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Background: Vibrio parahaemolyticus (Vp) is a naturally occurring bacterium found in marine environments worldwide. It can cause gastrointestinal illness in humans, primarily through raw oyster consumption. Water temperatures, and potentially other environmental factors, play an important role in the growth and proliferation of Vp in the environment. Quantifying the relationships between environmental variables and indicators or incidence of Vp illness is valuable for public health surveillance to inform and enable suitable preventative measures. This study aimed to assess the relationship between environmental parameters and Vp in British Columbia (BC), Canada.Methods: The study used Vp counts in oyster meat from 2002-2015 and laboratory confirmed Vp illnesses from 2011-2015 for the province of BC. The data were matched to environmental parameters from publicly available sources, including remote sensing measurements of nighttime sea surface temperature (SST) obtained from satellite readings at a spatial resolution of 1 km. Using three separate models, this paper assessed the relationship between (1) daily SST and Vp counts in oyster meat, (2) weekly mean Vp counts in oysters and weekly Vp illnesses, and (3) weekly mean SST and weekly Vp illnesses. The effects of salinity and chlorophyll a were also evaluated. Linear regression was used to quantify the relationship between SST and Vp, and piecewise regression was used to identify SST thresholds of concern.Results: A total of 2327 oyster samples and 293 laboratory confirmed illnesses were included. In model 1, both SST and salinity were significant predictors of log(Vp) counts in oyster meat. In model 2, the mean log(Vp) count in oyster meat was a significant predictor of Vp illnesses. In model 3, weekly mean SST was a significant predictor of weekly Vp illnesses. The piecewise regression models identified a SST threshold of approximately 14oC for both model 1 and 3, indicating increased risk of Vp in oyster meat and Vp illnesses at higher temperatures.Conclusion: Monitoring of SST, particularly through readily accessible remote sensing data, could serve as a warning signal for Vp and help inform the introduction and cessation of preventative or control measures. [ABSTRACT FROM AUTHOR]

Ocean acidification (OA) reduces seawater pH and calcium carbonate saturation states (Ω), which can have detrimental effects on calcifying organisms such as shellfish. Nearshore areas, where shellfish aquaculture typically operates, have limited data available to characterize variability in key ocean acidification parameters pH and Ω , as samples are costly to analyze and difficult to collect. This study collected samples from four nearshore locations at shellfish aquaculture sites on the Canadian Pacific coast from 2015–2018 and analyzed them for dissolved inorganic carbon (DIC) and total alkalinity (TA), enabling the calculation of pH and Ω for all seasons. The study evaluated the diel and seasonal variability in carbonate chemistry conditions at each location and estimated the contribution of drivers to seasonal and diel changes in pH and Ω. Nearshore locations experience a greater range of variability and seasonal and daily changes in pH and Ω than open waters. Biological uptake of DIC by phytoplankton is the major driver of seasonal and diel changes in pH and Ω at our nearshore sites. The study found that freshwater is not a key driver of diel variability, despite large changes over the day in some locations. We find that during summer at mid-depth (5–20 m), where it is cooler, pH, Ω , and oxygen conditions are still favourable for shellfish. These results suggest that if shellfish are hung lower in the water column, they may avoid high sea surface temperatures, without inducing OA and oxygen stress. [ABSTRACT FROM AUTHOR]

