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The disaggregated inorganic grain size (DIGS) of bottom sediment analyzed with a Coulter Counter (CC) has been used to show that the fraction of sediment deposited in flocs (floc fraction) increased in both the near and far field after the introduction of open cage salmon aquaculture, altering benthic habitat and species composition. As a result, DIGS was identified as a potential indicator of regional environmental changes due to aquaculture. Laser diffraction is an attractive alternative to the CC because of its greater efficiency and larger size range. To determine if a laser diffraction instrument, Beckman-Coulter LS 13 320 (LS), could replace the CC within a Canadian national aquaculture monitoring program, the DIGS of 581 samples from five different regions in eastern Canada were analyzed with an LS and a CC. Results show that the LS could not be used to calculate floc fraction. Instead, % sortable silt and the volume % of inorganic particles < 16 µm were evaluated as alternative proxies for fine sediment properties. LS and CC values for these parameters were correlated, but they were significantly different and the relationship between the instruments was dependent on the area sampled. The LS did not capture variations between areas seen in the CC DIGS data. Where the DIGS from the CC found no sorting in the finest size classes, all the LS samples had similar size distributions characterized by smooth modal peaks. The LS and CC both return values that can be used to monitor changes in the deposition of fine-grained sediment, but the LS cannot determine changes in floc deposition and caution is required if comparing different sedimentary environments. [ABSTRACT FROM AUTHOR]

Introduction: Ocean equity is a key aim of blue economy frameworks globally and is a pillar of the international High Level Panel for A Sustainable Ocean Economy. However, the Panel offers only a general definition of ocean equity, with limited guidance for countries. Canada, as a party to the High Level Panel's blue economy agenda, is developing its own blue economy strategy, seeking to reshape its ocean-based industries and advocate for new ones. How equity will be incorporated across scales is not yet known but has implications for how countries like Canada will develop their ocean-based industries. This raises important questions, including what are Canada's equity commitments in relation to its blue economy and how will they be met? Currently, the industries identified in Canada's emerging blue economy narratives are governed through both federal and provincial legislation and policies. These will shape how equity is implemented at different scales. Methods: In this paper, we examine how the term equity is defined in relevant federal and provincial legislation and look to how understandings of equity found in critical feminist, environmental justice, and climate justice scholarship could inform policy and its implementation within Canada's blue economy. We focus on two industries that are important for Canada's blue economy: offshore oil and marine salmon aquaculture in the Canadian province of Newfoundland and Labrador. We investigate how existing legislation and policy shapes the characterization, incorporation, and implementation of equity in these industries. Results and discussion: Our analysis highlights how a cohesive approach to ocean equity across the scales of legislation and policy is needed to ensure more robust engagement with social and environmental equity issues in blue economy discourse and implementation. [ABSTRACT FROM AUTHOR]

This article provides an overview of the working life of veterinarians in aquaculture, specifically focusing on salmon farming in Canada. It explains the two phases of salmon farming, the challenges of providing veterinary care in aquaculture, and the importance of water quality and environmental monitoring. Vaccination and routine disease screening are crucial tools used to prevent diseases in farmed salmon. The article also discusses the use of antibacterial and antiparasitic drugs in aquaculture, the regulations surrounding their usage, and the challenges faced by aquaculture veterinarians. It acknowledges the controversies surrounding salmon net-pen farming and concludes by highlighting the importance of fish farming in sustainable food production and coastal communities in Canada. [Extracted from the article]

Salmon aquaculture generates 80% of the total revenue of finfish aquaculture across Canada. Salmon farming is carried out in a multilevel process, and at least 60% of the total production is considered as by-products, including skin, head, viscera, trimmings, frames, bones, and roes. These by-products are an excellent source of protein, which can be converted to protein hydrolysates through enzymatic hydrolysis and non-enzymatic processes such as chemical hydrolysis (acid and alkaline) in order to utilize them into value-added products. Several studies have reported that peptides from salmon protein hydrolysates possess bioactivities, including antihypertensive, antioxidant, anticancer, antimicrobial, antidiabetic, anti-allergic, and cholesterol-lowering effects. Incorporating in silico computational methods is gaining more attention to identify potential peptides from source proteins. The in silico methods can be used to predict the properties of the peptides and thereby predetermine the processing, isolation, and purification steps that can be used for the peptides of interest. Therefore, it is essential to implement robust, standardized, and cost-effective processing techniques that can easily be transferrable and scale up for industrial applications in view of circular economy and upcycling concept. This contribution summarizes the latest research information on Atlantic salmon, production statistics, growth lifecycle, processing, protein production techniques, nutritional and functional properties, peptide production and purification processes, as well as potential health benefits as a nutraceutical product. [ABSTRACT FROM AUTHOR]

Aquaculture eco-certification is associated with some producer-level benefits including price premiums and market access; however, reputational benefits from eco-certification are unclear. A public survey was used to understand the effect of eco-certification on opinion of salmon farming in two Canadian provinces (British Columbia and Nova Scotia) and differences between communities where farms are located (communities of place) and communities geographically distant from farms (communities of interest). Eco-certification had an overall positive effect on opinion, especially amongst people with a negative opinion of salmon farming who value far-reaching social outcomes of farming. Communities of interest had a more negative opinion of salmon farming and eco-certified salmon farming and were more concerned about local environmental impacts than communities of place while communities of place valued economic outcomes more than communities of interest. The role of eco-certification in public acceptance of aquaculture is limited by a lack of trust in eco-certification and failure to address local issues including conflict amongst marine users. [ABSTRACT FROM AUTHOR]

Improving the status of endangered species can be challenging because the efficacy of conservation actions is often uncertain. Conservation aquaculture has been the main recovery action for endangered white sturgeon (Acipenser transmontanus) in the Transboundary Reach of the upper Columbia River. Using long-term mark-recapture data (2002–2018), we predicted variation in growth rates due to genetic, environmental, and competition effects to evaluate the efficacy of the aquaculture program. Environmental conditions (by season and country) and competition had the greatest effects on growth. Growth, length-at-age, weight-at-age, and condition factor were higher for fish residing in reservoir habitats (US) compared to those in riverine habitat (Canada). Growth declined over the study period but growth in length for larger fish remained higher in the US as fish > 100 cm fork length in Canada were not growing. Small differences in growth among families indicate that differences in genetics among parents spawned in the hatchery had negligible effects on growth in the wild. Our estimate of substantive negative density-dependent growth in Canada is important for management of conservation aquaculture for sturgeons. [ABSTRACT FROM AUTHOR]

