Nutrition Studies of the Brindled Madtom, Noturus miurus Jordan, Based on Stomach Content Analysis

Brindled madtoms and small channel catfish (140 mm or less) were examined to determine their food habits and the possibility of competition for food organisms between the two species when collected from the same area. Two hundred twenty-three brindled madtoms were collected from Polecat Creek (study area I) 3 miles southwest of Ashmore, Coles County, Illinois. The study in Polecat Creek was conducted from July 10, 1967 to June 5, 1968, collections being made approximately every month. Two hundred forty-five brindled madtoms and 140 channel catfish were collected from the Embarras River (study area II) 2 miles south of Charleston, Coles County, Illinois. Madtoms and small channel catfish were collected from the Embarras River during the months of July through October, 1970. All specimens used in the study were collected by seining at night. Madtoms were easier to collect at this time and food organisms had undergone little digestion, which aided in their identification. Specimens collected by day seining either had empty stomachs or food organisms were in an advanced state of digestion, making identification difficult. Chironomidae larvae were the most important food item of madtoms in both study areas. Chironomidae pupae, Trichoptera larvae, and Ephemeroptera nymphs, along with Chironomidae larvae make up the major portion of the food of brindled madtoms. Seasonal variations in items eaten appeared to coincide with the availability of the particular organisms. Chironomidae larvae and pupae, and Trichoptera larvae were the most common organisms eaten by small channel catfish. The important food items of brindled madtoms from study area II were nearly identical to those fed on by small channel catfish. This competition for food could possibly limit the populations of both species when found in the same habitat. During the study it was discovered that brindled madtoms could be collected by pouring the contents of tin cans found in the water into a small net. Several madtoms were collected in this manner. Fifty tin cans were randomly placed in study area I. These were checked weekly during the summer of 1970. Each time one to 3 madtoms were collected from the 50 tin cans. Tin cans make up a minor artificial habitat for the brindled madtom