Canadian Marine Research Articles

Climate bottlenecks off Newfoundland and Labrador for Atlantic cod in relation to eastern Canadian marine protected areas

Climate change presents challenges for marine area-based conservation measures through altered habitat and associated species range shifts. We conducted statistical downscaling for the eastern Canadian coastal domain over a range of global climate models, focusing on habitat suitability for Atlantic cod ( Gadus morhua), a numerically depressed, but ecologically, economically, and culturally important species in this region. We examined cod egg survival, juvenile growth, and spawning habitat suitability, combining these into one habitat index to compare within-closure habitat suitability for multiple life stages through time. Areas of high cod egg habitat suitability are projected to shift northward and increase across all area closures studied, while optimum juvenile habitat shifts north and eastward, increasing in almost all closures except the south. Spawning habitat as a function of temperature and oxygen will likely decrease through time across the entire region, but less in northern locations. Overall cod habitat is forecasted to decline in the south of the region while increasing at central and northern latitudes, highlighting the importance of existing and developing northern shelf area closures. While warming will bring temperatures closer to optimum levels for cod in this cold-water system, oxygen limitation will become more prevalent in the south of the region and should be monitored as an important ocean health indicator.

Is scientific inquiry still incompatible with government information control? A quarter-century later

Twenty-six years ago, in response to regionally devastating fisheries collapses in Canada, Hutchings et al. asked “Is scientific inquiry incompatible with government information control?” Now, a quarter-century later, we review how government science advice continues to be influenced by non-science interests, particularly those with a financial stake in the outcome of the advice. We use the example of salmon aquaculture in British Columbia, Canada, to demonstrate how science advice from Fisheries and Oceans Canada (DFO) can fail to be impartial, evidence-based, transparent, and independently reviewed—four widely implemented standards of robust science advice. Consequently, DFO's policies are not always supported by the best available science. These observations are particularly important in the context of DFO having struggled to sustainably manage Canada's marine resources, creating socio-economic uncertainty and putting the country's international reputation at risk as it lags behind its peers. We conclude by reiterating Hutchings et al.’s unheeded recommendation for a truly independent fisheries-science advisory body in Canada to be enshrined in the decision-making process.

Connecting conservation & culture: The importance of Indigenous Knowledge in conservation decision-making and resource management of migratory marine species

Migratory marine species (e.g., seabirds, marine mammals, fish, and sea turtles) cross and connect distant communities and ecosystems throughout their transboundary journeys. Due to their multi-jurisdictional and cross-cultural movements, studying, managing, and protecting migratory marine species as well as their habitats and migration routes are deeply political and geographically complex tasks. Despite a place-based cultural connection to migratory marine species; inherent rights, responsibilities, and authority to manage Sea Country (marine territory), Indigenous communities are far too often excluded from marine conservation decision-making. In this paper we conduct a narrative review and synthesis of relevant literature and analyze four community-driven case studies (both terrestrial and marine) that recognize the incorporation of Indigenous knowledge to support the governance and management of a culturally significant migratory species. The case studies are presented from an Australian Sea Country context as well as from a Canadian marine territory setting. Together these case studies highlight how Indigenous knowledge can increase the understanding of connectivity as well as provide a spatio-temporal baseline for species with limited science-based knowledge. It is essential that Indigenous communities as rights holders to Sea Country (marine territory) and owners of vast amounts of relevant marine knowledge be at the forefront of migratory marine species conservation decision-making for both coastal and distant offshore areas such as Areas Beyond National Jurisdiction. Bringing Indigenous knowledge and scientific monitoring data together has the potential to respond to Indigenous priorities for Sea Country and further contribute to the understanding of migratory marine species distribution, abundance, life cycles, threats, and oceanic connectivity.

Environmental characterization of the estuarine zone of the Gulf of Montijo, province of Veraguas, Panama.