Although exclusive common pool resource management regimes have locally been applied since time immemorial in many coastal and fjord areas, in the legal conceptualization of space, the oceans and their living resources were traditionally treated as a "global commons." The idea of restricting access to coastal oceanic resources and delegating their governance to state instruments has become increasingly popular since the middle of the previous century when political economy models predicted the eventual overexploitation or degradation of all resources used in common. While state jurisdictions overall continue to preserve the idea of common access to marine living resources for a state's people, the rapid privatization of marine living resources and the subsequent development of aquaculture over the last few decades, often confront this understanding, leading to enclosure of a delineated maritime area that was initially intended to be accessible to the public. Enclosing the sea for the purpose of aquaculture development leads to a semantic change in property institutions that govern coastal areas and provides for a form of enclosure of the commons in key locations designated for marine aquaculture development. This article explores the concept of "ocean commons" and debates how the enclosure of common areas for the purposes of aquaculture development may collide with Indigenous and local conceptions of common pool resource management. The article applies this theoretical investigation on two examples from Canada and Norway, and suggests that rethinking aquaculture development in coastal waters through the lens of "ocean commons" may provide a guiding ethos for revisiting current approaches of access to the sea and ensuring the harmonious coexistence between aquaculture development and local/Indigenous traditional activities. [ABSTRACT FROM AUTHOR]

In British Columbia (BC; Canada) Atlantic salmon (Salmo salar L.) production, Tenacibaculum members are associated with 'mouthrot' and disease identification is based on gross observation and clinical data. Genomic similarities (i.e., putative virulence factors) between T. ovolyticum and other better-characterized agents of mouthrot could imply potential pathogenicity. While T. ovolyticum has not been directly linked to salmon mortality events in BC, it has been isolated from diseased marine fish. To investigate T. ovolyticum's pathogenicity in situ, a T. ovolyticum 16S rDNA qPCR assay targeting a ~155 bp amplicon was developed. The assay was used to screen 67 biotic and 33 abiotic samples collected from a BC Atlantic salmon (Salmo salar L.) net-pen site before, during, and after a mouthrot outbreak. The assay was specific, quantifiable and detectable for T. ovolyticum over 6-log and 8-log units, respectively. However, cycle quotients differed between the BC isolate and type strain of T. ovolyticum, suggesting that qualitative use of the qPCR assay in field samples would be more accurate. Only two out of 100 samples were T. ovolyticum-positive, indicating limited involvement in this particular outbreak. However, the ecological role of T. ovolyticum and its involvement in the pathogenesis of other mouthrot outbreaks in Atlantic salmon is unknown. [ABSTRACT FROM AUTHOR]

Research in animal geographies is increasingly paying attention to hierarchies and inequalities within and between nonhuman animals. The way that animals are valued differently and hierarchically within this growing body of scholarship has tended to focus on a range of biopolitical differences between and within species. Collard and Dempsey's recent contribution, in contrast, points to the importance of hierarchy and difference in the valuation of nonhuman animals under capitalism. Their framework identifies five orientations of human and nonhuman bodies in relation to capitalist value, which in turn provides a heuristic to explore how capitalist accumulation produces and depends on differentially oriented natures. Our contribution to these debates – and to the Collard and Dempsey framework – draws on our ongoing research in Eastern Canada where salmon aquaculture is a growing yet highly contested industry. We focus on two instances of multispecies hierarchy and difference in and around the salmon cage that are central to this form of ocean-based production. In focusing on multispecies relations, we build on Collard and Dempsey's framework in two main ways. First, we show how valuation and devaluation reflect competing but relational capitalist interests, which rely on and produce different natures refracted through the logic of the nature/culture divide: Atlantic salmon are valued as game fish, and as the key species for Canada's aquaculture sector. Second, we show how capital's valuation of one species, in our case farmed salmon, implicates the valuation of others, namely sea lice and lumpfish. Our case studies extend Collard and Dempsey's framework by demonstrating how capitalist differentiation produces violence through and outside of commodification in terms of multispecies difference and hierarchy; the lives and futures of wild and farmed salmon, lumpfish and sea lice are entangled, and reflect relational and changing orientations to capitalist value over time. [ABSTRACT FROM AUTHOR]

Gene flow between wild and domestic populations has been repeatedly demonstrated across a diverse range of taxa. Ultimately, the genetic impacts of gene flow from domestic into wild populations depend both on the degree of domestication and the original source of the domesticated population. Atlantic salmon, Salmo salar, used in North American aquaculture are ostensibly of North American origin. However, evidence of European introgression into North American aquaculture salmon has accumulated in recent decades, even though the use of diploid European salmon has never been approved in Canada. The full extent of such introgression as well as the potential impacts on wild salmon in the Northwest Atlantic remains uncertain. Here, we extend previous work comparing North American and European wild salmon (n = 5799) using a 220 K SNP array to quantify levels of recent European introgression into samples of domestic salmon, aquaculture escapees, and wild salmon collected throughout Atlantic Canada. Analysis of North American farmed salmon (n = 403) and escapees (n = 289) displayed significantly elevated levels of European ancestry by comparison with wild individuals (p < 0.001). Of North American farmed salmon sampled between 2011 and 2018, ~17% had more than 10% European ancestry and several individuals exceeded 40% European ancestry. Samples of escaped farmed salmon similarly displayed elevated levels of European ancestry, with two individuals classified as 100% European. Analysis of juvenile salmon collected in rivers proximate to aquaculture locations also revealed evidence of elevated European ancestry and larger admixture tract in comparison to individuals collected at distance from aquaculture. Overall, our results demonstrate that even though diploid European salmon have never been approved for use in Canada, individuals of full and partial European ancestry have been in use over the last decade, and that some of these individuals have escaped and hybridized in the wild. [ABSTRACT FROM AUTHOR]

Sablefish (Anoplopoma fimbria) is a commercially valuable species in Canada with limited aquaculture development. In this study, we partner with Golden Eagle Sablefish in British Columbia (Canada) to assess the role of brood stock selection in hatchery production. Mortality in the hatchery setting is high, especially during the first year of development; thus, interventions that enhance early survival have the potential to dramatically improve productivity. Here, we determined the parentage of offspring produced by a brood stock population of 12 females and 6 males. Focusing on a 2019 hatchery cohort ('Implant 5 2019'), we sampled offspring at 9 months (N = 70) and 12 months of age (N = 124). We observed considerable family‐level variation in productivity; out of 30 crosses, 5 pairs produced 69% of the progeny. At the individual level, 5 of the 12 brood stock females produced 90% of the offspring surveyed, and 3 of the 6 males sired 93% of the offspring. These data provide strong support for the hypothesis that sablefish survival in the hatchery setting can be improved through selective breeding. [ABSTRACT FROM AUTHOR]

The salmon aquaculture industry is an important economic activity established on both the west and east coast of Canada. To control sea lice infestations, in-feed products like emamectin benzoate (EMB) are widely used. Due to its low solubility and persistence EMB can accumulate in marine sediments and be potentially bioavailable to non-target organisms from months to years. The American lobster (Homarus americanus) is a key species in the Northwest Atlantic with high economic and ecological value. It may be exposed to therapeutants considering lobster habitats overlap with aquaculture locations requiring a better understanding of the potential impact of these therapeutants through varied pathways of exposure. In this study, we investigated the exposure of gravid female lobsters to EMB spiked sediment to mimic the likely presence of these females at aquaculture sites for a 10-day period. We completed testing by assessing EMB effects on adult molting and quality, embryo hatching rates, and larval offspring quality and larval molting. Our results show that a single, 10-day exposure of ovigerous females to EMB concentrations higher than environmentally relevant values did not affect females or their offspring., Competing Interests: Declaration of competing interest The authors declare that they have no known competing interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2024. Published by Elsevier B.V. All rights reserved.)

