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Despite being an abundant group of significant ecological importance the phylogenetic relationships of the Octocorallia remain poorly understood and very much understudied. We used 1132 bp of two mitochondrial protein-coding genes, nad2 and mtMutS (previously referred to as msh1), to construct a phylogeny for 161 octocoral specimens from the Atlantic, including both Isididae and non-Isididae species. We found that four clades were supported using a concatenated alignment. Two of these (A and B) were in general agreement with the of Holaxonia–Alcyoniina and Anthomastus–Corallium clades identified by previous work. The third and fourth clades represent a split of the Calcaxonia–Pennatulacea clade resulting in a clade containing the Pennatulacea and a small number of Isididae specimens and a second clade containing the remaining Calcaxonia. When individual genes were considered nad2 largely agreed with previous work with MtMutS also producing a fourth clade corresponding to a split of Isididae species from the Calcaxonia–Pennatulacea clade. It is expected these difference are a consequence of the inclusion of Isisdae species that have undergone a gene inversion in the mtMutS gene causing their separation in the MtMutS only tree. The fourth clade in the concatenated tree is also suspected to be a result of this gene inversion, as there were very few Isidiae species included in previous work tree and thus this separation would not be clearly resolved. A~larger phylogeny including both Isididae and non Isididae species is required to further resolve these clades.

The Hakon Mosby Mud Volcano is a highly active methane seep hosting different chemosynthetic communities such as thiotrophic bacterial mats and siboglinid tubeworm assemblages. This study focuses on in situ measurements of methane fluxes to and from these different habitats, in comparison to benthic methane and oxygen consumption rates. By quantifying in situ oxygen, methane, and sulfide fluxes in different habitats, a spatial budget covering areas of 10-1000 -m diameter was established. The range of dissolved methane efflux (770-2 mmol m-2 d-1) from the center to the outer rim was associated with a decrease in temperature gradients from 46°C to < 1°C m-1, indicating that spatial variations in fluid flow control the distribution of benthic habitats and activities. Accordingly, total oxygen uptake (TOU) varied between the different habitats by one order of magnitude from 15 mmol m-2 d-1 to 161 mmol m-2 d-1. High fluid flow rates appeared to suppress benthic activities by limiting the availability of electron acceptors. Accordingly, the highest TOU was associated with the lowest fluid flow and methane efflux. This was most likely due to the aerobic oxidation of methane, which may be more relevant as a sink for methane as previously considered in submarine ecosystems.

This deliverable presents the results of the bio-economic modelling assessments carried out under tasks 2.3 and 2.4. Task 2.3 covered the choice and initial parametrisation of relevant bio-economic models for the included case studies, and formulation of scenarios to be analysed. Models were chosen on the basis that they were already operational (i.e. had been used in other applications previously to Discardless) and as such thoroughly tested and documented in peer-reviewed journals, to secure a high scientific standard of the models and the expected assessment results. The selected scenarios firstly included, for all considered case studies, two benchmark scenarios; (i) ‘Business as usual‘, i.e. how the economic outcome of the fishery would evolve if the Landing Obligation (LO) was not implemented, and (ii) ‘Full implementation‘, i.e. what the predicted economic consequences for the fishery will be given a full implementation of the LO with no exemptions or mitigation measures implemented. Secondly a number of relevant scenarios were defined for each case study based on either expectations on or direct knowledge about how the LO, and possible exemptions and mitigation strategies will be implemented in the specific case study. And finally, each case study has assessed and applied outputs from Work Packages (WPs) 3-7, to the extend possible given the bio-economic model in use. Task 2.4 has firstly throughout the project updated the parametrisation of the chosen bio-economic models given the newest knowledge about the fisheries in question. Secondly task 2.4 has covered the running of the models, given the scenarios identified in task 2.3, and documentation of the resulting outputs. The following case studies have been analysed (parenthesis displaying the bio-economic model used): The Danish North Sea Demersal fishery (Fishrent) The UK mixed demersal fisheries in the North Sea, West of Scotland and Area 7 (SEAFISH model) The French mixed demersal fishery in the Eastern English Channel (ISIS-Fish) The Spanish mixed demersal fishery in the Bay of Biscay (FLBeia) The Icelandic