Hvor allsidig er bardehvalenes kosthold?

Gjengitt med tillatelse fra Universitetsbiblioteket i TromsøBardehvaler er store og tallrike og viktige predatorer i Barentshavet. Hvor beiter de, hva beiter de på og hva gjør de når bestander av byttedyr kollapser? For å lære mer om dette observerte vi bardehvaler under Havforskningsinstituttets økosystemtokt i Barentshavet. Resultatene tyder på en variert diett nord i Barentshavet

Opportunities for advancing ecosystem-based management in a rapidly changing, high latitude ecosystem

Unprecedented and rapid changes are ongoing in northern high latitude, marine ecosystems, due to climate warming. Species distributions and abundances are changing, altering both ecosystem structure and dynamics. At the same time, human impacts are increasing. Less sea ice opens for the opportunity of more petroleum-related activities, shipping and tourism. Fisheries are moving into previously unfished habitats, targeting more species across more trophic levels. There is a need for ecosystem-based fisheries management (EBFM) and ecosystem-based management (EBM) to take the rapid, climate driven changes into account. Recently, there has been much development in qualitative, semi-quantitative, and quantitative scientific approaches to support EBFM and EBM. Here, we present some of these approaches, and discuss how they provide opportunities for advancing EBFM and EBM in one high-latitude system, namely the Barents Sea. We propose that advancing EBFM and EBM is more about adding tools to the toolbox than replacing tools, and to use the tools in coordinated efforts to tackle the increasing complexities in scientific support to management. Collaborative and participatory processes among stakeholders and scientists are pivotal for both scoping and prioritizing, and for efficient knowledge exchange. Finally, we argue that increasing uncertainty with increasing complexity is fundamental to decision making in EBFM and EBM and needs to be handled, rather than being a reason for inaction or irrelevance.publishedVersio

Ecosystem-related monitoring, assessments and management advices for the Norwegian, Barents and North Seas

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Set-up of the Nordic and Barents Seas (NoBa) Atlantis model

End-to-end models are important tools when moving towards an ecosystem based approach to fisheries management. Atlantis is one such end-to-end model. Atlantis has been developed forseveral areas, including Australia, U.S., and European waters, and models for other areas are under development, The models give unique opportunities to explore spatial impact of climate and fisheries, and includes all levels from physical forcing to top predators in the system, including bacteria, phytoplankton, zooplankton, fish, benthos and marine mammals. Atlantis for the Nordic and Barents Seas (NoBa) has been built with the aim of representing the key species and processes in the areas, where the main objective is to explore combined climate and fisheries scenarios. In setting up the model several thousand parameters need to be defined This report provides an overview and explanations of key parameters used to initialize the model

Parasite development affect dispersal dynamics; infectivity, activity and energetic status in cohorts of salmon louse copepodids

The salmon louse, Lepeophtheirus salmonis, is a parasitic copepod infecting wild and farmed salmonid fishes in the northern hemisphere. It has a direct lifecycle with a planktonic dispersal phase and an infective copepodid stage preceding five host bound stages. Several models predicting the dispersal of this ecologically and economically important pathogen have been developed, but none include variability in capability to infect. Therefore, the effect of age and temperature on infectivity and lipid metabolism was investigated experimentally using seven synchronized cohorts of copepodids at 5, 10 and 15 °C. In newly molted copepodids infectivity initially increase and then decrease with senescence. Within the experimental temperature range, peak infectivity was higher and occurred earlier at higher temperatures. While degree-days may serve as a useful crude descriptor of developmental age, it did not allow accurate prediction of infectivity peak timing and magnitude unless temperature was included as a separate factor in the derived infectivity model. Senescence was reflected in lipid store depletion and a temperature dependent variability in membrane lipid composition was evident. Interestingly, copepodids developing at 5 °C had approximately 50% less storage lipids when they molted into the parasitic stage than those developing at 10 and 15 °C. The declines in infectivity and storage energy were mirrored in decreasing copepodid swimming activity. When incorporating the copepodid infectivity results from this study into salmon louse dispersal model parameterization, the predictions suggest that earlier models may have underestimated the seasonal differences in salmon louse infection risk.publishedVersio

