Important runs of salmon and steelhead pass Rock Island Dam on the Columbia River. Annual records of fish movement past the dam are available from 1933. Count of 23,352 chinook salmon in 1959 was less than half the peak year of 1957. Sockeye count of 72,351 exceeded the 26-year mean of 52,073. Only 118 coho salmon were recorded. Greatest count of coho, 229, occurred in 1947. Numbers of steelhead passing Rock Island Dam increased in 1959. The 26-year mean of 2,900 steelhead was less than 1959 count of 4,138.