47 research outputs found

    Assessing alternative aquaculture technologies: life cycle assessment of salmonid culture systems in Canada

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    Keywords: LCA Alternative aquaculture technologies Salmonid culture systems Canadian aquaculture a b s t r a c t This study employed life cycle assessment (LCA) to quantify and compare the potential environmental impacts of culturing salmonids in a conventional marine net-pen system with those of three reportedly environmentally-friendly alternatives; a marine floating bag system; a land-based saltwater flowthrough system; and a land-based freshwater recirculating system. Results of the study indicate that while the use of these closed-containment systems may reduce the local ecological impacts typically associated with net-pen salmon farming, the increase in material and energy demands associated with their use may result in significantly increased contributions to several environmental impacts of global concern, including global warming, non-renewable resource depletion, and acidification. It is recommended that these unanticipated impacts be carefully considered in further assessments of the sustainability of closed-containment systems and in ongoing efforts to develop and employ these technologies on a larger scale

    Commentary: comparing efficiency in aquatic and terrestrial animal production systems

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    First paragraph: Aquaculture is receiving increased attention from a variety of stakeholders. This is largely due to its current role in the global food system of supplying more than half of the seafood consumed, and also because the industry continues to steadily expand (UN Food and Agriculture Organization 2018). A recent article in Environmental Research Letters, 'Feed conversion efficiency in aquaculture: do we measure it correctly?', by Fry et al (2018a) found that measuring feed conversion efficiency of selected aquatic and terrestrial farmed animals using protein and calorie retention resulted in species comparisons (least to most efficient) and overlap among species dissimilar from comparisons based on widely used weight-based feed conversion ratio (FCR) values. The study prompted spirited discussions among researchers, industry representatives, and others. A group assembled to write a standard rebuttal, but during this process, decided it was best to engage the study's original authors to join the discourse. Through this collaboration, we provide the resultant additional context relevant to the study in order to advance conversations and research on the use of efficiency measures in aquatic and terrestrial animal production systems

    Forest cover enhances natural enemy diversity and biological control services in Brazilian sun coffee plantations

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    Published VersionLandscape structure and crop management directly affect insect communities, which can influence agriculturally relevant ecosystem services and disservices. However, little is known about the effect of landscape structure and local factors on pests, natural enemies, and biological control services in the Neotropics. We investigated how environmental conditions at local and landscape levels affect Leucoptera coffeella (insect pest), social wasps (natural enemies), and the provision of biological control services in 16 Brazilian coffee plantations under different crop management and landscape contexts. We considered microclimatic conditions, coffee plantation size, and management intensity at the local level; and forest cover, landscape diversity, and edge density at the landscape level. Pest population, wasp communities, and biocontrol services were monitored in wet and dry seasons when L. coffeella outbreaks occur. We found that the amount of forest in the surrounding landscape was more important for explaining patterns than the local environment, landscape diversity, or landscape configuration. In both seasons, L. coffeella was negatively affected by forest cover, whereas biological control and richness and abundance of social wasps increased with increasing forest cover at multiple spatial scales. Moreover, biological control was positively correlated with wasp abundance during pest outbreaks, suggesting that social wasps are important natural enemies and provide pest control services within coffee plantations. We provide the first empirical evidence that forest cover is important for the maintenance of social wasp diversity and associated pest control services in a Brazilian coffee-producing region

