Search

The Working Group on Multispecies Assessment Methods (WGSAM) aims to advance the operational use of knowledge on predator-prey interactions for advice on fisheries and ecosystem management. Key runs of multispecies and ecosystem models provided by WGSAM are integral to this mission. They serve as a robust component of ecosystem science that seamlessly integrates into the ICES advice. This report presents an update of the multispecies SMS key-run model for the North Sea and its review by the working group based on established review criteria. The updated model extends to input time-series to 2022 and includes a more extensive revision of the time-series of marine birds and grey seal population numbers. Additional improvements of this key-run include (i) one extra year of grey seal diet data (i.e., 1985, 2002, 2010); (ii) plaice is now a prey species, although predation is at the moment limited to grey seal; (iii) improved compilation of fish diet data including estimation of variance of the estimated prey proportions. WGSAM recommends the use of natural mortality estimates from the North Sea SMS key-run for use in single species stock assessment models of North Sea haddock, herring, Norway pout, sandeel (estimates are disaggregated for the southern and northern North Sea), sprat, and whiting. The SMS key-run continues to assume a single North Sea cod stock in contrast to the recent split into three components which makes assimilation of the natural mortality estimates into the new cod assessments problematic. More work is needed to harmonise the new fish stomachs with the old ones before they could be integrated in the North Sea key-run.

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

Technical interactions (multiple fleets fishing multiple species with various gears, as either target or bycatch), bycatch regulations through a landing obligation, and biological and economic effects of climate change, affecting fisheries yield and profits, provide a challenge for demersal mixed fisheries of the North Sea. A multi-stock, multi-fleet, bioeconomic model was used to understand management options under these combined influences. Scenarios considered climate change effects on recruitment of three main gadoid stocks (cod – Gadus morhua, saithe – Pollachius virens, whiting – Merlangius merlangus), possible future developments of fuel and fish prices, and strict implementation of a landing obligation. The latter leads to decreased yield and profits in the short term due to increased choke effects, mainly of North Sea cod, being influenced by climate-induced productivity changes. Allowing fishing above FMSY, but within sustainable limits, or limiting year-to-year quota changes, could help buffer initial losses at the expense of decreased profits in the mid- to long-term. Economic performance of individual fleets was linked to their main target's stock status, cost structure, and fuel and fish prices. The results highlight a need to consider both biological and economic consequences of climate change in the management of mixed fisheries.

A first workshop on guidelines and methods for the design and evaluation of rebuilding plans for category 1-2 stocks, WKREBUILD, took place in 2020. WKREBUILD generated a guidance on best practices for evaluation of rebuilding plans against potential criteria of acceptability. However, it did not propose specific rebuilding plans or harvest control rules (HCRs). Instead, the workshop recommended that a follow-up workshop be organized for testing the guidelines with actual test cases, with the aim of defining more specific criteria and guidelines. Thus, the main objective of WKREBUILD2 was to propose performance indicators and thresholds for the implementation and acceptability of rebuilding plans and a framework for the integration of rebuilding advice rules within the ICES advice framework. To facilitate the evaluation of rebuilding plans a simulation tool was developed. The tool is based on FLR libraries and the application to specific cases is facilitated through a template consistent with TAF (Transparent Assessment Framework) and ensures an easy integration of the analysis into the ICES TAF system. The tool was tested in three specific case studies, Celtic Sea Whiting, Western Horse Mackerel and Western Baltic Herring. The application to the case studies served to validate the tool and to provide the science base to propose operational performance thresholds and criteria for the evaluation and implementation of rebuilding strategies in ICES. WKREBUILD2 proposes to use BPA as the entry point to the rebuilding phase and MSY Btrigger as the exit point. Once a stock is estimated to be below BPA in the last assessment year, stock specific rebuilding strategies should be tested by means of simulations, preferably using the WKREBUILD2 simulation tool as the performance of HCRs are dependent on depletion rate and life history. The harvest control rule that fulfils the rebuilding criteria could then be selected to provide headline catch advi

Incorrect Affiliation In the published article, there was an error regarding the affiliation for Jasper Van Vlasselaer. Instead of: 13 Spanish Institute of Oceanography (IEO-CSIC) (Palma), Ecosystem Oceanography Group (GRECO), Palma de Mallorca, Spain, he should have: 11 Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Fisheries and Aquatic Production, Oostende, Belgium. In the published article, there was an error regarding the affiliation for Luc Van Hoof. Instead of: 14 Department of Marine Sciences, University of the Aegean, Mytilene, Greece he should have 3 Wageningen Marine Research, Wageningen University and Research, Ijmuiden, Netherlands The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.

