A hypothesis-driven statistical approach for identifying ecosystem indicators of coho and Chinook salmon marine survival

Sobocinski, Kathryn L.; Greene, Correigh M.; Kendall, Neala W.; Schmidt, Michael W.; Zimmerman, Mara S.; Kemp, Iris M.; Kim, Su; Ruff, Casey P.

doi:10.1016/j.ecolind.2021.107403

Cited by 23 publications

(21 citation statements)

References 95 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Fig 7 shows the statistically significant linkages between salmon counts, temperature, and flows in terms of MI and TE , for spring and fall runs, in addition to lagged linear correlations. As found in previous studies focusing on marine survival [ 19 ], the complete life-cycle [ 3 ], or adult returns [ 17 ], this indicates a high level of connectivity within the system, and no single variable is likely to explain more than half of the observational uncertainty. While TE < MI overall (circle sizes and link widths in Fig 7 ), the higher TE in spring indicates less redundancy, and more unique drivers of salmon counts during that season.…”

Section: Results: Seasonally Varying Chinook Driverssupporting

confidence: 53%

“…For example, considering nonlinear environmental drivers has been found to improve forecast accuracy in fisheries models [ 16 ] and the extent to which a variable is predictive can depend on nonlinear thresholds [ 13 ]. It has also been found that there are multiple relevant indicators of salmon returns [ 17 ], carryover effects within salmon lifecyles in which conditions experienced at one life stage affect a subsequent stage [ 18 ] and marine survival [ 19 ], but no single indicator or subset of indicators is highly explanatory. Moreover, it has been found that the relationships between indicator variables themselves can be non-stationary [ 20 , 21 ], which has implications for predictive skills of models based on certain input combinations, and indicates the difficulty in distinguishing causal drivers from temporary correlations.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An information theory-based approach to characterize drivers of upstream salmon migration

Goodwell

Campbell

2022

PLoS ONE

View full text Add to dashboard Cite

The migration timing of Pacific salmon in the Columbia River basin is subject to multiple influences related to climate, human water resource management, and lagged effects such as oceanic conditions. We apply an information theory-based approach to analyze drivers of adult Chinook salmon migration within the spring and fall spawning seasons and between years based on salmon counts at dams along the Columbia and Snake Rivers. Time-lagged mutual information and information decomposition measures, which characterize lagged and nonlinear dependencies as reductions in uncertainty, are used to detect interactions between salmon counts and lagged streamflows, air and water temperatures, precipitation, snowpack, climate indices and downstream salmon counts. At a daily timescale, these interdependencies reflect migration timing and show differences between fall and spring run salmon, while dependencies based on variables at an annual resolution reflect long-term predictability. We also highlight several types of joint dependencies where predictability of salmon counts depends on the knowledge of multiple lagged sources. This study illustrates how co-varying human and natural drivers could propagate to influence salmon migration timing or overall returns, and how nonlinear types of dependencies between variables enhance predictability of a target. This information-based framework is broadly applicable to assess driving factors in other types of complex water resources systems or species life cycles.

show abstract

Section: Results: Seasonally Varying Chinook Driverssupporting

confidence: 53%

Section: Introductionmentioning

confidence: 99%

An information theory-based approach to characterize drivers of upstream salmon migration

Goodwell

Campbell

2022

PLoS ONE

View full text Add to dashboard Cite

show abstract

“…The extended spatial and temporal characteristics of salmonid migration mean that factors acting over long periods and broad geographic scales may all contribute, both cumulatively and synergistically, to the currently depressed populations (Knudsen & McDonald, 2020; Thorstad et al, 2012). Thus, the freshwater and marine survival of anadromous salmonids are known to be intertwined at the population level, although our knowledge of the relationship between the two is limited (McCormick et al, 2009; Sobocinski et al, 2021). Anadromous salmonid marine mortality is considered to be density‐independent (Flávio et al, 2019; Jonsson et al, 1998), which implies that the number of juvenile individuals, the smolts, entering seawater will broadly determine the number of adults that return from sea to spawn (McCormick et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