Set-up of the Nordic and Barents Seas (NoBa) Atlantis model

End-to-end models are important tools when moving towards an ecosystem based approach to fisheries management. Atlantis is one such end-to-end model. Atlantis has been developed forseveral areas, including Australia, U.S., and European waters, and models for other areas are under development, The models give unique opportunities to explore spatial impact of climate and fisheries, and includes all levels from physical forcing to top predators in the system, including bacteria, phytoplankton, zooplankton, fish, benthos and marine mammals. Atlantis for the Nordic and Barents Seas (NoBa) has been built with the aim of representing the key species and processes in the areas, where the main objective is to explore combined climate and fisheries scenarios. In setting up the model several thousand parameters need to be defined This report provides an overview and explanations of key parameters used to initialize the model

Operationalising ODEMM risk assessment for Integrated Ecosystem Assessment scoping: Complexity vs. manageability

Integrated Ecosystem Assessments (IEA) require consideration of the full suite of pressures and impacts affecting ecosystems. However, capacity limitations often severely limit our ability to do everything that we want or ‘should’ do, outside of short-term fully-funded focused research projects. In order to make IEA a reality in many contexts, priority consideration has to be given to how to achieve such comprehensive assessments. Ecoregions and Large Marine Ecosystems (LMEs) have been identified as potential management units, however these large areas encompass diverse habitats, and multiple nations with diverse human communities and use of marine environments, and a multitude of different management strategies. In this context, how can we make IEA an operational tool that can be applied at such high-level in a comparable, yet regionally-relevant adaptable approach? This paper outlines the demonstration and adaptation of an established risk assessment approach (Options for Delivering Ecosystem-Based Marine Management: ODEMM) to a rapid risk scoping tool, and how this approach has been applied using open source common analytical tools to improve operationality in both the Mission Atlantic project and the International Council for the Exploration of the Seas (ICES) Integrated Ecosystem Assessment Working Groups. Furthermore, a hierarchical approach is detailed that allows the integration of different levels of detail into a common format. The resulting assessments are then ground-truthed with stakeholders to identify issues, omissions, potential conflicts, and key areas of interest for the next steps of the IEA process

Sensitivity of the Norwegian and Barents Sea Atlantis end-to-end ecosystem model to parameter perturbations of key species

Using end-to-end models for ecosystem-based management requires knowledge of the structure, uncertainty and sensitivity of the model. The Norwegian and Barents Seas (NoBa) Atlantis model was implemented for use in ‘what if’ scenarios, combining fisheries management strategies with the influences of climate change and climate variability. Before being used for this purpose, we wanted to evaluate and identify sensitive parameters and whether the species position in the foodweb influenced their sensitivity to parameter perturbation. Perturbing recruitment, mortality, prey consumption and growth by +/- 25% for nine biomass-dominating key species in the Barents Sea, while keeping the physical climate constant, proved the growth rate to be the most sensitive parameter in the model. Their trophic position in the ecosystem (lower trophic level, mid trophic level, top predators) influenced their responses to the perturbations. Top-predators, being generalists, responded mostly to perturbations on their individual life-history parameters. Mid-level species were the most vulnerable to perturbations, not only to their own individual life-history parameters, but also to perturbations on other trophic levels (higher or lower). Perturbations on the lower trophic levels had by far the strongest impact on the system, resulting in biomass changes for nearly all components in the system. Combined perturbations often resulted in non-additive model responses, including both dampened effects and increased impact of combined perturbations. Identifying sensitive parameters and species in end-to-end models will not only provide insights about the structure and functioning of the ecosystem in the model, but also highlight areas where more information and research would be useful—both for model parameterization, but also for constraining or quantifying model uncertainty.publishedVersio

Towards ecosystem-based fisheries management in Norway – Practical tools for keeping track of relevant issues and prioritising management efforts

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