The homing of salmon to the rivers where they originated is one of the great mysteries of animal behavior. It is known that young salmon learn the odors of their home river and seek these odors when they return as adults. However, it is not known whether they retrace a sequence of odors or merely seek the odor that they experienced prior to seaward migration. It is also not known whether they can learn odors only at specific developmental stages or at any time during their period of freshwaterresidence. To help resolve these questions, Dr. Quinn and his colleagues reared juvenile coho salmon and exposed them to the odors of the University of Washington's hatchery at specific times and developmental stages in 1988. They were released from another hatchery and are expected to return as adults in fall 1989 and 1990. Depending on where the salmon from the different experimental groups return, Dr. Quinn hopes to determine the ways in which they learned the odors of their environment as young fish and how they use these odors to return years later. Homing is an essential feature of the life history of salmon. Knowledge of the patterns of behavior underlying homing will enhance the ability to protect and rehabilitate populations of these extremely valuable fishes.
