The standing crops of fishes which inhabited three small lakes were estimated immediately after rotenone treatment by combinations of procedures which included collections of all fish along the shorelines, from the surface waters offshore, and from the bottoms in shallow water; collections and counts from random sampling areas on shore and in shallow water; and collections and counts from randomly selected transect lines on bottom in deep water by SCUBA divers. Estimates of the net primary productivities of the lakes were made by the C14method. When the lakes are ranked according to their estimated standing crops, the order of ranking is confirmed by the estimated net primary productivity of the most productive lake, but is in conflict with the productivity estimates from the intermediate and least productive lakes. Analyses of the structures of the fish populations of the lakes before reclamation and evaluations of techniques are also presented.