The study was performed in the Republic of Panama. Panama has a coastline of 2,988.3 km, of which 1,700.6 km corresponds to the Pacific coast. Most of the coast is flat, and several geomorphological features characterize the Panamanian coastal sector, such as the Gulf of Montijo, which is located towards the west of the Panamanian Pacific coast in the province of Veraguas. The Gulf is a remarkable ecosystem of mangroves well preserved and internationally recognized as a Ramsar area. It represents the buffer zone of Coiba Island (Coiba National Park). Sixteen sampling stations were established along the coast to analyze the vertical and spatial variability of physical and chemical parameters (temperature, salinity, dissolved oxygen, pH, and conductivity). The quality of unexposed marine sediment was evaluated in four samples from the western sector of the Gulf of Montijo. The marine sediment samples were collected with a Dietz-LaFond Snapper dredge, between 1.5 and 3.0 m depth. Physical and chemical observations and marine sediment sampling were carried out during high tide +4 to low tide +3, in negative syzygy phase tide. The analysis of the oceanographic conditions, especially the physical and chemical properties of the water along with the longitudinal profile, showed a conservative distribution increasing gradually towards the outer region in an approximately linear way due to the dilution and mixing processes, both in the surface layer and at the bottom, and a not very developed vertical gradient, with slight stratification. The results of heavy metal analyses in marine sediments report high cadmium concentrations along the west coast, with concentrations above the limit levels of the Canadian marine sediment quality guidelines. The study area requires continuous monitoring that is representative of seasonality (dry, intermediate, and rainy periods), including a more significant number of stations since it is evidence of an affectation of the environmental quality of the marine ecosystem due to possible anthropogenic activities.

Canada's marine carbon sink: an early career perspective on the state of research and existing knowledge gaps

Improving our understanding of how the ocean absorbs carbon dioxide is critical to climate change mitigation efforts. We, a group of early career ocean professionals working in Canada, summarize current research and identify steps forward to improve our understanding of the marine carbon sink in Canadian national and offshore waters. We have compiled an extensive collection of reported surface ocean air–sea carbon dioxide exchange values within each of Canada's three adjacent ocean basins. We review the current understanding of air–sea carbon fluxes and identify major challenges limiting our understanding in the Pacific, the Arctic, and the Atlantic Ocean. We focus on ways of reducing uncertainty to inform Canada's carbon stocktake, establish baselines for marine carbon dioxide removal projects, and support efforts to mitigate and adapt to ocean acidification. Future directions recommended by this group include investing in maturing and building capacity in the use of marine carbon sensors, improving ocean biogeochemical models fit-for-purpose in regional and ocean carbon dioxide removal applications, creating transparent and robust monitoring, verification, and reporting protocols for marine carbon dioxide removal, tailoring community-specific approaches to co-generate knowledge with First Nations, and advancing training opportunities for early career ocean professionals in marine carbon science and technology.

A Comprehensive Review of Canadian Marine Oil Spill Response System through the Lens of Decanting Regulations and Practices