The spread of pathogens from farmed salmon is a conservation concern for wild Pacific salmon in British Columbia (BC), Canada. Three pathogens are prevalent in farmed Atlantic salmon in BC, spill over to wild Pacific salmon, and are linked to negative impacts on wild salmon: Piscine orthoreovirus, Tenacibaculum spp., and sea lice ( Lepeophtheirus salmonis ). Molecular screening of infectious agents in farmed and wild salmon and environmental DNA highlights a further 4 agents that are likely elevated near salmon farms and 37 that co-occur in wild and farmed salmon. Pathogens likely affect wild salmon indirectly by mediating migration, competition, and predation. Current net-pen aquaculture practices pose these risks to numerous populations of all species of wild salmon in BC, most of which are not covered in Government of Canada science and advisory reports. Climate change, pathogen evolution, and changes to disease management and aquaculture regulations will influence future risks.

The ocean frontier has become central to a range of new and emerging strategies aimed at realizing the potential of the ocean economy. The purpose of this paper is to critically examine the configuration of the ocean as a frontier and its role in transforming marine spaces through the case of salmon aquaculture in Canada. To this end, we engage with 'frontier assemblage', an analytic that is developed from scholarship on agrarian and extractive resource frontiers in Asia. We use this approach to identify and extend three interrelated conceptual sensibilities. First, we use 'frontierization' to suggest that ocean frontier spaces are not only articulated at leading edges. Instead, frontierization happens at indeterminate sites, including those that have undergone earlier rounds of capitalist resource extraction. Second, we explore how ocean frontier resource extraction is assembled in ways that are indeterminate, but not radically open. Using the case of salmon aquaculture in Newfoundland, we show how resource extraction could have been 'otherwise'. Third, we critically assess the promissory politics that are key to the ocean frontier. We argue that the frontier assemblage analytic—and the sensibilities we use—provides an approach to critically assess strategies aimed at realizing the 'untapped' resources of the ocean frontier. [ABSTRACT FROM AUTHOR]

Oysters are enriched with high-quality protein and are widely known for their exquisite taste. The production of oysters plays an important role in the local economies of coastal communities in many countries, including Atlantic Canada, because of their high economic value. However, because of the changing climatic conditions in recent years, oyster aquaculture faces potentially negative impacts, such as increasing water acidification, rising water temperatures, high salinity, invasive species, algal blooms, and other environmental factors. Although a few isolated effects of climate change on oyster aquaculture have been reported in recent years, it is not well understood how climate change will affect oyster aquaculture from a systematic perspective. In the first part of this study, we present a systematic review of the impacts of climate change and some key environmental factors affecting oyster production on a global scale. The study also identifies knowledge gaps and challenges. In addition, we present key research directions that will facilitate future investigations. [ABSTRACT FROM AUTHOR]

Opportunist gulls use anthropogenic food subsidies, which can bolster populations, but negatively influence sensitive local ecosystems and areas of human settlement. In the eastern Gulf of Maine, Canada, breeding herring gulls Larus argentatus have access to resources from aquaculture, fisheries and mink farms, but the relative influence of industry on local gull populations is unknown. Our objectives were to 1) assess use of natural and anthropogenic habitats by herring gulls from multiple colonies, 2) evaluate variation among colonies in use of distinct resource types within these habitats and 3) highlight areas of high gull:industry interaction. Using GPS devices on 39 gulls from four colonies, we identified visitation behaviour (slow, localized movements) and assigned visits to nine resource types. To evaluate the spatial distribution of visits, we created a use intensity index, reflecting both fidelity (i.e. repeated visits) and time spent in specific areas. All four anthropogenic resource types were heavily used (56 ± 11% of visiting time across colonies), notably, fish plants and mink farms. Despite large distances among three colonies, birds overlapped at particular distant, inland mink farms. In contrast, birds from close colonies overlapped in visitation to specific nearby resources (e.g. fish plants and human settlement), and otherwise diverged in distribution and use of offshore and coastal areas. Birds from three colonies also made frequent, long visits to uninhabited islands. Industry is clearly influencing the behaviour of breeding gulls in the eastern Gulf of Maine, Canada, where birds are travelling great distances or spending large proportions of time interacting with anthropogenic resources, while otherwise paying lengthy visits to nearby coastal islands. Studies have shown that concentrations of gulls can have harmful direct and indirect ecological and societal impacts. Our findings have implications for the management and regulation of industry to mitigate detrimental effects on local ecosystems and humans. [ABSTRACT FROM AUTHOR]

This paper focuses on the availability of economic indicators and metrics to assess effects of marine aquaculture production in the North Atlantic area (the EU, Norway, Canada and USA), including also social and environmental effects. We consider how aquaculture planning and management is organised in the different countries and the usefulness of economic information to address different aquaculture‐related policies. We find that the most relevant economic data for aquaculture management should be at the local and regional levels rather than nationally. The availability of such economic data is mapped for national, regional and local level. The focus is on data that are publicly available from authorities or research institutions. The availability of data is generally fairly good for national and regional data on the direct economic effects of aquaculture. Data on how aquaculture‐related products or input markets are affected are however poorly available, as are economic data on external effects from aquaculture. Countries with a larger aquaculture sector tend to have better availability of aquaculture‐related economic data than those with a smaller sector. An index is developed and calculated to show more specifically where the countries have relatively good or poor data availability compared to their needs. While it will not always be cost‐effective or meaningful to collect economic data on the effects of aquaculture, our study indicates that several countries could benefit from expanding such data collection. It can make trade‐off decisions more consistent and easier to perform, and aquaculture policies and measures can be better tailored to specific contexts. [ABSTRACT FROM AUTHOR]

