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Havet rummer en betydelig del af den danske natur og biodiversitet og er samtidig en kilde til sund mad, naturoplevelser, vedvarende energi og råstoffer. For at sikre et sundt og godt havmiljø til glæde og gavn også for de kommende generationer og samtidig opretholde en bæredygtig udnyttelse specificerer EU’s havstrategidirektiv fra 2008 og havstrategiloven fra 2010 retningslinjer for, hvordan vi identificerer væsentlige aspekter af havmiljøet. De væsentlige aspekter er inddelt i 11 deskriptorer: 1. Biodiversitet, 2. Ikke-hjemmehørende arter, 3. Kommercielle fisk, 4. Fødenet, 5. Eutrofiering, 6. Havbundens status, 7. Permanent ændring af hydrografiske forhold, 8. Forurenende stoffer i miljøet, 9. Forurenende stoffer i fisk og skaldyr, 10. Marint affald og 11. Indførelse af energi. For hver deskriptor er der defineret en række kriterier, der undersøges ved at følge udviklingen i specifikke indikatorer. Indikatorerne bruges sammen med tærskelværdier til at vurdere om det enkelte kriterie er i god tilstand (på den rigtige side af tærskelværdien). Denne rapport er en af en række af rapporter, som DTU Aqua har produceret for Miljøministeriet til den danske rapportering for havstrategidirektivets deskriptorer. Under havstrategiens deskriptor 6 moniteres tilstanden af havbunden ved at beregne det areal, der er påvirket af presfaktorer, havbundens følsomhed samt risikoen for at havbundens tilstand med denne følsomhed påvirkes negativt af presfaktorerne for henholdsvis tab (D6C1 og D6C4), fysisk påvirkning (D6C2, D6C3) og havbundens samlede tilstand (D6C5). Denne rapport viser analyser gennemført til støtte for Miljøministeriets statusanalyse for deskriptor 6 om havbundens tilstand. Rapporten omfatter detaljerede analyser af det areal, der er påvirket af presfaktorer, havbundens følsomhed samt risikoen for at havbundens tilstand med denne følsomhed påvirkes negativt af presfaktorerne. EU foreskriver at God miljøtilstand (GES) ift. tab (Loss) vurder

The sea contains a significant part of Danish nature and biodiversity and is also a source of healthy food, nature experiences, renewable energy and raw materials. In order to ensure a healthy and good marine environment for the enjoyment and benefit of future generations as well as maintaining sustainable exploitation, the EU's Marine Strategy Framework Directive from 2008 specifies how we identify significant aspects of the marine environment. The significant aspects are divided into 11 descriptors: 1. Marine biodiversity, 2. Non-indigenous species, 3. Commercial fish and shellfish, 4. Food webs, 5. Eutrophication, 6. Seabed integrity, 7. Hydrographical conditions, 8. Contaminants. 9. Contaminants in seafood, 10. Marine litter and 11. Energy. For each descriptor, a number of criteria have been defined and these are examined by following the development of specific indicators. The indicators are used together with threshold values to assess whether the individual criterion is in good environmental status (on the right side of the threshold value). This report is one of a number of reports DTU Aqua has produced for the Ministry of the Environment for the Danish reporting for the marine strategy directive's descriptors. Descriptor 1 aims to maintain biodiversity, including that of fish (European Commission, 2008). It is recommended that the list of species is developed through regional cooperation, preferably using regional seas conventions such as OSPAR (European Commission 2021). The present report provides an update of analyses in support of Marine Strategy Directive descriptor 1. It is an update of the report ”Abundance and catch of sensitive non-commercial species in Danish waters” (Gislason et al., 2017). The methodology for estimating stock abundance from survey catch rate has been improved and data from survey and fisheries have been updated to also include the period 2017-2022. The aim of the study was to evaluate the temporal deve

This report investigates how key environmental variables influence the recruitment process of target fish stocks. Understanding how the environment affects recruitment may allow more accurate predictions of fish stock dynamics under scenarios of environmental change and in particular their response to global warming, supporting the development and implementation of robust management policies. Case studies from the four Seawise case study regions have been analysed, and the main results obtained so far are summarized below. In the Baltic Sea, the Gulf of Riga spring spawning herring showed effects of spawning stock biomass on individual weight of age-1 fish, with prey abundance in May and previous year feeding period temperature also playing significant roles. The explanatory power of the final model was moderate. Higher weight of herring is achieved at higher prey densities, lower SSB levels and lower temperatures during the main feeding season of age-0 fish. Recruitment of Western Baltic cod and herring showed decreasing reproductive potential at increasing temperature. In the North Sea, the effects of temperature, salinity, currents, chlorophyll and zooplankton on recruitment of cod, haddock, saithe, whiting, plaice, sole, sprat and herring were investigated using a semi-automated, machine learning framework. The incorporation of environmental signals in recruitment predictions showed improved predictions over a stock recruitment model without environmental effects in six out of the eight stocks. For small pelagic foirage fish, four stock-recruitment models were fitted for three sandeel stocks and the North Sea sprat stock Linear regressions revealed various relationships between recruitment and environmental variables. Short-term time scales based on monthly averages produced a noisier and less consistent pattern for most stock. In the Western Waters, Bayesian online change point detection models were applied to thr