Amos, C.L.; Martino, S.; Sutherland, T.F., and Al Rashidi, T., 2015. Sea surface temperature trends in the coastal zone of British Columbia, Canada. Coastal sea surface temperature (SST), measured daily at the British Columbia (BC) Lighthouse network of stations, has been analyzed in this paper. A network of 14 of the 27 stations had (near) continuous data sets. These stations were clustered previously into exposed (northern/outer) and sheltered (southern/inner) sites. SST trends, evaluated between 1973 and 2010, show that the temperature contrast between these clusters is becoming greater: The northern/exposed stations are strongly influenced by interdecadal (Pacific Decadal oscillation [PDO]) and multidecadal oscillations in the north Pacific that are coherent with HadISST1.1 data for the region. There is no statistically significant warming trend for this region. The stations in the Strait of Georgia are much less influenced by the PDO and show a statistically significant mean increase in SST of up to 0.56°C/decade (Anomaly 1). This is higher than the global average and contrasts markedly with the trends from the northern stations. The warming trends of the southern stations are significant at all months of the year but are most evident during summer (July-September). The summertime anomalies in temperature at Active Pass are significantly correlated ( p < 0.001) with the temperature of the Fraser River water. Temperature differences between the Strait of Georgia and the outer shelf (Anomaly 2) are increasing in time; this is particularly evident since 2000. Monthly averaged MODIS satellite data (4×4-km resolution) show that trends in SST at two selected sites in the Strait of Georgia are very similar to the BC Lighthouse measurements and support the spatial extrapolation of the Lighthouse measurements. At present rates of SST rise, the southern coastal waters of BC will be about 3°C warmer by the end of the 21st century. [ABSTRACT FROM AUTHOR]

Salmon hatcheries are management tools intended to stabilize declining abundance in salmon populations and sustain salmon fisheries. One key area of uncertainty is how hatchery release practices influence juvenile-to-adult survival. Data quality and quantity vary considerably among hatcheries making it difficult to assess the role of release practices. Using a Bayesian hierarchical approach, we analyzed releases and recoveries of Chinook (Oncorhynchus tshawytscha; 21 hatcheries) and coho (Oncorhynchus kisutch; 16 hatcheries) salmon in British Columbia from 1972 to 2017. Higher survival rates were associated with increasing weights-at-release, earlier releases of Chinook salmon, and later releases of coho salmon. The addition of environmental (sea surface temperature, Pacific Decadal Oscillation), and predator (harbour seals, killer whales) covariates did not improve model performance relative to models that used year effects to account for declines in survival and interannual variability in ocean conditions. Optimizing release practices could increase returns by 6%–245% for Chinook salmon and 5%–160% for coho salmon based on median posterior estimates for each hatchery. With these results, a large-scale adaptive management approach could be implemented to test our understanding of release practice–survival relationships and evaluate cost–benefit trade-offs. [ABSTRACT FROM AUTHOR]

Quantifying the marine radiocarbon reservoir effect, offsets (ΔR), and ΔR variability over time is critical to improving dating estimates of marine samples while also providing a proxy of water mass dynamics. In the northeastern Pacific, where no high-resolution time series of ΔR has yet been established, we sampled radiocarbon (14C) from exactly dated growth increments in a multicentennial chronology of the long-lived bivalve, Pacific geoduck (Paneopea generosa) at the Tree Nob site, coastal British Columbia, Canada. Samples were taken at approximately decadal time intervals from 1725 CE to 1920 CE and indicate average ΔR values of 256 ± 22 years (1σ) consistent with existing discrete estimates. Temporal variability in ΔR is small relative to analogous Atlantic records except for an unusually old-water event, 1802–1812. The correlation between ΔR and sea surface temperature (SST) reconstructed from geoduck increment width is weakly significant (r2 =.29, p =.03), indicating warm water is generally old, when the 1802–1812 interval is excluded. This interval contains the oldest (–2.1σ) anomaly, and that is coincident with the coldest (–2.7σ) anomalies of the temperature reconstruction. An additional 32 14C values spanning 1952–1980 were detrended using a northeastern Pacific bomb pulse curve. Significant positive correlations were identified between the detrended 14C data and annual El Niño Southern Oscillation (ENSO) and summer SST such that cooler conditions are associated with older water. Thus, 14C is generally relatively stable with weak, potentially inconsistent associations to climate variables, but capable of infrequent excursions as illustrated by the unusually cold, old-water 1802–1812 interval. [ABSTRACT FROM AUTHOR]

