Increases in synchrony among Central Coast salmon populations in British Columbia over the last 60 years

Understanding the dynamics of salmon populations is important for conservation and management, but the factors driving spatial and temporal variation in many salmon populations remain poorly understood. Understanding these patterns is important for many coastal First Nations, who play an important role in the monitoring and management of salmon in their traditional territories. Using data from 200 unique spawning locations on the Central Coast of British Columbia, we quantified patterns in abundance and coherence of salmon over space and time to measure the extent to which portfolio effects stabilize variation in stocks. We found strong declines in Sockeye Salmon abundance across the Central Coast. This decline was accompanied by an increase in population synchrony among stocks. Chum and Pink Salmon also showed generally similar patterns to Sockeye, though the odd-year lineage of Pink Salmon showed increased abundance in recent years. These changes in synchrony within salmon populations may be important as synchronization increases the risk of declines due to boom and bust dynamics. To explore possible drivers of changes, we test if factors such as changes in fishing rates, ocean conditions, or increased competition on the high seas explained changes in synchrony through time. To expand this work, over the next two years we will be working with First Nations throughout the Salish Sea to assess the status of salmon and their habitats. This future work will position us to better understand the drivers of changes in the synchrony among salmon populations on wider spatial scales

Designing data collection for decision-making: shaping the coastal First Nations regional monitoring system to meet the needs of the Nations

The Coastal First Nations (CFN) Regional Monitoring System (RMS) was redeveloped to support decisions related to threats to ecological and cultural values, resulting from changes to existing and impending resource use on the North and Central Coast of British Columbia. As First Nations reassert their governance authority, participate in shared decision-making with other governments, undertake land and marine use planning, and manage their territories and resources, the need for coordinated regional monitoring efforts are increasingly important. We used a systematic and inclusive strategy to determine a suitable monitoring approach to meet the needs of a diverse group of Nations across a broad geographic region. Linking data collection to decision-making and planning processes was central to our strategy. We began with engaging individuals at each Nation’s resource management office to gain a comprehensive understanding of the monitoring activities undertaken, the data being collected, the data desired, and the way data are used to support decision-making and planning processes. Concurrently, we worked with the member Nations to develop a decision-making framework to identify the monitoring activities best suited for the RMS based on the goals of the system. Applying the framework to the suite of monitoring activities being undertaken or desired resulted in a suite of monitoring activities that was further refined in a workshop with the Nations. We produced monitoring cards for each monitoring activity, which detail the monitoring research question(s), the data to collect, the sampling design and data collection protocols, and the decision-making and planning processes the data support. The RMS is designed to be adaptable as new priorities emerge. It is the only system of its kind on the coast of British Columbia, and it is increasingly looked to as a model for how First Nations-led monitoring programs can inform planning and decision-making processes

Genetics of Century-Old Fish Scales Reveal Population Patterns of Decline

Conservation scientists rarely have the information required to understand changes in abundance over more than a few decades, even for important species like Pacific salmon. Such lack of historical information can underestimate the magnitude of decline for depressed populations. We applied genetic tools to a unique collection of 100‐year‐old salmon scales to reveal declines of 56%–99% in wild sockeye populations across Canada\u27s second largest salmon watershed, the Skeena River. These analyses reveal century‐long declines that are much greater than those based on modern era abundance data, which suggested that only 7 of 13 populations declined over the last five decades. Populations of larger‐bodied fish have declined the most in abundance, likely because of size‐selective commercial fisheries. Our findings illustrate how a deep historical perspective can expand our understanding of past abundances to a time before species incurred significant losses from fishing, and help inform conservation for diminished populations

Enhanced volatile organic compounds emissions and organic aerosol mass increase the oligomer content of atmospheric aerosols

Secondary organic aerosol (SOA) accounts for a dominant fraction of the submicron atmospheric particle mass, but knowledge of the formation, composition and climate effects of SOA is incomplete and limits our understanding of overall aerosol effects in the atmosphere. Organic oligomers were discovered as dominant components in SOA over a decade ago in laboratory experiments and have since been proposed to play a dominant role in many aerosol processes. However, it remains unclear whether oligomers are relevant under ambient atmospheric conditions because they are often not clearly observed in field samples. Here we resolve this long-standing discrepancy by showing that elevated SOA mass is one of the key drivers of oligomer formation in the ambient atmosphere and laboratory experiments. We show for the first time that a specific organic compound class in aerosols, oligomers, is strongly correlated with cloud condensation nuclei (CCN) activities of SOA particles. These findings might have important implications for future climate scenarios where increased temperatures cause higher biogenic volatile organic compound (VOC) emissions, which in turn lead to higher SOA mass formation and significant changes in SOA composition. Such processes would need to be considered in climate models for a realistic representation of future aerosol-climate-biosphere feedbacks

Minimal residual disease in Myeloma: Application for clinical care and new drug registration

The development of novel agents has transformed the treatment paradigm for multiple myeloma, with minimal residual disease (MRD) negativity now achievable across the entire disease spectrum. Bone marrow–based technologies to assess MRD, including approaches using next-generation flow and next-generation sequencing, have provided real-time clinical tools for the sensitive detection and monitoring of MRD in patients with multiple myeloma. Complementary liquid biopsy–based assays are now quickly progressing with some, such as mass spectrometry methods, being very close to clinical use, while others utilizing nucleic acid–based technologies are still developing and will prove important to further our understanding of the biology of MRD. On the regulatory front, multiple retrospective individual patient and clinical trial level meta-analyses have already shown and will continue to assess the potential of MRD as a surrogate for patient outcome. Given all this progress, it is not surprising that a number of clinicians are now considering using MRD to inform real-world clinical care of patients across the spectrum from smoldering myeloma to relapsed refractory multiple myeloma, with each disease setting presenting key challenges and questions that will need to be addressed through clinical trials. The pace of advances in targeted and immune therapies in multiple myeloma is unprecedented, and novel MRD-driven biomarker strategies are essential to accelerate innovative clinical trials leading to regulatory approval of novel treatments and continued improvement in patient outcomes

