A collaboration between Washington State University and the Washington Department of Fish and Wildlife will help determine whether drones can be used to enhance, and eventually replace, some of the tedious fieldwork of fish biologists.
Over the next four months, WDFW fish biologist McLain Johnson and WSU graduate student Daniel Auerbach are teaming up to conduct an intensive survey of 3 km (about 1.8 miles) of the Wenatchee River.
The drone will be used to identify and photograph summer Chinook redds, the spawning nests where salmon lay their eggs. Fish biologists will also survey these areas on foot or by boat, along with the other 77 km on the Wenatchee River, Johnson told Clearing Up.
The drone will monitor three separate sections of the river twice a week, which is much more frequently than biologists can survey the area in wading boots, Johnson said.
The high resolution photos that the drone provides will help identify spawning locations and characteristics of the habitat. The redd abundance and distribution is expected to provide better data which can then be used for a more accurate estimate of adult populations.
Johnson said comparing the images with the locations where hatchery Chinook carcasses are found will also show where hatchery salmon are spawning and whether the ratio of hatchery salmon to naturally-spawning salmon is meeting goals.
WDFW has already used drones in fieldwork for a handful of other applications, Johnson said, such as counting clam-diggers or surveying habitat. He noted that for the current project, “We’re using it to do a lot more detailed fish work.”
To do that, he said, they need a more sophisticated and expensive drone that takes high resolution photos and is capable of staying in the air for long periods.
Using this work as his graduate thesis, Auerbach is supplying both the drone and his piloting experience. Without the cost of the drone, surveying redds by drone is expected to be less expensive than the labor intensive manual counting methods.
“We do a lot of salmon monitoring, but when it comes to new technologies, we don’t get too much time for research and development,” Johnson said, adding, “Every tool you use has benefits and drawbacks. This first year, we really want to see what those are.”