Aspects of Brown Madtom, Noturus phaeus, Life History in Northern Mississippi
Life-history aspects of Noturus phaeus, the Brown Madtom, were studied from August 1993 to July 1994 using samples collected from Bay Springs Branch (Little Tallahatchie River drainage), Mississippi. Noturus phaeus exhibited nocturnal feeding with a diet composed primarily of dipteran larvae, trichopteran larvae, and decapods (crayfish). Annuli from otoliths were successfully used to assist in age-class identification. It was common for individuals of both sexes to reach age-3, whereas some males were age-4 or older. Brown madtoms used woody debris and undercut banks as their primary daytime microhabitat, and stream flow (complex, run, pool) was the best predictor of the presence/absence of madtoms, being most often found in areas of complex (varying) flow. Abundance (density) was similar to those of other species, and N. phaeus was not collected in areas without either debris, aquatic vegetation, or undercut banks.Abstract
Average index of digestion of stomach contents (upper) and average number of prey items per stomach (lower), for a 24-h collection, 1–2 October 1993 (DI = 0 means empty, DI = 1 means well digested, DI = 2 means mostly digested, DI = 3 means partially digested, and DI = 4 means fresh material). Bars represent standard error
Seasonal length-frequency histograms of brown madtoms collected in Bay Springs Branch, 1993–1994. Interpretation of age classes is drawn on the October-to-December graph
Length at age curves using otolith aging (Von Bertalanffy model) and length-frequency data for brown madtoms in Bay Springs Branch. Circles represent individual madtoms. Sample size was three individuals for each count category except two rings (no individuals sampled had two rings) and four rings, which has only two individuals. Squares identify the modes of age classes from the October-to-December, length-frequency histogram in Figure 1