HYDROACOUSTIC SURVEY PROCESS In hydroacoustic surveys, two transducers send sound waves into the water. One of them points down and the other to the side. This allows fish below and to the side of the watercraft to be detected. Fish biologists planned and mapped their pathways of travel at Rob Roy Reservoir prior to setting out. This ensured the best population counts for the reservoir. Once adequate data was collected from a specific route, the equipment was turned off and the boat continued to the starting point of the next path. Path of hydroacoustic measurements (Illustration by Patrick Owen) 30 | September 2024