Marine oil spill response operations could generate a large volume of liquid oily wastes (e.g., emulsified oil, non-emulsified oil, and wastewater) that can be up to 30 to 40 times greater than the original volume of spilled oil. Oil decanting technologies are used globally for recovering spilled oil and handling liquid wastes. Canada follows the standards set out in the MARPOL 73/78 Annex 1 International regulations in most areas, with more strict discharge requirements in certain locations. For instance, inland waters discharge should not exceed 5 ppm, and in special areas, such as the Great Lakes, the discharge standard is under 0 ppm. In the event of an oil spill, decanted seawater should be barged to shore for disposal, which significantly constrains the response capacity and efficiency of oil recovery by skimmers due to limited temporary storage space in barges and the long time and high cost of transportation. This has become one of the greatest challenges the Canadian governments and oil spill response industries are facing in Canada. Moreover, when the spill response team decides that decanting is an appropriate way to handle the spilled oil, the approval process may take a long time, which negatively impacts the spill that has already occurred. Moreover, Canada uses a 10,000-tonne planning standard for oil spill preparedness, whereas the United States uses a worst-case scenario, and Europe uses a 60,000 m3 planning standard. The existing planning threshold in Canada can cause the country to be not fully prepared when it comes to responding to a very large oil spill if one should occur. This study conducted a comprehensive review of the current Canadian oil spill response system and framework, regulations, roles and responsibilities of federal and provincial governments, existing decanting capabilities, and capacities of Canadian oil spill responders. More importantly, this study identified the gaps in the current oil spill response system and regulatory and technological barriers to oil decanting. Marine oil decanting regulations and practices in the US and selected European countries have also been reviewed to support addressing the challenges and improving the Canadian experience. It is expected that this study would help the stakeholders and professionals to better understand the oil spill response system and oil decanting status quo in Canada and facilitate Canadian governments and industries to better address the challenges in oil spill regulations and practices.

A climate-resilient marine conservation network for Canada

Climate change and biodiversity loss are twin crises that are driving global marine conservation efforts. However, if unaccounted for, climate change can undermine the efficacy of such efforts. Despite this, integration of climate change adaptation and resilience into spatial marine conservation and management has been limited in Canada and elsewhere. With climate change impacts becoming increasingly severe, now is the time to anticipate and reduce impacts wherever possible. We provide five recommendations for an inclusive, proactive, climate-ready approach for Canada’s growing marine conservation network: (1) integrating climate-resilience as a universal objective of the Canadian Marine Conservation Network, creating and implementing (2) national transdisciplinary working groups with representation from all knowledge holders and (3) necessary tools that integrate climate change into conservation design, (4) defining operational and climate-relevant monitoring and management objectives, and (5) strengthening communication and increasing knowledge exchange around the roles and benefits of protected areas within government and towards the public. Canada’s extensive marine and coastal areas reflect national and international responsibility to engage on this issue. Canada is well positioned to assume a leading role in climate change adaptation for marine conservation and help accelerate progress towards international commitments around mitigating ongoing biodiversity loss and climate change.

Canadian Aquaculture: Supporting the need to develop sentinel surveillance programs for antimicrobial resistance among Canadian marine aquaculture facilities

BACKGROUND AND AIM: Marine aquaculture is a rapidly expanding industry globally. Antimicrobial resistance (AMR) stemming from aquaculture is a public and occupational health concern but is poorly understood. Prescribed antibiotics are administered via fish-feed to treat infected fish, which also non-selectively exposes healthy stocks to the agents and increases antibiotic loads in surrounding environments. Consequential selection and amplification of AMR bacteria may create hotspots affecting aquaculture workers and their communities via consumption of contaminated fish and through direct or indirect occupational and environmental exposures to contaminants. Mitigative efforts have purportedly reduced antibiotic use but past and contemporary impacts on AMR exposures are unknown. This case study will identify regulatory and data gaps that currently hinder the implementation of sentinel surveillance strategies in Canada. METHODS: i) Profile antibiotic use by Canada’s marine aquaculture industry from 2016 to 2018 in comparison with other global industry leaders. ii) Comparative analysis of regulatory regime and surveillance differences across aquaculture-practicing leaders. RESULTS:Public reporting reveals Canadian marine aquaculture’s use of antibiotics was higher than reported in Norway, but lower than reported in Chile. There is no standardized monitoring for AMR via aquatic contaminants or identification of potential pathways from those contaminants to aquaculture workers and communities in Canada. This situation is somewhat different in other countries. Current data repositories are insufficient to elucidate the extent of human and environmental risk stemming from AMR emergence from within and around aquaculture sites. CONCLUSIONS:Canada should develop protective sentinel surveillance programs, but currently lacks the baseline studies required to stimulate evidence-based dialogue. Harmonization of data collection across jurisdictions can help define factors that increase selection pressure for the development of AMR in aquaculture settings. Furthermore, coordinated data management at the public health level can help flag health challenges potentially emerging from environmental exposures to AMR bacteria. KEYWORDS: Policy and practice, Pharmaceuticals, Occupational exposures

