A persistent deep anticyclonic vortex in the Rockall Trough sustained by Anticyclonic Vortices Shed From the slope current and wintertime convection

The presence of a persistent surface anticyclone centered at approximately 55°N, 12°W in the Rockall Trough, northeast North Atlantic, has been previously noted in satellite altimetry data. Here, we show that this surface anticyclone is the imprint of a deep, persistent, non‐stationary anticyclonic vortex. Using wintertime 2007 and 2011 ship‐board data, we describe the anticyclone's vertical structure for the first time and find that the anticyclone core is partly made of warm and salty Mediterranean Overflow Water. The anticyclone has a radius of ~40 km, it stretches down to 2,000 m, with a velocity maximum around 500 m. To analyze the anticyclone's generating mechanism, we use a mesoscale‐resolving (~2 km) simulation, which produces a realistic pattern of the Rockall Trough anticyclone. The simulation indicates that the anticyclone is locally formed and sustained by two types of processes: wintertime convection and merger with anticyclonic vortices shed from the slope current flowing poleward along the eastern Rockall Trough slope. Intense negative vorticity filaments are generated along the Rockall Trough south‐eastern slope, and they encapsulate Mediterranean Overflow Water as they detach and grow into anticyclonic vortices. These Mediterranean Overflow Water‐rich vortices are advected into the trough, consequently merging with the Rockall Trough anticyclone and sustaining it. We suggest that the Rockall Trough anticyclone impacts regional intermediate water masses modifications, heat and salt budgets locally, and further afield into the neighboring subpolar northeast North Atlantic

A Standardized Workflow Based on the STAVIRO Unbaited Underwater Video System for Monitoring Fish and Habitat Essential Biodiversity Variables in Coastal Areas

Essential Biodiversity Variables (EBV) related to benthic habitats and high trophic levels such as fish communities must be measured at fine scale but monitored and assessed at spatial scales that are relevant for policy and management actions. Local scales are important for assessing anthropogenic impacts, and conservation-related and fisheries management actions, while reporting on the conservation status of biodiversity to formulate national and international policies requires much broader scales. Measurements must account for the fact that coastal habitats and fish communities are heterogeneously distributed locally and at larger scales. Assessments based on in situ monitoring generally suffer from poor spatial replication and limited geographical coverage, which is challenging for area-wide assessments. Requirements for appropriate monitoring comprise cost-efficient and standardized observation protocols and data formats, spatially scalable and versatile data workflows, data that comply with the FAIR (Findable, Accessible, Interoperable, and Reusable) principles, while minimizing the environmental impact of measurements. This paper describes a standardized workflow based on remote underwater video that aims to assess fishes (at species and community levels) and habitat-related EBVs in coastal areas. This panoramic unbaited video technique was developed in 2007 to survey both fishes and benthic habitats in a cost-efficient manner, and with minimal effect on biodiversity. It can be deployed in areas where low underwater visibility is not a permanent or major limitation. The technique was consolidated and standardized and has been successfully used in varied settings over the last 12 years. We operationalized the EBV workflow by documenting the field protocol, survey design, image post-processing, EBV production and data curation. Applications of the workflow are illustrated here based on some 4,500 observations (fishes and benthic habitats) in the Pacific, Indian and Atlantic Oceans, and Mediterranean Sea. The STAVIRO’s proven track-record of utility and cost-effectiveness indicates that it should be considered by other researchers for future applications.publishedVersio

Panel-based Assessment of Ecosystem Condition of the North Sea Shelf Ecosystem

The System for Assessment of Ecological Condition, coordinated by the Norwegian Environment Agency, is intended to form the foundation for evidence-based assessments of the ecological condition of Norwegian terrestrial and marine ecosystems not covered by the EU Water Framework Directive. The reference condition is defined as “intact ecosystems”, i.e., a condition that is largely unimpacted by modern industrial anthropogenic activities. An ecosystem in good ecological condition does not deviate substantially from this reference condition in structure, functions or productivity. This report describes the first operational assessment of the ecological condition of the marine shelf ecosystem in the Norwegian sector of the North Sea and Skagerrak. The assessment method employed is the Panel-based Assessment of Ecosystem Condition (PAEC1) and the current assessment has considered to what extent the North Sea and Skagerrak shelf ecosystem deviates from the reference condition2 by evaluating change trajectories.Panel-based Assessment of Ecosystem Condition of the North Sea Shelf EcosystempublishedVersio

