Ouachita Madtom (Noturus lachneri) Metapopulation Dynamics in Intermittent Ouachita Mountain Streams
The U.S. Fish and Wildlife Service has considered listing the Ouachita madtom (Noturus lachneri) as a threatened species. We estimated the abundance of Ouachita madtoms and evaluated the accuracy and the precision of those estimates in an adjacent pool and riffle habitat in each of three steams. Ouachita madtom density was higher than expected with an average of 95/100 m2 (range from 17.2/100 m2 to 204/1002 at six sites). We also sampled Ouachita madtoms and associated fish in three streams when the stream bed was dry for hundreds of meters and fish were concentrated in the remaining pools (up to 32/m2). Fish were extirpated as most of these pools completely dried (at least 270 fish including 34 Ouachita madtoms). We excavated 7, 0.5-m3 pits along the midline of recently dry sections of two streams to determine whether fish avoided mortality by burrowing into the hyporheic zone. Water and invertebrates were found in the pits; however, the lack of fish led us to reject this hypothesis. Because fish rapidly recolonized extirpated stream reaches from the large, deep, pools, we consider these pools to be critical, "source habitats."
Gagen, C J, Standage, R W, and Stoeckel, J N. 1998. Ouachita Madtom (Noturus lachneri) Metapopulation Dynamics in Intermittent Ouachita Mountain Streams. Copeia. 1998(4): 874-882.