Marking, Tagging, and Tracking of Fish and Wildlife: Part III


8:00AM Virdct: A New Release-Recapture Model for Cost-Effective Dam Passage Survival Estimation
  Ryan Harnish
The ViRDCt (Virtual Release/Dead Fish Correction) release-recapture model was designed to obtain cost-effective estimates of passage survival for acoustic- or radio-tagged fish migrating downstream past a dam or other inriver structure. ViRDCt utilizes a virtual release group formed at the upstream face of the dam (V1) from fish released farther upstream. Survival of the V1 group is estimated from the dam face to a detection array located in the tailrace. Dead tagged fish are released at the dam and detections of these fish on the tailrace array are used to correct the bias that occurs from detecting V1 fish that died during passage but still retain an active tag. A field study was conducted at the Snake River’s Lower Granite Dam in 2018 to compare the performance of ViRDCt to the existing virtual/paired-release (VIPRE) model in terms of dam passage survival point estimates, precision, and cost. ViRDCt point estimates were within 1 standard error (SE) of the VIPRE estimates. The SEs of the ViRDCt survival estimates were less than half the VIPRE model SEs despite using less than half the number of tagged fish used by VIPRE. Thus, ViRDCt dramatically improved precision and reduced the cost of estimating passage survival.
8:20AM Behavioral Thermoregulation By Adult Chinook Salmon in Estuary and Freshwater Habitats Prior to Spawning, and Comparison to Sockeye Salmon
  Fred Goetz
The movements and thermal experience of salmon during their homeward migration pose challenges for their physiology, especially in developed basins with increasing temperatures. This study determined the thermal regimes experienced by Chinook entering the Lake Washington basin via locks and ship canal, and migrating through the lake to spawning grounds. We compared these patterns, from acoustic tracking and temperature loggers, with data on sockeye. Chinook entered during peak temperatures whereas sockeye entered earlier in the year, when the water was cooler. Chinook were predicted to display greater tolerance of warm water than sockeye. Chinook often moved back into the cool marine waters but then travelled more quickly to Lake Washington and experienced higher temperatures than did sockeye. In Lake Washington, Chinook swam above and below the thermocline and made little use of the lake as a thermal refuge before they ascended rivers to spawn. In contrast, sockeye were predominantly in cool-water below the lake’s thermocline before ascending streams to spawn. Thus the Chinook timing and tactics indicate a higher tolerance for warm water than the sockeye but the ability of each species to exploit multiple refuges in this highly modified migratory corridor may be essential for persistence with increasing temperatures.
8:40AM Assessing the Performance of Washington State Hatchery Chinook Salmon with Coded-Wire Tag Data
  Gary Marston
Each year millions of Coded Wire Tagged (CWT) salmon are released from hatcheries operated by the Washington Department of Fish and Wildlife. These tagged salmon provide a useful tool for managing fisheries and gauging the performance of hatcheries based off of smolt to adult survival and contributions to specific fisheries. CWT recoveries were analyzed for Chinook salmon derived from harvest programs across four production regions in Washington State (Puget Sound, Coast, Lower Columbia River and Interior Columbia). This data was used to determine smolt-to-adult survival rates for each program, where fisheries benefits are achieved, the value of mark selective fisheries, and stray rates from the hatcheries. To investigate the effectiveness of mark selective fisheries, three Puget Sound Fall Chinook double index tag (DIT) groups were used. Hatcheries across these regions contributed to fisheries in very different ways, with coastal hatcheries primarily benefiting northern fisheries, while Puget Sound and Columbia River hatcheries showed stronger contributions to sport and commercial fisheries within Washington and Oregon. The information provided by tag recoveries is an important step in assuring that informed decisions are made regarding the management the State’s hatchery system and this valuable resource.
9:00AM Reduced Dam Passage Success of a Migrating Salmonid Between Consecutive Attempts
  Matt Drenner
Fish passage is commonly evaluated using tagged fish. Frequently, fish are collected from the passage structure then released back into the system; thus, performance metrics are generated from fish that entered passage structures at least twice. This may bias passage estimates low if success is reduced during second passage attempts. To test for differences in passage success between consecutive attempts, adult steelhead were collected from the Merwin Dam fish trap (Lewis River, WA), tagged with radio transmitters, and released downstream of the trap (trap Non-Naïve). Movements and passage success of trap Non-Naïve fish were compared with fish captured, tagged, and released in the river downstream of the fish trap (assumed trap Naïve). Compared to trap Naïve fish, trap Non-Naïve fish were less direct in their movements upstream after release. We found an 80% posterior probability that passage success frequency was approximately 5 percentage points lower for trap Non-Naive fish compared to trap Naive fish. Reduced passage could be related to negative operant conditioning, increased stress and energy use associated with additional handling and transport for Non-Naive fish, or differences in release locations between groups. Our results demonstrate that passage efficiency estimates generated from Non-Naïve fish may be biased low.
9:20AM Assessment of Stocked Rainbow Trout Persistence at Lees Ferry, Colorado River AZ.
  Devon Oliver
Catch rates remain below management goals for the Lees Ferry Rainbow Trout fishery, particularly at the ‘walk-in’ area, Arizona Game & Fish has considered management actions in order to address angler concerns. Stocking is an active management tool that provides fish directly to anglers and can in part address concerns over low catch rates and small average sizes as the fishery recovers. Although stocking is recognized as an effective management tool for addressing low catch rates, stocked trout represents a considerable investment by AZGFD in the form of the cost to purchase, raise, and distribute this resource to the public. As such, understanding what happens to fish following stocking is important to understanding what impact stocking will have on the system. We investigated persistence of stocked trout within Lees Ferry, and monitored any downstream movement out of the management area using acoustic telemetry. Quantifying downstream movement allowed us to evaluate the potential for negative impacts to native fish residing in warmer water areas downstream in the Grand Canyon, but also quantify the number of stocked fish that remain accessible to anglers within the walk-in area. Results from the study will inform management decisions on Rainbow Trout stocking of Lees Ferry.

Organizers: Michelle L. “Mick” Walsh, Jeff Jenness, Richard D. Methot, Sean M. Lucey, Rebecca M. Krogman, Quinton Phelps
Supported by: AFS Sections: Fish Culture; Fisheries Information and Technology; Marine Fisheries; Fisheries Management; TWS Working Group: Spatial Ecology and Telemetry; American Institute of Fishery Research Biologists

Location: Reno-Sparks CC Date: October 2, 2019 Time: 8:00 am - 9:40 am