Tenacibaculosis remains a major health issue for a number of important aquaculture species globally. On the west coast of Canada, yellow mouth (YM) disease is responsible for significant economic loss to the Atlantic salmon industry. While Tenacibaculum maritimum is considered to be the primary agent of clinical YM, the impact of YM on the resident microbial community and their influence on the oral cavity is poorly understood. Using a 16s rRNA amplicon sequencing analysis, the present study demonstrates a significant dysbiosis and a reduction in diversity of the microbial community in the YM affected Atlantic salmon. The microbial community of YM affected fish was dominated by two amplicon sequence variants (ASVs) of T. maritimum , although other less abundant ASVs were also found. Interestingly clinically unaffected (healthy) and YM surviving fish also had a high relative abundance of T. maritimum , suggesting that the presence of T. maritimum is not solely responsible for YM. A statistically significant association was observed between the abundance of T. maritimum and increased abundance of Vibrio spp. within fish displaying clinical signs of YM. Findings from our study provide further evidence that YM is a complex multifactorial disease, characterized by a profound dysbiosis of the microbial community which is dominated by distinct ASVs of T. maritimum. Opportunistic taxa, including Vibrio spp., may also play a role in clinical disease progression. [ABSTRACT FROM AUTHOR]

We assess the financial performance of an Atlantic salmon (Salmo salar) monoculture versus an Atlantic salmon, blue mussel (Mytilus edulis), and sugar kelp (Saccharina latissima) Integrated Multi-Trophic Aquaculture (IMTA) operation. Using updated methods and models, we improve on earlier studies of IMTA economics. A discounted cash-flow analysis was used to assess the profitability of hypothetical monoculture and IMTA operations over a 10-year period in the Bay of Fundy, New Brunswick, Canada. The IMTA operation was more profitable, even when no price premium was included for its products. A 10% price premium for IMTA salmon and mussels resulted in a substantially higher net present value for the IMTA operation than for salmon monoculture. However, uncertainty related to IMTA's financial and environmental performance, as well as IMTA's increased operational complexity, may be barriers to IMTA adoption in Canada at present. As a result, it is likely that IMTA must generate substantially greater profits than salmon monoculture to stimulate investment. Alternatively, declining salmon production in recent years may encourage IMTA adoption in the future since it can provide crop diversification and economic stability benefits. IMTA research may benefit from alternative assessment methods such as the real options approach that explicitly incorporate uncertainty. [ABSTRACT FROM AUTHOR]

Arctic char, Salvelinus alpinus L. is a promising candidate for aquaculture expansion in Northern Europe, Canada, and the United States because of its excellent growth at low temperature, tolerance to high rearing density, high fillet yield, and superior flesh texture and flavor. To support this industry, several breeding programs in these regions currently focus on selection for growth and delayed maturation. While the growth potential of existing strains has been improved, preharvest sexual maturation remains a problem in this industry. This article describes current knowledge on the control of preharvest maturation in Arctic char at the hatchery level through the production of single‐sex and triploid populations and during the grow‐out phase through the manipulation of photoperiod and feed intake. Research perspectives on the subject are also suggested in order to complement the efforts of ongoing breeding programs. [ABSTRACT FROM AUTHOR]

Finfish net-pen aquaculture in Canada is an important economic industry that supports coastal rural livelihoods. However, aquaculture development faces several types of barriers, including technological, environmental, regulatory, and social. Public perceptions linked to the aforementioned barriers have largely influenced aquaculture development in Canada, where maintaining social acceptance and public trust have been an enduring challenge. Since the media is important for spreading information and shaping public opinion, this study explored how media defines aquaculture to better understand the public discourse and implications for policy. Using qualitative and quantitative content analysis to explore the coverage of major Canadian newspapers in 2015 and 2016, we found a complex discourse expressing a range of aquaculture attributes and stakeholders. Our results indicate that media frames finfish net-pen aquaculture in a mostly negative tone, although there are considerable regional variabilities and differences across specific attributes. Risk-oriented frames focused on environmental challenges and management responses, while positive aspects surrounded scientific and technological advances and economic benefits. Complex interactions between environmental, social, economic, and management attributes further emphasizes the multi-faceted nature of the public discourse surrounding finfish aquaculture in Canada. Media relied not only on environmental groups or scientists in their reporting, but also considerably on fish farmers and government to offer expert opinions or as proponents of the industry. This supports a shift away from an 'elitist' role of the media, towards a more 'deliberative' role of balancing perspectives and democratic dialogue. These findings have implications for private and public responses and highlight the need for interdisciplinary solutions that emphasize transparency, communication, and accountability to improve public trust and guide sector development. • Content analysis of Canadian media coverage of net-pen aquaculture • Media coverage mainly risk-oriented but not unanimous across topics or regions • Diverse stakeholders hold various roles and positions within media discourses • Aquaculture portrayed as a complex activity encompassing interlinking environmental, social, economic, and management issues • Potential shifting discourse marked by an interest in public awareness, scientific advancements, and improved sustainability [ABSTRACT FROM AUTHOR]

Abstract Climate change, observed as warming sea surface temperatures, is expected to impact the Eastern coast of Canada at a rate higher than the global average. Changes in marine abiotic conditions will impact the growth and performance of economically important bivalve species, creating an increasingly uncertain future for the bivalve aquaculture industry. Site-selection for new farms, and the management of extant ones could mitigate these potential impacts, but the implementation of this planning process is dependent on stakeholder support and engagement. Recognizing the importance of stakeholder input in management decisions, this research analyzed the perspectives of farmers, researchers, and managers from Nova Scotia (NS) and Prince Edward Island (PEI) on the relationship between climate change and bivalve aquaculture. Stakeholder perspectives were analyzed using a semi-quantitative interview method (Q methodology). These perspectives indicated the need for a higher level of integration both between stakeholder groups, namely farmers and managers, and management tools and climate change. Increased understanding between farmers and managers could be achieved through the use of researchers as knowledge brokers, collaborating and communicating with both groups. Making use of management tools, such as the ecosystem approach to aquaculture, required insurance, and adaptive management, governmental bodies on both a federal and provincial level can act as channels by which uncertainty generated by climate change can be further reduced. In summary, stakeholder perception can be used by marine planners to adapt to these foreseen changes, and to promote the expansion of this industry. Highlights • Stakeholders differentially perceive how climate change impacts bivalve aquaculture. • All stakeholders acknowledged the occurrence of climate change. • Largest gap in perceptions was between managers and farmers. • Uncertainty regarding the effects of climate change on farm practices/economics. [ABSTRACT FROM AUTHOR]

