Madtoms of the OSUM Fish Division


Why are the ‘toms mad?  Might have to do with the fact that madtoms are so small and have a hard time competing with their larger con-familials (like Bullhead Catfish and Channel Catfish) for space and food.  But connate with several other small animal species they make up for their small size with a nastily painful poison sting.  Ask any catfish aficionado, or even a neophyte; and they will tell you that they pay careful attention to the sharp spines the catfishes carry at the front of their dorsal and pectoral fins.  Whereas catfishes of the North American Ictaluridae genera other than Noturus lack the actual venom, those other genera do carry bacteria on their spines that can cause infection in the wound. The madtoms secrete their venom in a sac at the base of their pectoral spine.  When threatened the madtoms lock their pectoral spine in an erect position, causing the sac to rupture and releasing the toxin into the water.

Another character that typifies smaller animals is their habit of remaining in the shadows.  Madtom species are quite furtive, hiding under rocks and logs or in crevices including crayfish burrows.   Like other catfish genera they tend to be most active at night.  A savvy madtom collector sallies forth in the darkness with a lantern that attracts the bewhiskered nocturnals like moths to a flame.  The best time for collecting many madtom species is in the cooler months of Autumn, up through December, when they congregate en-masse out in the open.  Madtoms spawn in late spring through summer, so could it be they carry out this excursion in the colder season for the simple reason that many larger predators have moved downstream to deeper waters?

This highly cryptic group of catfishes contains several species with populations that are imperiled to varying degrees.  Some, like Ohio’s Scioto Madtom, are Extinct while many are Endangered, Threatened or Of Special Concern at the State to Federal level.  Noturus species occupy a wide array of habitats but all rely on aquatic insects for their food.  Images of a few of the madtom species vouchered in the OSUM Fish Division are posted below.

OSUM 35531 Noturus flavipinnis 1 of 1 left lateral no label

OSUM 35531 Noturus flavipinnis Yellowfin Madtom.  Several populations of this species are imperiled or extirpated.  Listed as Federally Threatened.  They were successfully reintroduced by Conservation Fisheries International in Tennessee.

OSUM 61379 Noturus munitus 1 of 90 right lateral 3

OSUM 61379 Noturus munitus Frecklebelly Madtom.  Uncommon, declining in some areas of five small, disjunct populations in Gulf Coast drainages.

Noturus flavus 103721

OSUM 103721 Noturus flavus  The Stonecat Madtom is one of the most abundant, as well as the largest madtom species in Ohio with populations across the Mississippi River and Great Lakes drainages in the U.S. and lower Canada, frequently found in faster flowing riffles but also in lakes where there is at least a moderate current.

Stonecat by UT

Noturus flavus Stonecat Madtom, photo by Uland Thomas.

Noturus insignis 50143

OSUM 50143 Noturus insignis Margined Madtom.  Another widespread species with strong populations throughout the Atlantic Slope drainages in northeastern U.S.

Margined Madtom from the Blackwater River Roanoke Drainage VA 15JUL09 by BZ

Noturus insignis Margined Madtom from Blackwater River Virginia, photo by Brian Zimmerman.

Mountain Matom from the Little Miami by UT

Noturus eleutherus Mountain Madtom, photo by Uland Thomas.  Common in some areas but one of Ohio’s State Endangered madtom species.

Noturus miurus 86131

OSUM 86131 Noturus miurus Brindled Madtom.  Relatively common as madtoms go, prefers better oxygenated waters in streams with gravel or sand, likes to hide in leaves and sticks, also inhabits rocky lakeshores.


Noturus miurus Brindled Madtom about to be released/reintroduced from my hand after a trip to Leading Creek in a cooler.

Tadpole Madtom2 from the Maumee River April 2007 by BZ

Noturus gyrinus Tadpole Madtom, photo by Brian Zimmerman.  The Tadpole Madtom occupies quieter waters with sticks and other woody debris, and tolerates muddy, silty areas better than most other madtoms.

Elegant Madtom Noturus elegans from Kentucky photo by Ben Arthur

Noturus elegans Elegant Madtom, from Russel Creek Kentucky.  Photo by Ben Arthur.  Locally common albeit only found in the Green River drainage of Kentucky.  Note the sharp barbs on the rear of the pectoral fin spine that make it particularly hard to remove catfishes from a net!


