Search

This report discusses the concept of governance, how to understand ‘effective’ governance, and a research plan for further studies of the effectiveness of and potential for improving governance at the regional and sub-regional level in the SEAwise regions (Baltic Sea, North Sea, Western Waters, and the Mediterranean Sea). The theoretical insights from the first two main parts inform and are merged into the research plan, forming the last part of the report. The work is based on the recognition that fisheries management in Europe is still struggling to deliver on its objectives relating to ecology, economy, and social considerations although improvements have been made over the last decades. On top of this, marine biodiversity and ecosystem integrity can be identified as pressing challenges, while climate-change presents renewed uncertainties and risks. Improved governance, appropriately designed for Ecosystem Based Fisheries Management (EBFM), is key to improving the system performance towards the societal objectives. Lack of appropriate measures towards cooperation between the EU, national, and regional levels has led to uncoordinated decision-making processes and prevented coherent management through the implementation and adoption of EU legislation, leading to lower than desired performance both of fisheries and environmental policies. Referring specifically to the involvement of stakeholders, the European Commission stresses the importance of transparency, cooperation, outreach, information, and inclusiveness in developing and implementing measures to ensure that all stakeholders, not least fishers, have a say in the management process, and that their needs and concerns are considered (European Commission, 2023a). Improvement of what can broadly be defined as ‘governance’ is, thus, among the pathways that the European Commission has identified for improvements in the area.

Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report is the 10th of a suite of STECF EWG reports dedicated to the evaluation of the implementation of the Western Mediterranean Sea Multi-Annual management Plan (hereafter, MAP), following EWG reports 18-09, 18-13, 19-01, 19-14, 20-13, 21-01, 21- 13, 22-01 and 22-11. The group was requested to continue the development of socio-economic indicators to be used in the evaluation of management measures for the West Med MAP in both West Med management units (EMU1 and EMU 1) (TOR1). Two roadmaps were discussed, a short term approach and a long term approach which would consider the expansion of all the mixed-fisheries bio-economic models to both management units. As a first step, the group focused on the proposal of harmonizing the economic indicators across the models implemented (TOR2). The group was than requested to further develop the approach implemented during EWG 22-01 to identify persistence hotspots of the six target species of the West Med MAP using scientific survey data (MEDITS) in combination to commercial spatial data (VMS joined with logbooks), to test existing and additional closure areas (TOR 3). The group was also requested to revise Article 8 of the 2023 fishing opportunities for the West Med MAP (COUNCIL REGULATION (EU) 2023/195), which lists the compensation mechanisms that MSs can implement within the West Med MAP to obtain additional fishing days in 2023 (TOR 4). For TOR 1 a roadmap was discussed and proposed on how to organise the work on socio-economic assessments for the West Med MAP in 2023. The EWG suggests that here should be a three-step process: a scoping exercise (done with EWG 23- 01), a meeting with stakeholders in the middle of the year to discuss their perception of the socio-economic consequences of measures of the West Med MAP and the running of scenarios during EWG 23-11 with results from socio-economic assessments. The EWG notes that the modellers have only the five-day meeting in September to run scenarios. Therefore, it would be crucial for the success of the assessments that the 6 scenarios provided by DG Mare for the EWG 22-11 and with some adjustments for EWG 23-01 will not change for EWG 23-11. It is crucial because those scenarios are already implemented in the models and the implementation of new scenarios would take a lot of time. The EWG proposes to run a few additional scenarios with only one measures to separate impacts of certain measures from the six scenarios where a mixture of measures is included. This would hopefully allow to give an indication what additional efforts may be necessary to reach MSY (in 2025 but also beyond in case the objective is not reached by 2025) and when gains from the implementation of the West Med Plan could be expected. The EWG observes that modelers need to put in additional effort and resources to improve the models for an improved assessment of the West Med MAP. The models were not originally developed for the assessment of the West Med MAP and only cover parts of the area of the Western Mediterranean. Such an improvement of the models could also include work to provide longer-term socio-economic assessments of measures where modelers need to take additional assumptions into account. The EWG notes that it would be beneficial if modelers receive a basic list of assumptions for key economic variables before the EWG 23-11 meeting in September. In 2022, for example, the increased fuel costs were an important factor regarding the economic performance of the fleets. In 2023 fuel costs have decreased but there are other cost categories with a substantial increase. The EWG concludes that DG Mare should not change the 6 provided scenarios substantially before the EWG 23-11 meeting in September. This would allow the modelers to run the models during the meeting and provide the socio-economic results. The EWG concludes that STECF and DG Mare should further discuss how resources could be provided to modelers to improve the applied models. The EWG concludes that the chairs of EWG 23-01 and 23-11 will provide a list of assumptions for the implementation of the models regarding key variables for the socio-economic assessments (short- and long-term). For TOR 2 the EWG discussed what variables and indicators the applied models include and provide. From that discussion a list of indicators was developed for which modelers will be able to provide results in the EWG 23-11 report. The EWG concludes that a list of indicators is provided for which EWG 23-11 will present results in autumn 2023. For TOR 3 the EWG notes that new closure areas for 2023 were implemented only by Spain (EMU 1) (Orden APA/80/2023). All closures areas implemented under the West Med MAP are described to allow testing if their implementation would reduce the catches of juveniles and adults of the six target species of the MAP by 15-25%. The EWG notes that the methodology followed to prioritise, developing and updating closure areas based on their conservation value on the basis of existing closures, proposed closures from EWG 22-01 and new proposals developed by EWG 23-01 based on updated MEDISEH layers is similar to the one used during EWG 22- 01. Updated MEDISEH layers were used for priority species (ARA, MUT and HKE) in combination with old MEDISEH layers for other species and distribution maps of commercial effort from EWG 22-01. Calculation of the percentage of the trawlable GSA area closed to fishing is higher in EMU 1 than EMU 2, therefore the estimation of additional closure areas on top of the existing ones foccused on this management unit. Additional closure areas to test were based on persistence hotsposts from survey data and from areas of high effort in order to impact directly on the reduction of fishing mortality. The EWG notes that the exisiting and additional closures could be tested only in EMU 2 and GSA 7 as for GSA 1, 5 and 6 the extension of the spatially-explicit model ISIS-Fish is not complete yet and it is still limited to a single species (HKE). The EWG notes that closure areas in GSA 7 were tested with two different methods. A static method comparing effort distribution data before and after the closures implementation in 2020, and a dynamic method applying ISIS-Fish. The first method showed how the establishment of the spatio-temporal closure imposed a strong seasonal constraint to the fishing effort in the Gulf of Lions, and that the fishermen community responded quite well to the new rule, although vessels increased their fishing effort along the closure border, with a typical « fishing the line » pattern, especially in the fall. The second model showed that introducing an additional closure did not improve the rebuilding of the hake stock, while changing the closures from seasonal to permanent suggested the strongest effect. The EWG notes that in EMU 2 that temporal closures for the whole fleet reduce global effort while additional spatial closures increase effort towards coastal areas (depths

Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines This report documents the outcomes of STECF Expert Working Group 22-09: 2022 stock assessments of demersal stocks in the western Mediterranean Sea from the meeting held remotely from 5th to 11th September 2022. A total of 20 fish stocks considered and 18 were fully evaluated. Two stocks had prior advice from 2021 with catch advice for 2022 and 2023, and this is reiterated here. The EWG reports age based assessments, target Fs, with short term forecasts for 15 of the remaining 18 stocks, of these 15, 12 were also analysed for biomass reference points. Catch advice for three stocks was based on ICES category three evaluations of biomass indices. The content of the report gives the STECF terms of reference; the basis of the evaluations; assessments, reference point calculations; summaries of state of stock and advised catch or F based on either the MSY approach for assessed stocks and category 3 based advice for those without assessments. The report contains the full stock assessment reports for the 15 assessments, the exploration of assessments and category 3 evaluations for the remaining three stocks. The report also contains the STECF observations and conclusions on the assessment report. These conclusions come from the STECF Plenary meeting November 2022. European Union Published Refereed

The SEAwise project works to deliver a fully operational tool that will allow fishers, managers, and policy makers to easily apply Ecosystem Based Fisheries Management (EBFM) in their own fisheries. One of the key uncertainties in fisheries science and management can be linked to (our understanding of) fishers behaviour. In this report we describe the project efforts to better understand fishers behaviour by assessing literature, interviews and data to advance towards a better representation of fisher behaviour in our modelling. A better understanding of fisher behaviour is especially needed in the context of change affecting Europe’s marine ecosystems. Change is both related to the natural part of the ecosystem (i.e. climate change) as to the social side of the ecosystem (i.e. building of windparks). To that aim we present nine different case studies in Europe as examples of how fisher behaviour has been studied and which factors are (or can be) relevant for a better understanding of fisher behaviour. Each case study ends with a table summarising the factors influencing behaviour, the categories within that factor and the (potential) application in modelling as well as the implications for management. The table below summarises the factors found / used in the case studies and the elements (social, cultural, ecological, economic and institutional) to which the relate. A variety of social factors were identified that are promising for use in modelling. A key conclusion is that social data are often context dependant and cannot be copy pasted from one situation to the other and in some case, additional data needs to be collected. The cases also demonstrate that mixed methods approaches and interdisciplinary approaches are key to get in-depth of understanding of fisher behaviour in fisheries science.

Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report documents the outcomes of STECF Expert Working Group 22-16: 2022 stock assessments of demersal stocks in the Adtiat ic, Ionian and Aegean Seas from the meeting held in Rome from 17th to 23th October 2022. A total of 16 fish stocks were considered and 15 were fully evaluated. The EWG reports age based assessments, target Fs, with short term forecasts for 9 stocks of the remaining 6 stocks, four of these do not have short term forecasts as he assessments are not suitable, and one is given ICES category 3 advice. The content of the report gives the STECF terms of reference; the basis of the evaluations; assessments, summaries of state of stock and advised catch or F based on either the MSY approach for assessed stocks and category 3 based advice for those without assessments. The report contains the full stock assessment reports for the 14 assessments, the exploration of assessments and category 3 evaluations for the remaining stock. The report also contains the STECF observations and conclusions on the assessment report. These conclusions come from the STECF Plenary meeting November 2022. European Union Published Refereed

The state of marine systems subject to natural or anthropogenic impacts can be generally summarized by suites of ecological indicators carefully selected to avoid redundancy. Length-based indicators capture the status of fish community structure, fulfilling the Marine Strategy Framework Directive (MSFD) requirement for Descriptor 3 (status of commercial fish species). Although the MSFD recommends the development of regional indicators, a comparison among alternative length-based indicators is so far missing for the Mediterranean Sea. Using principal component analysis and dynamic factor analysis, we identified the most effective subset of length-based indicators, whether or not based on maximum length. Indicator trends and time series of fishing effort and environmental variables are also compared in order to highlight the individual and combined capability of indicators to track system changes across geographical sub-areas. Two indicators, typical length and mean maximum length, constitute the smallest set of non-redundant indicators, capturing together 87.45% of variability. Only in combination can these indicators disentangle changes in the fish community composition from modifications of size structure. Our study supports the inclusion of typical length among the regional MSFD Descriptor 3 indicators for the Mediterranean Sea. Finally, we show dissimilarity between the western and eastern-central Mediterranean, suggesting that there are sub-regional differences in stressors and community responses., Generalmente, el estado de los sistemas marinos sujetos a impactos naturales o antropogénicos puede ser resumido mediante un conjunto de indicadores ecológicos, cuidadosamente seleccionados para evitar la redundancia. Los indicadores basados en la talla reflejan el estado de la estructura de la comunidad de peces, cumpliendo el requisito de la Directiva Marco de la Estrategia Marina (MSFD) para el Descriptor 3 (estado de las especies de peces comerciales). Si bien MSFD recomienda el desarrollo de indicadores regionales, en el Mar Mediterráneo no se ha hecho hasta ahora una comparación entre los distintos indicadores disponibles basados en la talla. Mediante el análisis de componentes principales y el análisis de factores dinámicos, identificamos el subconjunto más eficaz de indicadores basados en la talla, estén o no basados en la talla máxima. Las tendencias de los indicadores y las series temporales del esfuerzo de pesca y las variables ambientales también son comparadas para resaltar la capacidad individual y combinada de los indicadores para detectar los cambios del sistema a través de las subáreas geográficas. Dos indicadores, Longitud Típica (TyL) y Longitud Máxima Media (MML), constituyen el conjunto más pequeño de indicadores no redundantes, captando juntos el 87.45% de variabilidad. Solo si se combinan, estos indicadores pueden discernir entre los cambios en la composición de la comunidad de peces y las modificaciones de la estructura de tallas. Nuestro estudio respalda la inclusión de TyL entre los indicadores regionales del descriptor 3 de MSFD para el mar Mediterráneo. Finalmente, mostramos diferencias entre el Mediterráneo occidental y el Mediterráneo centraloriental que sugieren diferencias subregionales en cuanto a factores impactantes y las respuestas de la comunidad.

Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report is from STECF Expert Working Group 21-15: 2021 stock assessments of demersal stocks in Adriatic, Ionian and Aegean Seas from the meeting held remotely from 18th to 22th October 2021. A total of 9 fish stocks were evaluated. One stock had prior advice from 2020 for 2021 and 2022, and this is reiterated here. Index advice for 2022 and 2023 is provide for one other stock. The EWG reports age based assessments and short term forecasts for 5 of the remaining 7 stocks and surplus production assessments for two stocks. The content of the report gives the STECF terms of reference, the basis of the evaluations and advice, summaries of state of stock and advised based on either the MSY approach for assessed stocks or the precautionary approach for category 3 based advice. The report contains the full stock assessment reports for the 7 assessments, the exploration of assessments and category 3 evaluations for the remaining five stocks. The report also contains the STECF observations and conclusions on the assessment report. These conclusions come from the STECF Plenary meeting November 2021. European Union Published Refereed

Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report, on methods for supporting stock assessment in the Mediterranean (STECF-21-02), addresses the data checking and preparation for stock assessment once the data has been submitted following the annual data calls. The report provides an overview of the data errors and quality control carried out on both commercial landings data and MEDITS survey data. The analyses reported also address the small fraction of commercial catch with sampling gaps, and how these are assigned appropriate length frequency distributions. The results of these check and assignments are provided by species, GSA and country. Quality checks were carried out on Medits data check consistency of the main reporting files and highlighting where data inconsistencies occurred. Additionally the total landings reported to the European Commission under the Black & Med-Sea data call, the Fisheries Independent Data call and the Annual Economic Report data call were compared at species aggregated to GSA. Some important differences were observed and these are reported. In addition the EWG reviewed a technical report on the sampling of commercial catch in the Greek Fisheries, the review and some suggested further work are included in this report. European Union, Joint Research Centre Published Refereed

Three groups of European sea bass (Dicentrarchus labrax) were fed for seven months, with either a conventional diet or two different organic diets, which contain organic vegetables and a natural antioxidant compound. The two organic diets differed themselves in terms of raw proteins, fish oil, and lipid contents. Sea bass welfare condition was assessed in relation to these three diets, using 16 different indicators. These were: swimming activity (recovery test, muscle activity), haematological and serological stress indicators (haematocrit, haemoglobin, red-blood-cell count, cortisol, glucose, lactate), aspecific immunity parameter (lysozyme), indicators of exposure to organic contaminants (7-ethoxyresorufin-O-deethylase and glutathione-S-transferase), and growth parameters (weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio, and hepato-somatic index). Most of these parameters individually did not give consistent responses, but their integration can provide an accurate evaluation of the fish welfare conditions among the three diet experimental groups. The multiparametric approach outlined a comprehensive picture of sea bass physiological state. The principal component analysis and the multi-criteria-decision-analysis were found to be useful tools for an integrated fish welfare assessment, highlighting that the best welfare condition was achieved in the experimental group fed with the protein-rich organic diet.

The large-scale distribution pattern of megafauna communities along the Mediterranean middle slope was explored. The study was conducted between 500 and 800 m depth where deep-water fishery occurs. Although community studies carried out deeper than 500 m are partly available for some geographic areas, few large-scale comparative studies have been carried out. Within the framework of the MEDITS survey programme, we compared the megafauna community structure in ten geographical sub-areas (GSAs) along the Mediterranean coasts. Additionally, the spatial distribution of fishing was analysed using vessel monitoring by satellite information. Overall, the community showed a significant difference between sub-areas, with a decreasing eastward pattern in abundance and biomass. Longitude was the main factor explaining variation among sub-areas (by generalized additive models). However, we found a region which did not follow the general pattern. GSA 6 (northern Spain) showed significantly lower abundance and a different composition structure to the adjacent areas. The decrease in community descriptors (i.e. abundance and biomass) in this area is probably a symptom of population changes induced by intense fishery exploitation. Overall, a combination of environmental variables and human-induced impacts appears to influence the bentho-pelagic communities along the slope areas of the Mediterranean., En este estudio se describe la estructura y patrones de distribución de la comunidad de megafauna que habita en el margen continental medio a lo largo del Mediterráneo. El estudio se realizó entre los 500 y 800 m, coincidiendo espacialmente con las pesquerías de profundidad. A pesar de que se conoce parcialmente la estructura de las comunidades que habitan por debajo de 500 m, existe la necesidad de estudiar estas comunidades a una escala espacial más amplia. Dentro del marco del proyecto internacional MEDITS, se comparó la estructura de las comunidades en diez sub-áreas geográficas (GSAs) a lo largo de las costas mediterráneas. Además se analizó la distribución espacial del esfuerzo pesquero utilizando la información de los datos de seguimiento de buques. En general los resultados mostraron diferencias significativas entre subáreas mostrando un patrón decreciente en los valores de biomasa hacia el este, siendo la longitud el principal factor explicativo del modelo de distribución (GAMs). Sin embargo, encontramos una subárea que no seguía el patrón general, la GSA6 (norte de España). La GSA6 mostró una biomasa y estructura de la comunidad diferente a las áreas adyacentes. La disminución de la biomasa en esta área parece ser un síntoma de los cambios poblaciones causados por la elevada intensidad de pesca en la zona. Los resultados sugieren que la distribución y estructura de las comunidades bento-pelágicas parecen estar moduladas por la combinación de las variables ambientales y los impactos producidos por la actividad humana.

