Conservation, Ecology, and Management of Catfish: The Second International Symposium

Feeding and Reproductive Biology of Ouachita Madtom

Joseph N. Stoeckel, Charles J. Gagen, and Richard W. Standadge

doi: https://doi.org/10.47886/9781934874257.ch23

Abstract.—The Ouachita madtom Noturus lachneri is endemic to south-central Arkansas. We investigated its feeding and reproductive biology to augment life history information and facilitate management of the species. We measured abundance of invertebrates in the environment and in the diet of Ouachita madtoms in pool and riffle habitats in three streams each season for 2 years. Feeding selection of Ouachita madtoms was determined by comparing the proportion of each taxon found in the environment to that consumed in the diet. Ouachita madtoms strongly selected for chironomids in all seasons in all habitats for both years. Coleopterans, ephemeropterans, and odonates were avoided or unavailable compared to their abundance in the environment. Nonetheless, Ouachita madtoms consumed high numbers of a wide variety of organisms and can best be classified as a feeding generalist. Oocyte diameters and gonadosomatic index values were measured from fish collected on a variety of dates over a 6-year period, and nest sites were examined during two spawning seasons. The maximum gonadosomatic index value was 22.0 for females and 0.83 for males. The diameter of oocytes at time of final maturation, based on the maximum oocyte diameter (3.5 mm) and the mean (±SD) yolk diameters of spawned eggs (3.3 ± 0.2 mm), is greater than 3.0 mm. Fecundity ranges from 6 to 69 oocytes (mean = 35 ± 15). The spawning season begins in early June and terminates by mid-August. Male Ouachita madtoms guard bowl-shaped nests containing 33 ± 13 ova. The nests are built in gravel or gravel/sand substrate located in glides above riffles and covered by slab rocks that range in size from 100 to 1,200 cm2 in area. Ouachita madtoms can nest successfully in areas of low current velocity, but siltation apparently inhibits spawning activity.