A revised coastal sensitivity index for Canada’s marine coasts calculated using nonparametric statistics

A coastal sensitivity index (CSI) is a measure of the sensitivity of a coastline to its physical environment, which provides information useful for coastal management. Traditionally, a CSI is calculated as the mathematical aggregation of coastal sensitivity indicators, which may include factors such as coastal material, relief, and wave energy. The indicators differ depending on study area, but generally are assigned a score ranging from one to five in order of increasing sensitivity. These scores are then aggregated using either the square root of the product mean (the “classic” method) or the geometric mean. Both of these methods are limited by mathematical assumptions, lack of comparability, and the need for empirical validation. In this study, we applied an alternative nonparametric method of calculation, known as μ-statistics, to Canada's marine coasts to provide an improved measure of coastal sensitivity. μ-statistics, which offer a mathematically sound method of aggregating ordinal indicators, have a number of theoretical advantages over the classic and geometric mean methods. In practice, when applied to Canada’s marine coasts, we find that the μ-statistics method (1) compresses the mid-range variability in the resulting sensitivity index, (2) accentuates positive and negative distribution tails, and (3) minimizes propagated errors by 190% and 50%, respectively, compared with the classic and geometric mean methods. Additionally, the μ-statistics method has a theoretical foundation that relieves the necessity to empirically validate the aggregating assumptions and relies only on the assumptions inherent in the scoring method. μ-statistics thus provide a new, rigourous method for the calculation of coastal sensitivity indices when the underlying variables have ordinal scores.

United States and Canada Transboundary Oil Spill Liability and Compensation Regimes: An Overview

Abstract # —1141278 — In 2018, the Canadian government purchased the Trans Mountain pipeline, running from Alberta to British Columbia, along with the plans for expansion. The expansion could triple the transport capacity from 300,000 to 890,000 barrels of oil per day, and would increase the tanker traffic in the inland waterways of the Salish Sea, an area known for its sensitive marine habitat, and narrow, difficult to navigate passages. The anticipated increase in tanker traffic in this busy waterway continues to raise concerns about the impact of an oil spill and the financial means to address related injuries, particularly to natural resources. The transboundary nature of any spill further complicates the situation vis-à-vis the applicable liability regimes and response resources. Under the Canada-United States Joint Marine Contingency Plan (“JCP”), the United States Coast Guard and Canadian Coast Guard acknowledge each country's responsibility to fund their own response actions and pursue reimbursement of those costs within their respective jurisdictions. The availability of funding for a response, and to compensate injured parties, however, including the limits of liability of the responsible party, differs under each regime, and could impact the nature and scope of a response. For spills into or posing a substantial threat to the navigable waters of the United States, the Oil Pollution Act of 1990 governs and a national fund, the Oil Spill Liability Trust Fund (“OSLTF”), is immediately available to address an incident, including emergency restoration to natural resources. Canada's Marine Liability Act enables the Ship-source Oil Pollution Fund (“SOPF”) to pay claimants who have incurred damages as a result of oil pollution. Both countries' funds operate under the same principal—the polluter pays—but the compensation structure, and claims processes and procedures are entirely different. This paper provides an overview of these funding sources and claims procedures, comparing and contrasting the different systems. The discussion is meant to provide an overall understanding of potential funding pools available for spill responses under each scheme in order to facilitate transboundary spill planning and discussion.

