SEASONAL-VARIATION IN HABITAT USE BY THE NEOSHO MADTOM (TELEOSTEL, ICTALURIDAE, NOTURUS-PLACIDUS)

We sampled a series of riffles and pools on the Cottonwood River, Kans as, for one year to determine seasonal densities, habitat use, and the extent of inter-riffle movements of the Neosho madtom (Noturus placid us), a federally threatened catfish. The species exhibited limited sea sonal variability in habitat use and appeared to be a year-round riffl e inhabitant. Neosho madtoms inhabited shallower riffle areas in sprin g and summer, sites with greater water velocities in spring, and slowe r velocities in winter. Madtoms used sites with greater percentage roc k substratum in winter, and substratum embeddedness was consistently l ow at sites of madtom presence. Current speed at the substrate surface , low variance of current speed, shallow water, and loosely embedded s ubstratum were variables most useful in predicting madtom presence. On ly one inter-riffle movement was documented, suggesting little dispers ion among riffles throughout the year. Two age classes were obvious in length-frequency histograms; young-of-year appeared in july, suggesti ng a June spawn. Neosho madtom populations were assessed by mark-recap ture (47 madtoms/100 m2), depletion removal (22 +/- 4/100 m2), species -specific (15.5/100 m2), and overall (3.3/100 m2) density calculations .