Pygmy madtom

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Pygmy madtom
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Siluriformes
Family: Ictaluridae
Genus: Noturus
Species:
N. stanauli
Binomial name
Noturus stanauli

The pygmy madtom (Noturus stanauli) is a species of fish in the family Ictaluridae endemic to the United States, in only two known regions of Tennessee. Madtoms are the smallest members of the Ictalurid catfish family. Members of the genus Noturus can be distinguished by their small size, unusually long adipose fin, and rounded caudal fin. Most specimens have been collected over shallow, fine gravel shoals with moderate to swift flow, usually near the stream bank. [1]

Contents


Distribution

The pygmy madtom has an extremely limited distribution, appearing only in samples taken from the Duck River, in Humphreys and Hickman Counties, Tennessee; and from the Clinch River, Hancock County, Tennessee. These two locations are separated by about 600 river miles, though no current evidence indicates the entire historical range of the species.

Ecology

The pygmy madtom is the smallest of madtoms, reaching only about 50 mm in length at adulthood. It is dark brown dorsally and nearly white ventrally, and is similar to the least madtom, but is distinguished by its white snout and large teeth on the front edge of the pectoral spine. The caudal fin has a dark band or dusky blotches in the middle. The anal fin has 14-17 rays.

N. stanauli has currently been observed and collected in moderate to swift gravel runs of clear medium-sized rivers in pea-sized gravel of fine sand substrates. Although no observations of seasonal habitat shifts have been made, the closely related smoky madtom is known to switch from riffles to overwinter in shallow pools. [2] Two closely related species, N. baileyi (smoky madtom) and N. flavipinnis (yellowfin madtom), are found in the flowing portions of pools during the reproductive season. [3]

Many specific biological traits of this madtom have not been gathered to date, mainly stemming from a lack of observable specimens in their natural environment. A total of 10 individuals have been found from both locations since the species was listed as endangered in 1993. Conservation Fisheries, Inc. of Knoxville, Tennessee, was able to propagate young on several instances and reported adult activity was limited only to the early evening hours. Because of this observation, the adults are believed to be crepuscular.

Madtoms almost exclusively prey on aquatic insect larvae. They are primarily opportunistic feeders and take prey items in proportion to their abundance. [4] [5]

Related madtoms nest in cavities beneath slab rocks and at times use other cover objects, such as cans and bottles. As native mussels are abundant in pygmy madtom habitat, this species might use empty mussel shells for nesting cover. Reproduction likely occurs from spring to early summer.

Management

The pygmy madtom was listed as federally endangered throughout its entire range in 1993, so a management plan was drafted in 1994 by the United States Fish and Wildlife Service outlining description of actions to be taken, time frame, responsible parties, labor type and various other activities relating to species repopulation.

The two known populations are isolated from each other by impoundments, making recolonization of any extirpated population impossible without human intervention. The absence of natural gene flow among the limited populations of these fishes leaves the long-term genetic viability of these isolated populations in question.

Additionally, several madtom species have, for unexplained reasons, been extirpated from sections of their naturally occurring range. One hypothesis states, "...in addition to visible habitat degradation be related to their being unable to cope with olfactory 'noise' being added to riverine ecosystems in the form of a wide variety of complex organic chemicals that may occur only in trace amounts." [6] Many species that once existed throughout major portions of the Tennessee River now exist only as isolated remnant populations, [7] and extirpations and extinctions are predicted. [8] [9]

Threats affecting the pygmy madtom are increased urbanization, coal mining, toxic chemical spills, siltation, improper pesticide use, and stream bank erosion. Additional threats include gravel dredging, water withdrawals, and agricultural practices. None of the threats has been eliminated since the fish was listed; consequently, both the Duck and Clinch River populations remain vulnerable to extirpation. Existing federal and state laws and regulations are applied to actions conducted within the range of pygmy madtom to protect the fish and its habitats. However, due to difficulty in finding the fish in surveys, the extent of its habitat is unknown.

Monitoring of the species is difficult due to its scarcity in both abundance and distribution. Given the current state of the population, monitoring techniques must minimize impact to the existing individuals.

Related Research Articles

<span class="mw-page-title-main">Ictaluridae</span> Family of fishes

The Ictaluridae, sometimes called ictalurids, are a family of catfish native to North America, where they are an important food source and sometimes fished for sport. The family includes about 51 species, some commonly known as bullheads, madtoms, channel catfish, and blue catfish.

