Management of some form is mandatory for the continuance or restoration of successful fishing in the majority of reservoirs in the Southern States. The selective killing of gizzard shad and some species of rough fish with rotenone shows promise as a management tool for some reservoirs. The use of rotenone as a selective toxicant in four Kentucky reservoirs is discussed. The total poundage of gizzard shad was drastically reduced in three reservoirs and this species was eliminated from a fourth reservoir. A definite improvement in fishing success was noted as a result of this chemical reduction of shad, buffalo, and carp. Also, an increase in the spawning success and apparently better survival of bass occurred following the selective kill.