Habitat Suitability and Reproductive Traits of the Orangefin Madtom Noturus gilberti (Pisces: Ictaluridae)

Abstract

-The orangefin madtom (Noturus gilberti), a candidate species for federal protection in Virginia and North Carolina, was sampled at 256 sites to characterize its habitat, species associations and reproductive traits. Only the Roanoke darter (Percina roanoka) consistently co-occurred with the orangefin madtom. Several fish species: Nocomis spp., Phoxinus oreas, Clinostomus funduloides and Notropis cerasinus, and crayfish were negatively associated with its presence at sites. Sand and silt levels were significantly lower at sites with orangefin madtoms, whereas small cobble, local gradient and water depth were significantly higher. Discriminant function analysis provided a predictive model that correctly classified 85% of the sites which contained this species. Spawning of the orangefin madtom occurred from late April through June at water temperatures from 18-22 C. Age 2 adults were the primary spawners of the three age groups in the population. Estimated longevity for this species is 24-28 mo.