The Benchmark Workshop on Sandeel (Ammodytes spp.) (WKSandeel) was conducted over an extended period, spanning 2021-2023, to agree the assessment methodology to be used in future update assessments of sandeel in areas 1–4 (Figure 1). The benchmark had a strong focus on investigating spatial stock boundaries within the North Sea, bringing catch and survey data compilation and standardization up to standard with the latest insights in ICES and updating the assessments accordingly. The data compilation workshop was preceded by several informal sessions to present the latest findings from an extensive study on stock structure identification, including tagging, otolith micro-chemistry, drift modelling and genetics research. The workshop proposed two alternative stock structure delineation scenarios as presented in Figure 2. The different research projects provided contrasting views on appropriate stock structure delineation, with evidence for residence within the delineated sandeel areas but also migration across the a and b borders as denoted in Figure 2. The group reached consensus that, as a pragmatic way forward, only scenario WKSAND2022a would be put forward for evaluation in the assessments, together with the existing WKSAND2016 delineation as a baseline. Catch numbers at age, fishing effort, maturity at age, weight at age, natural mortality at age and survey indices were recalculated based on the latest insights and tools provided through the ICES RDBES and statistical standardization. Key to this process was also the re-definition of sandeel banks, which are used directly to derive standardized survey indices for the different assessments (Figure 3). For all four sandeel areas, updated assessments were prepared for the WKSAND2022a and WKSAND2016 (baseline) area delineation scenarios. There is no change in area delineation for area 4 under both scenarios. Diagnostics on catch and survey residuals, parameter uncertainty

Multispecies models have existed in a fisheries context since at least the 1970s, but despite much exploration, advancement, and consideration of multispecies models, there remain limited examples of their operational use in fishery management. Given that species and fleet interactions are inherently multispecies problems and the push towards ecosystem-based fisheries management, the lack of more regular operational use is both surprising and compelling. We identify impediments hampering the regular operational use of multispecies models and provide recommendations to address those impediments. These recommendations are: (1) engage stakeholders and managers early and often; (2) improve messaging and communication about the various uses of multispecies models; (3) move forward with multispecies management under current authorities while exploring more inclusive governance structures and flexible decision-making frameworks for handling tradeoffs; (4) evaluate when a multispecies modelling approach may be more appropriate; (5) tailor the multispecies model to a clearly defined purpose; (6) develop interdisciplinary solutions to promoting multispecies model applications; (7) make guidelines available for multispecies model review and application; and (8) ensure code and models are well documented and reproducible. These recommendations draw from a global assemblage of subject matter experts who participated in a workshop entitled “Multispecies Modeling Applications in Fisheries Management”.

The production of this report was carried out through the HELCOM Project for the development of the Third Holistic Assessment of the Baltic Sea (HOLAS 3). The work builds on the previous assessment (HOLAS II) and methodologies, evaluations and assessments included in this report have been directly contributed to by the HELCOM BLUES project, the Baltic Data Flows project, the COMPLETE project, the COMPLETE PLUS project, and the PreEMPT project.

Sharks and rays are important components of marine biodiversity. This together with their life history with slow growth, late maturation and large asymptotic size makes them candidates for biodiversity indicators under descriptor 1 of the Marine Strategy Framework Directive. However, the assessment of their abundance and occurrence in the fishery is complicated by expected poor species identification. Further, landings of skates and rays (Rajidae) have historically often been reported as “wings” in commercial landings, rendering the catches by species unknown. For sharks, many species are easier to identify visually, but some, such as Mustelus asterias (starry smoothhound) and Mustelus mustelus (common smoothhound) can be difficult to distinguish from each other. These difficulties mean that the Danish monitoring undertaken prior to the previous MSFD assessments could not support the evaluation of the impacts of fishing on individual species. This report aims to ensure that the species composition of sharks and rays in the Danish commercial fishery can be assessed going forward, and that Denmark can fulfil the obligations of the common fisheries policy and the marine strategy directive. This was approached through developing and testing DNA-based monitoring of by-catch of sharks and rays in the Danish commercial fishery and providing a knowledge base for risk-based management in relation to unintentional by-catch of sharks and rays. The project is divided into two components, mapping of the species composition of rays and selected sharks in the Danish fishery and an analysis of the catches of skates and rays in the Danish fishery. The mapping of species composition is confirmed by tissue samples from rays and selected shark species during observer trips on commercial fishing vessels and samples at landing sites. A risk-based analysis combines results from the genetic analysis with the observer and landing data to rank fisheries and gear

