The yellowfin madtom (Noturus flavipinnis) is a species of fish in the family Ictaluridae endemic to the southeastern United States. 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.
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, 30 years after the Norris Dam on the Clinch River became operational. 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 extirpated in Georgia. 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.
Ecology
The yellowfin madtom is nocturnal, and very much an opportunistic feeder. It preys on aquatic invertebrates, small fish, and detritus. During the daytime, the yellowfin madtom often hides in brushpiles or bedrock crevices, and can even bury itself under several inches of gravel. 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. 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 to escape captivity. Generally, it inhabits pools and backwaters of streams no more than 2.0 m deep. The water usually has a moderate current and is siltless, which allows the fish to bury itself into the gravel and bedrock. The closely related N. baileyi is thought to be one of N. flavipinnis’s biggest competitors, though due to the building of a small dam in 1973, interactions between the two have lessened considerably. Both catfish are small and are present in the same river systems, with declining populations. The separation of the yellowfin madtom from its biggest competitor seems to have had negative effects on its populations, as they start to compete among themselves.
The yellowfin madtom has a relatively short lifespan. Generally, it lives up to four years, and are most often found in the pools and streams in which they were born. Their 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 and 100 eggs. Females, though, are able to reproduce twice in one breeding season and produce 121-278 eggs per 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 two years of and usually lives through two breeding seasons. Often, they use backwater pools and streams that are as clean and siltless as possible to breed and bury their eggs beneath rocks.