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

The implementation of ecosystem-based fisheries management requires knowledge on the ecological impact of fishing activities on species and their habitats – those both targeted and not targeted by fisheries. To identify whichecological impacts are key and what is known about them, SEAwise consulted stakeholders through European Advisory Councils and conducted a systematic review of the scientific literature to map the available knowledge and evidence. Specific reference was given to the bycatch of Protected, Endangered and Threatened (PET) species, benthic habitats, food webs and biodiversity, and impact from fisheries-related litter and ghost nets. At the stakeholder consultations, sharks and/or elasmobranchs, turtles, species interactions, and seals or marine mammals were identified as top ranked in at least three out of the five regions. Other terms identified by at least two Case Study regions were: seabirds, sensitive species, benthic habitats, litter, PET species, invasive species and species interactions.Relevant data were extracted from 549 retained papers. The majority of studies were conducted in the Mediterranean Sea, whereas only few papers reported on fishing impacts in the Baltic Sea (see figure below). Bony fish (teleosts) and benthos were the most studied ecosystem components in all Case Study regions, whereas marine mammals and cartilaginous fish were often studied in relation to bycatch of PET species. Out of the 549 papers, most of them were related to fishing impacts on food webs and biodiversity and benthic habitats, followed bybycatch of PET species and other fishing impact studies (not related to any task). Fewest studies were related to the impact of fisheries-related litter and ghost nets. Demersal trawls were by far the most studied gear in studies on commercial fishing impacts. For recreational fisheries, hooks and lines, in particular angling, was the most studied fishing activity. Among the items identified by the stakeholders, marine ma

An ecosystem approach to fisheries management requires the consideration of commercial species as components of an ecosystem and the acknowledgement of the links between their productivity and the surrounding environment. To provide a knowledge base for such links, SEAwise consulted stakeholders throughout Europe and conducted a systematic review of the scientific literature. The systematic review resulted in 2050 articles from the literature search that were screened for their tile and abstract. 516 of them were retained for data extraction. The majority of studies were conducted in the Baltic Sea and the North Sea, followed by the Western Waters, and with only a few dozen papers in the Mediterranean Sea. Cod and herring were the most studied species, temperature and more generally climate and hydrodynamics indicators were the main drivers investigated, and reproduction was the main productivity-related process. The output of the systematic review is a database of scientific articles organised by regions, species, environmental drivers and productivity-associated processes and where outcomes, but also spatial and time scales, analytical methods etc. are described in a standardised fashion. This database will be analysed in the coming months and used in the downstream tasks of WP3. The most frequently driver identified by stakeholders across regions was climate change followed by species interactions, cod, pollution, commercial fish/shellfish and plankton. Climate change effects on stocks through temperature and salinity are relatively well covered in the literature as are effects of plankton and species interaction. Studies of the effects of pollution do not occur frequently and as a consequence require a dedicated effort is made in SEAwise to remedy this. Species reported frequently by the stakeholders included cod, seabass, sardine, sole, crabs, flatfish, Norway lobster, octopus, shrimps, herring, sprat, anchovy, hake, new species (species increasing in abundance

To effectively future-proof the management of the European Union fishing fleets we have explored a suite of case studies encompassing the northeast and tropical Atlantic, the Mediterranean, Baltic and Black Seas. This study shows that European Union (EU) fisheries are likely resilient to climate-driven short-term stresses, but may be negatively impacted by long-term trends in climate change. However, fisheries’ long-term stock resilience can be improved (and therefore be more resilient to increasing changes in climate) by adopting robust and adaptive fisheries management, provided such measures are based on sound scientific advice which includes uncertainty. Such management requires regular updates of biological reference points. Such updates will delineate safe biological limits for exploitation, providing both high long-term yields with reduced risk of stock collapse when affected by short-term stresses, and enhanced compliance with advice to avoid higher than intended fishing mortality. However, high resilience of the exploited ecosystem does not necessarily lead to the resilience of the economy of EU fisheries from suffering shocks associated with reduced yields, neither to a reduced carbon footprint if fuel use increases from lower stock abundances. Fuel consumption is impacted by stock development, but also by changes in vessel and gear technologies, as well as fishing techniques. In this respect, energy-efficient fishing technologies already exist within the EU, though implementing them would require improving the uptake of innovations and demonstrating to stakeholders the potential for both reduced fuel costs and increased catch rates. A transition towards reducing fuel consumption and costs would need to be supported by the setup of EU regulatory instruments. Overall, to effectively manage EU fisheries within a changing climate, flexible, adaptive, well-informed and well-enforced management is needed, with incentives provided for innovations and ocean liter