We have generated a high-density, high-throughput genotyping array for characterizing genome-wide variation in Arctic charr (Salvelinus alpinus). Novel single nucleotide polymorphisms (SNPs) were identified in charr from the Fraser, Nauyuk and Tree River aquaculture strains, which originated from northern Canada and fish from Iceland using high coverage sequencing, reduced representation sequencing and RNA-seq datasets. The array was designed to capture genome-wide variation from a diverse suite of Arctic charr populations. Cross validation of SNPs from various sources and comparison with previously published Arctic charr SNP data provided a set of candidate SNPs that generalize across populations. Further candidate SNPs were identified based on minor allele frequency, association with RNA transcripts, even spacing across intergenic regions and association with the sex determining (sdY) gene. The performance of the 86,503 SNP array was assessed by genotyping Fraser, Nauyuk and Tree River strain individuals, as well as wild Icelandic Arctic charr. Overall, 63,060 of the SNPs were polymorphic within at least one group and 36.8% were unique to one of the four groups, suggesting that the array design allows for characterization of both within and across population genetic diversity. The concordance between sdY markers and known phenotypic sex indicated that the array can accurately determine the sex of individuals based on genotype alone. The Salp87k genotyping array provides researchers and breeders the opportunity to analyze genetic variation in Arctic charr at a more detailed level than previously possible. [ABSTRACT FROM AUTHOR]

The Yesso scallop Mizuhopecten yessoensis is an important aquaculture species that was introduced to Western Canada from Japan to establish an economically viable scallop farming industry. This highly fecund species has been propagated in Canadian aquaculture hatcheries for the past 40 years, raising questions about genetic diversity and genetic differences among hatchery stocks. In this study, we compare cultured Canadian and wild Japanese populations of Yesso scallop using double-digest restriction site-associated DNA (ddRAD) sequencing to genotype 21,048 variants in 71 wild-caught scallops from Japan, 65 scallops from the Vancouver Island University breeding population, and 37 scallops obtained from a commercial farm off Vancouver Island, British Columbia. The wild scallops are largely comprised of equally unrelated individuals, whereas cultured scallops are comprised of multiple families of related individuals. The polymorphism rate estimated in wild scallops was 1.7%, whereas in the cultured strains, it ranged between 1.35 and 1.07%. Interestingly, heterozygosity rates were highest in the cultured populations, which is likely due to shellfish hatchery practices of crossing divergent strains to gain benefits of heterosis and to avoid inbreeding. Evidence of founder effects and drift was observed in the cultured strains, including high genetic differentiation between cultured populations and between cultured populations and the wild population. Cultured populations had effective population sizes ranging from 9 to 26 individuals whereas the wild population was estimated at 25,048-56,291 individuals. Further, a depletion of low-frequency variants was observed in the cultured populations. These results indicate significant genetic diversity losses in cultured scallops in Canadian breeding programs., Competing Interests: Conflicts of interest BJGS is affiliated with Sutherland Bioinformatics. The author has no competing financial interests to declare. The other authors declare that no competing interests exist., (© The Author(s) 2023. Published by Oxford University Press on behalf of The Genetics Society of America.)

Eelgrass (Zostera marina) has been designated an Ecologically Significant Species in Atlantic Canada. The development and rapid expansion of netpen finfish aquaculture into sensitive coastal habitats has raised concerns about the impacts of finfish aquaculture on eelgrass habitats. To date, no studies have been done in Atlantic Canada to examine these impacts or to identify potential monitoring variables that would aid in the development of specific conservation and management objectives. As a first step in addressing this gap, we examined differences in environmental variables, eelgrass bed structure and macroinfauna communities at increasing distances from a finfish farm in Port Mouton Bay, a reference site in adjacent Port Joli Bay, and published survey results from other sites without finfish farms along the Atlantic Coast of Nova Scotia. Drawing on research done elsewhere and our results, we then identified possible metrics for assessing and monitoring local impacts of finfish aquaculture on eelgrass habitats. Our results suggest some nutrient and organic enrichment, higher epiphyte loads, lower eelgrass cover and biomass, and lower macroinfauna biomass closer to the farm. Moreover, community structure significantly differed between sites with some species increasing and others decreasing closer to the farm. Changes in the macroinfauna community could be linked to observed differences in environmental and eelgrass bed variables. These results provide new insights into the potential impacts of finfish aquaculture on eelgrass habitats in Atlantic Canada. We recommend a suite of measures for assessment and monitoring that take into account response time to disturbance and account for different levels of eelgrass organizational response (from physiological to community). [ABSTRACT FROM AUTHOR]

Thirty-nine years of scale growth measurements from Big Qualicum River chum salmon ( Oncorhynchus keta) in southern British Columbia demonstrated that competition and climate variation affect marine growth and age-at-maturity. A longitudinal study design that accounted for correlation among individuals revealed growth at all ages was reduced when the biomass of North American chum, sockeye ( Oncorhynchus nerka), and pink salmon ( Oncorhynchus gorbuscha) was high. When North Pacific Gyre Oscillation (NPGO) was positive, indicating increased primary productivity, predicted growth increased. Climate variation influenced competition effects. For instance, density-dependent competition effects increased when NPGO became more positive and Pacific Decadal Oscillation became more negative (indicating cool conditions), causing the greatest range in predicted scale size. Chum salmon are likely to exhibit continued reduction in growth at age due to increased ocean temperatures driven by climate change and high aggregate salmon biomass that includes hatchery releases. If evidence of biomass and climate effects presented here are common among Pacific salmon populations, reduction of hatchery releases should be considered. [ABSTRACT FROM AUTHOR]

Bacterial kidney disease ( BKD) is considered an important cause of loss in salmon aquaculture in Atlantic Canada. Causative agent of BKD is the Gram-positive bacteria Renibacterium salmoninarum. Infected salmon are often asymptomatic (subclinical infection), and the disease is considered chronic. One of the challenges in quantifying information from farm production and health records is the application of a standardized case definition. Case definitions for farm-level and cage-level clinical and subclinical BKD were developed using retrospective longitudinal data from aquaculture practices in New Brunswick, Canada, combining (i) industry records of weekly production data including mortalities, (ii) field observations for BKD using reports of veterinarians and/or fish health technicians, (iii) diagnostic submissions and test results and (iv) treatments used to control BKD. Case definitions were evaluated using veterinarians' expert judgements as reference standard. Eighty-nine and 66% of sites and fish groups, respectively, were associated with BKD at least once. For BKD present (subclinical or clinical), sensitivity and specificity of the case definition were 75-100% varying between event, fish group, site cycle and level (site pen). For clinical BKD, sensitivities were 29-64% and specificities 91-100%. Industry data can be used to develop sensitive case definitions. [ABSTRACT FROM AUTHOR]

Dense single nucleotide polymorphism (SNP) arrays are essential tools for rapid high-throughput genotyping for many genetic analyses, including genomic selection and high-resolution population genomic assessments. We present a high-density (200 K) SNP array developed for the Eastern oyster (Crassostrea virginica), which is a species of significant aquaculture production and restoration efforts throughout its native range. SNP discovery was performed using low-coverage whole-genome sequencing of 435 F1 oysters from families from 11 founder populations in New Brunswick, Canada. An Affymetrix Axiom Custom array was created with 219,447 SNPs meeting stringent selection criteria and validated by genotyping more than 4,000 oysters across 2 generations. In total, 144,570 SNPs had a call rate >90%, most of which (96%) were polymorphic and were distributed across the Eastern oyster reference genome, with similar levels of genetic diversity observed in both generations. Linkage disequilibrium was low (maximum r2 ∼0.32) and decayed moderately with increasing distance between SNP pairs. Taking advantage of our intergenerational data set, we quantified Mendelian inheritance errors to validate SNP selection. Although most of SNPs exhibited low Mendelian inheritance error rates overall, with 72% of called SNPs having an error rate of <1%, many loci had elevated Mendelian inheritance error rates, potentially indicating the presence of null alleles. This SNP panel provides a necessary tool to enable routine application of genomic approaches, including genomic selection, in C. virginica selective breeding programs. As demand for production increases, this resource will be essential for accelerating production and sustaining the Canadian oyster aquaculture industry., Competing Interests: Conflicts of interest The author(s) declare no conflict of interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of The Genetics Society of America.)

