Tradeoffs between physical captures and PIT tag antenna array detections: A case study for the Lower Colorado River Basin population of humpback chub (Gila cypha)

Fisheries Research
By: , and 

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Abstract

A key component of many monitoring programs for special status species involves capture and handling of individuals as part of capture-recapture efforts for tracking population health and demography. Minimizing negative impacts from sampling, such as through reduced handling, aids prevention of negative impacts on species from monitoring efforts. Using simulation analyses, we found that long-term population monitoring techniques, requiring physical capture (i.e. hoop-net sampling), can be reduced and supplemented with passive detections (i.e. PIT tag antenna array detections) without negatively affecting estimates of adult humpback chub (HBC; Gila cypha) survival (S) and skipped spawning probabilities (γ' = spawner transitions to a skipped spawner, γ′ = skipped spawner remains a skipped spawner). Based on our findings of the array’s in situ detection efficiency (0.42), estimability of such demographic parameters would improve over hoop-netting alone. In addition, the array provides insight into HBC population dynamics and movement patterns outside of traditional sampling periods. However, given current timing of sampling efforts, spawner abundance estimates were negatively biased when hoop-netting was reduced, suggesting not all spawning HBC are present during the current sampling events. Despite this, our findings demonstrate that PIT tag antenna arrays, even with moderate potential detectability, may allow for reduced handling of special status species while also offering potentially more efficient monitoring strategies, especially if ideal timing of sampling can be determined.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Tradeoffs between physical captures and PIT tag antenna array detections: A case study for the Lower Colorado River Basin population of humpback chub (Gila cypha)
Series title Fisheries Research
DOI 10.1016/j.fishres.2016.06.014
Volume 183
Year Published 2016
Language English
Publisher Elsevier
Publisher location New York
Contributing office(s) Coop Res Unit Seattle
Description 12 p.
First page 263
Last page 274
Country United States
State Arizona
Other Geospatial Little Colorado River