About the Author: Marc Kibbey is Assistant Curator of the OSU Fish Division at the Museum of Biological Diversity.

A State Treasure: Gone But Not Forgotten

Although Ohio has some 180 freshwater fish species living in the State’s lakes and streams, it is home to only one endemic species:  the Scioto Madtom, Noturus trautmani.

In November of 1943, when OSU Museum of Zoology Curator Milton Trautman captured the little catfish from his favorite locality, he recognized that it was not a form that he’d encountered during his multitudinous collecting trips.

OSUM 5914 Noturus trautmani right lateral 3 no label


OSUM 5914 – Noturus trautmani


These fish, which were later described and named in his honor, are similar to the Elegant Madtom, Noturus elegans.  A study carried out by W. Ralph Taylor (1969) recognized those similarities in describing the Scioto Madtom and placing it close to the Elegant Madtom phylogenetically (substantiated in a 2009 publication by Egge and Simons), although osteologically the two are quite different.  Icthyologists postulate that the Scioto Madtom may have speciated from an elegans population following a glaciation event.

OSUM 9575 Noturus trautmani C&S 1 with arrows pointing to anterior pectoral spine and humeral process



OSUM 9575 – Noturus trautmani – Cleared and Stained preparation.




Note arrows showing anterior pectoral fin spines and humeral process significantly shorter than those characters on the Noturus elegans specimen below (vertebral counts also separate the two species)

OSUM 18913 Noturus elegans head and trucnk C&S microscope shot with arrows pointing to anterior pectoral spines and humeral process



OSUM 18913 – Noturus elegans – Cleared and Stained preparation.



Although anatomical features and a unique color pattern were used to justify recognizing the Scioto madtom as a distinct species, several local fish enthusiasts have wondered whether the Scioto Madtom population were simply hybrids between the Stonecat Madtom Noturus flavus, which resembles the Scioto Madtom in coloration and in possessing a low adipose fin, and Noturus stigmosus, which has long pectoral barbs and humeral processes but strong saddle markings on its body. However, no instance of hybridization between these species has been reported, although other hybridizations are reported among madtoms.

The length of Big Darby Creek from which Milton captured almost all of what was later called the Scioto Madtom are recorded in our catalog book as 100-200’ above the State Route 104 bridge.  The first Scioto Madtom specimens collected were found in Riffle No. 3 of a series of four riffles and runs called “Trautman’s Riffle”.

Scan of drawing of Trautmans Riffle from Ohio Conservation Bulletin 1963


Drawing of Trautman’s Riffle from Gilfillan, Merrill C.  1963.  The Fishes of Trautman’s Riffle.  Ohio Conservation Bulletin, Vol. 27, No. 5.  pp. 22-24.


20140711BigDarbyCkRM3_4Trautmansriffle photo by Anthony Sasson


Trautman’s Riffle on Big Darby Creek upstream of State Route 104. Photo by Anthony Sasson of The Nature Conservancy.



Trautman and his successor in the OSUM Fish division, Ted Cavender, both searched extensively for populations of Scioto Madtoms outside of the type locality. These collections led to the discovery of other species of madtoms, but failed to unearth another population of Scioto Madtoms (the last one collected was in Autumn of 1957).

My introduction to Trautman’s Riffle didn’t happen until the mid-1990’s.  Although I’d spent many a day on lakes, reservoirs and rivers fishing with my grandfathers, my fishing experiences had not included seining until I took Ichthyology at OSU with Ted Cavender.



Ted Cavender (center), OSUM Curator 1970-2005, with his OSU Biology of Fishes class at the Scioto River fishing access just east of the Big Darby Creek confluence, ca. 2002.


In the 20 years since this introduction, I have personally observed some of the riffles in the vicinity of Trautman’s Riffle moving, due to the “flashy” flooding character of the stream.  One such riffle downstream from Trautman’s Riffle headed up under the State Route 104 bridge to about 50 yards downstream, and some of the structure appears to have moved down to an area at the next major bend in the stream’s course.  Despite the dynamism of the Big Darby in this stretch, Trautman’s Riffle remains mostly intact, although it seems to have been better defined when Milton collected the Scioto Madtom back in the 1940’s and 1950’s.

