Smoky madtom

The smoky madtom (Noturus baileyi) is a species of catfish. Little information exists about the smoky madtom, along with other members of the Noturus species, due to the high turbidity in which they spawn, preventing observation, as well as their nocturnal behaviors.^[1]

Anatomy and appearance

The madtom is a small member of the Ictaluridae family, only reaching a maximum of two inches. It is an olive brown on top with white to yellow below. Four saddles line the back of this species.^[2]

Geographic Distribution

The smoky madtom is endemic to Abrams Creek in the Great Smoky Mountains National Park, Tennessee.^[3] In 1957, Chilhowee Dam was closed and an ichthyocide was administered to Abrams Creek, in an attempt to improve trout fishery. Extirpation of the smoky madtom resulted. ^[4][5] The Smoky madtom was presumed extinct until in 1980, another population was found in Citico Creek in the Cherokee National Forest, Monroe County, TN.^[6] In 1986, a restoration project was begun to restore this native population. Efforts include collecting egg masses from Citico Creek, rearing them in the lab, and reintroducing them into Abrams Creek after a year.^[4]

Ecology

The smoky madtom is a very secretive catfish. During the day, it buries itself under gravel. It is nocturnal and feeds at night on aquatic invertebrates and small fish.^[7] It prefers areas of transition between pools and riffles and spawns in the summer under large, flat rocks.^[4][8] Specimens have been collected in areas of transition between pools and riffles in depths of about 25 cm. In the winter and spring it seems to prefer more gentle runs and pools. The area also includes large boulders for the madtom to hide under, which it has been documented to do when disturbed at night. The water is clear and its temperature is also intermediate between cold and cool water. Stream width is approximately 4–10 m.^[6] Small mouth bass have been recorded preying on the Smoky madtom.^[9] Noturus species can be used as an indicator of the environment. This is due to the fact that they are very susceptible to changes. Human disturbances such as logging, mining, and cattle grazing can cause siltation of the water and drop the populations dramatically.^[5]

The female madtom reaches maturity after two years. Spawning happens once a year and on average, 30 eggs are produced. The life expectancy is 4 years, allowing only 2 years of reproduction, with a total of 72 eggs.^[2] This low reproduction, coupled with extirpation and low tolerance, has led the Smoky madtom to be federally listed as endangered. The average spawning season is between June and July. In 1982, females were found between May 13 to July 7 with distended abdomens. Each nest will include up to 36 eggs, the average being 30. In 1982 the average was 35-42 eggs. Eggs have been collected in nests under large, flat, slabrocks.^[7] The Smoky madtom male, like other catfish, defends its nest. The muscles of the head also swell during the breeding season. The average life expectancy is 4 years.

Siltation plays a vital role in whether or not this species will reproduce. Too much silt in the water will smother the eggs. Like many fish species, the smoky madtom can be prone to fungal and bacterial infections.

Current Management

The restoration project in 1986 required the help of the North Carolina Wildlife Resources Commission, the Tennessee Wildlife Resources Agency, the US Fish and Wildlife Service, the US Forest Service, the National Park Service, and the University of Tennessee. Since the population was so low, the risk of stocking live fish into Abrams Creek was too high. Egg masses were collected during the spawning season and reared in the lab. The young were released after one year of age. They were also released at night to minimize predation risk and help them get used to their surroundings. Since then, ten to twenty clutches have been removed from Citico Creek and a total of 3,167 stocked in Abrams Creek. The average survivorship is 55%. Since 1990, observations of Smoky madtom in Abrams Creek have been increasingly abundant. In 2002, 43 out of 56 were young-of-year, indicating successful spawning. This species has been, and still is listed as endangered.^[4] In 1984 the population was as low as 500-1000 fishes. This is due to a combination of building the Chilhowee dam, poisoning the creek, and degrading the stream with livestock and tourists.^[7]

References