Causes and consequences of dispersal in a marine parasite (Lepeophtheirus salmonis)

This thesis examines the causes and consequences of the dispersal of a marine ectoparasite, the salmon louse (Lepeophtheirus salmonis), in an area of intensive salmon aquaculture where the transmission of lice from farmed salmon may have consequences for the dynamics of adjacent wild salmon populations. Salmon lice are capable of leaving one host in search of another as they approach sexual maturity; while previously thought to be an artefact of the confined conditions characteristic of experiments and salmon farms I show that this is common in nature with at least 50% of lice on juvenile pink (Oncorhynchus gorbuscha) and chum (O. keta) salmon moving from one host to another as they mature. I demonstrate that the underlying drivers of this dispersal shift with ontogeny from competition for resources to access to mates. Movement among hosts increases the probability that a louse interacts with multiple hosts potentially increasing the extent of louse transmission from farmed to wild salmon and the spread of other pathogens if lice can act as vectors. In addition, the movement of lice among hosts may have important consequences for predator-prey interactions between salmonids during early marine life. Coho salmon smolts (O. kisutch) selectively prey upon infected pinks. I show that sea lice transfer from pinks to coho during these interactions and as a result coho experience a 2 to 3 fold increase in parasite exposure over what they would otherwise experience through passive exposure to infective larvae from farms. To test for a population level response to this increase in louse exposure I examined coho population dynamics spanning a region of exposure to lice from infected pink salmon and salmon farms and show that populations exposed to recurrent infestations were depressed 7 fold relative to adjacent unexposed populations. These findings highlight the ecosystem context in which louse transmission from farmed to wild fish occurs and suggest that species interactions and parasite behaviour may cause the effects of parasite transmission from farmed to wild fish to propagate up marine food webs with broader consequences than previously appreciated

mikelitzow/salmon-attribution-risk: ERL release

<p>Data and code for processing salmon catches for use in:</p> <p>Michael A. Litzow, Michael J. Malick, Trond Kristiansen, Brendan M. Connors, and Gregory T. Ruggerone. 2023. Climate attribution time series track the evolution of human influence on North Pacific sea surface temperature. Environmental Research Letters, in press.</p&gt

Evaluating Relationships between Wild Skeena River Sockeye Salmon Productivity and the Abundance of Spawning Channel Enhanced Sockeye Smolts

The enhancement of salmon populations has long been used to increase the abundance of salmon returning to spawn and/or to be captured in fisheries. However, in some instances enhancement can have adverse impacts on adjacent non-enhanced populations. In Canada\u27s Skeena watershed, smolt-to-adult survival of Babine Lake sockeye from 1962–2002 was inversely related to the abundance of sockeye smolts leaving Babine Lake. This relationship has led to the concern that Babine Lake smolt production, which is primarily enhanced by spawning channels, may depress wild Skeena (Babine and non-Babine) sockeye populations as a result of increased competition between wild and enhanced sockeye smolts as they leave their natal lakes and co-migrate to sea. To test this hypothesis we used data on Skeena sockeye populations and oceanographic conditions to statistically examine the relationship between Skeena sockeye productivity (adult salmon produced per spawner) and an index of Babine Lake enhanced smolt abundance while accounting for the potential influence of early marine conditions. While we had relatively high power to detect large effects, we did not find support for the hypothesis that the productivity of wild Skeena sockeye is inversely related to the abundance of enhanced sockeye smolts leaving Babine Lake in a given year. Importantly, life-time productivity of Skeena sockeye is only partially explained by marine survival, and likely is an unreliable measure of the influence of smolt abundance. Limitations to our analyses, which include: (1) the reliance upon adult salmon produced per spawner (rather than per smolt) as an index of marine survival, and (2) incomplete age structure for most of the populations considered, highlight uncertainties that should be addressed if understanding relationships between wild and enhanced sockeye is a priority in the Skeena

Run-of-River hydropower and salmonids: potential effects and perspective on future research

The spatial footprint of individual run-of-river (RoR) hydropower facilities is smaller than reservoir-storage hydroelectric projects and their impacts to aquatic ecosystems are often assumed to be negligible. However, these effects are poorly understood, especially for salmonids whose freshwater habitat often overlaps with RoR hydropower potential. Flow regulation for RoR hydropower is unique in how it influences the seasonality and magnitude of flow diversion, and because low-head dams can be overtopped at high flows. Based on a review of the primary literature, we identified three pathways of effects by which RoR hydropower may influence salmonids: reduction of flow, presence of low-head dams impounding rivers, and anthropogenic flow fluctuations. We synthesized empirical evidence of effects of RoR hydropower on river ecosystems from 31 papers, of which only ten explicitly considered salmonids. We identified key research gaps including impacts of extended low flow periods, anthropogenic flow fluctuations, and cumulative effects of multiple RoR projects. Filling these gaps is necessary to help manage and conserve salmonid populations in the face of the growing global demand for small-scale hydropower.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author