Coastal Communities and Response Planning

Abstract The Coastal Response Program is a Western Canada Marine Response Corporation (WCMRC) initiative that brings existing response programs under one umbrella. The objective is to enhance these interrelated initiatives and ensure they have coordinated support to maintain an operational ready state. The program improves WCMRC's overall capacity by building strong relationships with industry, coastal communities and First Nations by involving them in spill response in a meaningful way. This paper will provide an update on how WCMRC is rolling out the program on Canada's west coast and will discuss some of the benefits and challenges that WCMRC has experienced. While local issues will bring unique challenges to every jurisdiction, some of the broader principles of the community involvement under the Coastal Response Program can help other response organizations and coastal communities be better prepared.

Geographic Response Strategies on Canada's West Coast

Abstract In 2012, Western Canada Marine Response Corporation (WCMRC) began developing site specific shoreline protection strategies, known at Geographic Response Strategies (GRS) for the entire coast of British Columbia (B.C.). The project started in Vancouver Harbour and has since spread along the Salish Sea and Strait of Juan de Fuca, as well as into Prince Rupert and Kitimat on the northern B.C. coast. Recognizing that B.C. has approximately 27,000 km of coastline (~16,777 miles) and with 450 strategies already developed only within a few hundred kilometres, WCMRC saw a need to automate the GRS development process from data collection all the way to the final GRS output. In conjunction with a local environmental consulting company, WCMRC developed a new sensitivity model. This new model can help the Response Readiness Team quickly assess intertidal sensitivity to oiling based on shoreline type, oil residency index, biological, archaeological, and/or socio-economic features of the shoreline, as well as operational protection feasibility. Now, using ESRI GIS web tools, a GRS can be developed automatically as a geo-referenced PDF, easily exportable to mobile devices for operational use. Overall, the automated enhancements have provided WCMRC with the tools necessary to manage the GRS program for B.C.'s entire coast. This means that more coastline can be assessed far more quickly and GRS's can be developed using fewer human resources. Additionally, if a spill occurs in a more remote area that has not yet had GRS's developed, they can be created within minutes based on the information from the Environment Unit in the Incident Command Post, or initial assessments by responders.

Occupational safety and health in marine aquaculture in Atlantic Canada: What can be learned from an analysis of provincial occupational injury compensation claims data?

BackgroundCommercial aquaculture employs roughly 19 million workers globally, yet research on aquaculture occupational safety and health is extremely limited, including in developed countries like Canada. Analyses of injury and fatality compensation claims data from Scandinavian countries, Australia, the United States, and Brazil reveal aquaculture is a high-risk industry, associated with multiple hazards and high injury and fatality rates. Marine aquaculture takes place on Canada's east and west coasts. It is expanding in Atlantic Canada where it consists mainly of salmon and shellfish production. This paper presents results from a descriptive analysis of data on accepted compensation claims for injured Atlantic Canada marine aquaculture workers. MethodsWorkers' compensation in Canada falls under provincial jurisdiction. Anonymous claims data between 1996 and 2017, provided by four Atlantic provincial compensation boards, captured injury claims broadly specific to the aquaculture industry, supporting a descriptive analysis of incidence rates and injury characteristics. ResultsAcross provinces, lost time injury rates among aquaculture workers fluctuated over time, but exceeded recent overall average provincial rates from 2010 to 2016. Consistent across provinces, almost half of all marine aquaculture injuries were caused by bodily reaction and (over)exertion (mean = 15.0%; SD = 6.4%), falls (14.4%; SD = 2.3%), or being struck by or against an object (mean = 13.7%; SD = 2.2%). Roughly half of the injuries were of three types: traumatic injuries to muscles, tendons, ligaments, and joints (mean = 33.0%; SD = 3.7%), open wounds (mean = 10.1%; SD = 2.5), and surface wounds and bruises (mean = 10.0%; SD = 5.2%). The back, including spine and spinal cord was the body part most commonly affected by workplace injuries (mean = 17.2%; SD = 1.4%), followed by leg(s) (mean = 10.8%; SD = 0.5%), and finger(s)/ fingernail(s) (mean = 10.4%, SD = 4.4%). ConclusionFindings indicate marine aquaculture workers are suffering from similar injuries (injury event, nature and source of injury, body parts) across provinces and these are similar to aquaculture sector injury claims patterns in Norway, Finland, Australia, and the United States. The high incidence rates are a strong signal that marine aquaculture in Canada, as elsewhere, is a hazardous sector. Compensation claims rates exceed overall provincial averages and have not declined. Ongoing surveillance, hazard assessments, and identification and implementation of prevention strategies could help this expanding industry reduce rates of injuries and illnesses.

