Aeromonas salmonicida, causative agent of salmonid furunculosis, isolated from the freshwater parasitic copepod, Salmincola californiensis.

Here, we provide evidence that the freshwater parasitic copepod, Salmincola californiensis, acts as a vector for Aeromonas salmonicida. While investigating the effects of S. californiensis on Chinoook salmon (Oncorhynchus tshawytscha), we tangentially observed that fish infected with the copepod developed furunculosis, caused by A.

Intestinal lesions and parasites associated with senescence and prespawn mortality in Chinook Salmon (Oncorhynchus tshawytscha).

Prespawn mortality (PSM) presents a major problem for the recovery of spring Chinook Salmon (Oncorhynchus tshawytscha) populations. In the Willamette River, Oregon, PSM exceeds 90% in some years but factors explaining it are not well understood. We examined intestinal tissue samples using histological slides from over 783 spring Chinook Salmon collected between 2009 and 2021, which included tissues from PSM fish, artificially spawned captive broodstock (BS) and normal river run fish, comprised of trapped (Live) and naturally post-spawned river (RPS) fish collected from the river.

IRF7 and UNC93B1 variants in an infant with recurrent herpes simplex virus infection.

Neonatal herpes simplex virus (HSV) infection is a devastating disease with substantial morbidity and mortality. The genetic basis of susceptibility to HSV in neonates remains undefined. We evaluated a male infant with neonatal skin/eye/mouth (SEM) HSV-1 disease, who had complete recovery after acyclovir but developed HSV-1 encephalitis at 1 year of age.

Gut microbiome composition associates with corticosteroid treatment, morbidity, and senescence in Chinook salmon (Oncorhynchus tshawytscha).

Pacific salmon experience prolonged elevation in corticosteroid hormones during important life history events including migration, reproduction, and senescence. These periods of elevated corticosteroids correspond with changes to immunity and energy metabolism; therefore, fish may be particularly vulnerable to mortality at these times. Recent studies found that stress-induced cortisol release associated with microbial community shifts in salmonids, raising the question of how longer-term corticosteroid dynamics that accompany life history transitions affect salmonid microbiomes.

Earlier onset of North Atlantic hurricane season with warming oceans.

Numerous Atlantic basin tropical cyclones have recently developed prior to the official start of hurricane season, including several pre-season landfalls in the continental United States. Pre-season and early-season tropical cyclones disproportionately affect populated landmasses, often producing outsized precipitation impacts. Here we show a significant trend towards earlier onset of tropical cyclone activity in the North Atlantic basin, with threshold dates of the first three percentiles of accumulated cyclone energy shifting earlier at a rate exceeding five days decade since 1979, even correcting for biases in climatology due to increased detection of short-lived storms.

Bacterial Filamentation Drives Colony Chirality.

Chirality is ubiquitous in nature, with consequences at the cellular and tissue scales. As Escherichia coli colonies expand radially, an orthogonal component of growth creates a pinwheel-like pattern that can be revealed by fluorescent markers. To elucidate the mechanistic basis of this colony chirality, we investigated its link to left-handed, single-cell twisting during E.

An assessment of terminology for intraspecific diversity in fishes, with a focus on "ecotypes" and "life histories".

Understanding and preserving intraspecific diversity (ISD) is important for species conservation. However, ISD units do not have taxonomic standards and are not universally recognized. The terminology used to describe ISD is varied and often used ambiguously.

Laboratory infection rates and associated mortality of juvenile Chinook Salmon (Oncorhynchus tshawytscha) from parasitic copepod (Salmincola californiensis).

Pacific salmon (Oncorhynchus spp.) rearing in lakes and reservoirs above dams have been known to become heavily infected with an ectoparasitic copepod (Salmincola californiensis). Little is known about the factors that affect the parasite infection prevalence and intensity.

PRECIPITATION AND FATAL MOTOR VEHICLE CRASHES: Continental Analysis with High-Resolution Radar Data.

Precipitation, even at light intensity, contributes a significant risk of fatal motor vehicle crashes across the United States, at nearly all times of day, and in all seasons.

Rearing environment affects spatial learning in juvenile Chinook salmon Oncorhynchus tshawytscha.

We tested the prediction that a complex physical rearing environment would enhance short-term spatial memory as assessed by learning ability in a spatial navigation task in juvenile Chinook salmon Oncorhynchus tshawytscha. We reared fish in two low-density treatments, where fish were either in bare fiberglass tanks (bare) or in tanks with physical structure (complex). We also tested conventionally reared high-density hatchery fish to compare with these other experimental treatments.

Biomechanical Feedback Strengthens Jammed Cellular Packings.

Growth in confined spaces can drive cellular populations through a jamming transition from a fluidlike state to a solidlike state. Experiments have found that jammed budding yeast populations can build up extreme compressive pressures (over 1 MPa), which in turn feed back onto cellular physiology by slowing or even stalling cell growth. Using numerical simulations, we investigate how this feedback impacts the mechanical properties of model jammed cell populations.

Collective motion conceals fitness differences in crowded cellular populations.

Many cellular populations are tightly packed, such as microbial colonies and biofilms, or tissues and tumours in multicellular organisms. The movement of one cell in these crowded assemblages requires motion of others, so that cell displacements are correlated over many cell diameters. Whenever movement is important for survival or growth, these correlated rearrangements could couple the evolutionary fate of different lineages.

Egg size and growth in steelhead Oncorhynchus mykiss.