The uncertainty in age estimation by otolith reading may be at the root of the large variability in red mullet (Mullus barbatus) growth models in the Mediterranean. In the MEDITS survey, red mullet age data are produced following the same sampling protocol and otolith reading methodology. However, ageing is assigned using different interpretation schemes, including variations in theoretical birthdate and number of false rings considered, in addition to differences in the experience level of readers. The present work analysed the influence of these variations and the geographical location of sampling on red mullet ageing using a multivariate approach (principal component analysis). Reader experience was the most important parameter correlated with the variability. The number of rings considered false showed a significant effect on the variability in the first age groups but had less influence on the older ones. The effect of the theoretical birthdate was low in all age groups. Geographical location had a significant influence, with longitude showing greater effects than latitude. In light of these results, workshops, exchanges and the adoption of a common ageing protocol based on age validation studies are considered fundamental tools for improving precision in red mullet ageing., La incertidumbre en la estimación de la edad mediante la lectura de otolitos puede ser la principal causa detrás de la gran variabilidad existente en los modelos de crecimiento del salmonete (Mullus barbatus) en el Mediterráneo. En la campaña MEDITS, los datos de edad del salmonete se generan siguiendo el mismo protocolo de muestreo y metodología de lectura de otolitos, aunque la asignación de la edad se lleva a cabo usando distintos esquemas para la interpretación de las lecturas, incluyendo variaciones en la fecha teórica de nacimiento y en el número de anillos considerados falsos, además de las diferencias existentes en cuanto al nivel de experiencia de los lectores. En este trabajo, la influencia de las variaciones en los esquemas de interpretación, el nivel de experiencia de los lectores, y la localización geográfica de las muestras, sobre la determinación de la edad en el salmonete se analiza mediante una aproximación multivariante (Análisis de Componentes Principales). La experiencia de los lectores fue el parámetro más correlacionado con la variabilidad. El número de anillos considerados falsos mostró un efecto significativo sobre la variabilidad de los primeros grupos de edad, mientras que su influencia sobre los más viejos fue menor. El efecto de la fecha teórica de nacimiento tuvo poca importancia en todos los grupos de edad. La localización geográfica tuvo una influencia significativa, con la longitud mostrando mayores efectos que la latitud. Teniendo en cuenta estos resultados, los grupos de trabajo e intercambios de otolitos así como la adopción de un protocolo de asignación de edad común basado en estudios de validación de edad, se consideran herramientas fundamentales para mejorar la precisión en la determinación de la edad del salmonete.

The aristeids Aristaeomorpha foliacea and Aristeus antennatus are two species of great economic importance in the Mediterranean Sea, where they are exploited almost exclusively by bottom trawlers. We analysed their geographical and inter-annual patterns using data collected, following a standardized protocol, during the MEDITS international experimental bottom trawl surveys. The data used consisted of standardized abundance and biomass indices, size structure and individual biological information collected in the northern Mediterranean for more than two decades. Several univariate and multivariate methodologies were used to analyse the data. The current study confirms previous findings, such as the longitudinal gradient in the relative presence of the aristeids, but also offers additional information for a better understanding of the intrinsic variability of the data over the years and between areas. Moreover, geographical variability in the somatic condition index is discussed, taking into account the role of environmental conditions and fishing pressure. The large geographical variability found for both species in this regional approach reflects the importance of additional studies at a small-scale geographical level. Such studies could be particularly important for managing and ensuring the stability of these species, for which large regional approaches may be inadequate., Los aristéidos Aristaeomorpha foliacea y Aristeus antennatus son dos especies de elevada importancia económica en el Mar Mediterráneo, donde se explotan casi exclusivamente con arrastreros de fondo. Se han analizado sus tendencias geográficas e interanuales utilizando datos recogidos, siguiendo un protocolo estandarizado durante las campañas con arte de arrastre de fondo experimental internacionales MEDITS. Los datos utilizados fueron índices de abundancia y biomasa, la estructura de tallas e información biológica individual, recogidos en el norte del Mediterráneo durante más de dos décadas. Los datos recogidos se han analizado mediante diferentes metodologías univariantes y multivariantes. Este estudio confirma algunos resultados previos, como el gradiente longitudinal de su presencia relativa, pero también añade información adicional que permite comprender mejor su variabilidad intrínseca a lo largo de los años y de las áreas. Además, se discute la variabilidad geográfica del índice de condición somática teniendo en cuenta el papel de las condiciones ambientales y de la presión pesquera. La gran variabilidad geográfica descrita para ambas especies en esta aproximación regional refleja la importancia de estudios adicionales a menor escala geográfica, lo que podría ser particularmente importante para la gestión de estas especies, para las que una amplia aproximación regional podría no ser adecuada para asegurar la sostenibilidad de estos importantes recursos marinos.

