This report describes the work conducted during the first year of a long-term study to assess the efficacy of a prototype strobe light system in eliciting a negative phototactic response in kokanee and rainbow trout. The strobe light system is being evaluated as a means to prevent entrainment (and subsequent loss) of fish at the entrance to the forebay adjacent to the third powerplant at Grand Coulee Dam. Pacific Northwest National Laboratory and the Colville Confederated Tribes are collaborating on the three-year study being conducted for the Bonneville Power Administration and the Northwest Power Planning Council.