mixed demersal fishery (Model for various use of unwanted catches) The Spanish demersal fishery in the Western Mediterranean (MEFISTO) The Greek demersal and small-scale fishery in the Thermaikos gulf (MEFISTO) The outcomes of the simulations are mixed and indicate that the economic effects of the LO for affected fishing fleets depends on both the fishery in question, on the management system on which the LO is superimposed, and on applied exemptions and mitigation strategies. A full implementation of the LO with no quota-uplifts and no exemptions or mitigation strategies applied will in the long run lead to on the average (average over all fleet segments considered in a given case study) reduced or at best similar economic outcomes, compared to the situation with no LO, for the considered fisheries. Application of mitigation strategies and exemptions improves this result for most considered cases, but has in few cases been predicted to make the economic situation worse given redistributional effects, i.e. that the applied mitigation strategy or exemption will have further consequences for the stocks and other fleets, and thus indirectly make the economic situation worse for the considered fleet. When individual fleet segments are considered the picture becomes even more complex as it is in most case studies predicted that some fleet segments will profit while others will loose out given the LO, both without and with added exemptions and/or mitigation strategies. Thus, in all it is concluded that the economic effects of the LO for affected fisheries are, according to model predictions, very varied, going from losses to actual gains. And that the effects to a high degree depends on (i) the management system on which the LO is superimposed, and (ii) on which and how exemptions and mitigation strategies are implemented. Finally, it must be emphasized that the work performed in tasks 2.3 and 2.4 has built up a valuable model library that can be used for ongoing assessments of the economic outcomes of introducing exemptions and mitigation strategies in relation to the LO in the case studies covered. Understanding the consequences of various approaches to the implementation of the LO, and possible mitigation strategies, on economic performance of affected fishing fleets (using these models) is of broad interest for fishers, policy makers and stakeholders, as well as for anybody interested in sustainable fisheries and life in the oceans. The Deliverable report consists of two sections. Section 1 presents a synthesis of the work performed in the seven case studies, and as such gives a short introduction to each case study, to the applied models, to the scenarios analysed and a final synthesis and discussion of the results. Section 2 includes individual case study chapters, that present in-depth information about the case study, the applied model, the reasoning behind the chosen scenarios, discussion on interaction with WP3-7, and detailed outline and discussion of the assessment results. Box 1: Highlights from the bio-economic model assessments The in-depth analysis of the effects of the landing obligation on the economy of the case study fishing fleets has been conducted in the project using complex bio-economic models. The results of these simulations indicate: In Denmark, the ITQ management system applied is predicted to mitigate the economic effects of the LO in the long run and use of exemptions and improved selectivity may reduce possible economic losses further. In UK, the LO will mean losses in revenue due to choke in the medium long run after full implementation of the policy in 2019. However, application of various mitigation strategies, including quota adjustments, catch allowances for zero TAC stocks, TAC deletions, vessel movements between metiers, quota swaps (both nationally and internationally) and selectivity measures, all to some degree mitigate these negative economic consequences. In West Mediterranean, a full implementation of the LO will lead to reduced profitability, but other measures such as reduced fishing mortality and improved selectivity, may lead to increased profitability in the long term due to increased SSB and Yield. In E. Mediterranean, a full implementation of the LO and partial implementations with reduced fishing mortality will lead to slightly reduced profitability, but improved selectivity may lead to increased SSB that will in turn increase catches and profitability in the long term. In Bay of Biscay, the Basque trawler fleet is better off with a fully implemented LO than without in terms of Gross value added (remuneration of labour and capital), as long-term gains outweigh short term losses. Inter-species year-to year flexibility and de minimis reduces this result and makes the fishery worse off than without the LO. On the other hand, application of improved selectivity makes the fishery significantly better off than without the LO. In the Eastern English Channel ISIS-Fish runs suggest that full