Technical Abstract: The passive sock grading method used by commercial channel catfish farmers to grade and reduce the number of under-sized fish delivered to processing plants was assessed. The assessment was conducted at the Aquaculture Research Station at the University of Arkansas, Pine Bluff in 0.1-ha earthen ponds. A rectangular holding sock approximately one-fifth the size of a commercial holding sock was used in the study. The mesh size and material of the experimental sock was similar to that used commercially. Seventeen groups of channel catfish were graded, with group weights ranging from approximately 115 to 370 kilograms. Fish were held in the sock for approximately three hours (+ 0.27 hours). The water temperature during the trials ranged from 7.30C to 28.70C. The percent removal of fish less than 0.45 kg during the three-hour holding period ranged from 27.6% to 73.3%. Overall, sock grading efficiency increased with increasing water temperature. At water temperatures above 150C a greater percentage of the under-sized fish ( < 0.45 kg) escaped from the holding sock with no disturbance during the holding period.