Atmospheric rivers (ARs) are intensive poleward moisture transport events that are essential to the global hydrological cycle and are often linked to extreme weather events. We categorize the winter North Pacific ARs into two "flavors": wind‐dominated (windy ARs) and moisture‐dominated (wet ARs) using 40 years of hourly data from fifth generation of the European Centre for Medium‐Range Weather Forecasts Interim Reanalysis. We compare the differences between windy ARs and wet ARs including the lifecycle characteristics (such as genesis locations and changes of meteorological elements through the lifecycle), overall AR frequency, landfall impacts, and variability. The windy ARs are more likely to occur in the midlatitudes, while wet ARs are more active in the subtropics. Windy ARs are associated with intensive surface pressure lows, where the strong pressure gradient can support the strong wind within ARs. Due to larger size and longer lifetime, wet ARs are more likely to produce more precipitation over a lifecycle. By scaling the landfalling ARs, we show that wet ARs dominate the high‐category ARs (Category 4 and 5) with higher spatial frequency and more precipitation, and windy ARs have higher contributions in the lower AR categories especially over British Columbia. Windy ARs are modulated by El Niño Southern Oscillation (ENSO) teleconnections via the anomalous geopotential height and extended subtropical jet. Wet ARs are affected by the anomalous sea surface temperature over the midlatitudes related to ENSO. Sensitivity analysis with an alternate AR detection algorithm shows consistent results on AR flavors but with disagreement on the amplitude. Plain Language Summary: Atmospheric rivers (ARs) are long and narrow plumes in the atmosphere that transport water vapor from the tropics to high latitudes. ARs generally have strong wind and rich moisture, but the relative strength of wind and moisture can be different for individual ARs. This study divides the ARs into two flavors: windy ARs (stronger wind and less moisture) and wet ARs (weaker wind and more moisture) and compares the differences within. Results show that windy ARs are more likely to occur in the midlatitudes and make landfall in British Columbia. Wet ARs are more active over the subtropics and more prevalent over the U.S. West Coast, especially in California. Windy ARs and wet ARs respond differently to climate variability like El Niño Southern Oscillation. This study could help us to understand the processes related to AR lifecycles and their variability, and help to address how ARs will change in the future warming climate. Key Points: Different atmospheric river (AR) flavors have distinct lifecycle characteristics including genesis, development, and landfall impactsWet ARs are more associated with the U.S. West Coast precipitation and windy ARs are more active over British ColumbiaThe two AR flavors respond differently to El Niño Southern Oscillation phases [ABSTRACT FROM AUTHOR]

Climate change is altering the distribution and composition of marine fish populations globally, which presents substantial risks to the social and economic well-being of humanity. While deriving long-term climatic baselines is an essential step for detecting and attributing the magnitude of climate change and its impacts, these baselines tend to be limited to historical datasets and palaeoecological sediment records. Here, we develop a method for estimating the 'ancient Mean Temperature of the Catch' (aMTC) using Indigenous fisheries catch records from two archaeological sites in the northeast Pacific. Despite different catch compositions, we observe an increase in aMTC over a 5,000-year period at two contemporaneously occupied archaeological sites in southwestern British Columbia, Canada. We document cooler catches from 5,000 to 3,000 cal yr BP and comparatively warmer catches from 1,800 to 250 cal yr BP. These warmer temperatures are broadly consistent with palaeoceanographic sea surface temperature proxies from British Columbia and Alaska. Because this method requires converting measures of fish bones into estimates of fish size structure, abundance, biomass, and finally aMTC, opportunities exist to account for both variation and uncertainty at every step. Nevertheless, given that preindustrial fisheries data are ubiquitous in coastal archaeological sites, this method has the potential to be applied globally to broaden the temporal and geographic scale of ocean temperature baselines. [ABSTRACT FROM AUTHOR]

Growth-increment widths of Pacific geoduck (Panopea generosa), a long-lived bivalve, are used to develop the first marine-based, multicentennial, annually resolved, and exactly dated archive of Northeast Pacific sea surface temperatures (SST). The chronology is sampled from the Tree Nob Islands, British Columbia, Canada, continuously covers 1725-2008, and also contains nine older radiocarbondated segments, which together span 58% of the last 1,500 years. Age-related growth declines were removed by aligning all increments relative to age of increment formation and fitting with a single detrending curve to preserve low-frequency signals. The geoduck chronology was used to reconstruct local SST variability across the seasonal window of April through November. The chronology at both the concurrent (lag-0) and following (lag+1) year are both highly significant predictors of SST in a stepwise multiple linear regression, explaining 54% of the variance in the period of instrumental overlap (1940-2001), passing strict tests of calibration-verification. Reconstructed SSTs contained significant spectral power at periods from 3 to 64 years, suggesting that 20th century variability in these periodicities is not unusual in the longer-term context. The period of lowest growth coincided with the Dalton minimum, an episode of reduced solar irradiance from 1790-1830, as well as the 1809 Unknown eruption, suggesting that solar and volcanic signals are present in the SST history. The most conspicuous aspect of the reconstruction is the steady and unprecedented warming trend that began in the mid-1800s and continues through present. The post-1976 interval includes the two warmest decades of the reconstruction. [ABSTRACT FROM AUTHOR]

