Measuring the Performance of Two Stationary Interrogation Systems for Detecting Downstream and Upstream Movement of PIT‐Tagged Salmonids

Abstract

We tested the performance of two stationary interrogation systems designed for detecting the movement of fish with passive integrated transponder (PIT) tags. These systems allowed us to determine the direction of fish movement with high detection efficiency and high precision in a dynamic stream environment. We describe an indirect method for deriving an estimate for detection efficiency and the associated variance that does not rely on a known number of fish passing the system. By using six antennas arranged in a longitudinal series of three arrays, we attained detection efficiencies for downstream-and upstream-moving fish exceeding 96% during high-flow periods and approached 100% during low-flow periods for the two interrogation systems we tested. Because these systems did not rely on structural components, such as bridges or culverts, they were readily adaptable to remote, natural stream sites. Because of built-in redundancy, these systems were able to perform even with a loss of one or more antennas owing to dislodgement or electrical failure. However, the reduction in redundancy resulted in decreased efficiency and precision and the potential loss of ability to determine the direction of fish movement. What we learned about these systems should be applicable to a wide variety of other antenna configurations and to other types of PIT tags and transceivers.

Potential Effects of Changes in Temperature and Food Resources on Life History Trajectories of Juvenile Oncorhynchus mykiss

“…Passive integrated transponder tags were used to detect fish movement via instream antennas known as PIT tag interrogation systems (river kilometer [rkm] 3.5 in Beaver Creek), and some were captured at a weir near the mouth of Beaver Creek (rkm 1; Connolly et al 2008;Martens and Connolly 2010). For juvenile Steelhead, we have observed three life history trajectories; the majority will smolt at age 2 or 3 (66% and 30%, respectively), with some (∼4%) age-4 smolts being observed (P. J. Connolly, unpublished data).…”

The Influences of Body Size, Habitat Quality, and Competition on the Movement and Survival of Juvenile Coho Salmon during the Early Stages of Stream Recolonization

“…Three pairs of antennas spanned the stream in each location, allowing us to identify the direction of movement by individual fish based on the sequence of detections as the fish passed the antennas (Connelly et al 2008). In stream systems that have a wetted channel width of less than 15 m, PIT tag antenna arrays like ours typically produce average detection efficiencies greater than 95% (60-100%) over a range of flows (Connelly et al 2008). Another antenna array at the Hiram M. Chittenden Locks (hereafter, "Ballard Locks"; the outlet of the Lake Washington system) detected coho salmon smolts migrating into Puget Sound ( Figure 2; DeVries et al 2004;DeVries 2007).…”

Seasonal cues of Arctic grayling movement in a small Arctic stream: the importance of surface water connectivity

“…It is important to consider detection efficiency in PIT tag studies (Zydlewski et al 2006;Connolly et al 2008). We evaluated the overall …”

“…Even so, 71 % efficiency is informative, especially since this estimate considers seven antenna stations simultaneously. Although similar studies report detection efficiencies of 50-100 % at single antenna stations (Connolly et al 2008;Homel and Budy 2008) many studies fail to calculate antenna efficiency altogether. It is important to consider temporal changes in antenna performance, as they have the potential to influence results and conclusions.…”