implementation of the LO induces a slight increase in long-run gross revenues at about 2.5% relative to the no-LO case. Introducing de minimis increases this to about 12.5% relative to the no-LO case. However, fleet opportunism, i.e. how flexible the fishers are in their choice of metiers, may affect these results both negatively (low flexibility) and positively (high flexibility). Closures of fishing grounds to protect whiting and sole has a negative effect for the economic outcome but allows delaying TAC exhaustion. For Iceland the model works opposite to the other models in the WP2 modelling, as the baseline is a fishery under LO. This case is used to contrast the results of the other case studies and reflect the possible value of landing UUC. It is found that the combined yearly value of products produced from these UUC is around 12.5 M Euros. Box 2: The Methods/Approaches followed Existing numerical bio-economic models have been applied with focus on assessment of the effects of the LO on the economic performance of European fishing fleets affected by the LO, and to test the economic effects of possible discard mitigation strategies. Analysed scenarios have been designed based on the problems faced, given the LO, by the specific case study and the management system on which the LO is superimposed. These problems may differ depending on whether the case study fishery is managed primarily through quotas or through Minimum Conservation Reference Size (MCRS) regulation. Analysed scenarios have been designed based on current knowledge on how the LO will be implemented and on mitigation strategies expected to be introduced in the given case study. Interaction with Discardless Work Packages 3-7 and implementation of results from these have been performed where possible in the different case study models. Box 3: How these results can be used and by whom Understanding the consequences of various approaches to the implementation of the LO, and possible mitigation strategies, on economic performance of affected fishing fleets (using bio-economic models) is of very broad interest for fishermen, policy makers and stakeholders, as well as for anybody interested in sustainable fisheries and life in the oceans.

Large organic food falls to the deep sea - such as whale carcasses and wood logs - support the development of reduced, sulfidic niches in an otherwise oxygenated, oligotrophic deep-sea environment. These transient hot spot ecosystems may serve the dispersal of highly adapted chemosynthetic organisms such as thiotrophic bivalves and siboglinid worms. Here we investigated the biogeochemical and microbiological processes leading to the development of sulfidic niches. Wood colonization experiments were carried out for the duration of one year in the vicinity of a cold seep area in the Nile deep-sea fan (Eastern Mediterranean) at depths of 1690 m. Wood logs were deployed in 2006 during the BIONIL cruise (RV Meteor M70/2 with ROV Quest, Marum, Germany) and sampled in 2007 during the Medeco-2 cruise (RV Pourquoi Pas? with ROV Victor 6000, Ifremer, France). Wood-boring bivalves played a key role in the initial degradation of the wood, the dispersal of wood chips and fecal matter around the wood log, and the provision of colonization surfaces to other organisms. Total oxygen uptake measured with a ROV-operated benthic chamber module was higher at the wood (0.5 m away) in contrast to 10 m away at a reference site (25 mmol m-2 d-1 and 1 mmol m-2 d-1, respectively), indicating an increased activity of sedimentary communities around the wood falls. Bacterial cell numbers associated with wood increased substantially from freshly submerged wood to the wood chip/fecal matter layer next to the wood experiments, as determined with Acridine Orange Direct Counts (AODC) and DAPI-stained counts. Microsensor measurements of sulfide, oxygen and pH were conducted ex situ. Sulfide fluxes were higher at the wood experiments when compared to reference measurements (19 and 32 mmol m-2 d-1 vs. 0 and 16 mmol -2 d-1, respectively). Sulfate reduction (SR) rates at the wood experiments were determined in ex situ incubations (1.3 and 2.0 mmol m-2 d-1) and fell into the lower range of SR rates previously observed from other chemosynthetic habitats at cold seeps. There was no influence of wood deposition on phosphate, silicate and nitrate concentrations, but ammonium concentrations were elevated at the wood chip-sediment boundary layer. Concentrations of dissolved organic carbon were much higher at the wood experiments (wood chip-sediment boundary layer) in comparison to measurements at the reference sites, which may indicate that cellulose degradation was highest under anoxic conditions and hence enabled by anaerobic benthic bacteria, e.g. fermenters and sulfate reducers. Our observations demonstrate that, after one year, the presence of wood at the seafloor had led to the creation of sulfidic niches, comparable to what has been observed at whale falls, albeit at lower rates.

