FY19-21 Skagit spring Chinook escapement assessment using Unmanned Aerial Vehicle

This project is a data collection and research project to improve Management of a valuable tribal resource. The project is designed to evaluate the use of unmanned aerial vehicle (UAV) system technology as an alternative method for implementing aerial spawning surveys to estimate salmon escapements. The present method deploys helicopter flights. These helicopter surveys are operated by Washington Department of Fish and Wildlife. The method is performing poorly consequently limiting our ability to manage the Skagit Chinook populations due to lack of escapement data.

This proposal compliments an existing unmanned aerial vehicle (UAV) project assessing Chinook spawning abundance for the two Skagit River summer/fall populations. The emphasis of UAV missions for this project are the three spring Chinook populations on the Cascade, Suiattle, and Sauk Rivers. Surveys will be implemented once every week per population as water clarity conditions dictate. Spawning occurs over an 8 to 9-week period. The Cascade and Suiattle populations spawn August through September while the Sauk spring Chinook population spawns mid-August to mid-October.

The major project objective is to assess the accuracy of UAV aerial escapement surveys for Skagit spring Chinook populations by comparing results with Washington Department of Fish and Wildlife foot surveys and helicopter aerial surveys. Chinook Redd identification error can occur therefore follow-upriver surveys will occur to ground truth video imagery identification of redds. UAV flights will always be in-line-of-sight with ground station. Accurate Chinook escapement estimates supply necessary information for harvest management and recovery planning.

Another important element is to log UAV flight time to establish a performance record for future beyond-line-of-sight waiver (BLOS). A BLOS waiver permits UAV mission to fly by GPS (waypoints) exclusively therefore not requiring pilot to stay within visual sight of drone. This would give us the ability to expand surveys in more remote areas.