Northern madtom
The northern madtom (Noturus stigmosus) is a freshwater fish. Ranges and habitat N. stigmosus can be found in the Ohio River valley stretching into distinct locations in Canada, where it is considered endangered. It is a fairly rare species with little data available because such small numbers are observed. The northern madtom prefers habitats with relatively swift currents along with sand, silt, or rocky substrates. The species begins spawning around 23 °C, which is sometime in early summer throughout its range. It is a cavity nester and builds its nests under large rocks and logs. Presently, not much is known about the ecology or life history of this species because it is found in such small numbers throughout its range. The species can survive in waters with some turbidity, but not in waters with a high amount of sediment pollution. One of the leading management actions aiding in the successful reproduction of this species is keeping the waters void of sediment pollution and habitat alterations. The northern madtom is also found along the Allegheny River system running from Canada through the Northeastern United States to Tennessee. However, over much of its range, the species is found in only a few