Northern pike (Esox lucius) are ecologically and socioeconomically important throughout Canada and the northern United States. In Minnesota, USA, large northern pike were historically abundant, but size-selective harvest and poor growth (i.e., stunting), in combination with thermal warming and prey resource limitation, have hindered development of fisheries with trophy individuals (≥ 43 inches) in recent decades. Despite strong interest of fisheries managers and public stakeholders in trophy management, historical approaches to improve population size structure (e.g., stocking, removal of small individuals, minimum length limits, liberalized creel limits) were largely unsuccessful. Currently, more than 100 Minnesota water bodies are managed under a series of special and experimental regulations (e.g., protected slot limits, minimum length limits, maximum length limits) intended to enhance size structure and promote trophy angling. These regulations have improved size structure in some lakes, yet trophy management can be improved by diversifying harvest regulations and enhancing public engagement strategies. It is particularly important to minimize or eliminate harvest of trophy individuals; protect and restore critical habitats; maintain high-energy prey resources; limit density of small individuals; experimentally evaluate regulation effects; and actively engage the public in the management process. Overall, fisheries managers can sustain trophy fisheries for present and future generations by solidifying the nexus among northern pike research, management, and human dimensions. [ABSTRACT FROM PUBLISHER]

Integrated multi-trophic aquaculture (IMTA) is the farming, in proximity, of aquaculture species from different trophic levels and with complementary ecosystem functions. IMTA allows one species’ uneaten feed and wastes, nutrients, and by-products to be recaptured and converted into fertilizer, feed, and energy for the other crops. By taking advantage of synergistic interactions between species, IMTA can help aquaculture evolve towards more responsible and sustainable systems. This study uses data from a contingent valuation survey to provide an estimation of the non-use benefits that, in the form of biomitigation of the external costs imposed on the marine environment, would be derived by Canadians from the adoption of IMTA for Atlantic salmon aquaculture. We find the benefits accruing to households who do not purchase salmon habitually would range between about $43 million/year and about $65 million/year for the next five years, depending on the treatment of ‘don’t know’ responses to the payment question. [ABSTRACT FROM PUBLISHER]

Due to potential use in aquacultured fish products, the Canadian Food Inspection Agency has identified residue testing for steroids as a priority. These compounds are used in aquaculture primarily to direct sexual differentiation with both androgens and estrogens applied depending on the desired outcome. Published research is lacking with respect to steroid residue testing in fish; however, recent studies in other matrixes provided transferable cleanup techniques. A simple, rapid, and sensitive method was developed and validated for use in monitoring aquacultured fish products for the presence of methyltestosterone, nandrolone, epinandrolone, boldenone, and epiboldenone residues. The developed method consists of solvent extraction followed by cleanup using hexane and dual cartridge SPE with analysis by ultra-HPLC-MS/MS. The method is capable of detecting and confirming steroid residue levels ranging from 0.05 to 25 ng/g in salmon and tilapia, depending on the analyte. Recoveries ranged from 88 to 130% for the analytes. Instrument repeatability was less than 13% for all compounds, while intermediate precision ranged from 5 to 25% RSD. HorRat values were within acceptable ranges. [ABSTRACT FROM AUTHOR]

The global geoduck market evolved substantially over the past four decades. This paper identifies the key transitional periods and discusses the catalysts that contributed to the evolution of the global geoduck market since its commercial inception during the 1970s. Specifically, this paper focuses on how the transition to rights-based fisheries management in Canada׳s wild geoduck fishery fostered changes in product form and ex-vessel prices that impacted the entire wild geoduck industry. This evolution in turn facilitated the emergence of intertidal and subtidal geoduck aquaculture, which led to further changes in the global geoduck industry including changes in: sources of supply, volume of production, trade patterns, primary markets, preference for product attributes, and fishery value. The global geoduck industry is still evolving, and this paper identifies and discusses the key drivers and constraints facing the market as it moves forward. [ABSTRACT FROM AUTHOR]

In Newfoundland, Canada, aquaculture sites set up over deep, hard bottom substrates dictate the use of visual indicators to monitor aquaculture footprints on the seafloor. Opportunistic annelids (referred to as opportunistic polychaete complexes, or OPC) are among these indicators. The effect of temperature on the distribution and survival of Ophryotrocha cyclops , the species constituting OPC in Newfoundland aquaculture sites is not known. To address this knowledge gap, this study assesses O. cyclops survival at different temperatures in the laboratory, and describes relationships between O. cyclops presence and seafloor temperatures measured in the field. Results show that worms died within two days at temperatures > 12 °C in the laboratory, and appear restricted to temperatures below 7.9 °C at aquaculture sites, tending to be more frequent at temperatures below 5 °C. We recommend that seafloor temperature be recorded and considered in the assessment of benthic aquaculture impact based on OPC presence. [ABSTRACT FROM AUTHOR]

The development of the aquaculture industry in Canada has triggered a conflict of a scope never seen before. As stated in Young and Matthews' The Aquaculture Controversy, this debate has 'mushroomed over the past several decades to become one of the most bitter and stubborn face-offs over industrial development ever witnessed in Canada' (Young and Matthews in The aquaculture controversy in Canada. Activism, policy and contested science. UBC Press, Vancouver, p 3, ). It opposes a wide variety of actors: from industrial investors, scientists, politicians and environmentalists to Native associations and communities, citizens groups and local stakeholders. The opposition is fierce between those in favor of a flourishing and modern aquaculture of industrial nature and those who fear the dreadful consequences of such an industry. In particular, the possible implementation of biotechnology innovations, such as a genetically modified salmon, has made this debate coextensive with the GMO debate, thus multiplying the opposition's spectrum of arguments against the industry. Throughout the debate, Canadian environmental NGOs like the Suzuki Foundation and Greenpeace Canada have assumed leadership over the opposition to aquaculture development with certain success. Their participation in the debate features numerous ethical concerns related to environmental health, a respect for wilderness and local human communities. Such a position can be associated overall with a form of ecocentric ethics or concern. Nevertheless, a careful examination of the technical solutions proposed by these NGOs reveals their embeddedness in biocentrism. Through the example taken from the Canadian debate on aquaculture development, this paper aims to highlight the conceptual difficulty of enacting ecocentric ethical positions beyond formal arguments. Because ecocentrism implies a true paradigm shift, not only in mentality, but also in the way we conceive our technical interventions in nature, biocentrism remains an important practical method to enact ethical positions related to environmental concerns in public debates. [ABSTRACT FROM AUTHOR]

