitoring of the yellowfin madtom. Historically, the yellowfin madtom was widespread throughout the upper Tennessee River drainage, but was thought to be extinct by the time it was formally described.^[1] Since then, populations of the yellowfin madtom have been found in Copper Creek and the Clinch River in Virginia, the Powell River and Citico Creek in Tennessee, and a few populations have also been found in the streams of northern Georgia, though the yellowfin madtom is now listed as extripated in Georgia.^[2] Sites in Citico Creek where the yellowfin madtom has been collected notably have been upstream of a dam built in 1973 while its neighbor Noturus baileyi occupies the downstream portion of the river. Yellowfin madtom are found in backwaters and pools around rocks less than 30 cm in diameter and tree roots in clear creeks and small rivers.^[3] Yellowfin madtoms are primarily nocturnal and presumably opportunistic feeders, preying on aquatic invertebrates, small fish, and scavenging. During the daytime, the yellowfin madtom often hides in brushpiles, bedrock crevices, and can even bury itself under several inches of gravel.^[4] Since 1986, populations of the yellowfin madtom from Citico Creek have been captured and bred in laboratory to be reintroduced into Abrams Creek in Blount County, Tennessee, which in 1957 had half of its 64 species extirpated by ichthyocides with the intention to increase trout fishery. From 1986 until 2003, the population of the yellowfin madtom in Abrams Creek has increased to 1574. Currently, yellowfin madtom are no longer stocked and released into Abrams Creek.^[5]

Geographic Distribution

The yellowfin madtom is largely found in Citico Creek of Monroe County, Tennessee and reintroduced into Abrams Creek in Frederick County, Virginia. Prior to 1893, N. flavipinnis is thought to have been present throughout the upper Tennessee River drainage system. The species was thought to be extinct when it was described in 1969; thirty years after the Norris Dam on the Clinch River became operational.^[4] While the newly built dam isolated populations of the yellowfin madtom, it also led to the discovery of N. flavipinnis in Citico Creek. One hypothesis as to why the yellow fin madtom is poorly distributed can be attributed to the building of dams in the Clinch River system. The dam affects the distribution of yellowfin madtom, who most notably are found upstream, from being able to have their populations from coming into contact with one another. Another hypothesis is that increased siltation in the small river streams has had negative effects on N. flavipinnis. Soil erosion brought on by poor agricultural practices in the constantly flooding Tennessee River Valley brought more siltation into the streams where for unknown reasons the yellowfin madtom was not able to adjust properly.^[6]

Ecology

The yellowfin madtom is a nocturnal animal and very much an opportunistic feeder. The yellowfin madtom preys on aquatic invertebrates, small fish, and is able to become a scavenger^[7]. N. flavipinnis is able to survive in a wide range of environments, from small, pristine silt-free waters in Citico Creek to the larger, warm, and very silty Powell River ^[2]. While no specific predator is known, the yellowfin madtom exhibits cryptic coloration and also hides itself in the daytime, both of which are predator avoidance strategies. The yellowfin madtom is an extremely nocturnal animal and has been known not to try and escape captivation^[8]. Generally, the yellowfin madtom inhabits pools and backwaters of streams no more than two meters deep. The water usually has a moderate current and is silt-less, which allows the yellowfin madtom to bury itself into the gravel and bedrock.^[9] What is thought to be one of N. flavipinnis’s biggest competitors is the closely related N. baileyi, though due to the building of a small dam in 1973 interactions between the two have lessened considerably. Both catfish are small and are found present in the same river systems with declining populations. The separation of the yellowfin madtom’s biggest competitor seems to have had negative effects on its populations as they start to compete among themselves.