The effects of egg size on early development and growth of steelhead Oncorhynchus mykiss were recorded for more than 200 days following hatching. Fish from smaller eggs hatched sooner and at a smaller size than fish from larger eggs, but fish from smaller eggs showed consistently higher growth rates than fish from larger eggs. Since many life-history attributes appear to be determined by size or growth rate at age during the first year, egg size could be a significant predictor of important changes in the life history of individuals.

The effect of rearing structures on behaviour and movement of juvenile steelhead Oncorhynchus mykiss.

The relative movement of juvenile steelhead Oncorhynchus mykiss reared on two treatments was investigated to provide insight on the effect of structure in the rearing environment on the behaviour of the fish before potential release into a natural river system. The progeny of wild broodstock were reared either in the presence or absence of structure in the tank environment for 7 months at the Oregon Hatchery Research Center located in Oregon, U.S.

Emergence of evolutionary driving forces in pattern-forming microbial populations.

Evolutionary dynamics are controlled by a number of driving forces, such as natural selection, random genetic drift and dispersal. In this perspective article, we aim to emphasize that these forces act at the population level, and that it is a challenge to understand how they emerge from the stochastic and deterministic behaviour of individual cells. Even the most basic steric interactions between neighbouring cells can couple evolutionary outcomes of otherwise unrelated individuals, thereby weakening natural selection and enhancing random genetic drift.

Egg size and emergence timing affect morphology and behavior in juvenile Chinook Salmon, .

Variation in early life history traits often leads to differentially expressed morphological and behavioral phenotypes. We investigated whether variation in egg size and emergence timing influence subsequent morphology associated with migration timing in juvenile spring Chinook Salmon, . Based on evidence for a positive relationship between growth rate and migration timing, we predicted that fish from small eggs and fish that emerged earlier would have similar morphology to fall migrants, while fish from large eggs and individuals that emerged later would be more similar to older spring yearling migrants.

Changes in extreme events and the potential impacts on human health.

Unlabelled: Extreme weather and climate-related events affect human health by causing death, injury, and illness, as well as having large socioeconomic impacts. Climate change has caused changes in extreme event frequency, intensity, and geographic distribution, and will continue to be a driver for change in the future. Some of these events include heat waves, droughts, wildfires, dust storms, flooding rains, coastal flooding, storm surges, and hurricanes.

Self-Driven Jamming in Growing Microbial Populations.

In natural settings, microbes tend to grow in dense populations [1-4] where they need to push against their surroundings to accommodate space for new cells. The associated contact forces play a critical role in a variety of population-level processes, including biofilm formation [5-7], the colonization of porous media [8, 9], and the invasion of biological tissues [10-12]. Although mechanical forces have been characterized at the single cell level [13-16], it remains elusive how collective pushing forces result from the combination of single cell forces.

Pacific lamprey (Entosphenus tridentatus) ammocoetes exposed to contaminated Portland Harbor sediments: Method development and effects on survival, growth, and behavior.

Many anthropogenic disturbances have contributed to the decline of Pacific lampreys (Entosphenus tridentatus), but potential negative effects of contaminants on lampreys are unclear. Lamprey ammocoetes are the only detritivorous fish in the lower Willamette River, Oregon, USA, and have been observed in Portland Harbor sediments. Their long benthic larval stage places them at risk from the effects of contaminated sediment.

Salinity effects on plasma ion levels, cortisol, and osmolality in Chinook salmon following lethal sampling.

Studies on hydromineral balance in fishes frequently employ measurements of electrolytes following euthanasia. We tested the effects of fresh- or salt-water euthanasia baths of tricaine mesylate (MS-222) on plasma magnesium (Mg(2+)) and sodium (Na(+)) ions, cortisol and osmolality in fish exposed to saltwater challenges, and the ion and steroid hormone fluctuations over time following euthanasia in juvenile spring Chinook salmon (Oncorhynchus tshawytscha). Salinity of the euthanasia bath affected plasma Mg(2+) and Na(+) concentrations as well as osmolality, with higher concentrations in fish euthanized in saltwater.

Innate and adaptive immune responses in migrating spring-run adult chinook salmon, Oncorhynchus tshawytscha.

Adult Chinook salmon (Oncorhynchus tshawytscha) migrate from salt water to freshwater streams to spawn. Immune responses in migrating adult salmon are thought to diminish in the run up to spawning, though the exact mechanisms for diminished immune responses remain unknown. Here we examine both adaptive and innate immune responses as well as pathogen burdens in migrating adult Chinook salmon in the Upper Willamette River basin.

Designing a Monitoring Program to Estimate Estuarine Survival of Anadromous Salmon Smolts: Simulating the Effect of Sample Design on Inference.

A number of researchers have attempted to estimate salmonid smolt survival during outmigration through an estuary. However, it is currently unclear how the design of such studies influences the accuracy and precision of survival estimates. In this simulation study we consider four patterns of smolt survival probability in the estuary, and test the performance of several different sampling strategies for estimating estuarine survival assuming perfect detection.

Migratory Patterns of Wild Chinook Salmon Oncorhynchus tshawytscha Returning to a Large, Free-Flowing River Basin.

Upriver movements were determined for Chinook salmon Oncorhynchus tshawytscha returning to the Yukon River, a large, virtually pristine river basin. These returns have declined dramatically since the late 1990s, and information is needed to better manage the run and facilitate conservation efforts. A total of 2,860 fish were radio tagged during 2002-2004.