This report aims to investigate the available tools for predicting the impact of various spatial management options on fisheries distribution, yield, profitability, and selectivity. Such spatial plans may affect the remaining ‘fishable’ areas by displacing and concentrating the fishing pressure, and so may alter stock abundances, distributions, size- and species catch composition and fuel expenditure and cost. The report provides early insights into how spatial plans that exclude certain fishing activities may affect these outcomes. Spatially explicit approaches are used, along with scenarios of underlying stock productivities and distributions, to assess the performance of spatial management measures. Scenario-based testing is conducted to examine the interrelated effects of management options and stock productivity. A major aspect of the work involved gathering and organizing information on specific zones from several sources such as Natura2000, CDDA, SPA, SAC, and UK-defined areas. We found that most of these zones did not have any previous management plans in place that would outline fishing restrictions. Therefore, we developed a method of assigning limitations to certain fishing techniques based on the perceived vulnerability of specific areas to these practices. This approach has allowed for an examination of how these restrictions potentially affect fish and fisheries. Initially, we used a static approach in anticipating the potential fishing effort displacement to measure the impact of fishing in the Northeast Atlantic area. Our research shows that while such spatial management measures may reduce fishing opportunities, it may be possible to offset in the short term some of these spatial opportunity losses by fishing in nearby locations (Figure 1). On the Med side, an analysis of fishing effort displacement from restricted areas in the Adriatic Sea is exemplified in a before/after situation, showing that the effort is not reduced but redistr

The ICES herring assessment working group (HAWG) met online for nine days in March 2023 to assess the state of six herring (Clupea harengus) and three sprat (Sprattus sprattus) stocks. Additionally, HAWG provided advice for eight Sandeel (Ammodytes spp.) in January 2023. The working group conducted update category 1 assessments for four of the herring stocks and category 3 assessments for 2 herring stocks. An analytical assessment was performed for the combined North Sea and Division 3.a sprat, and data limited assessment (ICES category 3) was conducted for English Channel sprat (spr.27.7de). Biennial advice is given for sprat in the Celtic Seas and West of Scotland with advice provided in 2023. North Sea autumn spawning herring (her.27.3a47d). SSB in 2022 was estimated at 1.65 million tonnes while F 2–6 in 2021 was estimated at 0.23, which is below FMSY. Recruitment in 2022 is at its highest since 2014, which is expected to contribute positively to SSB levels from 2024 onwards. ICES considers that the stock is still in a low productivity phase. Western Baltic spring-spawning herring (her.27.20-24). SSB in 2022 was estimated at 75,548 tonnes and is below MSY Btrigger, Bpa, and Blim. Recruitment has been low since 2007 and has been deteriorating further with time. F3-6 has been decreasing since 2018 and is now week below FMSY (0.31) at 0.05. The stock has decreased consistently during the second half of the 2000s and given the continued low recruitments, the stock is not able to recover above Blim unless a drastic reduction in fishing effort is applied for several years. Celtic Sea autumn and winter spawning stock (her.27.irls). SSB in 2022 was estimated at 16,539 tonnes, though is increasing from its lowest level seen in 2018 (6,474 tonnes), but remains below Blim (34,000 tonnes). F(2-5 rings) in 2022 was estima