Most studies on European hake focus on the recruitment process and nursery areas, whereas the information is comparatively limited on the ecology of the juvenile stage (ca. second year of life)—the one most exploited by the Mediterranean trawl fisheries. Using information of the MEDITS programme, we provide a spatial and temporal assessment of the influence of body size and growth on hake survival from recruits (age 0) to juveniles (age 1), along with the impact of surface temperature and chlorophyll variability. At a biogeographic scale, size-dependent survival is supported, with areas with higher mean length of recruits and juveniles yielding higher survival. A similar pattern was observed at interannual level in some western Mediterranean areas, also mediated by a density-dependent effect on growth. However, the most recurrent inter-annual pattern was a negative effect of size on survival, which could be attributed to potential ontogenetic changes in catchability and underrepresentation of intra-annual recruitment pulses that are seasonally inaccessible to the MEDITS survey. Results also evidence that survival in the Alboran and Adriatic seas is dependent on the primary production variability, and that Corsica and Sardinia could be potential feeding grounds receiving juveniles from neighbouring areas. The present study reveals the importance of size- and growth-dependent survival in the juvenile stage of European hake in the Mediterranean Sea., La mayoría de estudios de merluza europea se han centrado en el proceso de reclutamiento y sus hábitats preferentes, mientras que la información es mucho más escasa sobre los procesos ecológicos asociados a la fase juvenil (i.e. segundo año de vida aproximadamente), la cual se considera la más impactada por la pesca de arrastre en el Mediterráneo. En este estudio usamos la información del programa MEDITS para investigar, temporal y espacialmente, la posible influencia del tamaño corporal y el crecimiento sobre la supervivencia desde la fase de reclutas (edad 0) a la de juveniles (edad 1). También se ha evaluado la posible influencia de la temperatura y la clorofila superficial. A una escala biogeográfica, los resultados corroboran la influencia de la talla sobre la supervivencia, con mayor supervivencia asociada a áreas de mayor talla media de reclutas y juveniles. El mismo patrón se observó a escala interanual en algunas zonas del oeste el Mediterráneo, en las cuales se detectó también un efecto de denso-dependencia en el reclutamiento. Sin embargo, el patrón interanual más recurrente fue un efecto negativo de la talla sobre la supervivencia, que podría ser atribuido tanto a cambios ontogenéticos en la capturabilidad de los peces como a la posible infraestimación de los pulsos interanuales de reclutamiento que pueden resultar estacionalmente inaccesibles a las campañas MEDITS. Los resultados también evidencian que la supervivencia en Alborán y el Adriático depende de la variabilidad de la producción primaria, y que Córcega y Cerdeña podrían ser potencialmente áreas de alimentación que reciben juveniles de áreas adyacentes. El presente estudio evidencia la importancia de la influencia de la talla corporal y el crecimiento sobre la supervivencia juvenil de la merluza europea en el mar Mediterráneo.

