Adult fish surveys are typically conducted by walking in or along the stream during spawning season, looking for the remains of fish that have made their way upstream to spawn. These surveys, conducted by the California Department of Fish & Game, are used to determine population growth or decline in species of concern, as well as to help determine the occurrence/abundance of species that are found on PALCO property.

Another way to count adult fish is to block off a cross section of stream, forcing all migrating fish to pass by one point. This is called an adult escapement survey. The only survey area of this type near PALCO's property is just downstream of the Company's ownership on Freshwater Creek. The Humboldt Fish Action Council, with support from PALCO, maintains this station.