Changes in marine net primary productivity (PP) and export of particulate organic carbon (EP) are projected over the 21st century with four global coupled carbon cycle-climate models. These include representations of marine ecosystems and the carbon cycle of different structure and complexity. All four models show a decrease in global mean PP and EP between 2 and 20% by 2100 relative to preindustrial conditions, for the SRES A2 emission scenario. Two different regimes for productivity changes are consistently identified in all models. The first chain of mechanisms is dominant in the low- and mid-latitude ocean and in the North Atlantic: reduced input of macro-nutrients into the euphotic zone related to enhanced stratification, reduced mixed layer depth, and slowed circulation causes a decrease in macro-nutrient concentrations and in PP and EP. The second regime is projected for parts of the Southern Ocean: an alleviation of light and/or temperature limitation leads to an increase in PP and EP as productivity is fueled by a sustained nutrient input. A region of disagreement among the models is the Arctic, where three models project an increase in PP while one model projects a decrease. Projected changes in seasonal and interannual variability are modest in most regions. Regional model skill metrics are proposed to generate multi-model mean fields that show an improved skill in representing observation-based estimates compared to a simple multi-model average. Model results are compared to recent productivity projections with three different algorithms, usually applied to infer net primary production from satellite observations.

Macrophytes growing in shallow coastal zones characterised by intense metabolic activity have the capacity to modify pH within their canopy and beyond. We observed diel pH changes in shallow (5–12 m) seagrass (Posidonia oceanica) meadows spanning 0.06 pH units in September to 0.24 units in June. The carbonate system (pH, DIC, and aragonite saturation state (ΩAr)) and O2 within the meadows displayed strong diel variability driven by primary productivity, and changes in chemistry were related to structural parameters of the meadow, in particular, the leaf surface area available for photosynthesis (LAI). LAI was positively correlated to mean, max and range pHNBS and max and range ΩAr. In June, vertical mixing (as Turbulent Kinetic Energy) influenced max and min ΩAr, while in September there was no effect of hydrodynamics on the carbonate system within the canopy. Max and range ΩAr within the meadow showed a positive trend with the calcium carbonate load of the leaves, pointing to a possible link between structural parameters, ΩAr and carbonate deposition. Calcifying organisms, e.g. epiphytes with carbonate skeletons, may benefit from the modification of the carbonate system by the meadow. There is, however, concern for the ability of seagrasses to provide modifications of similar importance in the future. The predicted decline of seagrass meadows may alter the scope for alteration of pH within a seagrass meadow and in the water column above the meadow, particularly if shoot density and biomass decline, on which LAI is based. Organisms associated with seagrass communities may therefore suffer from the loss of pH buffering capacity in degraded meadows.

This Policy Brief provides an overview of the current status, initial experiences, barriers, and opportunities with regard to applying the LO in mixed demersal fisheries in the North Sea, North Western Waters and South Western Waters, the Mediterranean and the Azores. This area covers the all DiscardLess case studies, including the North Sea/West of Scotland, Celtic Sea, Eastern Channel & Bay of Biscay, the western and eastern Mediterranean, and the Azores. In quota managed fisheries, Mixed demersal fisheries provide the biggest challenge for implementation of the LO due to the difficulty of matching quotas with catches for multiple species which are caught simultaneously but in varying proportions. The policy brief reviews where we are with the LO now and what the main issues are. The main orientation of the policy brief is forward looking: what do stakeholders and researchers consider as the main approaches are to deal with the issues in each region until the next CFP reform? To conclude, we take a longer perspective, providing suggestions for how to implement a workable discard policy with the next reform of the CFP. The Policy Brief is written for policy makers, the fishing industry, NGO’s and citizens with an interest in fisheries management and is based on policy documents, stakeholder interviews, meetings and literature. Box 1: Report Highlights Implementation of the LO is occurring across all DiscardLess case studies with measures such as trials of selective gears, provision of information on implementation requirements and the use of exemptions among the aspects most evident. There is very little evidence to date of changes in discard rates or fishing practices although that is not confirmation that these are not occurring but reflects a lack of data to draw such conclusions at present. Recording of discards under exemptions and unwanted catches remains lower than expected although there is evidence of some increase in these practices in early 2019. It is difficult to assess whether changes in fishing practices to promote selectivity and avoid discards are taking place. Given some delays in sanctioning and gradual uptake of new gears (e.g. for trawlers catching Baltic Cod), recent changes to permitted gears (e.g. new mesh size and TCM requirements in the Celtic Sea) and the upcoming