Panel-based Assessment of Ecosystem Condition of the North Sea Shelf Ecosystem - Appendices

publishedVersio

International Bottom Trawl Survey Working Group (IBTSWG). ICES Scientific Reports, 04:65

The International Bottom Trawl Survey Working Group (IBTSWG) coordinates fishery-independent bottom trawl surveys in the ICES area in the Northeast Atlantic and the North Sea. These long-term monitoring surveys provide data for stock assessments and facilitate examina-tion of changes in fish distribution and relative abundance. The group also promotes the stand-ardization of fishing gears and methods as well as survey coordination. This report summarizes the national contributions in 2021–2022 and plans for the 2022–2023 surveys coordinated by IBTSWG

Highly mixed impacts of near-future climate change on stock productivity proxies in the North East Atlantic

Impacts of climate change on ocean productivity sustaining world fisheries are predominantly negative but vary greatly among regions. We assessed how 39 fisheries resources—ranging from data-poor to data-rich stocks—in the North East Atlantic are most likely affected under the intermediate climate emission scenario RCP4.5 towards 2050. This region is one of the most productive waters in the world but subjected to pronounced climate change, especially in the northernmost part. In this climate impact assessment, we applied a hybrid solution combining expert opinions (scorings)—supported by an extensive literature review—with mechanistic approaches, considering stocks in three different large marine ecosystems, the North, Norwegian and Barents Seas. This approach enabled calculation of the directional effect as a function of climate exposure and sensitivity attributes (life-history schedules), focusing on local stocks (conspecifics) across latitudes rather than the species in general. The resulting synopsis (50–82°N) contributes substantially to global assessments of major fisheries (FAO, The State of World Fisheries and Aquaculture, 2020), complementing related studies off northeast United States (35–45°N) (Hare et al., PLoS One, 2016, 11, e0146756) and Portugal (37–42°N) (Bueno-Pardo et al., Scientific Reports, 2021, 11, 2958). Contrary to prevailing fisheries forecasts elsewhere, we found that most assessed stocks respond positively. However, the underlying, extensive environmental clines implied that North East Atlantic stocks will develop entirely different depending upon the encountered stressors: cold-temperate stocks at the southern and Arctic stocks at the northern fringes appeared severely negatively impacted, whereas warm-temperate stocks expanding from south were found to do well along with cold-temperate stocks currently inhabiting below-optimal temperatures in the northern subregion.publishedVersio

Workshop on Raising Data using the RDBES and TAF (WKRDBESRaiseTAF; outputs from 2022 meeting)

41 páginasThe Workshop on Raising Data using the RDBES and TAF (WKRDBES-Raise&TAF) met online (26–30 of September 2022) to evaluate the use of the Regional Database and Estimation System (RDBES) format to reproduce the 2022 InterCatch input and output, identifying a Transparent Assessment Framework (TAF) structure to organize the intermediate steps and to propose standardized output formats. The main outcomes of WKRDBES-Raise&TAF were: · RDBES provides sufficient support for current national estimation protocols. However, some minor issues were reported that hampered an exact reproduction of the estimates. Therefore, adaptations of the data model should not be excluded completely. · All the input to stock assessment that InterCatch currently provides, could be reproduced. The participants started from the current stock extracts that can be downloaded from InterCatch. · A workflow was proposed with a national TAF repository for each country, a stock estimation repository and a stock assessment repository. The intermediate output of those repositories will be stored in an ‘intermediate output database’ and depending on the user role, you will get access to the relevant stages in this workflow. · The following requirements for the standard output formats were defined: they cannot be more restrictive than the InterCatch input and output format; they should present measures of uncertainty and sample sizes (for national estimates) and should have a configurable domain definition (for national estimates). Despite those successful outcomes, the current plan for transition to an operational system was concluded to be too optimistic. WKRDBES-Raise&TAF therefore recommends to the Working Group on Governance of the Regional Database and Estimation System (WGRDBESGOV) to revise the roadmap and allow RDBES to be in a test phase also for 2023. WKRDBES-Raise&TAF felt the need to test the proposed workflow on a small scale and therefore recommends to the WGRDBESGOV to arrange a workshop where two stocks (pok.27.3a46 (Saithe (Pollachius virens) in Subareas 4, 6 and Division 3.a (North Sea, Rockall and West of Scotland, Skagerrak and Kattegat) and wit.27.3a47d (Witch (Glyptocephalus cynoglossus) in Subarea 4 and Divisions 3.a and 7.d (North Sea, Skagerrak and Kattegat, eastern English Channel)) will be set up to go through the whole flow.Peer reviewe

