PIT Tag Antenna Systems
Stationary antennas capable of sampling the entire
width of streams, culverts, spillways, or fish
ladders provide water resource managers a costeffective way to monitor fish populations. Fish
distribution, seasonal migrations, individual
growth, population abundance, life stage and
survival history can all be monitored through
this passive system that is adaptable to most
natural and regulated stream environments.
How does it work?
Fish are implanted with a Passive Integrated Transponder
(PIT) tag containing a code specific to each individual fish. The
PIT-tagged fish swim through or in the vicinity of an antenna
where the date and time of passage, along with each fish’s unique
tag number is detected by the antenna receiver, recorded, and
stored. Antennas can be designed to span stream channels or other
structures (e.g. culverts). Stillwater Sciences has also developed
innovative approaches to deploying antennas in deep reservoirs in
areas where fish congregate. Antenna systems can be set up to operate
individually or together in a multiplex configuration. The system can be
powered using a number of options including deep cycle rechargeable
batteries, AC/DC power supply, solar panels, or a micro-hydro power
unit.
Why use an antenna system?
Minimum maintenance helps keep field monitoring costs down
while continuously providing data collection. Reductions in
fish capture and handling saves field crew time and labor
costs, while at the same time reducing deleterious impacts on
fish growth and survival. In many applications, fish are only
captured and handled for the initial PIT tag insertion, while
data can be passively collected on that fish at antennas for
weeks or years, depending on the life span of the individual.
Stillwater Sciences has constructed PIT antenna monitoring
systems for bull trout, Chinook salmon, cutthroat trout, rainbow
trout, and brook trout in a number of environments including:
• Deep reservoirs to estimate bull trout abundance, movement and
survival
• Dam spillways and tailraces to detect fish entrainment
• Culverts and fish ladders to verify fish passage
• Stream and river channels up to 66 m in width, to determine habitat
utilization and seasonal migration
• Spawning channels to determine use and migration timing
Population dynamics of bull trout and spring Chinook
salmon on the Smith River, OR
Extensive field studies were conducted on the McKenzie River in
Oregon using numerous stationary PIT tag antennas to estimate
population sizes, life history, habitat use, and survival of bull
trout, and Chinook salmon. Our results were used in a set of
quantitative models that identified factors affecting bull trout and
spring Chinook salmon populations within the project area to
evaluate the effects of alternative management scenarios.
Post-construction evaluation testing on the North
Umpqua River, OR
PIT antennae were constructed in a modified ladder to
determine fish directional movement and upstream passage
at Lemolo No. 2 diversion dam for the North Umpqua
Hydroelectric Project in Oregon. The antennae were also
used to confirm passage of resident trout.
Effects of winter high flows on coho, Devil’s Gulch,
CA
Fish movement during winter high flows in Devil’s Gulch,
Lagunitas Creek watershed, California was documented using
a combination of electrofishing, handheld PIT tag reader, and
an array of stationary PIT tag monitoring stations within the
study reach. Stationary antenna were installed at seven locations
within the lower 600 m of the study reach and were arranged to
bracket study units with contrasting habitat characteristics.
For more information, please contact Ethan Bell, at [email protected] or 707.822.9607 x203.