implementation of the new Technical Measures framework some improvements in selectivity and discard rates would be expected. The quality of discard data is not improving due to industry fears about the potential negative impact of providing discard data and subsequent decrease in observer coverage in some Member States. Stakeholders across all backgrounds have expressed concerns about the risks associated with potential rises in fishing mortality. Concerns about efficient and effective monitoring of the LO are increasingly being channeled into calls for electronic monitoring across all fleets or on a risk assessment basis. These calls are particularly strong in some MS such as Denmark. A move towards a Results Based Management approach involving electronic monitoring is being advocated with some industry stakeholders specifying that it would require changes to the LO in order for it to gain industry support. Despite a general negative attitude towards the LO among fishers contributions to the final DiscardLess conference in January 2019 including from fishers outlined both positives, such as the incentivising of change, as well as implementation barriers. These are described in greater detail in Section 8.2 below. Box 2: The methods/approaches followed Interviews with a broad range of stakeholders from Commission level, through national administrators, industry and NGO representatives and individual fishermen. Participation in relevant national, regional and EU meetings. Analysis of relevant policy statements, regulatory documents and academic literature. Box 3: How these results can be used and by who? The policy brief on guidelines for the implementation of the discard policy in European regions is of interest to stakeholders at all levels in EU fisheries as the question of what is actually happening with the LO in other fisheries and regions is asked regularly. Box 4: Policy Recommendations Data shortfalls make it difficult to make a reliable assessment of the extent of LO implementation and it’s impact. Improvements in the following areas of data provision would greatly assist with this assessment process. Recording of discards and unwanted catches at vessel level is poor across all case studies and has been identified by STECF as the most significant problem with monitoring LO implementation. MS will have to develop stronger accounting measures based on last haul analysis if this trend continues. As part of annual reporting on LO implementation MS should provide data not just on selectivity trials undertaken but also on the uptake rates for the use of such gears beyond trial situations. This would allow assessments of changes in selectivity patterns within fisheries to be made. The uptake rates of selective gears could be potentially accelerated by incentivising their use with additional quota. Negative industry attitudes towards the LO across all case studies point to the necessity to find workable discard reduction plans at regional level. The evolving regionalisation process which now incorporates technical measures, multi-annual plans, discard plans and in some cases bycatch reduction plans may provide the necessary framework to overcome industry fears particularly regarding choke closures. Reduced uncertainty regarding the use of measures such as inter-species flexibility and it’s effect on relative stability would assist with mitigating potential chokes. The need for effective monitoring and control of the LO is clear. Calls for the use of electronic monitoring as the solution will also require some degree of industry acceptance in order for this to be viable. Implementing an electronic monitoring approach either on a risk basis or as part of a wider results-based management approach could make this a more feasible option.

First results of a coupled modelling and forecasting system for fisheries on habitat-bound stocks are being presented. The system consists currently of three mathematically, fundamentally different model subsystems coupled offline: POLCOMS providing the physical environment implemented in the domain of the north-west European shelf, the SPAM model which describes sandeel stocks in the North Sea, and the third component, the SLAM model, which connects POLCOMS and SPAM by computing the physical–biological interaction. Our major experience by the coupling model subsystems is that well-defined and generic model interfaces are very important for a successful and extendable coupled model framework. The integrated approach, simulating ecosystem dynamics from physics to fish, allows for analysis of the pathways in the ecosystem to investigate the propagation of changes in the ocean climate and to quantify the impacts on the higher trophic level, in this case the sandeel population, demonstrated here on the basis of hindcast data. The coupled forecasting system is tested for some typical scientific questions appearing in spatial fish stock management and marine spatial planning, including determination of local and basin-scale maximum sustainable yield, stock connectivity and source/sink structure. Our presented simulations indicate that sandeel stocks are currently exploited close to the maximum sustainable yield, even though periodic overfishing seems to have occurred, but large uncertainty is associated with determining stock maximum sustainable yield due to stock inherent dynamics and climatic variability. Our statistical ensemble simulations indicates that the predictive horizon set by climate interannual variability is 2–6 yr, after which only an asymptotic probability distribution of stock properties, like biomass, are predictable.