Effets directs et indirects de la pêche sur des groupes trophiques de poissons démersaux, définis par une approche écomorphologique

La dynamique de groupes fonctionnels dans une communauté peut permettre de mieux comprendre les impacts d une perturbation sur le fonctionnement du système. Nous nous attendons en particulier à ce que les groupes fonctionnels répondent différemment à la pression de pêche, en fonction de leur exposition directe et de leurs interactions (effets indirects). Une méthode basée sur une approche écomorphologique a été développée, en se focalisant sur les fonctions de prédation, pour définir des groupes fonctionnels basés sur la taille et la taxonomie des individus, dans les communautés de poissons démersaux de mer Celtique et de mer du Nord. Onze traits fonctionnels ont été utilisés pour définir 12 groupes fonctionnels en mer Celtique (basés sur 930 individus appartenant à 33 espèces) et 7 en mer du nord (basés sur 710 individus de 22 espèces). En mer Celtique, les groupes fonctionnels expliquent mieux le régime alimentaire que des groupes de taille tandis que le régime alimentaire en mer du Nord semble davantage gouverné par la taille des individus. Des séries temporelles de biomasse des groupes fonctionnels ont été reconstituées d après des données de campagnes scientifiques de chalutage de fond. Dans les deux communautés, la pêche semble affecter inégalement différentes fonctions trophiques. Nous montrons par ailleurs (i) une propagation des effets de la pêche des hauts vers les bas nivaux trophiques (effets top-down) en mer du Nord et (ii) des phénomènes de compensation écologique intra-groupe en mer Celtique. Le fonctionnement des deux communautés paraît affecté par la pêche. La mer Celtique semble toutefois plus résiliente aux perturbations que la mer du Nord.Functional groups dynamics in marine communities may help to understand how perturbations impact the functioning of an ecosystem. It is notably expected that functional groups respond differently to fishing pressure owing to their direct exposure to fishing and interactions between groups (indirect effects). A method was developed, based on an ecomorphological approach focusing on predation functions, to define size- and taxonomy-driven functional groups in demersal fish communities from Celtic and North seas. Eleven functional traits were used to define 12 functional groups in Celtic sea (based on measurements on 930 individuals from 33 species) and seven groups in North sea (710 individual from 22 species). In Celtic sea, the functional groups better explained diet than size groups whereas diet in North sea appeared rather size-driven. Functional groups biomass time-series were assessed using ground-fish surveys data. Fishing seems to unequally affect different ecological functions in both communities. It was furthermore shown that (i) fishing effects propagate from high to low trophic levels (top-down effects) in North sea and (ii) ecological compensation may occur within functional groups in Celtic sea. The functioning of both communities appeared impacted by fishing pressure. Nevertheless, the Celtic sea fish community appeared more resilient to perturbation than the one from North sea.BREST-BU Droit-Sciences-Sports (290192103) / SudocPLOUZANE-Bibl.La Pérouse (290195209) / SudocSudocFranceF

Toward a Dynamical Approach for Systematic Conservation Planning of Eastern English Channel Fisheries

In the past decade, systematic conservation planning tools have been increasingly and successfully used to set spatial conservation plans that meet quantitative protection targets while minimizing enforcement and socioeconomic costs. However, when applied to fisheries, systematic conservation planning fails to account for (1) changes in fleet dynamics induced by new conservation constraints and their associated feedbacks on conservation costs or (2) their influence on fish population dynamics and distributions, which may in turn alter the achievement of conservation targets. Such a static approach may therefore lead to short- or medium-term misestimates in forecasted costs and target achievements. In order to circumvent such limitations of systematic conservation planning, we present a first attempt to couple a conservation planning tool (Marxan with Zones) with a mixed fisheries dynamics simulation model (ISIS-Fish), applied to the Eastern English Channel fisheries. Broad principles and perspectives are discussed and anticipated future challenges of such an approach are presented

PAMPA - Indicateurs de la Performance d’Aires Marines Protégées pour la gestion des écosystèmes côtiers, des ressources et de leurs usAges. Rapport du site Nouvelle-Calédonie

This documents reports activities conducted within the PAMPA project for the New Caledonia case study (Noumea Marine Reserves)Ce document rapporte les activités menées dans le cadre du projet PAMPA pour le cas d'étude "Nouvelle-Calédonie" (Réserves Marines du Grand Nouméa