Effect of release timing on apparent survival of juvenile fall run Chinook Salmon from Coleman National Fish Hatchery

Zeug, Steven C.; Null, Robert E.; Brodsky, Annie; Johnston, Myfanwy; Ammann, Arnold J.

doi:10.1007/s10641-020-00968-7

Cited by 8 publications

(8 citation statements)

References 35 publications

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“…1). In addition, most CCV juvenile Chinook salmon hatchery releases also peak in spring (Huber and Carlson 2015), during which their outmigration survival rates also appear to be sensitive to flow rates (Zeug et al 2020).…”

Section: Methodsmentioning

confidence: 99%

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Nonlinear survival of imperiled fish informs managed flows in a highly modified river

et al. 2021

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Water is a fundamental resource in freshwater ecosystems, and streamflow plays a pivotal role in driving riverine ecology and biodiversity. Ecologically functional flows, managed hydrographs that are meant to reproduce the primary components of the natural hydrograph, are touted as a potential way forward to restore ecological functions of highly modified rivers, while also balancing human water needs. A major challenge in implementing functional flows will be establishing the shape of the managed hydrograph so as to optimize improvements to the ecosystem given the limited resources. Identifying the shape of the flow-biology relationship is thus critical for determining the environmental consequences of flow regulation. In California's Central Valley, studies have found that increased streamflow can improve survival of imperiled juvenile salmon populations during their oceanward migration. These studies have not explored the potential nonlinearities between flow and survival, giving resource managers the difficult task of designing flows intended to help salmon without clear guidance on flow targets. We used an information theoretic approach to analyze migration survival data from 2436 acoustic-tagged juvenile Chinook salmon from studies spanning differing water years (2013)(2014)(2015)(2016)(2017)(2018)(2019) to extract actionable information on the flow-survival relationship. This relationship was best described by a step function, with three flow thresholds that we defined as minimum (4259 cfs), historic mean (10,712 cfs), and high (22,872 cfs). Survival varied by flow threshold: 3.0% below minimum, 18.9% between minimum and historic mean, 50.8% between historic mean and high, and 35.3% above high. We used these thresholds to design alternative hydrographs over the same years that included an important component of functional flows: spring pulse flows. We compared predicted cohort migration survival between actual and alternative hydrographs. Managed hydrographs with pulse flows that targeted high survival thresholds were predicted to increase annual cohort migration survival by 55-132% without any additions to the water budget and by 79-330% with a modest addition to the water budget. These quantitative estimates of the biological consequences of different flow thresholds provide resource managers with critical information for designing functional flow regimes that benefit salmon in California's highly constrained water management arena.

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Section: Methodsmentioning

confidence: 99%

“…All stream gauges are operated by either USGS, US Bureau of Reclamation, or California Department of Water Resources. hatchery releases also peak in spring (Huber and Carlson 2015), during which their outmigration survival rates also appear to be sensitive to flow rates (Zeug et al 2020).…”

Section: Study Fish and Seasonmentioning

confidence: 99%

Nonlinear survival of imperiled fish informs managed flows in a highly modified river

et al. 2021

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“…We included groups for which 40 or more smolts were known to have entered the Delta (defined by being detected at Freeport, CA, or anywhere downstream). This resulted in data for 19 release groups, consisting of multiple runs: wild-origin spring-run (Cordoleani et al, 2018), hatchery-origin spring-run (Singer et al, 2020), and hatchery-origin fall run (Singer et al, 2020;Zeug et al, 2020) for a period starting at the mean fish arrival time at Freeport (the northern edge of the Delta) and ending 72 hr later. This 3-day period was meant to approximate the travel time of most smolts between Freeport and Benicia.…”

Section: Questionmentioning

confidence: 99%

Coldwater fish in a warm water world: Implications for predation of salmon smolts during estuary transit

Nobriga

Michel

Johnson

et al. 2021

Ecology and Evolution

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1. Predator-prey systems face intensifying pressure from human exploitation and a warming climate with implications for where and how natural resource management can successfully intervene. We hypothesized young salmon migrating to the Pacific Ocean face a seasonally intensifying predator gauntlet when warming water temperature intensifies a multiple predator effect (MPE) from Striped Bass Morone saxatilis and Largemouth Bass Micropterus salmoides. We evaluated this hypothesis using data synthesis and simulation modeling.

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“…In California's Central Valley, fall-, spring-, and winter-run Chinook Salmon juveniles have been tagged with JSATS transmitters to identify mechanistic drivers of variable out-migration success (Klimley et al 2017a;Zeug et al 2017;Cordoleani et al 2018). In fisheries studies worldwide, it is relatively common for run-of-theriver fish to be captured in a rotary screw trap, tagged with a transmitter, and subsequently released within 24 h of tagging-and often within 1-4 h of tagging.…”

Section: Discussionmentioning

confidence: 99%

Behavioral Response of Juvenile Chinook Salmon to Surgical Implantation of Micro‐acoustic Transmitters

Singer

Hansen

et al. 2019

Trans Am Fish Soc

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Acoustic telemetry, a commonly used tool for examining movements and survival of aquatic species, is often applied without a comprehensive understanding of transmitter implantation effects. This can be problematic when the goal of the study is to use telemetry results to make inferences regarding broader populations. Here, we examined juvenile Chinook Salmon Oncorhynchus tshawytscha at varying time intervals after transmitter implantation to assess the behavioral implications of tagging. The following behavioral metrics in response to a novel environment were compared across treatment and control groups: time to emergence from shelter into the open portion of the test arena, rheotactic response, total activity, and rates of exploration. Tagged fish (114–132 mm FL) were tested at 0, 1, or 4 d postsurgery (day‐0, day‐1, and day‐4 groups, respectively), and their behavior was compared to that of similarly handled control fish. Emergence from refuge was the only metric that differed significantly between treatment and control groups. Fish tested on the same day as the surgery were less likely to emerge from the refuge, with only 46% of the day‐0 tagged fish emerging compared to 88, 93, and 80% of the day‐1, day‐4, and control groups, respectively. However, day‐0 fish that did emerge from the refuge had rheotactic responses, total activity, and exploration rates similar to those of fish from the other treatment and control groups. This study may have fisheries research and management implications, especially for telemetry studies and monitoring efforts. We encourage researchers using this technology to consider (1) observing a post‐transmitter‐implantation recovery period of at least 24 h prior to release, adjusting study plans and logistics accordingly; (2) applying sufficient scientific rigor to emerging tagging technology prior to wide‐scale adoption; and (3) when possible, conducting concurrent battery life and tag effects studies with any field release of tagged fishes, as differing relationships between fish size, tag size, and tagging techniques may yield variable results.

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Effect of release timing on apparent survival of juvenile fall run Chinook Salmon from Coleman National Fish Hatchery

Cited by 8 publications

References 35 publications

Nonlinear survival of imperiled fish informs managed flows in a highly modified river

Nonlinear survival of imperiled fish informs managed flows in a highly modified river

Coldwater fish in a warm water world: Implications for predation of salmon smolts during estuary transit

Behavioral Response of Juvenile Chinook Salmon to Surgical Implantation of Micro‐acoustic Transmitters

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