Intra-Stream Movement and Distribution of Channel Catfish

Channel catfish were marked and tagged in a 20-mile stretch of the lower Des Moines River. The experimental area was separated into eight segments of 2.5 miles each. Dispersion of recaptured fish from these segments was used to describe movement. Of the 4,988 catfish tagged, 345 were recaptured in the following two years. Approximately 50% of the recaptured fish did not move from the segment in which they were originally marked. Moving catfish were distributed in a normal fashion in upstream and downstream directions. Mean distances of movement was 5.6 miles downstream and 5.1 miles upstream. The greatest distances recorded were 70 miles downstream and 155 miles upstream. Description of catfish movement and the probability of movement in either direction are discussed. Equations for the computation of the number of tagged fish in any of the segments before sampling are presented. The effects of movement on population estimates are discussed