Life History

The yellowfin madtom has a relatively short lifespan and an even shorter reproduction span. Generally, the yellowfin madtom lives 3–4 years, the recorded maximum of 4 years, and are most often found in the pools and streams in which they were born. The yellowfin madtom’s breeding season begins in late May and continues through late July. The males are able to mate once during the breeding season and build and guard the nests containing between 30-100 eggs. Females on the other hand are able to reproduce twice in one breeding season and produce 121-278 eggs per breeding season, with an average of 89 hatching. Hatching usually takes eight days and the male guards the eggs and hatchlings for two weeks. N.flavipinnis reaches sexual maturity at 2 years of and usually lives through two breeding seasons. Often times the yellowfin madtom uses backwater pools and streams that are as clean and siltless as possible to breed and bury their eggs beneath slabs of rock.^[10] Human interference on yellowfin madtom populations includes man made dams and bad agricultural practices. The dams are able to separate yellowfin madtom populations from coming into contact with one another and possibly could separate a population from itself if placed just right. Another human inhibitor on yellowfin madtom populations is the increase is cattle near the streams that yellowfin madtom inhabits, which increases siltation in the water. The increased siltation in the streams of the yellowfin madtom has proven to be a strong opponent for population growth among the species.

Current Management

The yellowfin madtom is federally listed as a threatened species and as endangered in both Tennessee and Virginia. Bad agricultural practices around the shallow creeks and streams where N.flavipinnis resides has decreased the population and has made it difficult for the yellowfin madtom to recover. Efforts to increase the population of the yellowfin madtom began in 1986 at the University of Tennessee and later moved to Conservation Fisheries, Inc.(CFI) in Knoxville. Since the population was to low to take individuals away from Citico Creek, eggs were taken from nests and reared in aquatic laboratories at CFI. CFI was also allowed to maintain a captive adult population to breed inside their aquatic laboratories. From 1986 until 2003, two to three yellowfin madtom clutches were taken from Citico Creek for captive propagation to be stocked into Abrams Creek. Finally, the captured yellowfin madtom were released into both Abrams Creek and Citico Creek irregularly to try and restore a population and save a population respectively. The yellowfin madtom has had a 53% survivorship rate among its captured egg clutches and new yellowfin madtom have been found in Abrams Creek almost every year since 1994. In 2003, though only nine yellowfin madtom were found in Abrams Creek, they were believed to be wild spawned since tagged fish had not been released since 2001, marking what looks to have been a successful project in restoring the yellowfin madtom in Abrams Creek. In order to help the restoration project in Abrams Creek, the National Park Service, US Forrest Service, University of Tennessee, and Tennessee Valley Authority have taken up the duty to improve the water and habitat of Abrams Creek. The groups helped to remove cattle and restore riparian vegetation around Abrams Creek and its tributaries. The hope is that the restoration of the Abrams Creek habitat decreases its silt content which has been proven to be the yellowfin madtom’s worst enemy.^[11]

Management Recommendations

The yellowfin madtom is strictly nocturnal and has proven to be troublesome in finding out its population because of this. The yellowfin madtom hides under rocks and gravel during the day and darts from leaf cover to rock cover at night. Since the yellowfin madtom is not a traveler and rarely goes further than the back streams and pools from which it was hatched, a good starting place to monitor the yellowfin madtom would be in its breeding waters. An estimate of about 20 meters from the breeding ground downstream would contain most of the yellowfin madtom adult population and hatchlings. The yellowfin madtom contains no known predators in either the Citico Creek or Abrams Creek; therefore it would not be necessary to contain N.flavipinnis with barriers to prevent its interactions with other fish species. The populations of the yellowfin madtom in both Citico Creek and Abrams Creek are small, and thus their population densities should not be taken more than twice a year, once at the beginning of breeding season in late May and once again in early November, 4 months after the breeding season ends. This would help to cause as little disturbance as possible among the small population, though interactions with the yellowfin madtom have shown that they are not bothered by being captured or disturbed. Using electroshockers at night, when the yellowfin madtom is by far the most active, at established breeding grounds would yield the most success at determining the species’ population densities. One major component to keeping the yellowfin madtom population stable would be to block off land around the yellowfin madtom’s breeding grounds, as increased silt would hamper the growth of the yellowfin madtom population. If cattle are not fenced off or removed from the area around the yellowfin madtom breeding grounds then clutch sizes as well as adult populations will decline and once again find itself on the brink of extinction.