The increased propensity for flooding and the increased impact of these floods in Big Darby Creek is due at least in part to anthropogenic changes to the topography of the watershed as well as to its hydrology.  Clearing of the riparian area right up to the edge of the creek removes the trees, brush and grasses that serve as a natural filter for pollutants like smothering silt loads from farm field tillage and removes tree roots that hold the upper layer of dirt and enable the stream to create undercut areas where fish hide.  A natural riparian buffer also furnishes woody debris that falls into the stream, creating more habitat and egg laying areas for fish.

Could a flooding event, other weather conditions, or impacts such as siltation of substrates from agricultural tillage, have affected the Scioto Madtom population severely enough that they were unable to propagate?  A catastrophic release of silage on Little Darby Creek in the 1980’s wiped out an otherwise healthy population of Least brook lampreys at Mechanicsburg Ohio, demonstrating the potential impact of a rare event.

Since the Scioto Madtom was only ever found in a very small population, and subsequently not found for many years, the species was listed for decades as an endangered species. Several governmental and private monitoring agencies have sampled the site and conducted exhaustive sampling of other localities in the Scioto River and other major Ohio River tributaries, especially those that focused exclusively on habitats where Madtoms could be expected.  One such effort was funded by the U.S. Fish and Wildlife Service. The 3-year project to sample the major Ohio River tributaries within the state for Madtoms turned up nets full of Northern Madtoms, Mountain Madtoms and Stonecat Madtoms, but unfortunately no Scioto Madtoms.  Because of the lack of results despite intensive expert searches, many suspected it was extinct. The U.S. Fish and Wildlife Service and the Ohio Division of Wildlife concur, and have recently declared the Scioto Madtom extinct. This new listing notwithstanding, we can’t help but keep an eye out every time we are in suitable habitat for the elusive, endemic, endangered Scioto Madtom.


About the Author: Marc Kibbey is Assistant Curator of the OSU Fish Division at the Museum of Biological Diversity.

Old collections, new tricks


Research collections are built through two primary avenues. Many specimens belonging to a single genus or family may be collected from a broad geographic area as part of a research project into the diversity, distribution, or biology of that lineage. Alternatively, specimens belonging to multiple lineages may be collected from a single place as part of studies into the diversity of a geographic region or drainage.

Field team leader Brian Zimmerman in his natural habitat: a boat!  His expertise with the diversity and distribution of fish is invaluable as we survey new habitats. Photo by Paul Larson

Field team leader Brian Zimmerman in his natural habitat: a boat! His expertise with the diversity and distribution of fish is invaluable as we survey new habitats. Photo by Paul Larson

Our collaboration with the Ohio Division of Wildlife ( to assess the diversity of fishes in Ohio has followed both of these paths, exploring the distribution and genetic diversity of species of particular conservation concern across Ohio and capturing the diversity of particular rivers or drainages.

One of the “tricks of the trade” for our surveys has been to use diverse techniques. To make sure we have sampled all of the microhabitats within a waterway, we use everything from electrofishing to seines to trawls to snorkels.

This week we demo’ed a new net system in the Muskingum River and were pleased with the biomass and diversity of fish and other animals that we caught, including some HUGE flathead catfish as well as bycatch of softshell and snapping turtles. This is a new sampling method to us but has long been used by commercial fisherman and fisheries professionals alike. These nets will be part of our arsenal of methods as we establish baselines for the species diversity of the Muskingum River.

Collections manager Marc Kibbey mans the nets. The snapping turtle (left) and spiny softshell turtle (top) are released back into the river.  The Northern Pike (middle) and Bowfin (bottom) are measured and recorded. Photo on left by Paul Larson; photos on right by Brian Zimmerman.

Collections manager Marc Kibbey mans the nets. The snapping turtle (left) and spiny softshell turtle (top) are released back into the river. The Northern Pike (middle) and Bowfin (bottom) are measured and recorded. Photo on left by Paul Larson; photos on right by Brian Zimmerman.

Our electronic database and tissue voucher collection means that we can record occurrence, size and abundance, and sample animals with the safest, most effective methods.

Most of the fish we catch are identified, measured, photographed, and released. Specimens belonging to species whose distribution, diversity, or identity are questioned and species not well represented in museum collections are brought back to the museum for further study.

A global database called “Fishnet” ( integrates our database with those of other museums, making these collections visible, searchable, and accessible to scientists around the world.


About the AuthorDr. Marymegan Daly is an Associate Professor in the Department of Evolution, Ecology and Organismal Biology and Director of the OSU Fish Division.