In 1967, the Michigan Department of Natural Resources planted Chinook in Lake Michigan to control the alewife, an invasive species of nuisance fish from the Atlantic Ocean. In the 1960s, alewives constituted 90% of the biota in these lakes. Coho salmon had been introduced the year before, and the program was a success. Chinook and Coho salmon thrived on the alewives and spawned in the lakes’ tributaries. After this success, Chinook were planted in the other Great Lakes, where sport fishermen prize them for their aggressive behaviour on the hook.