Mean temperature (MTC) and mean trophic level (MTL) spatiotemporal patterns of MEDITS survey catches were examined in 13 geographic statistical areas (GSAs) of the Mediterranean between 1994 and 2016. The study aimed to detect changes in the demersal community structure related to anthropogenic impacts. A generalized additive modelling approach was used to examine the effects of year and GSA on the MTC and MTL indexes and on bottom temperature by haul. For the MTC index, the year was significant only in 4 GSAs, while for MTL it was significant in 5. Higher MTC values were observed in central and eastern areas. Bottom temperature increased after 2010, and also from west to east and from north to south. Our results indicate that the recently observed increase in bottom sea temperature has not resulted in an immediate response by demersal marine communities, but areas with higher warming rates or shallow depths were found to be more susceptible to sea warming. For MTL, decreasing trends were observed in only 2 GSAs, while the temporal trends observed in 5 GSAs may have reflected changes in fishing activity patterns. However, higher MTL values were observed in GSAs with generally higher exploitation rates, indicating that factors other than fishing play an important structuring role in marine communities. The present results indicate differences among Mediterranean subareas in regard to changes in the community structure attributed to environmental conditions and exploitation patterns and have implications for the ecology and dynamics of the stocks., Se analizaron los patrones espaciotemporales de la temperatura media inferida (TMI) y el nivel trófico medio (NTM) de las capturas de la campaña MEDITS en trece áreas (GSAs) del Mediterráneo entre 1994 y 2016. El estudio pretendía detectar cambios en la estructura de la comunidad demersal relacionados con impactos antropogénicos. Se utilizó un modelo aditivo generalizado (GAM) para examinar los efectos del año y GSA sobre la temperatura del fondo y los índices de TMI y NTM. De las trece GSAs analizadas, el año y la TMI solo fueron significativos en cuatro y cinco áreas, respectivamente. Los mayores valores de NTM se observaron en el centro y el este del Mediterráneo. La temperatura del fondo aumentó desde el año 2010, así como de oeste a este y de norte a sur. Nuestros resultados indicaron que el reciente incremento de temperatura del fondo observado en el Mediterráneo no ha dado lugar a una respuesta inmediata en las comunidades demersales; no obstante, en áreas con mayores niveles de calentamiento o de menores profundidades las comunidades fueron más susceptibles a dicho calentamiento. En cuanto al NTM, solo se observaron tendencias decrecientes en dos GSAs, mientras que los patrones temporales detectados en cinco GSAs posiblemente reflejaron cambios en la actividad pesquera. Sin embargo, se observaron mayores valores de NTM en GSAs con mayores niveles de explotación, indicando que otros factores, aparte de la pesca, juegan un papel importante en la estructuración de las comunidades marinas. Los resultados del estudio indican la existencia de diferencias en la estructura de las comunidades entre subáreas del Mediterráneo que podrían ser atribuidas a diferencias en las condiciones ambientales y en los patrones de explotación que afectan a la ecología y dinámica de los stocks.

The present study provides updated information on the occurrence, abundance and biomass distribution patterns and length frequencies of Merluccius merluccius in the Mediterranean Sea, by analysing a time series of data from the Mediterranean International Trawl Surveys (MEDITS) from 1994 to 2015. The highest values of abundance and biomass were observed in the Sardinian Seas. The use of a generalized additive model, in which standardized biomass indices (kg km–2) were analysed as a function of environmental variables, explained how ecological factors could affect the spatio-temporal distribution of European hake biomass in the basin. High biomass levels predicted by the model were observed especially at 200 m depth and between 14°C and 18°C, highlighting the preference of the species for colder waters. A strong reduction of biomass was observed since the year 2009, probably due to the strengthening of the seasonal thermocline that had greatly reduced the availability of food. The general decrease in biomass of several stocks of anchovy and sardine, preys of European hake, might be indirectly connected to the decreasing biomass detected in the present study. The length analysis shows median values lower than 200 mm total length of most of the investigated areas., El presente estudio proporciona información sobre los patrones de ocurrencia, abundancia y distribución de biomasa, y las longitudes de Merluccius merluccius en el mar Mediterráneo, considerando el análisis de una serie temporal proveniente de las campañas internacionales de pesca de arrastre en el Mediterráneo (MEDITS) de 1994 a 2015. Los valores más altos de abundancia y biomasa se observaron en los mares de Cerdeña. El uso del modelo GAM, en el que se analizaron los índices estandarizados de biomasa (BI, kg km–2) en función de las variables ambientales, permitió explicar cómo los factores ecológicos podrían afectar la distribución espacio-temporal de la biomasa de merluza europea en la cuenca. Los niveles altos de biomasa pronosticados por el modelo se observaron especialmente a 200 m de profundidad y entre 14 y 18°C, destacando la preferencia de la especie por aguas más frías. Se observó una fuerte reducción de la biomasa desde el año 2009, probablemente debido al fortalecimiento de la termoclina estacional que había reducido en gran medida la disponibilidad de alimentos. Otros procesos como la disminución general de la biomasa de varias poblaciones de anchoa y sardina, las presas de merluza europea, podrían estar indirectamente relacionadas con la disminución de la biomasa detectada en el presente estudio. El análisis de longitud muestra valores medios inferiores a 200 mm TL de la mayoría de las áreas investigadas.