The issue of sustainability of salmonid culture has been the focus of considerable media coverage and debate between environmental activists and aquaculture industry stakeholders, particularly regarding the use of ingredients derived from wild fisheries (fishmeal and fish oil) in salmonid feeds. This study attempts to summarize recent data and to calculate the conversion efficiency of feed resources by Canadian farmed salmon in order objectively to assess the sustainability of this industry in this regard. Using updated information regarding domestic aquafeeds this review reports advances that have been made in diet formulation, fish in-fish out ( FIFO) and feed conversion ratios ( FCR) and demonstrates that production efficiency of farmed salmonids has significantly improved over time due to continued innovations in the aquafeed sector. The results suggest that the Canadian salmon aquaculture industry efficiently converts wild fish resources into high-value fish products. [ABSTRACT FROM AUTHOR]

Abstract: This article interrogates shellfish aquaculture expansion efforts and outcomes in British Columbia (BC), Canada. While the clearest objectives of the Provincial Government's 1998 Shellfish Development Initiative were to privatize new ocean tenures and increase the wholesale value of the BC shellfish aquaculture sector, the analysis identifies and explores a range of government-led and government-funded interventions that emerged to discipline coastal space and subjects accordingly. These include: classifying productive space and projecting economic potential; identifying beneficiaries and enrolling Indigenous First Nations entrepreneurs; and, generating supportive knowledge, practice and public relations. I argue that these efforts work to produce ‘new shellfish growing regions’ imagined to be homogeneously ideal for shellfish aquaculture. They also reinforce the notion that coastal residents, especially First Nations, must adopt very specific outlooks and practices before the sector's full economic potential can be met. Theorizing these processes in terms of neoliberalization provides important perspective at a time when aquaculture is being widely promoted for its potential as an approach to economic modernization and sustainability in coastal communities in BC and beyond. [Copyright &y& Elsevier]

In the Atlantic region of Canada, there are close to 50 land-based freshwater aquaculture facilities, most of which discharge wastewater to freshwater receiving environments. This study was designed to assess the chemical and toxicological characteristics of sediments in those receiving environments. Thirty sediment samples were collected from 3 locations (upstream, outfall and downstream) at seven freshwater aquaculture facilities. Toxicity tests conducted included amphipod growth, amphipod survival and Microtox™. Sediments were also analysed for ammonia/porewater ammonia, redox and sulphide. Porewater ammonia concentration for the amphipod survival test ranged from 0.01 to 42 mg/L at the conclusion of the 14-day survival test. Ammonia concentration in sediment ranged from 0.3–202 μg/g, sulphide concentration ranged from 0.15 to 17.4 μg/g, yet redox ranged from 32 to 594 mV. Microtox™  IC50values ranged from 108,00 to >164,000 mg/L, yet amphipod survival ranged from 0 to 100%, depending on sampling locations. Amphipod survival was significantly related (P< 0.05) to porewater ammonia (at time = 0 and 14 days) and Microtox™  IC50was significantly related (P< 0.05) to ammonia, sulphide and redox levels. These results indicate that discharges from some the land-based aquaculture facilities are impacting sediment dwelling benthic invertebrates at the outfall but that impact largely disappears by 100 m downstream. Furthermore those impacts were rarely detected during the early winter season, when biomass production was at the lowest. [ABSTRACT FROM AUTHOR]

Abstract: Integrated Multi-Trophic Aquaculture (IMTA) is a recycling concept in which waste nutrient discharges from high trophic levels become an additional energetic input for extractive organisms such as bivalves. The aim of this study was to measure the seston levels and absorption efficiency of mussels reared in the proximity of fish net-pens. The absorption efficiency of mussels Mytilus galloprovincialis and Mytilus edulis cultured at sites adjacent to red sea bream (Pagellus bogaraveo) and salmon (Salmo salar) cages was assessed on site, using natural seston diets and compared with mussels reared distant from the cages in the Ría de Ares-Betanzos (Galicia, N.W. Spain) and the Bay of Fundy (S.W. New Brunswick, Canada), respectively. Total particulate matter and the organic and the inorganic fractions of the seston were measured simultaneously. Seston parameters were generally similar at the mussel sites close to the fish cages and at the reference sites. However, significantly higher particulate inorganic matter coupled with lower food quality (seston organic content) observed at the sites close to the fish cages suggested occasional sediment resuspension events in the Ría de Ares-Betanzos and the Bay of Fundy. Owing to the reduced food quality, 20% lower absorption efficiency was measured for mussels in the proximity to the cages during the resuspension events. No significant differences in absorption efficiency were detected between the fish cages and the reference sites outside the resuspension events. Consequently, differences in absorption efficiency were attributed to natural variations in seston organic content, and absorption increased with increasing food quality. The results showed no evidence of increased organic content of the seston resulting from proximity to the fish-farm. It was concluded that proximity of cultured mussels to the fish cages did not result in an enhancement of the absorption efficiency. [Copyright &y& Elsevier]

The resilience of coastal social–ecological systems may depend on adaptive responses to aquaculture disease outbreaks that can threaten wild and farm fish. A nine‐year study of parasitic sea lice (Lepeophtheirus salmonis) and pink salmon (Oncorhynchus gorbuscha) from Pacific Canada indicates that adaptive changes in parasite management on salmon farms have yielded positive conservation outcomes. After four years of sea lice epizootics and wild salmon population decline, parasiticide application on salmon farms was adapted to the timing of wild salmon migrations. Winter treatment of farm fish with parasiticides, prior to the out‐migration of wild juvenile salmon, has reduced epizootics of wild salmon without significantly increasing the annual number of treatments. Levels of parasites on wild juvenile salmon significantly influence the growth rate of affected salmon populations, suggesting that these changes in management have had positive outcomes for wild salmon populations. These adaptive changes have not occurred through formal adaptive management, but rather, through multi‐stakeholder processes arising from a contentious scientific and public debate. Despite the apparent success of parasite control on salmon farms in the study region, there remain concerns about the long‐term sustainability of this approach because of the unknown ecological effects of parasticides and the potential for parasite resistance to chemical treatments. [ABSTRACT FROM AUTHOR]

