Paradigm Shift: Applying Capture–Recapture Techniques to Electronic Licensing System Data to Estimate Chinook Salmon Harvest

Abstract

Implementing creel surveys that produce robust and unbiased estimates of harvest can be complicated, expensive, and labor intensive. Additionally, field personnel often face safety risks associated with traversing roads and highways, occasionally under inclement travel conditions. Here, we develop an alternative method to estimate recreational fish harvest using a hybrid creel that employs capture–recapture techniques in conjunction with data collected from the Oregon Department of Fish and Wildlife's electronic licensing system. We evaluated the method by comparing harvest estimates between the new approach (e-creel) and estimates from a traditional roving creel conducted on four of Oregon's coastal Chinook Salmon Oncorhynchus tshawytscha populations in 2019. Our results indicated that Chinook Salmon harvest estimates derived from our hybrid creel approach were more precise than estimates using traditional creel methods. Both methods generated statistically equivalent estimates of Chinook Salmon recreational harvest, differing by only 3.4%. Estimated mean harvest was 1,264 Chinook Salmon based on the e-creel approach versus 1,258 based on the traditional creel approach. On average, the e-creel estimates reduced the SE by 41% relative to traditional creel estimates. Post hoc assessment of spending associated with creel projects in 2019 suggested that a total savings of US$74,525 in personnel and operational cost, corresponding to an average 15% budget reduction per investigation, could be realized by transitioning from a traditional creel design to an e-creel design.