To effectively future-proof the management of the European Union fishing fleets we have explored a suite of case studies encompassing the northeast and tropical Atlantic, the Mediterranean, Baltic and Black Seas. This study shows that European Union (EU) fisheries are likely resilient to climate-driven short-term stresses, but may be negatively impacted by long-term trends in climate change. However, fisheries’ long-term stock resilience can be improved (and therefore be more resilient to increasing changes in climate) by adopting robust and adaptive fisheries management, provided such measures are based on sound scientific advice which includes uncertainty. Such management requires regular updates of biological reference points. Such updates will delineate safe biological limits for exploitation, providing both high long-term yields with reduced risk of stock collapse when affected by short-term stresses, and enhanced compliance with advice to avoid higher than intended fishing mortality. However, high resilience of the exploited ecosystem does not necessarily lead to the resilience of the economy of EU fisheries from suffering shocks associated with reduced yields, neither to a reduced carbon footprint if fuel use increases from lower stock abundances. Fuel consumption is impacted by stock development, but also by changes in vessel and gear technologies, as well as fishing techniques. In this respect, energy-efficient fishing technologies already exist within the EU, though implementing them would require improving the uptake of innovations and demonstrating to stakeholders the potential for both reduced fuel costs and increased catch rates. A transition towards reducing fuel consumption and costs would need to be supported by the setup of EU regulatory instruments. Overall, to effectively manage EU fisheries within a changing climate, flexible, adaptive, well-informed and well-enforced management is needed, with incentives provided for innovations and ocean liter

This report describes the SEAwise data procedures and guidelines with the aim to increase the awareness about the data collected, processed and stored in the project, to ensure that all relevant data collected and used in the project is available in a well-documented, discoverable, standardised and easily accessible form, to give information on data quality and sampling protocols and, to clearly state the usage rights on the different data and to ensure use and handling of data is in accordance with Regulation 2016/679 of the European Parliament and of the Council on the protection of natural persons with regard to the processing of personal data and on the free movement of such data (General Data Protection Regulation, GDPR). Sharing research knowledge and data is integral to the SEAwise project and this is attained through implementing the FAIR principles, employing dedicated quality assurance processes and carefully considering ethical aspects of knowledge and data storing and sharing.

The ICES Workshop on ICES reference points (WKREF2) was tasked review the WKREF1 report and based on the outcome develop updated guidelines for the ICES reference points system and recommendations for ACOM consideration. The WKREF1 report has suggested 5 key recommendations to simplify and harmonise the ICES reference points framework representing a major change to the current guidelines. At WKREF2, we detailed discussions and four key concerns were raised about the proposed approach. The first related to the simplification of rules to define Blim. Around two thirds of category 1 stocks would end up as WKREF1 “Blim Type 2” where Blim would be set as a fraction of B0. The Allee effect or “depensation” maybe more important than previously thought and should be furthered explored for ICES stocks since it has important consequences for Blim. A number of challenges and issues around defining Blim using the current guidelines were documented. Some suggestions on improvement criteria were discussed including using classifiers to define spasmodic stocks and using change point algorithms to address non-stationary productivity regimes. However, further work is need to make these approaches operational and there was no consensus that the WKREF1 Blim types should replace the current guidelines. WKREF1 recommended that the FMSY proxy should be based on a biological proxies and should be less than the deterministic FMSY. It was pointed out that the stochastic FMSY estimated in EqSim for example, is lower than the deterministic FMSY and that the current guidelines ensure that the FMSY should not pose a more than 5% risk to Blim. A large amount of work described in WD 1 was carried out to develop an MSE framework to consistency and robustness test a candidate reference point system for North East Atlantic stocks. However, WKREF2 recommended tha

An ecosystem approach to fisheries management requires the consideration of spatially explicit management measures and other impacts on species and the links between the distribution of fished species, their surrounding environment and productivity. Quantification of the spatial aspects of fisheries and ecology of commercially fished stocks may improve the accuracy of the predicted changes in fish productivity, fisheries yield and costs, benefits and selectivity. To provide a knowledge base for spatially explicit considerations, SEAwise consulted stakeholders throughout Europe and conducted a systematic review of the scientific literature. As a first step, engagement with relevant stakeholder groups in each Case Study identified key issues of relevance to spatial management. The input from this stakeholder consultation was supplemented by a systematic literature review with careful consideration of the objectives, search terms, inclusion/exclusion criteria, the method for data/knowledge extraction and ultimately how these data and knowledge will be used. The purpose of the task was to quantify the key drivers and pressures behind the changes occurring in commercial fish stocks and fisheries distribution that have a spatially explicit content, map the relevant existing scientific knowledge and provide input to the subsequent SEAwise tasks. The words identified by the stakeholders consulted focused on factors causing changes to the distribution of commercial fish/shellfish (climate change, MPAs, species interactions, pollution, habitats and invasive species) and fisheries (windfarms, MPAs, Marine spatial planning) as well as the other human impacts. The systematic review extracted data from 331 papers. The most frequently studied topic was the distribution of fish and the region with most papers was the North Sea with about the twice the amount of papers in each of the other regions. The most frequently studied species in the literature were cod, hake and plaice and b