<span class="mw-page-title-main">Madtom</span> Genus of fishes

Madtoms are freshwater catfishes of the genus Noturus of the family Ictaluridae. It is the most species-rich family of catfish in North America, native to the central and eastern United States, and adjacent parts of Canada. Their fin spines contain a mild venom with a sting comparable to that of a honey bee.

The ashy darter is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is endemic to the eastern United States.

<span class="mw-page-title-main">Yellowfin madtom</span> Species of fish

The yellowfin madtom 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.

<span class="mw-page-title-main">Carolina madtom</span> Species of fish

The Carolina madtom is an endangered species of fish in the family Ictaluridae. It is endemic to North Carolina. It is a small catfish, reaching a maximum length of nearly five inches. Described in the late-1800s by ichthyologists Jordan and Meek, this fish is the only madtom that is endemic to North Carolina, as indicated by its common name.

<span class="mw-page-title-main">Frecklebelly madtom</span> Species of fish

The frecklebelly madtom is a species of fish in the family Ictaluridae endemic to the United States. Madtoms are in the genus Noturus, which is a group of catfish prevalent in North America. In 2023, the Upper Coosa River distinct population segment (DPS) of N. munitus was listed as federally threatened under the Endangered Species Act of 1973.

The Caddo madtom is a species of fish in the family Ictaluridae endemic to the United States. N. taylori was named in honor of William Ralph Taylor, U.S. National Museum, in recognition of his contributions to the knowledge of catfishes. They average 2 to 4 inches long and weigh no more than a few ounces. N. taylori has a small to tiny, fragmented range, but is mostly found in the Caddo, Ouachita, and Little Missouri rivers in southwestern Arkansas. Ecological studies indicate that dam and bridge construction poses barriers to dispersal and migration of fish in the Ouachita Highlands. IUCNredlist.org states that better information is needed on the life history, reproductive biology, and ecology of the Caddo madtom. This species is listed as endangered on the IUCN Red List. Limited range makes this species vulnerable to habitat destruction/degradation from impoundment, pollution, and other factors. Robison and Buchanan (1988) stated, "this rare species should be considered threatened due to loss of habitat". Warren et al. (2000) categorized the species as "threatened".

The smoky madtom 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.

<span class="mw-page-title-main">Chucky madtom</span> Species of fish

The chucky madtom is a critically endangered freshwater fish endemic to the U.S. state of Tennessee.

The elegant madtom is a fish native to Tennessee, Alabama, and Kentucky, and is one of twenty-nine species of madtom. It prefers to live in small rivers and gravel-bottomed creeks. The average lifespan of the elegant madtom is two years.

The mountain madtom is a North American species of temperate freshwater fish belonging to the Noturus genus of the family Ictaluridae. The species was first described to the United States National Museum by Professors Jordan and Gilbert in the Big Pigeon River. The mountain madtom has a body that is characterized as being robust, and by the toxic sting that is associated with their pectoral and dorsal spines. Currently, the Pigeon River Recovery Project is working to try to restore the mountain madtom population that was lost in fisheries. Aside from the Pigeon River Recovery Project, there is little management being applied to this species, and it is currently listed on the threatened species list for the state of Tennessee.

<i>Noturus exilis</i> Species of fish

Noturus exilis, also called the slender madtom, is a species of the catfish family Ictaluridae. Ictaluridae includes bullheads, madtoms, channel catfish, and blue catfish. Noturus exilis is found in the central portion of the Mississippi River basin, but is most abundant in Ozarkian streams. Slender madtoms occur west of the Mississippi River in the Ozarks of Oklahoma, Arkansas, and Missouri north to southern Wisconsin and Minnesota. It also occurs east of the Mississippi River in the uplands of Alabama, Tennessee, and Kentucky in the Tennessee, Cumberland, and Green drainages. Edward Nelson first described Noturus exilis in 1876. The slender madtom is moderately large with a terminal to sub-terminal mouth, flat head, small eyes, and black marginal bands on the median fins. Most slender madtoms are less than 90 millimetres (3.5 in). Noturus flavus and Noturus nocturnus are rather similar in shape and coloration to Norturus exilis. Slender madtoms inhabit small to medium-sized streams, in riffle and flowing pool habitats with coarse gravel to slab rock substrates. The presence of a shelter object, such as a large rock, seems to be important in habitat selection.

