The Upper Skagit Indian Tribe is tracking steelhead from the sky, using drones in tributaries that can’t be surveyed on foot.

Estimates for steelhead returns depend on counting their egg nests (redds). Some waterways can be walked or floated, and others can be viewed from a helicopter, but that requires advance planning.

“The Suiattle and Whitechuck rivers can be very problematic to survey,” said Gabe McGuire, stock assessment biologist for the tribe. “As soon as the weather heats up, the glacial sediment is released and visibility goes to zero.”

When there are small windows of clarity, natural resources staff don’t always have the flexibility to book a helicopter on short notice. Last year, McGuire began testing drones to see if they can survey streams as well or better than the current method.

“In 2017, we tested our ability to survey with drones in the Sauk,” he said. “We counted redds in a small index during the mainstem helicopter surveys, then surveyed the same index with drones for a count comparison. We found counts were similar and therefore are optimistic with using drones for redd counts elsewhere.”

In April, the tribe hired a drone pilot from the media company Soulcraft to survey the Suiattle River within days of a helicopter survey of the same area.

“We are relatively comfortable with mainstem surveys given conditions allow us to survey at adequate frequencies,” McGuire said. “Since the large tributaries like the Suiattle River are not physically surveyed and are a product of the mainstem redd density, we’d like to validate that the densities that are used to expand to streams like the Suiattle are reasonably similar.”

The tribe is also exploring the use of drones in smaller unsurveyed tributaries. Drones surveys were conducted in Bacon Creek in tandem with traditional redd surveys. Both methodologies will be compared and if the results are similar, McGuire is optimistic that drones can be used in these streams.

“Spring runoff in places like Bacon Creek can pose safety concerns as flows increase with warmer weather,” he said. ‘We hope that drones will allow us to monitor these unsurveyed streams that we just can’t safely survey throughout the spawning period.”

Puget Sound steelhead have been listed as threatened under the Endangered Species Act (ESA) since 2007. Skagit River steelhead account for approximately 40 percent of all the steelhead in Puget Sound. The Upper Skagit Tribe plans to develop an independent recovery plan as a way to improve management.

For more information, contact gabem@upperskagit.com.

Photo: Josh Adams, Upper Skagit natural resources technician, surveys steelhead redds. His count will be compared to an aerial survey conducted with a drone.