Screening for High-Risk Marine Invaders in the Hudson Bay Region, Canadian Arctic

The Canadian Arctic is receiving increased ship traffic, largely related to non-renewable resource exploitation and facilitated by climate change. This traffic, much of which arrives in ballast, increases opportunities for the spread of aquatic invasive species (AIS). One of the regions at greatest risk is the Hudson Bay Complex. A horizon scanning exercise was conducted using the semi-quantitative Canadian Marine Invasive Screening Tool (CMIST) to identify AIS of potential concern to the region. This screening-level risk assessment tool, uses documented information to answer questions related to the likelihood and impact of invasion. Species were analyzed by ecological categories (zoobenthos, zooplankton, phytobenthos) and taxonomic groups, with 14 species (out of 31) identified as being of highest relative risk. Crabs, mollusks, macrozooplankton and macroalgae were the taxonomic groups with the highest overall risk scores, through a combination of higher likelihood of invasion and impact scores relative to other taxa. Species that may pose the highest AIS risk are currently mainly distributed on the east and west coasts of the North Atlantic Ocean. Their distributions coincide with source ports and shipping pathways that are well connected to the Hudson Bay Complex. This first horizon scan to identify potential high-risk AIS for the Canadian Arctic incorporated two novel approaches into the CMIST analysis: i) use of the tool to assess two new ecological categories (phytobenthos and zooplankton), and ii) use of averaged CMIST results to interpret general risk patterns of ecological categories. This study is also the first to use CMIST scores to highlight common source regions and connected ports for the highest risk species. In a scenario of climate change and increasing ship traffic, this information can be used to support management actions such as the creation of watch lists to inform adaptive management for preventing AIS establishment, and mitigating associated environmental and economic impacts.

A decision support tool to prioritize ballast water compliance monitoring by ranking risk of non‐indigenous species establishment

Abstract Despite the availability of research which has direct applications to environmental management, there is often a disconnect between scientific research and applied management that presents challenges for using academic knowledge in day‐to‐day operations by non‐scientists. A science‐based decision support tool was developed in partnership with Canada's marine authority, Transport Canada, for use by ballast water inspectors in their daily operations to inform prioritization of ships for regulatory compliance inspections. This science‐based tool combines information on the two primary pathway‐level predictors of species establishment success: environmental matching between source and recipient locations and propagule pressure (introduction effort), to generate risk estimates and relative rankings using data taken directly from ballast water reporting forms submitted by arriving ships. This tool thus packages the best available scientific knowledge in such a way as to be readily accessible for day‐to‐day decision‐making. While this tool was developed for Canada, it could be applied in any country with very little, if any, modification. This tool can also be updated in the future to incorporate advances in scientific understanding of ballast‐mediated introductions of non‐indigenous species. Synthesis and applications. Partnerships between scientists and managers are essential for ensuring that best‐available science translates into effective adaptive management. Recognizing a need to inform ballast water management compliance inspections, a tool was created that automatically estimates relative risk of establishment of non‐indigenous species for arriving ships. This information can be used by ballast water inspectors developing priorities for resource‐limited regulatory compliance inspections.

