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PTAGIS - Development of Large PIT-Tag Antennas to Estimate Migration Timing and Survival
for Adult Salmonids near Pile Dikes in the Columbia River Estuary
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We continued research and development of a passive PIT-tag detection system along
a pile dike in the estuary (rkm 70). Target fish for this system are returning adult
salmonids, whose detection in the mid-estuary can be compared with subsequent detections
at upstream dams to determine timing and survival during the adult migration. In 2013
we changed all system
electronics from the MUX used in 2011 and 2012 to the MTS transceiver. This system
upgrade allowed us to quadruple the size of antennas, and thus fish passage openings,
to an area of 2.4 6.1 m. In March, we installed three new antennas encased in a rigid
PVC housing (10 cm diameter) onto the pile dike system (PTAGIS site code PD7). One
of these eventually leaked, and we replaced it in July using an antenna with an experimental
housing. The new housing was smaller in diameter (19 mm) and made of flexible PVC
hose. We expanded the system with 2 additional antennas placed further inshore along
the pile dike (5 total). Except for interruptions to replace antennas and a few brief
interruptions in late fall due to solar power shortage; the new system has remained
operational from March through October 2013.
In 2013, we detected 375 adult and jack salmonids including 96 spring Chinook, 104
summer Chinook, 106 fall Chinook, 54 steelhead, 12 sockeye, and 3 coho salmon. We
also detected 612 juvenile salmonids, 5 sturgeon, 1 pikeminnow, and 32 fish with PIT
tags yet to be identified in PTAGIS. Survival estimates (SE) of adults to passage
over Bonneville Dam were 90.5% (15%), 88.2% (8%), 92.1% (5%), and 90.7 (8%), respectively
for spring, summer, and fall Chinook salmon and steelhead. Median travel times from
detection at PD7 to Bonneville Dam for the same fish groups were 4.0d, 3.7d, 3.2d
and 4.6d.
Stationary PIT-tag antennas are used to interrogate PIT-tagged fish throughout the
Columbia River hydrosystem and in streams to evaluate fish passage and survival for
both juvenile and adult fish. Pile dikes are common in the estuary and in some areas
located less than 0.5 kms apart and can be a substantial obstacle for migrating fish
along the shoreline. Fishermen often utilize the area near pile dikes to target adult
fish believing they become more concentrated as they circumvent the outermost piling
during their upstream migration. This strategy was similar to that used in the late
19th and early 20th centuries by designers of effective fish wheel leads utilized
with great success until banned. Estuary PIT-tag data obtained with a pair-trawl
characteristically shows an increase in detection rate of juvenile fish when passing
just outside of these pile dikes. In fall 2011 and continuing through fall 2012, we
deployed a 4 to 6-coil configuration of detection antennas using an industry standard
MUX transceiver system (site code PD7 in PTAGIS). Fish passage openings were limited
to 4X10 with the MUX but we created a matrix of coils spanning 8.5 X 20 in water 20
deep. In 2013, we adapted a Bata version of a new IS1001 transceiver system and deployed
antennas with individual coils as large as 10X 20 in the same location. We propose
continued deployment of stationary PIT-tag antennas on representative pile dikes to
evaluate the potential of establishing a network of stationary monitoring sites in
the estuary for long-term data collection. A proto-type Pile Dike Antenna (PDA) system
deployed near river kilometer 70 since 2011 has enabled collection of limited timing
and species composition data for adult salmonids (primary target) entering the estuary
and juvenile salmonids (secondary target) exiting the estuary. Expansion of such
antenna systems to passively sample passing fish at various fixed locations in the
estuary enable calculation of survival rates to Bonneville Dam for adult salmonids
to better evaluate impacts by marine mammals. PDAs would potentially provide full
year detection capability for both adult and juvenile salmonids in the estuary. .
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