Incorporating GPS and Mobile Radio Frequency Identification to Detect PIT-Tagged Fish and Evaluate Habitat Utilization in Streams

Abstract

The use of mobile radio frequency identification (RFID) systems to detect PIT tags has increased in support of research on fish movement, population dynamics, and habitat use. We describe the development and application of a mobile RFID system that incorporates GPS to detect PIT-tagged fish and evaluate habitat utilization in streams. The study was conducted in two distinct phases. First, development and testing of the RFID–GPS system were conducted using georeferenced, PIT-tagged rocks to evaluate detection probability and GPS accuracy. Second, the system was field deployed to estimate the abundance of PIT-tagged fish and evaluate habitat utilization. Detection probability was negatively influenced by stream width, distance from the stream center, and water depth, whereas detection probability increased with the number of passes. The GPS error between detected and surveyed positions averaged 4.5 m, with greater error observed in longitude than in latitude. Because of high capture and recapture probabilities, abundance estimation of PIT-tagged fish was not only possible but also relatively precise. All detections during field deployment were assigned habitat types using the “intersect,” “closest,” and “buffer” methods in ArcGIS. Analysis of habitat utilization was limited to two bedform classes, riffles and pools, because the average area of runs and glides was smaller than the average GPS error. More Brown Trout Salmo trutta were detected in pools (76–80%) than in riffles, and all Rainbow Trout Oncorhynchus mykiss and cutbow trout (Cutthroat Trout O. clarkii × Rainbow Trout) were detected in pools. The detection field covered more cross-sectional area in pools than in riffles, which could have influenced the analysis of habitat utilization. The influence of GPS error on habitat evaluations will depend on stream size, as erroneous habitat associations should diminish as stream size increases. The flexibility of the RFID–GPS system makes it useful for a variety of studies related to habitat utilization, fish migration, and population trends.

Received March 31, 2017; accepted August 19, 2017 Published online October 20, 2017

Acknowledgments

This work was sponsored by Colorado Parks and Wildlife, and funding was provided in part by the Federal Aid in Sport Fish Restoration Program (Projects F-161-R, Stream Habitat Investigations and Assistance, and F-394-R, Sport Fish Research Studies) and by the Park County Land and Water Trust Fund. We thank Jeff Spohn, George Schisler, and Ben Stout (Colorado Parks and Wildlife) for their help with tagging fish and antenna deployment. We are grateful for programming assistance from Dirk Baker (Campbell Scientific) and technical support from Warren Leach (Oregon RFID). We also thank Michael Cotter (U.S. Fish and Wildlife Service) and Mark Beardsley, Dave Sutherland, and Jessica Doran (EcoMetrics) for assistance with data collection.