<i>Noturus fasciatus</i> Species of fish

Noturus fasciatus is a rare freshwater fish native to the U.S. state of Tennessee. It was first described as a species separate from Noturus crypticus in 2005. It is restricted to the Duck River system and is also found in two minor tributaries on the lower section of the Tennessee River. This species dwells in small to medium-sized streams where they can be found under gravel, rubble, and slab rock. They feed mostly on insects such as: stone, cattus and mayfly larvae.

The piebald madtom is a species of madtom catfish that is found in seven river systems in the Tennessee and Mississippi coastal tributaries. The most common systems N. gladiator is found in are, the Hatchie River, Obion River, and Wolf River. This species is very susceptible to environmental changes including flow regimes, siltation in nesting sites, and poor environmental quality. The Noturus catfish reproduces from February to September and females reach sexual maturity in only one year. Current management strategies for this recently discovered species haven't been completely developed yet, but could be comparative to the management of other madtom species. Siltation in the southern portions of the rivers, inhabited by Noturus gladiator that comes from the northern aspects of the waterways is causing stress on the reproductive success due to nest suffocation. There are records as close as twenty years ago showing the species inhabiting multiple other rivers around the areas it currently inhabits. This could be a sign that the species is in a decline. There should be population surveys done on the existing habitat and water quality surveys done in the inhabited areas as well as the uninhabited neighboring areas to see what the limiting pollutant might be in the water causing habitats to shrink. The area that this species inhabits needs to be managed in a way that could see a resurgence in gladiators numbers.

The speckled madtom is a small freshwater fish found in the southeastern United States that belongs to the genus Noturus of the family Ictaluridae.

<span class="mw-page-title-main">Brindled madtom</span> Species of fish

The brindled madtom is a small catfish of the family Ictaluridae that is native to the eastern United States.

<span class="mw-page-title-main">Freckled madtom</span> Species of fish

The freckled madtom a species of freshwater madtom (catfish) found in the eastern United States. The freckled madtom is a benthic feeder mostly of invertebrates and usually inhabits waters that are medium to large in size, living mostly in riffle areas that have mostly clear waters and rocky bottoms. Its spawning season occurs from spring to early summer in riffle areas, and sexual maturation occurs after two years.

The black madtom is a nocturnal, freshwater, diminutive catfish found in watersheds in Florida, Louisiana, Alabama, and Mississippi, and is one of 29 species of madtom.

The checkered madtom is a small freshwater catfish found in the United States, in the rivers of Arkansas and Missouri. It is one of 29 species of madtom.

References

  1. 1 2 NatureServe (2013). "Noturus stanauli". IUCN Red List of Threatened Species . 2013: e.T14906A19032599. doi: 10.2305/IUCN.UK.2013-1.RLTS.T14906A19032599.en . Retrieved 17 November 2021.
  2. Dinkins, G.R. 1984. Aspects of the life history of the smoky madtom (Noturus baileyi) in Citico Creek. M.S. Thesis, University of Tennessee, Knoxville, TN. 50pp.
  3. Dinkins, G.R., and P.W. Shute. 1993. Life histories of two federally listed madtom catfish, Noturus baileyi (smoky madtom) and N. flavipinnis (yellowfin madtom). Unpublished manuscript.
  4. Starnes, W. C., and L. B. Starnes. 1985. Ecology and life history of the mountain madtom, Noturus eleutherus (Pisces: Ictaluridae). Am. Midl. Nat. 114:331-341.
  5. Gutowski, M. J., and J. R. Stauffer, Jr. 1990. Feeding ecology of the margined madtom Noturus insignis (Richardson) (Teleos-tei: Ictaluridae). Abstract, 70th annual meeting ASIH (p. 95).
  6. Etnier and Jenkins 1980
  7. Neves, R. J., and P. L. Angermeier. 1990. Habitat alteration and its effects on native fishes in the upper Tennessee River system, east-central U.S.A. J. Fish Biol. 37 (Supplement A), pp. 45–52.
  8. Etnier, D. A., and R. E. Jenkins. 1980. Noturus stanauli, a new madtom catfish (Ictaluridae) from the Clinch and Duck Rivers, Tennessee. Bull. Alabama Mus. Nat. Hist. 5:17-22.
  9. Sheldon, A. L. 1988. Conservation of stream fishes: patterns of diversity, rarity, and risk. Conservation Biology. 2:149-156.

Further reading