Sources

• Gimenez Dixon, M. 1996. Noturus flavipinnis. 2006 IUCN Red List of Threatened Species. Downloaded on 4 August 2007.
• Bauer B.H., G. Dinkins and D. Etnier. 1983. Discovery of Noturus-baileyi and Noturus-flavipinnis in Citico Creek, Little Tennessee River System. Copeia 2:558-560.
• Dinkins Gerald R. and P. Shute. 1996. Life histories of Noturus baileyi and N. flavipinnis (Pisces: Ictaluridae), two rare madtom catfishes in Citico Creek, Monroe County, Tennessee. Bulletin Alabama Museum of Natural History 18: 43-69.
• Etnier, David A. and Wayne C. Starnes. 1993. The Fishes of Tennessee. University of Tennessee Press. Knoxville, Tennessee.
• Legrande W.H. 1981. Chromosomal evolution in North-American catfishes(Siluriformes, Ictaluridae) with particular emphasis on the madtoms, Noturus. Copeia 1:33-52.
• Shute J.R. and P. Rakes, P. Shute. 2005. Reproduction of four imperiled fishes in Abrams Creek, Tennessee. Southeastern Naturalist 4: 93-110.
• Shute, P. W. 1984. Ecology of the rare yellowfin madtom, Noturus flavipinnis Taylor, in Citico Creek, Tennessee. M. S. Thesis, Univ. Tenn.
• Shute P.W, Rakes P.L, Shute J.R. and Tullock J.H. 1991. A second chance for two native catfish species. Freshwater and Marine Aquarium 14: 92-94, 180.
• Taylor, W. R. 1969. A revision of the catfish genus Noturus Rafinesque with an analysis of higher groups in the Ictaluridae. Bull. U. S. Nat. Mus. 282:1-315.
• Virginia Tech Fish and Wildlife Information Exchange, 1996. "Madtom and Yellowfin" (On-line). Endangered Species Information System. http://fwie.fw.vt.edu/WWW/esis/lists/e254002.htm.

References

1. ^ Taylor. 1969. A revision of the catfish genus Noturus Rafinesque with an analysis of higher groups in the Ictaluridae. Bull. U. S. Nat. Mus. 282:1-315.
2. ^ ^{a b} Shute, P. W. 1984. Ecology of the rare yellowfin madtom, Noturus flavipinnis Taylor, in Citico Creek, Tennessee. M. S. Thesis, Univ. Tenn.
3. ^ Bauer B.H., G. Dinkins and D. Etnier.1983. Discovery of Noturus-baileyi and Noturus-flavipinnis in Citico Creek, Little Tennessee River System. Copeia 2:558-560.
4. ^ ^{a b} Etnier, David A. and Wayne C. Starnes. 1993. The Fishes of Tennessee. University of Tennessee Press. Knoxville, Tennessee.
5. ^ Shute J.R. and P. Rakes, P. Shute.2005. Reproduction of four imperiled fishes in Abrams Creek, Tennessee. Southeastern Naturalist 4: 93-110.
6. ^ Dinkins Gerald R. and P. Shute. 1996. Life histories of Noturus baileyi and N. flavipinnis (Pisces: Ictaluridae), two rare madtom catfishes in Citico Creek, Monroe County, Tennessee. Bulletin Alabama Museum of Natural History 18: 43-69.
7. ^ Stegman, J. L. and W. L. Minckley. 1959. Occurrence of three species of fishes in interstices of gravel in an area of subsurface flow. Copeia 1959:341.
8. ^ Bauer B.H., G. Dinkins and D. Etnier. 1983. Discovery of Noturus-baileyi and Noturus-flavipinnis in Citico Creek, Little Tennessee River System. Copeia 2:558-560.
9. ^ Shute, P. W. 1984. Ecology of the rare yellowfin madtom, Noturus flavipinnis Taylor, in Citico Creek, Tennessee. M. S. Thesis, Univ. Tenn.
10. ^ Virginia Tech Fish and Wildlife Information Exchange, 1996. "Madtom and Yellowfin" (On-line). Endangered Species Information System.
11. ^ Shute J.R. and P. Rakes, P. Shute. 2005. Reproduction of four imperiled fishes in Abrams Creek, Tennessee. Southeastern Naturalist 4: 93-110.