An Analysis of Selected Oil Spill Case Studies on the Shorelines of Canada

After an oil spill, oil may wash ashore and there is only a short window of opportunity to respond. Analysis of historical incident data is valuable to guide future responses and cleanup practices. This study summarized the oil spill accidents that impacted the Canadian shoreline and analyzed the related information including location, incident characteristics, and shoreline treatment. Major spills due to tanker accidents in Canadian marine waters fortunately have been infrequent. Most of the accidents have happened on Canada’s Pacific coast, accounting for 52% of the total accidents recorded. The Atlantic coast accounted for 39% and the remaining accidents happened in the Arctic region. Regarding spilled volume, 55% of the accidents spilled oil volumes smaller than 100 m3. Spilled volumes between 100 ~ 1000 m3 represent 30% of the incidents and 15% had spilled volume greater than 1000 m3. Bunker C fuel and diesel were the main types of the spilled oil, accounting for 33% of the spills, respectively. Within the oil spill accidents impacting Canadian shore- lines, marine vessel accidents were the major sources accounting for 70% of the spill accidents. In terms of the shoreline treatment, the commonly employed treatments were manual, vacuum, mechanical, and sorbent removal. The dataset highlighted the significance of a more comprehensive record for response phase details and environmental effects monitoring.

An Analysis of Selected Oil Spill Case Studies on the Shorelines of Canada

After an oil spill, oil may wash ashore and there is only a short window of opportunity to respond. Analysis of historical incident data is valuable to guide future responses and cleanup practices. This study summarized the oil spill accidents that impacted the Canadian shoreline and analyzed the related information including location, incident characteristics, and shoreline treatment. Major spills due to tanker accidents in Canadian marine waters fortunately have been infrequent. Most of the accidents have happened on Canada’s Pacific coast, accounting for 52% of the total accidents recorded. The Atlantic coast accounted for 39% and the remaining accidents happened in the Arctic region. Regarding spilled volume, 55% of the accidents spilled oil volumes smaller than 100 m3. Spilled volumes between 100 ~ 1000 m3 represent 30% of the incidents and 15% had spilled volume greater than 1000 m3. Bunker C fuel and diesel were the main types of the spilled oil, accounting for 33% of the spills, respectively. Within the oil spill accidents impacting Canadian shore- lines, marine vessel accidents were the major sources accounting for 70% of the spill accidents. In terms of the shoreline treatment, the commonly employed treatments were manual, vacuum, mechanical, and sorbent removal. The dataset highlighted the significance of a more comprehensive record for response phase details and environmental effects monitoring.

Shear behaviour of Canadian marine clay/geomembrane interface under freeze–thaw cycles

The influence of the number of freeze–thaw (F–T) cycles on the interface shear behaviour of a compacted marine clay (Leda clay)/smooth high-density polyethylene (HDPE) geomembrane is investigated in this paper. Shear tests are performed on samples subjected to various numbers of F–T cycles: zero, one, two, three, five and ten. The test results show that the interface shear strength of the Leda clay/smooth HDPE geomembrane is lower than that of Leda clay. The interface shear strength of the Leda clay/smooth HDPE geomembrane decreases with increasing number of F–T cycles. Furthermore, the interface shear friction angles of the Leda clay/smooth HDPE geomembrane are significantly reduced within the first three F–T cycles. The reduction in strength beyond the three F–T cycles is negligible. The total decrease in the shear strength of the samples that are not subjected to an F–T cycle compared to that of samples subjected to ten F–T cycles is 18·3, 17·6 and 13·6% under a vertical stress of 150, 250 and 350 kPa, respectively.

Copy number variants outperform SNPs to reveal genotype-temperature association in a marine species.

