The shallow areas in which the shocker was used in 1959 are the prevalent habitat in the upper Neosho River. The relative abundance of fishes found in these areas is presented in Table 13. The red shiner was most abundant and was followed (in decreasing order) by long-eared sunfish, minnows of the genus _Pimephales_, green sunfish, red-finned shiner, channel catfish, and stoneroller. Other species combined comprise less than ten per cent of the population. Table 13 also shows the variability in relative abundance of different species among areas that have the same general kind of habitat. The species composition is similar in all areas. The sample obtained with rotenone in 1959 is included in Table 13 to show differences in the fauna of deep, slowly flowing areas and shallower areas with stronger current. The differences in relative abundance indicate the kind of habitat that each species is able to utilize most fully. Golden redhorse and black bullhead were most abundant in large, deep, quiet pools (5.7 per cent and 32 per cent of the total population) and were more abundant in Area 5 (3.2 per cent and 7.3 per cent respectively) than in any of the other shallow areas. Area 5 has greater average depth, more mud bottom, and less riffle area than areas 1, 3 and 6. The golden redhorse and black bullhead have specific habitat preferences that are not evident in the above discussion. My collections indicate that the golden redhorse prefers deep water having some current, whereas the black bullhead prefers little or no current. Species that prevailed in or near riffles were: creek chub, sucker-mouthed minnow, stoneroller, channel catfish (young-of-the-year only), flathead (young-of-the-year only), stonecat, slender-headed darter, and orange-throated darter. Of these species, the sucker-mouthed minnow, slender-headed darter and orange-throated darter reached their greatest abundance at Area 3, where the riffle is shallow, slow, and has a bottom composed of flat limestone rubble. The riffle at Area 1 is, for the most part, deeper and faster than at Area 3 and has a bottom composed of gravel and small rocks. The creek chub, stoneroller, channel catfish (young-of-the-year), flathead (young-of-the-year), and stonecat reached their greatest abundance in Area 1. All species that showed a preference for riffles were rare or absent in Area 5 where no riffle-habitat was sampled. The riffle-dwelling species that were present in collections made with rotenone in the deeper pools were taken from the riffle into which rotenone was introduced. The river carpsucker, blunt-nosed minnow, fat-headed minnow, channel catfish (yearlings and two-year-olds), flathead (yearlings and two-year-olds), green sunfish and long-eared sunfish showed a preference for shallow, quiet water. All of these species were more common in collections from Areas 5 and 6 than in collections from other areas.