~ 17 B. Chinook salmon experiment-~1949 brood year During the fall of 1949, chinook salmon eggs were obtained at Green River Station (20 miles south of Seattle), Washington State Department of Fisheries. These eggs were transferred to the 146 Building, Hanford Works, where they were incubated and the young fish reared until June 1950, at which time the survivors were hauled in tank trucks to the Applied Fisheries Laboratory at the University of Washington. The fingerlings were held and fed in the pools at the University until July 1, 1950, when they were released. During the incubation of the eggs and early feeding of the fish at 146 Building, Hanford Works, in dilute effluent water (five per cent) reared in controlled river water. marked, some lots were retained and a like number were Before release the fish were the former by removal of the right ventral fin, the latter by removal of the left ventral. These fish were well represented in both the sports and commercial fisheries as is shown in the following table compiled from data collected by the Washington State Department of Fisheries. The actual recaptures are many times greater than the numbers recorded in the table since only a small percentage of the marked fish caught are reported to the Fisheries Department. Since the catch in the fishery of the RV-marked salmon was considerably greater than that of the control salmon, it appears