Coronary circulation enhances the aerobic performance of wild Pacific salmon.

Female Pacific salmon often experience higher mortality than males during their once-in-a-lifetime up-river spawning migration, particularly when exposed to secondary stressors (e.g. high temperatures).

Novel application of two- and four-lobed noise-canceling passive integrated transponder antennas for tracking fish in areas of high ambient electromagnetic interference.

Passive integrated transponder (PIT) technology is a leading tool for tracking fish in freshwater systems. PIT is highly applicable for assessing fish passage at anthropogenic infrastructure (e.g.

Chinook salmon depth distributions on the continental shelf are shaped by interactions between location, season, and individual condition.

Background: Ecological and physical conditions vary with depth in aquatic ecosystems, resulting in gradients of habitat suitability. Although variation in vertical distributions among individuals provides evidence of habitat selection, it has been challenging to disentangle how processes at multiple spatio-temporal scales shape behaviour.

Methods: We collected thousands of observations of depth from acoustically tagged adult Chinook salmon Oncorhynchus tshawytscha, spanning multiple seasons and years.

Genomic vulnerability of a freshwater salmonid under climate change.

Understanding the adaptive potential of populations and species is pivotal for minimizing the loss of biodiversity in this era of rapid climate change. Adaptive potential has been estimated in various ways, including based on levels of standing genetic variation, presence of potentially beneficial alleles, and/or the severity of environmental change. Kokanee salmon, the non-migratory ecotype of sockeye salmon (), is culturally and economically important and has already been impacted by the effects of climate change.

Modeling instream temperature from solar insolation under varying timber harvesting intensities using RPAS laser scanning.

Stream temperatures are influenced by the amount of solar insolation they receive. Increasing stream temperatures associated with climate warming pose detrimental health risks to freshwater ecosystems. In British Columbia (BC), Canada, timber harvesting along forested streams is managed using riparian buffer zones of varying widths and designations.

Impairing cardiac oxygen supply in swimming coho salmon compromises their heart function and tolerance to acute warming.

Climatic warming elevates mortality for many salmonid populations during their physically challenging up-river spawning migrations, yet, the mechanisms underlying the increased mortality remain elusive. One hypothesis posits that a cardiac oxygen insufficiency impairs the heart's capacity to pump sufficient oxygen to body tissues to sustain up-river swimming, especially in warm water when oxygen availability declines and cardiac and whole-animal oxygen demand increases. We tested this hypothesis by measuring cardiac and metabolic (cardiorespiratory) performance, and assessing the upper thermal tolerance of coho salmon (Oncorhynchus kisutch) during sustained swimming and acute warming.

Infectious agents and their physiological correlates in early marine Chinook salmon ().

The early marine life of Pacific salmon is believed to be a critical period limiting population-level survival. Recent evidence suggests that some infectious agents are associated with survival but linkages with underlying physiological mechanisms are lacking. While challenge studies can demonstrate cause and effect relationships between infection and pathological change or mortality, in some cases pathological change may only manifest in the presence of environmental stressors; thus, it is important to gain context from field observations.

Population variability in thermal performance of pre-spawning adult Chinook salmon.

Climate change is causing large declines in many Pacific salmon populations. In particular, warm rivers are associated with high levels of premature mortality in migrating adults. The Fraser River watershed in British Columbia, Canada, supports some of the largest Chinook salmon () runs in the world.

Metabolic constraints and individual variation shape the trade-off between physiological recovery and anti-predator responses in adult sockeye salmon.

Metabolic scope represents the aerobic energy budget available to an organism to perform non-maintenance activities (e.g., escape a predator, recover from a fisheries interaction, compete for a mate).

The spatial distribution of infectious agents in wild Pacific salmon along the British Columbia coast.

Although infectious agents can act as strong population regulators, knowledge of their spatial distributions in wild Pacific salmon is limited, especially in the marine environment. Characterizing pathogen distributions during early marine residence, a period considered a survival bottleneck for Pacific salmon, may reveal where salmon populations are exposed to potentially detrimental pathogens. Using high-throughput qPCR, we determined the prevalence of 56 infectious agents in 5719 Chinook, 2032 Coho and 4062 Sockeye salmon, sampled between 2008 and 2018, in their first year of marine residence along coastal Western Canada.

Host-pathogen-environment interactions predict survival outcomes of adult sockeye salmon (Oncorhynchus nerka) released from fisheries.

Incorporating host-pathogen(s)-environment axes into management and conservation planning is critical to preserving species in a warming climate. However, the role pathogens play in host stress resilience remains largely unexplored in wild animal populations. We experimentally characterized how independent and cumulative stressors (fisheries handling, high water temperature) and natural infections affected the health and longevity of released wild adult sockeye salmon (Oncorhynchus nerka) in British Columbia, Canada.

Infected juvenile salmon can experience increased predation during freshwater migration.

Predation risk for animal migrants can be impacted by physical condition. Although size- or condition-based selection is often observed, observing infection-based predation is rare due to the difficulties in assessing infectious agents in predated samples. We examined predation of outmigrating sockeye salmon () smolts by bull trout () in south-central British Columbia, Canada.

Maxed Out: Optimizing Accuracy, Precision, and Power for Field Measures of Maximum Metabolic Rate in Fishes.