The benefits of merging passive and active tracking approaches: New insights into riverine migration by salmonid smolts

et al. 2022

View full text Add to dashboard Cite

The process of smolting is a critical phase in the life cycle of anadromous salmonids, and it has been associated with substantial rates of mortality. Survival during freshwater and marine migration is known to have population-level effects; thus, an understanding of the patterns of mortality has the potential to yield important insights into population bottlenecks. Despite important advancements in tracking techniques, the specifics of mortality events in anadromous salmonids during their initial migration to sea remain somewhat elusive. Here, we develop a framework combining spatial and temporal detections of smolt riverine migration from two tracking techniques, which enable inferences to be made about mortality locations, causes, and rates. In this study, we demonstrate that during their initial riverine transitional phase, smolts were particularly vulnerable to predators. Specifically, avian predation appeared to be the main cause of mortality (42%), although piscine predation events were not trivial (14%). Our results suggested some direct and indirect tagging-induced mortality (e.g., through increased predation vulnerability), which highlights the importance of determining tagging mortality in a telemetry study to ensure adequate interpretation of migration success. Overall, by estimating migration loss and its variability, our study framework should help to guide management actions to mitigate the widespread population declines these species are currently facing.

show abstract

“…The extended spatial and temporal characteristics of salmonid migration means that factors acting over long periods and broad geographic scales may all contribute, both cumulatively and synergistically, to the currently depressed populations (Knudsen andMcDonald 2020, Thorstad, et al 2012). Thus, the freshwater and marine survival of anadromous salmonids are known to be intertwined at the population level, although our knowledge of the relationship between the two is limited (McCormick et al 2009, Sobocinski et al 2021. Anadromous salmonid marine mortality is considered to be density-independent (Flávio et al 2019, Jonsson et al 1998, which implies that the number of juvenile individuals, the smolts, entering seawater will broadly determine the number of adults that return from sea to spawn ).…”

Section: Discussionmentioning

confidence: 99%

The benefits of merging passive and active tracking approaches: new insights into riverine migration by salmonid smolts

Chavarie

Honkanen

Newton

et al. 2021

Preprint

View full text Add to dashboard Cite

The process of smolting is a critical phase in the life-cycle of anadromous salmonids and it has been associated with substantial rates of mortality. Survival during freshwater and marine migration is known to have population level effects, thus an understanding of the patterns of mortality has the potential to yield important insights into population bottlenecks. Despite important advancements in tracking techniques, the specifics of mortality events in anadromous salmonids during their initial migration to sea remains somewhat elusive. Here, we develop a framework combining spatial and temporal detections of smolt riverine migration from two tracking techniques, which enable inferences to be made about mortality locations, causes, and rates. We embed this framework into a fine-scale behaviour study of migration and social structure. In this study, we demonstrate that during their initial riverine transitional phase, smolts were particularly vulnerable to predators. Specifically, avian predation appeared to be the main cause of mortality (42%), although piscine predation events were not trivial (14%). Our results suggested some direct and indirect tagging-induced mortality (e.g., through increased predation vulnerability), which highlights the importance of determining tagging mortality in a telemetry study to ensure adequate interpretation of migration success. There is evidence that predation induced selection on smolt morphology. Unsuccessful river salmon migrants with a phenotype comprising a shorter head and jaw and smaller eye had a higher probability of mortality in the later parts of riverine migration where avian and aquatic predation mortality dominated. In contrast, mortality earlier in river migration was independent of phenotype, most likely a result of tagging effects. Successfully river migrants were found to be interacting with each other, often in a pair or as a trio, indicating that a few individuals of Atlantic salmon and sea trout formed notable intra- and interspecific social associations. However, the heterogeneity of the social associations of successful migrants did not support the assumption that social network features attributed any clear specific benefits of reduced predation risk. Overall, by estimating migration loss and its variability, our study framework should help to guide management actions to mitigate the widespread population declines these species are currently facing.

show abstract

A hypothesis-driven statistical approach for identifying ecosystem indicators of coho and Chinook salmon marine survival

Cited by 23 publications

References 95 publications

An information theory-based approach to characterize drivers of upstream salmon migration

An information theory-based approach to characterize drivers of upstream salmon migration

The benefits of merging passive and active tracking approaches: New insights into riverine migration by salmonid smolts

The benefits of merging passive and active tracking approaches: new insights into riverine migration by salmonid smolts

Contact Info

Product

Resources

About