    Reframing the sustainable seafood narrative

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    The dominant sustainable seafood narrative is one where developed world markets catalyze practice improvements by fisheries and aquaculture producers that enhance ocean health. The narrow framing of seafood sustainability in terms of aquaculture or fisheries management and ocean health has contributed to the omission of these important food production systems from the discussion on global food system sustainability. This omission is problematic. Seafood makes critical contributions to food and nutrition security, particularly in low income countries, and is often a more sustainable and nutrient rich source of animal sourced-food than terrestrial meat production. We argue that to maximize the positive contributions that seafood can make to sustainable food systems, the conventional narratives that prioritize seafood's role in promoting ‘ocean health’ need to be reframed and cover a broader set of environmental and social dimensions of sustainability. The focus of the narrative also needs to move from a producer-centric to a ‘whole chain’ perspective that includes greater inclusion of the later stages with a focus on food waste, by-product utilization and consumption. Moreover, seafood should not be treated as a single aggregated item in sustainability assessments. Rather, it should be recognized as a highly diverse set of foods, with variable environmental impacts, edible yield rates and nutritional profiles. Clarifying discussions around seafood will help to deepen the integration of fisheries and aquaculture into the global agenda on sustainable food production, trade and consumption, and assist governments, private sector actors, NGOs and academics alike in identifying where improvements can be made.Until 15 December 2019, this article can be freely accessed online at: https://authors.elsevier.com/c/1ZyqC3Q8oP-AK

    Integration of environment and nutrition in life cycle assessment of food items: opportunities and challenges

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    This report is the outcome of a consensus-building project to agree on best practices for environmental and nutritional Life Cycle Assessment (nLCA) methodology, and identify future research needs. The project involved 30 nutritional and environmental LCA researchers from 18 countries. It focused on the assessment of food items (as opposed to meals or diets).Best practice recommendations were developed to address the intended purpose of an LCA study and related modeling approach, choice of an appropriate functional unit, assessment of nutritional value, and reporting nLCA results. An nLCA study should report the quantities of as many essential nutrients as possible and aim to provide information on the nutritional quality and/or health impacts in addition to nutrient quantities. Outstanding issues requiring further research attention include: defining a minimum number of nutrients to be considered in an nLCA study; treatment of nutrients to limit; use of nutrient indexes; further development of Impact Assessment methods; representation of nutritional changes that may occur during subsequent distribution and food preparation in cradle-to-gate nLCA studies; and communication of data uncertainty and variability. More data are required for different regions (particularly developing countries); for the processing, distribution, retail, and consumption life cycle stages; and for food loss and waste. Finally, there is a need to extend nLCA methodology for the assessment of meals and diets, to consider further how to account for the multi-functionality of food in a sustainability framework, and to set nLCA studies within the context of environmental limits.These results provide a robust basis for improving nLCA methodology and applying it to identify solutions that minimize the trade-offs between nourishing populations and safeguarding the environment

    Fitness Landscape Transformation through a Single Amino Acid Change in the Rho Terminator

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    Regulatory networks allow organisms to match adaptive behavior to the complex and dynamic contingencies of their native habitats. Upon a sudden transition to a novel environment, the mismatch between the native behavior and the new niche provides selective pressure for adaptive evolution through mutations in elements that control gene expression. In the case of core components of cellular regulation and metabolism, with broad control over diverse biological processes, such mutations may have substantial pleiotropic consequences. Through extensive phenotypic analyses, we have characterized the systems-level consequences of one such mutation (rho*) in the global transcriptional terminator Rho of Escherichia coli. We find that a single amino acid change in Rho results in a massive change in the fitness landscape of the cell, with widely discrepant fitness consequences of identical single locus perturbations in rho* versus rhoWT backgrounds. Our observations reveal the extent to which a single regulatory mutation can transform the entire fitness landscape of the cell, causing a massive change in the interpretation of individual mutations and altering the evolutionary trajectories which may be accessible to a bacterial population