The objective of WKFISHDISH2 was to develop a standardized and open-source way of routinely using trawl survey data to produce distribution maps which can be easily updated. To do so, workshop participants (i) reviewed models that can produce distribution maps from survey data in DATRAS and MEDITS formats, (ii) considered best practice guidance for data, and models, (iii) implemented best practice to produce distribution maps in a transparent manner, and (iv) populated an ICES repository with distribution maps and associated scripts. Nine models were reviewed, seven of which were considered appropriate to produce distribution maps using survey data. The two models excluded failed to estimate gear standardization factors. Best practice for data should consider the following: correct/remove erroneous observations, account for changes in haul duration/timing affecting catchability, use species-specific modelled areas, remove gears/surveys with no observations to reduce model converging time, and include appropriate explanatory variables. A step-by-step list to preprocess survey data was provided. Best practice for models should consider the following: account for skewed distribution of survey data by exploring different statistical error distributions, use open-source models able to reproduce distributions from simulated data, consider the complexity of the model required vs. the run-time (e.g. number of knots), avoid extrapolating the model to areas/depths where the species is not observed, and perform relevant model diagnostics/model selection. To compare distribution estimated by different models, the SPAtial EFficiency metric (SPAEF) was used together with centres of gravity, biomass hot spots (90 th percentile), and effective occupied areas. All seven models were able to produce satisfactory distribution maps for at least one species within the workshop time constraints, both with DATRAS data in the Atlantic and the MEDITS data in the Mediterranean. Comparisons be

We studied the ten most frequently encountered litter items from the seafloor in European seas to advance actions and inform future mitigation measures to reduce marine litter and the associated social, economic and environmental impacts it has on European seas and beyond. Data were collected during trawl surveys from 2012 to 2020 as part of national and regional marine litter monitoring programmes in the Greater North Sea (5652 trawls), Celtic Seas (3505), Bay of Biscay (651), and Baltic Sea (3688). A Bayesian approach is used to quantify the variation in the item rankings. Overall, plastic items predominate in the top positions in each area. Synthetic rope, plastic sheets, monofilament fishing line and plastic bags occupy four of the top five positions for each of the Greater North Sea, Celtic Seas and the Bay of Biscay. Items from fishing and rope (representing mainly other maritime activities) are strongly represented in the top ten lists from three of our four areas, with synthetic rope, fishing nets, and tangled and untangled monofilament fishing line listed in the top seven positions for the Greater North Sea, Celtic Seas and the Bay of Biscay. The top ten items in the Baltic Sea are of a different profile to the other regions, but the most commonly caught items are still predominantly plastic, with plastic sheets, other plastic items and plastic bags occupying three of the top four positions. The findings in this study highlight the need to address sea-based sources to try and eliminate litter from fishing and maritime activities. Measures such as improved port reception facilities, marking of fishing gear, promoting reporting of the loss of fishing gear and increasing public awareness should be introduced.

The Marine Strategy Framework Directive (MSFD) Technical Group on Marine Litter developed the on monitoring of marine litter in European s in 2013 to enable EU Member States to launch monitoring programmes for MSFD Descriptor 10: no harm caused by marine litter . The maturity of methodological protocols for marine litter monitoring has increased over the last 10 years, based on research advances and M efforts.This document updates the previous guidance to facilitate the harmonisation of the monitoring framework for the MSFD, including protocols, recommendations, and information required to increase the comparability of data and assessments among Member States. The document comprises chapters dedicated to the protocols for monitoring marine litter across different marine environmental compartments (i.e. the coastline/beach, the surface layer of the water column, the seafloor/seabed) and types of litter (i.e. macro litter, mesolitter, microlitter, ingested litter and microlitter by biota, and entanglement with litter).

SEAwise deliverable 6.7 is the first of two deliverables in task 6.4. It investigates the consistency of existing targets and limits from the Common Fisheries Policy (CFP) and the Marine Strategy Framework Directive (MSFD). Trade-offs between different objectives (ecological, economic, social), targets and limits are highlighted. A wide range of model types (from bio-economic to full ecosystem models) has been applied to various case study areas across the North East Atlantic and Mediterranean. Although model predictions are by nature uncertain, this study provides important information on likely inconsistencies between existing targets and limits and trade-offs expected under ecosystem- based fisheries management (EBFM). The scenarios investigated include the current range of management applied in terms of the Maximum Sustainable Yield (MSY) concept (i.e. strict MSY approach vs. Pretty Good Yield (PGY) approach allowing sustainable deviations from single species FMSY point estimates). The landing obligation is a key aspect of current fisheries management and was fully considered, in particular for mixed demersal fisheries. Maintaining current fishing effort without further management measures was the least sustainable option in nearly all cases studies. This approach led to increased risk of stocks falling below critical biomass limits. Although the fishing effort adaptions needed is highly case specific, this indicates that further management measures are likely to be needed to ensure a sustainable exploitation of all stocks. Scenarios applying a strict MSY approach in combination with the landing obligation (i.e. FMSY as upper limit with fisheries ending when the first stock reaches FMSY) in most case studies led to the lowest fishing effort. This had positive effects on MSFD related indicators such as bycatch of Protected, Endangered and Threatened (PET) species, benthic impact and the Large Fish Indicator as well as global indicators such as CO2 emission or eco