Both laboratory and field respirometry are rapidly growing techniques to determine animal performance thresholds. However, replicating protocols to estimate maximum metabolic rate (MMR) between species, populations, and individuals can be difficult, especially in the field. We therefore evaluated seven different exercise treatments-four laboratory methods involving a swim tunnel (critical swim speed [], postswim fatigue, maximum swim speed [], and postswim fatigue) and three field-based chasing methods (3-min chase with 1-min air exposure, 3-min chase with no air exposure, and chase to exhaustion)-in adult coho salmon () as a case study to determine best general practices for measuring and quantifying MMR in fish.

Erratum to: Simulated maternal stress reduces offspring aerobic swimming performance in Pacific salmon.

[This corrects the article DOI: 10.1093/conphys/coz095.].

Simulated maternal stress reduces offspring aerobic swimming performance in Pacific salmon.

Pacific salmon routinely encounter stressors during their upriver spawning migration, which have the potential to influence offspring through hormonally-mediated maternal effects. To disentangle genetic vs. hormonal effects on offspring swimming performance, we collected gametes from three species of Pacific salmon (Chinook, pink and sockeye) at the end of migration and exposed a subset of eggs from each female to cortisol baths to simulate high levels of maternal stress.

"Consulted to death": Personal stress as a major barrier to environmental co-management.

Co-management is widely seen as a way of improving environmental governance and empowering communities. When successful, co-management enhances the validity and legitimacy of decision-making, while providing stakeholders with influence over processes and outcomes that directly impact them. However, our research with participants in co-management across several cases leads us to argue that many of the individuals who contribute to co-management are subject to significant personal stress arising from both the logistical and social/emotional demands of participation in these processes.

Linking environmental factors with reflex action mortality predictors, physiological stress, and post-release movement behaviour to evaluate the response of white sturgeon (Acipenser transmontanus Richardson, 1836) to catch-and-release angling.

White sturgeon are the largest freshwater fish in North America and are the focus of an intense catch-and-release (C&R) fishery; the effects are largely unknown. We assessed the effect of fight and handling time, water temperature, river discharge rate, and fish size on physiological and reflex impairment responses of wild white sturgeon to angling. Sixty of these fish were tagged with acoustic transmitters to assess survival and post-release behaviour.

Discovery and validation of candidate smoltification gene expression biomarkers across multiple species and ecotypes of Pacific salmonids.

Early marine survival of juvenile salmon is intimately associated with their physiological condition during smoltification and ocean entry. Smoltification (parr-smolt transformation) is a developmental process that allows salmon to acquire seawater tolerance in preparation for marine living. Traditionally, this developmental process has been monitored using gill Na/K-ATPase (NKA) activity or plasma hormones, but gill gene expression offers the possibility of another method.

Cumulative Effects of Thermal and Fisheries Stressors Reveal Sex-Specific Effects on Infection Development and Early Mortality of Adult Coho Salmon ().

Multiple stressors are commonly encountered by wild animals, but their cumulative effects are poorly understood, especially regarding infection development. We conducted a holding study with repeated gill and blood sampling to characterize the effects of cumulative stressors on infection development in adult coho salmon. Treatments included chronic thermal stress (15°C vs.

Salmonid gene expression biomarkers indicative of physiological responses to changes in salinity and temperature, but not dissolved oxygen.

An organism's ability to respond effectively to environmental change is critical to its survival. Yet, life stage and overall condition can dictate tolerance thresholds to heightened environmental stressors, such that stress may not be equally felt across individuals and at all times. Also, the transcriptional responses induced by environmental changes can reflect both generalized responses as well as others that are highly specific to the type of change being experienced.

Migratory coupling between predators and prey.

Animal migrations act to couple ecosystems and are undertaken by some of the world's most endangered taxa. Predators often exploit migrant prey, but the movements taken by these consumers are rarely studied or understood. We define such movements, where migrant prey induce large-scale movements of predators, as migratory coupling.

Transcriptional shifts during juvenile Coho salmon (Oncorhynchus kisutch) life stage changes in freshwater and early marine environments.

There is a paucity of information on the physiological changes that occur over the course of salmon early marine migration. Here we aim to provide insight on juvenile Coho salmon (Oncorhynchus kisutch) physiology using the changes in gene expression (cGRASP 44K microarray) of four tissues (brain, gill, muscle, and liver) across the parr to smolt transition in freshwater and through the first eight months of ocean residence. We also examined transcriptome changes with body size as a covariate.

Developing specific molecular biomarkers for thermal stress in salmonids.

Background: Pacific salmon (Oncorhynchus spp.) serve as good biological indicators of the breadth of climate warming effects on fish because their anadromous life cycle exposes them to environmental challenges in both marine and freshwater environments. Our study sought to mine the extensive functional genomic studies in fishes to identify robust thermally-responsive biomarkers that could monitor molecular physiological signatures of chronic thermal stress in fish using non-lethal sampling of gill tissue.

Dermal injuries caused by purse seine capture result in lasting physiological disturbances in coho salmon.

Fish vitality can be measured by classifying reflex impairments (i.e., a visual impression of the ability to respond to induced stimuli) and visible injuries.

Thiamine Levels in Muscle and Eggs of Adult Pacific Salmon from the Fraser River, British Columbia.

Multiple species and stocks of Pacific salmon Oncorhynchus spp. have experienced large declines in the number of returning adults over a wide region of the Pacific Northwest due to poor marine survival (low smolt-to-adult survival rates). One possible explanation for reduced survival is thiamine deficiency.