    Environmental performance of blue foods

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    Fish and other aquatic foods (blue foods) present an opportunity for more sustainable diets1,2. Yet comprehensive comparison has been limited due to sparse inclusion of blue foods in environmental impact studies3,4 relative to the vast diversity of production5. Here we provide standardized estimates of greenhouse gas, nitrogen, phosphorus, freshwater and land stressors for species groups covering nearly three quarters of global production. We find that across all blue foods, farmed bivalves and seaweeds generate the lowest stressors. Capture fisheries predominantly generate greenhouse gas emissions, with small pelagic fishes generating lower emissions than all fed aquaculture, but flatfish and crustaceans generating the highest. Among farmed finfish and crustaceans, silver and bighead carps have the lowest greenhouse gas, nitrogen and phosphorus emissions, but highest water use, while farmed salmon and trout use the least land and water. Finally, we model intervention scenarios and find improving feed conversion ratios reduces stressors across all fed groups, increasing fish yield reduces land and water use by up to half, and optimizing gears reduces capture fishery emissions by more than half for some groups. Collectively, our analysis identifies high-performing blue foods, highlights opportunities to improve environmental performance, advances data-poor environmental assessments, and informs sustainable diets

    Unraveling infectious structures, strain variants and species barriers for the yeast prion [PSI+]

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    Prions are proteins that can access multiple conformations, at least one of which is beta-sheet rich, infectious and self-perpetuating in nature. These infectious proteins show several remarkable biological activities, including the ability to form multiple infectious prion conformations, also known as strains or variants, encoding unique biological phenotypes, and to establish and overcome prion species (transmission) barriers. In this Perspective, we highlight recent studies of the yeast prion [PSI+], using various biochemical and structural methods, that have begun to illuminate the molecular mechanisms by which self-perpetuating prions encipher such biological activities. We also discuss several aspects of prion conformational change and structure that remain either unknown or controversial, and we propose approaches to accelerate the understanding of these enigmatic, infectious conformers

    Salmon and sustainability : the biophysical cost of producing salmon through the commercial salmon fishery and the intensive salmon culture industry

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    Technologies play a critical role in mediating the impact of the human enterprise on the ecosphere. Consequently, the adoption of more biophysically efficient technologies is essential if the sustainability of the human enterprise is to improve as populations and per capita consumption demands increase. Within this context, the biophysical efficiency of two salmon production technology systems were analysed and compared using ecological footprint and energy analysis. The two systems evaluated are the vessel-based commercial salmon fishery and the salmon farming industry, as both exist in British Columbia, Canada. In addition, the relative efficiency of the three harvesting technologies employed within the commercial fishery were also evaluated. The ecological footprint analyses entailed quantifying the marine and terrestrial ecosystem support areas needed to grow salmon, sustain labour inputs, and assimilate COâ‚‚ equivalent to the greenhouse gases that result from industrial energy and material inputs. The energy analyses focussed exclusively on the direct and indirect industrial energy inputs to both systems. The results of both the ecological footprint and energy analyses indicate that salmon farming is the least biophysically efficient, and hence least sustainable system for producing salmon currently operating in British Columbia. On a species-specific basis, farmed chinook salmon (Oncorhynchus tshawytscha) appropriated .the largest total area of ecosystem support at 16 ha/tonne. This was followed by farmed Atlantic salmon (Salmo salar) at 12.7 ha/tonne, and commercially caught chinook and coho salmon (Oncorhynchus kisutch) at 11 ha/tonne and 10.2 ha/tonne, respectively. Commercially caught sockeye (Oncorhynchus nerka), chum (Oncorhynchus keta), and pink salmon (Oncorhynchus gorbuscha) had the smallest total ecological footprints at 5.7, 5.2 and 5 ha/tonne, respectively. Results of the energy analyses followed a similar pattern. Farmed chinook salmon required a total fossil fuel equivalent industrial energy input of about 117 GJ/tonne while at the other extreme, total energy inputs to commercially harvested pink salmon amounted to only 22 GJ/tonne. Within both systems, however, opportunities exist to improve the biophysical efficiency of salmon production. Finally, amongst the three commercial fishing technologies evaluated, purse seining was approximately twice as efficient at harvesting an average tonne o f salmon as were either gillnetting or trolling.Science, Faculty ofResources, Environment and Sustainability (IRES), Institute forGraduat
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