Increasing anthropogenic CO2 emissions to the atmosphere are causing a rise in pCO2 concentrations in the ocean surface and lowering pH. To predict the effects of these changes, we need to improve our understanding of the responses of marine primary producers since these drive biogeochemical cycles and profoundly affect the structure and function of benthic habitats. The effects of increasing CO2 levels on the colonisation of artificial substrata by microalgal assemblages (periphyton) were examined across a CO2 gradient off the volcanic island of Vulcano (NE Sicily). We show that periphyton communities altered significantly as CO2 concentrations increased. CO2 enrichment caused significant increases in chlorophyll a concentrations and in diatom abundance although we did not detect any changes in cyanobacteria. SEM analysis revealed major shifts in diatom assemblage composition as CO2 levels increased. The responses of benthic microalgae to rising anthropogenic CO2 emissions are likely to have significant ecological ramifications for coastal systems.

The Black Sea northwestern shelf (NWS) is a shallow eutrophic area in which the seasonal stratification of the water column isolates the bottom waters from the atmosphere. This prevents ventilation from counterbalancing the large consumption of oxygen due to respiration in the bottom waters and in the sediments, and sets the stage for the development of seasonal hypoxia. A three-dimensional (3-D) coupled physical–biogeochemical model is used to investigate the dynamics of bottom hypoxia in the Black Sea NWS, first at seasonal and then at interannual scales (1981–2009), and to differentiate its driving factors (climatic versus eutrophication). Model skills are evaluated by a quantitative comparison of the model results to 14 123 in situ oxygen measurements available in the NOAA World Ocean and the Black Sea Commission databases, using different error metrics. This validation exercise shows that the model is able to represent the seasonal and interannual variability of the oxygen concentration and of the occurrence of hypoxia, as well as the spatial distribution of oxygen-depleted waters. During the period 1981–2009, each year exhibits seasonal bottom hypoxia at the end of summer. This phenomenon essentially covers the northern part of the NWS – which receives large inputs of nutrients from the Danube, Dniester and Dnieper rivers – and extends, during the years of severe hypoxia, towards the Romanian bay of Constanta. An index H which merges the aspects of the spatial and temporal extension of the hypoxic event is proposed to quantify, for each year, the intensity of hypoxia as an environmental stressor. In order to explain the interannual variability of H and to disentangle its drivers, we analyze the long time series of model results by means of a stepwise multiple linear regression. This statistical model gives a general relationship that links the intensity of hypoxia to eutrophication and climate-related variables. A total of 82% of the interannual variability of H is explained by the combination of four predictors: the annual riverine nitrate load (N), the sea surface temperature in the month preceding stratification (Ts), the amount of semi-labile organic matter accumulated in the sediments (C) and the sea surface temperature during late summer (Tf). Partial regression indicates that the climatic impact on hypoxia is almost as important as that of eutrophication. Accumulation of organic matter in the sediments introduces an important inertia in the recovery process after eutrophication, with a typical timescale of 9.3 yr. Seasonal fluctuations and the heterogeneous spatial distribution complicate the monitoring of bottom hypoxia, leading to contradictory conclusions when the interpretation is done from different sets of data. In particular, it appears that the recovery reported in the literature after 1995 was overestimated due to the use of observations concentrated in areas and months not typically affected by hypoxia. This stresses the urgent need for a dedicated monitoring effort in the Black Sea NWS focused on the areas and months concerned by recurrent hypoxic events.