{{Short description|Species of fish}} {{Speciesbox | name = Freckled madtom | status = LC | status_system = IUCN3.1 | status_ref = <ref name="iucn status 19 November 2021">{{cite iucn |author=NatureServe |date=2013 |title=''Noturus nocturnus'' |volume=2013 |article-number=e.T202696A18236833 |doi=10.2305/IUCN.UK.2013-1.RLTS.T202696A18236833.en |access-date=19 November 2021}}</ref> | image = Freckled madtom (Noturus nocturnus) (4015394815).jpg | taxon = Noturus nocturnus | authority = D. S. Jordan & C. H. Gilbert, 1886 }} The '''freckled madtom''' ('''''Noturus nocturnus''''') 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.
== Geographic distribution == The freckled madtom is a freshwater species found across the eastern United States; it is common across most of its range. This range includes the Mississippi River basin and tributaries of the Gulf of Mexico in Alabama, Mississippi, Louisiana, and Texas. This species is also found in the lower Ohio River basin in Kentucky, Indiana, and Illinois.<ref name=bonner>Bonner, T., "Noturus nocturnus: Freckled Madtom." Texas State Department of Biology. http://www.bio.txstate.edu/~tbonner/txfishes/noturus%20nocturnus.htm</ref><ref name=page>Page, L.M., "Freckled Madtom: Noturus nocturnus." Florida Museum of Natural History. http://www.flmnh.ufl.edu/catfish/ictaluridae/freckledmadtom.htm</ref> Other areas it is found include Oklahoma, southeastern Iowa, central Kansas, Arkansas, Georgia, and western Tennessee.<ref name=page /><ref name=willink>Willink, P.W., F.M. Veraldi, and J.B. Ladonski, "Rediscovery of the Freckled Madtom Noturus nocturnus Jordan & Gilbert in the Des Plaines River, Illinois." Transactions of the Illinois State Academy of Science 99 (2006).</ref><ref>U.S. Geological Survey, "Noturus nocturnus Jordan and Gilbert, 1886." U.S. Department of the Interior. https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=2536</ref> Latitudinally it is found mostly between 41 and 30°N.<ref name=fishbase>FishBase, "Noturus nocturnus Jordan & Gilbert, 1886: Freckled Madtom." FishBase. http://www.fishbase.org/summary/Noturus-nocturnus.html</ref> This range has been identified since at least 1980; the current distribution is similar to the historical one, though some small extensions have been driven north, possibly as a result of global warming.<ref name="Bernstein, N.P 2001">Bernstein, N.P. and Olson, J.R., "Ecological Problems with Iowa's Invasive and Introduced Fishes." Journal of the Iowa Academy of Science 108 (2001): 185–209.</ref> This species is not known to travel often, especially over long distances.<ref name="tnfish.org">NatureServe, "Noturus nocturnus - Jordan and Gilbert: Freckled Madtom." NatureServe Explorer. http://www.tnfish.org/SpeciesFishInformation_TWRA/Research/FreckledMadtomNoturusNocturnus_NatureServeExplorer.pdf</ref> Further, its distribution is not entirely known due to its small population sizes and tendency to be easily misidentified. Freckled madtoms are often misidentified as bullheads or other catfish.<ref name=willink />
Further, the freckled madtom is said to be an intolerant species that sometimes disappears after a disturbance. These individuals are fluvial specialists, meaning they are specialized to a particular habitat, theirs being fast-moving riffle habitats.<ref name=page /> Human litter may be a potential disturbance to the species; young and breeding adult male individuals have often been found in beverage cans and other human-created debris.<ref name=willink /> It may be difficult to determine range expansion, though, because of its small population sizes in certain areas, including central Oklahoma.<ref>Orth, D.J. and Jones, R.N. "Range Extensions of the Orangethroat Darter (Etheostoma spectabile) and the Freckled Madtom (Noturus nocturnus) into Western Oklahoma." Proceedings of the Oklahoma Academy of Science 60 (1980): 98–99.</ref> However, freckled madtom distributions may have extended slightly as water quality in certain regions has improved.<ref name=willink />
== Ecology == The freckled madtom is known to inhabit fast-moving and permanently moving streams that are medium to large in size. The streams usually contain rocky bottoms. Further, this species is sometimes found in the vicinity of undercut banks near masses of sticks and roots.<ref name=bonner />
