Researchers at Washington State University have developed a method of using drones in measuring the abundance of salmon nests in rivers. The development could mean more accurate and less tiring estimates of a key fisheries resource not just in the Northwest United States but beyond. Salmon swim from the ocean upstream to the riverbeds where they were born. Estimating their reproduction activity in these rivers helps fishery managers determine how many new salmon are likely to swim to the ocean where commercial fishermen, subject to harvest quotas set by the managers, wait.
Tracking salmon nests is one way to estimate how many salmon there will be. But trudging along riverbeds looking for nests in the water is hard on the legs and eyes. Even floating in a boat, peering into the water, can be tedious. But with drones, the work is easier and more accurate. There is less walking, although there is some because U.S. law requires a civilian drone opera- tor to have the drone always in sight. The photos taken by the drone can be measured against pictures taken earlier to see what new nests have appeared, which can be more accurate than photos taken while walking.
The scientists behind this research hope the new technological method catches on. The researchers found that drones capture images of more nests than walkers do, suggesting greater accuracy. As well, with more frames taken, other environmental changes can be observed than just salmon nests, potentially helping those concerned with river ecology in many other ways.