Development and use of in-stream PIT-tag detection systems to assess
movement behavior of fish in tributaries of the Columbia River Basin,
USA
P.J. Connolly1, I.G. Jezorek1 and E.F. Prentice2
1U.S. Geological Survey, Western Fisheries Research Center,
Columbia River Research Laboratory, Cook, WA,
2National Marine Fisheries Service, Manchester Research Center, Manchester,
WA, USA
USA
We have developed detector systems for fish implanted with Passive Integrated
Transponder (PIT) tags to assess their movement behavior and habitat use
within fast flowing streams. Fish tested have primarily been wild anadromous
and resident forms of rainbow trout Oncorhynchus mykiss and cutthroat
trout O. clarki. Longitudinal arrangements of two- and six-antennas
allow determination of direction of movement and efficiency of detection.
Our first detector system became operational in August 2001, with subsequent
improvements over time. In tests with a two-antenna system, detection
efficiency of tagged, downstreammoving fish was high (96%) during low
flows, but less (69%) during high flows. With an increase in the number
of antennas to six, arranged in a 2x3 array, the detection efficiency
of downstream-moving fish was increased to 95-100% at all flows. Detection
efficiency of upstream-moving fish was high (95-100%) in both the two-and
six-antenna system during all flows. Antennas were anchored to the substrate
and largely spanned the bank-full width. Modifications to the methods
used to anchor antennas have increased the likelihood of the system remaining
intact and running at full detection capability during challenging flow
and debris conditions, largely achieving our goal to have continuous monitoring
of fish movement throughout an annual cycle. In August 2004, we placed
a similar detector system in another watershed. Success has much relied
on the quality of transceivers and electrical power. Detection of tagged
fish passing our static PIT-tag detectors has produced valuable information
on how selected fish species use the network of streams in a watershed.
Integrating information from our detectors in tributary streams with that
from detectors downstream at dams in the Columbia River has promise to
be a powerful tool for monitoring movement patterns of anadromous fish
species and to understanding full lifecycle fish behavior and habitat
use.
Paper presented
at Measuring Behavior 2005
, 5th International Conference on Methods and Techniques
in Behavioral Research, 30 August - 2 September 2005, Wageningen, The
Netherlands.
© 2005 Noldus
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