The freckled madtom is primarily an invertivore (feeding on invertebrates). It uses ambush tactics in benthic regions largely at night to feed. It notably consumes insect larvae, including mayfly, black fly, caddisfly, and midge larvae.<ref name=bonner /> It also occasionally eats crustaceans.<ref name=willink /> Though it is largely an invertivore, it has also been known to occasionally eat other fish. In southern Mississippi, evidence was found of freckled madtoms feeding on the smaller speckled madtom (''N. leptacanthus''). To aid in devouring victims, this catfish has venom glands along smooth spines on the pectoral and dorsal fins.<ref>Egge, J.J.D. and Simons, A.M., "Evolution of Venom Delivery Structures in Madtom Catfishes (Siluriformes: Ictaluridae)." Biological Journal of the Linnean Society 102 (2011): 115–129.</ref><ref>Wright, J.J., "Diversity, Phylogenetic Distribution, and Origins of Venomous Catfishes." BMC Evolutionary Biology 9 (2009): 1–12.</ref>
== Life history ==
The maximum reported size of the freckled madtom is {{convert|15|cm|in|abbr=on}}. One source lists the average size as {{convert|4.6|cm|in|abbr=on}}, and another source lists an average size range between {{convert|5|and|13.5|cm|in|abbr=on}} long.<ref name=fishbase /><ref name="eol.org">Encyclopedia of Life, "Noturus nocturnus: Freckled Madtom." Encyclopedia of Life. http://eol.org/pages/208076/details</ref><ref name="outdooralabama.com">Outdoor Alabama, [https://web.archive.org/web/20130806132009/https://www.outdooralabama.com/fishing/freshwater/fish/other/madtom/freckled/ "Freckled Madtom"]. Alabama Department of Conservation and Natural Resources.</ref>
The maximum age reported is 4.0 to 4.5 years.<ref name="tnfish.org"/><ref name="eol.org"/> Males become sexually mature by 2 years, most females by their second summer if not sooner, and polygamy is common among this species, as well as other ''Noturus'' species.<ref name="tnfish.org"/><ref name="darlingtonschool.org">Kinney, O. "Freckled Madtom (Noturus nocturnus)." Darlington School. http://www.darlingtonschool.org/faculty/okinney/Natural%20History/Fish/Student%20fish/freckled_madtom.htm {{Webarchive|url=https://web.archive.org/web/20140826115100/http://www.darlingtonschool.org/faculty/okinney/Natural%20History/Fish/Student%20fish/freckled_madtom.htm |date=2014-08-26 }}</ref> Females produce an average of around 100 eggs per summer.<ref name="darlingtonschool.org"/> The oocytes mature by late May to early July, and males guard the nests usually by late June. Optimal water temperature surrounding the nests is {{convert|25|C|F}}.<ref name="tnfish.org"/> Nests have been found under flat rocks, though still in the same fast-moving riffle areas this species inhabits.<ref name="outdooralabama.com"/>
== Conservation and management==
The freckled madtom is not considered an endangered species at the federal level, and it is not found on the International Union for Conservation of Nature's endangered species lists. However, it has been listed as an endangered species in Iowa since 1984.<ref>Iowa Department of Natural Resources, "Chapter 77: Endangered and Threatened Plant and Animal Species." The Natural Resource Commission. http://www.iowadnr.gov/Environment/ThreatenedEndangered.aspx {{Webarchive|url=https://web.archive.org/web/20150924035847/http://www.iowadnr.gov/Environment/ThreatenedEndangered.aspx |date=2015-09-24 }}</ref><ref>Iowa Fish Atlas, "Freckled Madtom – Noturus nocturnus." Iowa State University. http://maps.gis.iastate.edu/iris/fishatlas/IA164005.html {{Webarchive|url=https://web.archive.org/web/20100624005451/http://maps.gis.iastate.edu/iris/fishatlas/IA164005.html |date=2010-06-24 }}</ref>
==References== {{Reflist}}
==External links== *[https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=2536 Photo, distribution map, and further information]
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Category:Noturus Category:Freshwater fish of the United States Category:Fish of the Eastern United States Category:Endemic fish of the United States Category:Fauna of the Plains-Midwest (United States) Category:Fauna of the Southeastern United States Category:Fish described in 1886 Category:Taxa named by David Starr Jordan Category:Taxa named by Charles Henry Gilbert