Copy number variants (CNVs) are a major component of genotypic and phenotypic variation in genomes. To date, our knowledge of genotypic variation and evolution has largely been acquired by means of single nucleotide polymorphism (SNPs) analyses. Until recently, the adaptive role of structural variants (SVs) and particularly that of CNVs has been overlooked in wild populations, partly due to their challenging identification. Here, we document the usefulness of Rapture, a derived reduced-representation shotgun sequencing approach, to detect and investigate copy number variants (CNVs) alongside SNPs in American lobster (Homarus americanus) populations. We conducted a comparative study to examine the potential role of SNPs and CNVs in local adaptation by sequencing 1,141 lobsters from 21 sampling sites within the southern Gulf of St. Lawrence, which experiences the highest yearly thermal variance of the Canadian marine coastal waters. Our results demonstrated that CNVs account for higher genetic differentiation than SNP markers. Contrary to SNPs, for which no significant genetic-environment association was found, 48 CNV candidates were significantly associated with the annual variance of sea surface temperature, leading to the genetic clustering of sampling locations despite their geographic separation. Altogether, we provide a strong empirical case that CNVs putatively contribute to local adaptation in marine species and unveil stronger spatial signal of population structure than SNPs. Our study provides the means to study CNVs in nonmodel species and highlights the importance of considering structural variants alongside SNPs to enhance our understanding of ecological and evolutionary processes shaping adaptive population structure.

Three decades of Canadian marine harmful algal events: Phytoplankton and phycotoxins of concern to human and ecosystem health

Spatial and temporal trends of marine harmful algal events in Canada over the last three decades were examined using data from the Harmful Algal Event Database (HAEDAT). This database contains the most complete record of algal blooms, phycotoxins and shellfish harvesting area closures in Canada since 1987. This 30-year review of 593 Canadian HAEDAT records from 1988 to 2017, together with other Canadian data and publications, shows that recurring harmful algal events have been widespread throughout both the Atlantic and Pacific coastal regions. The 367 paralytic shellfish toxin (PST) reports revealed annual and frequent recurrence throughout both the Atlantic and Pacific regions, including multi-year PST events in the Bay of Fundy, the Estuary and Gulf of St. Lawrence and the Strait of Georgia. The 70 amnesic shellfish toxin (AST) records revealed no recognizable trend, as these events were usually area specific and did not recur annually. The increasing frequency of diarrhetic shellfish toxin (DST) events over the period of this review, in total 59 records, can be at least partially explained by increased sampling effort. Marine species mortalities caused by harmful algae (including diatoms, dictyochophytes, dinoflagellates, and raphidophytes), were a common occurrence in the Pacific region (87 reports), but have been reported much less frequently in the Atlantic region (10 reports). Notable Canadian records contained in HAEDAT include the first detection worldwide of amnesic shellfish poisoning (ASP), attributed to the production of domoic acid (an AST) by a diatom (Pseudo-nitzschia multiseries) in Prince Edward Island in 1987. The first proven case of diarrhetic shellfish poisoning (DSP) in Canada and North America was recorded in 1990, and the first closures of shellfish harvesting due to DST (associated with the presence of Dinophysis norvegica) occurred in Nova Scotia in 1992, followed by closures in Newfoundland and Labrador in 1993. In 2008, mass mortalities of fishes, birds and mammals in the St. Lawrence Estuary were caused by Alexandrium catenella and high levels of PST. During 2015, the Pacific coast experienced a large algal bloom that extended from California to Alaska. It resulted in the closure of several shellfish harvesting areas in British Columbia due to AST, produced by Pseudo-nitzschia australis. Data from the Canadian Arctic coast is not included in HAEDAT. However, because of the emerging importance of climate change and increased vessel traffic in the Arctic, information on the occurrence of harmful algal species (pelagic and sympagic = sea ice-associated) in that region was compiled from relevant literature and data. The results suggest that these taxa may be more widespread than previously thought in the Canadian Arctic. Information in HAEDAT was not always robust or complete enough to provide conclusions about temporal trends. Compilation of spatial and temporal information from HAEDAT and other records is nevertheless important for evaluating the potential role of harmful algae as a stressor on Canadian marine ecosystems, and will support the next step: developing a knowledge gap analysis that will establish research priorities for determining their consequences on human and ecosystem health.