Species that migrate long distances or between distinct habitats— for example, anadromous or catadromous fish—experience the consequences of climate change in each habitat and are therefore particularly at risk in a changing world. Studies of anadromous species often focus on freshwater despite the ocean's disproportionate influence on survival and growth. To understand a prominent anadromous species' response to ocean climate, we use a new spatio‐temporal model jointly estimating the ocean distribution of all major fall‐run Chinook salmon (Oncorhynchus tshawytscha, Salmonidae) stocks from California to British Columbia over 40 years. We model hundreds of millions of tagged individuals, finding that different stocks have fundamentally different ocean distributions, distinct associations with sea surface temperature (SST), and contrasting distributional responses to historical ocean SST variation. We show species‐level estimates of ocean distribution that ignore among‐stock variation will lead to errant predictions of spatial distribution. Using future (2030–2090) SST projections to model focal stocks of fisheries importance we predict substantial ocean redistribution in response to SST change. Predicted aggregate distributional changes do not follow a simple, poleward shift. Instead, we predict net movement into some ocean regions (British Columbia, central California) but net movement out of others (northern California, Washington). Distribution shifts have implications for both major fisheries and marine mammal predators of Chinook salmon. We focus on the consequences of spatial changes in ocean distribution, but our approach provides a general structure to link marine and freshwater components of anadromous species under climate change. [ABSTRACT FROM AUTHOR]

Background: Vibrio growth in the environment is related to sea surface temperature (SST). The incidence of human Vibrio illness increased sharply in British Columbia (BC) between 2008 and 2015 for unknown reasons, culminating in the largest outbreak of shellfish-associated Vibrio parahaemolyticus (Vp) in Canadian history in 2015. Our objective was to assess the relationship between SST and Vibrio illness in BC, Canada during 1992-2017 and assess the role of SST and other environmental factors in the 2015 Vp outbreak.Methods: Cases of Vibrio infection reported to the BC Centre for Disease Control during 1992-2017 were used. SST data were obtained from NOAA and NASA. We assessed changes in incidence trend of annual Vibrio cases during 1992-2017 using a Poisson regression. We assessed the correlation between annual Vibrio cases and the average annual maximum SST using a Spearman rank-order correlation. We modeled the association between weekly Vp case counts, SST and other environmental factors during 2007-2017 using a Poisson regression.Results: There was a significant increase in Vibrio cases between 2008 and 2015 (annual slope = 0.163, P < 0.001). Increased Vibrio incidence was observed in most El Niño years. There was a significant correlation between annual Vibrio cases and maximum SST from 1992 to 2017 (r = 0.46, P = 0.018). Our model captured observed seasonal variation in shellfish-associated Vp in most years, but underestimated the 2015 Vp outbreak.Conclusions: Vibrio incidence has been increasing concurrently with increasing SST in BC during 2008-2015. The 2015 Vp outbreak was not fully explained by climatic factors and may in part have been associated with other factors. Vp subtyping would be useful in the future to understand the combined effects of SST changes and strain emergence. [ABSTRACT FROM AUTHOR]