BACKGROUND: The aquaculture industry is growing in Canada and is particularly strong in Atlantic Canada. Workers in the fish processing industry are required to complete a variety of tasks in a typical day and there is concern for musculoskeletal disorder. OBJECTIVE: The purpose of this study was to examine the daily operations of fish processing workers to determine any musculoskeletal concerns. METHODS: The ergonomic assessment consisted of several plant visits to observe the processing line and the requirements of the workers. Video recordings were made of each stage of the assembly lines. The video data was analyzed to determine high-risk jobs and to identify areas of concern. Cumulative loading was assessed using posture matching software and the video data. A Job Strain Index (JSI), Rapid Upper Limb Assessment (RULA) and the revised NIOSH lifting equation were used to identify high-risk tasks. RESULTS: The data showed that six tasks were considered high risk; sorting fish, removal of fish bones, trimming of fish, pallet loading/conveyor operation, fish processing and cleaning of the trim machine. In addition, four categories of occupational health and safety (OHS) hazard concerns were identified (physical, chemical, biological, and psychosocial). Each category was then broken into their causative agents and potential health effects on the worker. CONCLUSIONS: Several areas for improvement were identified at this seafood processing plant. Six jobs were identified as high risk and in need of intervention. Changes in pace of work, workstation height, and new equipment would also help reduce the number of musculoskeletal injuries. The issue of job rotation should also be examined to determine its impact on musculoskeletal health. Implementation of strategies to reduce musculoskeletal disorders will help to improve the health of these workers. [ABSTRACT FROM AUTHOR]

Climate change, fishing, and aquaculture have affected and will continue to influence Canadian marine biodiversity, albeit at different spatial scales. The Arctic is notably affected by reduced quality and quantity of sea ice caused by global warming, and by concomitant and forecasted changes in ocean productivity, species ecology, and human activity. The Atlantic has been especially impacted by severe overfishing and human-induced alterations to food webs. Climate change, fishing, and aquaculture have all affected, to varying degrees, biodiversity on Canada's Pacific coast. Past and projected trends in key biodiversity stressors reveal marked change. Oceanographic trends include increasing surface water temperatures, reduced salinity, increased acidity, and, in some areas, reduced oxygen. Reductions in Canada's fishery catches (those in 2009 were half those of the late 1980s), followed by reductions in fishing pressure, are associated with dramatic changes in the species composition of commercial catches in the Atlantic (formerly groundfish, now predominantly invertebrates and pelagic fish) and the Pacific (formerly salmon, now predominantly groundfish). Aquaculture, dominated by the farming of Atlantic salmon, grew rapidly from the early 1980s until 2002 and has since stabilized. Climate change is forecast to affect marine biodiversity by shifting species distributions, changing species community composition, decoupling the timing of species' resource requirements and resource availability, and reducing habitat quality. Harvest-related reductions in fish abundance, many by 80% or more, coupled with fishing-induced changes to food webs, are impairing the capacity of species to recover or even persist. Open-sea aquaculture net pens affect biodiversity by ( i) habitat alteration resulting from organic wastes, chemical inputs, and use of nonnative species; ( ii) exchange of pathogens between farmed and wild species; and ( iii) interbreeding between wild fish and farmed escapees. Physical and biological changes in the oceans, along with direct anthropogenic impacts, are modifying Canadian marine biodiversity with implications for food security and the social and economic well-being of coastal communities. To assess the consequences of changes in biodiversity for Canada's oceans and society, it is necessary to understand the current state of marine biodiversity and how it might be affected by projected changes in climate and human uses. [ABSTRACT FROM AUTHOR]

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This study investigated the occurrence of oxytetracycline (OTC) and emamectin benzoate (EB) in sediments located near the effluent outfall from four freshwater aquaculture facilities in Atlantic Canada. While two facilities had no detectable concentrations of EB or OTC, two facilities had detectable concentrations of one or both of these chemicals. Concentrations ranged from <0.05-18 mg/kg to <0.01-2.5 mg/kg for OTC and EB respectively. Although these values could not be compared with freshwater toxicant values, some of the concentrations of EB and OTC detected were higher than LC values calculated for marine invertebrates. OTC concentrations measured in this study are also of a magnitude which has been known to produce resistant bacteria. [ABSTRACT FROM AUTHOR]

Abstract: This study examines the effect of mussel farming on benthic infaunal communities in baie de Gaspé, eastern Canada, at two spatial scales: 10m (directly under vs. between mussel longlines — Position) and 100m (between mussel farm and reference locations — Treatment, each of which was replicated at 4 Sites). None of the evaluated univariate descriptors of benthic communities (abundance, taxonomic richness, Shannon–Weiner diversity, AMBI, and M-AMBI) differed between Treatments or among Positions within Sites in any consistent way. Similarly, multivariate community structure also did not differ among Treatments. In contrast, multivariate community structure directly under mussel lines differed from that between mussel lines in 3 of 4 mussel farm sites whereas none of the reference sites showed such 10m-scale variation. Of the species that accounted for the greatest proportion of the dissimilarity between Positions within mussel farm sites, second-order opportunistic species (Prionospio steenstrupi and Pectinaria granulata) were consistently more abundant directly under mussel lines than between them. Species belonging to other ecological groups did not show any consistent trends. It is suggested that studies that do not consider within-site (10m-scale, below vs. between longlines) variation may fail to detect the influence of suspended bivalve culture in some cases. Overall, effects of mussel culture in baie de Gaspé were slight and within the natural variation of benthic communities in the area. This suggests that the current industry should be sustainable. However, plans to expand the industry in the region remain to be evaluated with respect to the ecological carrying capacity of the entire bay. [Copyright &y& Elsevier]

Benthic invertebrate communities have been known to change due to impacts from nutrient-rich industrial outputs, such as those from pulp and paper, sewage-treatment plants, or aquaculture. Fish-processing plants have been recognized as contributors of large volumes of nutrient rich effluent to marine and estuarine environments, but their effect on benthic invertebrate communities is unknown. Benthic invertebrates and sediment samples were obtained from marine sampling stations at 0-, 10-, 30-, and 100-m distances from two fish-processing outfalls in Atlantic Canada. Sediment grain size, total organic carbon (TOC), ammonia, sulphide, and redox, as well as invertebrate abundance, density, taxa richness, Simpson's Inverse Diversity Index, Bray-Curtis Index of (%) Similarity, and the AZTI marine biotic index (AMBI), were determined for all sampling sites. Results from this study illustrate that taxa richness and density significantly increased as distance from the outfall discharge increased. In our study, TOC was only significantly correlated to AMBI but not to the other benthic invertebrate assemblage descriptors calculated in this study (invertebrate density, taxa richness, Simpson's Inverse Diversity Index). The study results suggest that taxa richness and density may be affected by effluent from fish-processing plants. [ABSTRACT FROM AUTHOR]