Aim: We modelled isoscapes in the Northeast (NE) Pacific using satellite‐based data, with the main objective of testing whether isoscapes defined by a few key parameters can be used as a proxy for secondary productivity. Location: Northeast Pacific; 46–60° N and 125–165° W. Time period: From 1998 to 2017 (ongoing). Major taxa studied: Zooplankton, with a focus on large herbivores. Methods: Approximately 280 summer zooplankton samples were analysed for carbon (δ13C) and nitrogen (δ15N) stable isotope (SI) ratios. Environmental conditions experienced by zooplankton organisms were extracted from satellite, in situ sensor and model databases. A generalized additive model approach was used to explain the spatial variability of δ13C and δ15N values and to predict isoscapes. Results: Sea surface temperature (SST), sea level anomaly (SLA) and chlorophyll‐a concentration emerged as the significant SI predictors. Modelled isoscapes reproduced patterns observed in δ13C and δ15N value distribution, such as a decrease from the coast to offshore. The contribution of eddies in enhancing local production in the open ocean was also well captured by the models. In the central part of the NE Pacific, higher SI values were correlated with higher large copepod biomass measured by the North Pacific Continuous Plankton Recorder (CPR) survey. However, in the area off the coast of British Columbia, high δ15N variability appeared to be associated with episodic intrusions of coastal waters, demonstrating that caution is needed when interpreting sharp changes in SI ratios. Main conclusions: Although the mechanisms driving SI ratio variability are complex, we demonstrate that a few parameters used as a proxy for some of these major mechanisms are able to produce successful isoscape models. This approach was proved useful to provide a qualitative estimate of secondary production, which can be particularly valuable in a region where few data are available. [ABSTRACT FROM AUTHOR]

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Historical ecology can provide insights into the long-term and complex relationships between humans and culturally important species and ecosystems, thereby extending baselines for modern management. We bring together paleoecological, archaeological, and modern clam records to explore the relationship between humans and butter clams (Saxidomus gigantea) throughout the Holocene in the northern Salish Sea of British Columbia, Canada. We compare butter clam size and growth patterns from different temporal, environmental, and cultural contexts spanning 11,500 y to present. Butter clam size and growth were restricted in early postglacial times but increased over the next few millennia. During the early-Late Holocene, humans took increasing advantage of robust clam populations and after 3.5 ka, began constructing clam gardens (intertidal rock-walled terraces). Environmental and cultural variables, including coarse substrate, stabilized sea surface temperature, and the presence of a clam garden wall, increased clam growth throughout the Holocene. Measurements of clams collected in active clam gardens and deposited in middens suggest that clam gardens as well as other mariculture activities enhanced clam production despite increased harvesting pressure. Since European contact, decline of traditional management practices and increases in industrial activities are associated with reduced clam size and growth similar to those of the early postglacial clams. Deeper-time baselines that more accurately represent clam population variability and allow us to assess magnitudes of change throughout time as well as the complex interactions among humans and clams are useful for modern marine resource management. [ABSTRACT FROM AUTHOR]

In recent years, extreme weather has frequently occurred worldwide and caused significant disasters, including large-scale forest fires, rare heat waves, heavy rains, floods, and tornadoes. Those have caused unprecedented losses of human lives and property in some countries, affecting the livelihoods of many people. Climate change and natural disasters are the two hotspots of scientific research today, and there is a certain degree of correlation between the two. Although countries worldwide have long known about climate change and its threats to human existence and have been discussing countermeasures, they have still not been able to carry out concerted and practical actions. The study takes Canada as an example, and selects six representative provinces to evaluate the temporal change characteristics of extreme temperature at different sites. We use MATLAB software to perform multiple linear regression, linear fitting methods, and Pearson correlation analysis to analyze spatial changes and time-space trends. The method studies the relationship between the emergence of extreme weather and climate change and uses the evolutionary game theory to explore whether there is any contradiction between global warming and extreme local cold. The study found: (i) The maximum temperature of most provinces in Canada will be constantly higher, and the minimum temperature will be lower. Generally speaking, the average temperature of each year is slowly decreasing. (ii) The average temperature data of British Columbia (Eastern Pacific) and Quebec (West Atlantic) show that ocean temperature has a specific effect on land temperature in surrounding areas. (iii) Pearson correlation analysis shows that the emergence of extreme weather is closely related to climate change. (iv) The evolution path of the two-party game shows that global warming and the occurrence of extreme local cold are not contradictory. Under the conditions, there is a certain degree of synchronization between the two, interacting and influencing each other. [ABSTRACT FROM AUTHOR]