615 pages, Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This reportis from STECF Expert Working Group19-10: 2019stock assessments ofdemersal stocks in the western Mediterranean Seafrom the meeting in Arona Italy from 9thto 15rdSeptember 2019. A total of 19 fish stocks were evaluated. The EWG reports age based assessments and short term forecasts for 15 of the 19 stocks. Catch advice for the other four stocks was based on ICES category 3 evaluations of biomass indices. The content of the report gives the STECF terms of reference, the basis of the evaluationsand advice, summaries of state of stock and advised based on either the MSY approach for assessed stocks or the precautionary approachfor category 3 based advice. Thereport contains the full stock assessment reports for the 15 assessments, one full category3 evaluation and briefre-evaluations and validations of the 2018 results for the final three stocks for which two year’sadvice was given in 2018.The report also contains the STECF observations and conclusions on the assessment report. These conclusionscome from the STECF Plenary meeting November 2019

The third Workshop on Optimization of Biological Sampling (WKBIOPTIM3) convened to dis-cuss practical aspects of optimization of sampling and provide a compilation of methods so that this information is well documented and organized for end users. New optimization algorithms were presented alongside developments and improvements of the work carried out in the earlier 2017 and 2018 workshops. Six different approaches/tools were presented: code developed under WKBIOPTIM 1 and 2 for optimization at sample level (SampleLevelOptim), SampleOptim R-tool to optimize fish sampling for biological parameters, code for quantifying robustness of a length frequency distribution shape (SampleReferenceLevel), SDTool and BioSimTool as contri-butions from the STREAM Project to the optimization at sample-level and sampling design level, respectively, WKBIOPTIM code used for optimization at sampling design level (SimPop). Addi-tionally, data exploration and biological simulation tools developed under the framework of fishPi2 (FishPi4WKBioptim). R-scripts for the different tools are available on the WKBIOPTIM3 GitHub (https://github.com/ices-eg/wk_WKBIOPTIM3).Usability testing, including thorough instructions, were a focus of the workshop. As such, the group used a two-tiered system to evaluate the methods. The first subgroup tested the different scripts with their own data to see if they were of easy use. This first group also evaluated the documentation needed and whether it was clear how to interpret the results properly, how to decide on the best procedure according to their objectives, and how to compare results obtained using similar approaches. Based on this assessment, the second subgroup then cleaned and doc-umented the code, discussing the approaches used in the different scripts and potential options for integration. In parallel, some participants developed a first draft of standardized notation aimed at harmonizing the documentation of simulation procedures used in the different codes, tested a new quality indicator for length frequency and developed scripts that demonstrate the effects of the common options of resampling ‘with replacement’ (wr) and ‘without replacement’ (wor) in the precision and bias of estimates. The workshop concluded with participants high-lighting that specific documentation regarding quality indicators concepts and functions could also be very practical and useful for end users. Work of WKBIOPTIM will continue intersession-ally towards a final discussion of methodologies and results in 2020.

The uncertainty in age estimation by otolith reading may be at the root of the large variability in red mullet (Mullus barbatus) growth models in the Mediterranean. In the MEDITS survey, red mullet age data are produced following the same sampling protocol and otolith reading methodology. However, ageing is assigned using different interpretation schemes, including variations in theoretical birthdate and number of false rings considered, in addition to differences in the experience level of readers. The present work analysed the influence of these variations and the geographical location of sampling on red mullet ageing using a multivariate approach (principal component analysis). Reader experience was the most important parameter correlated with the variability. The number of rings considered false showed a significant effect on the variability in the first age groups but had less influence on the older ones. The effect of the theoretical birthdate was low in all age groups. Geographical location had a significant influence, with longitude showing greater effects than latitude. In light of these results. workshops, exchanges and the adoption of a common ageing protocol based on age validation studies are considered fundamental tools for improving precision in red mullet ageing.

The present study provides updated information on the occurrence, abundance and biomass distribution patterns and length frequencies of Merluccius merluccius in the Mediterranean Sea, by analysing a time series of data from the Medi- terranean International Trawl Surveys (MEDITS) from 1994 to 2015. The highest values of abundance and biomass were observed in the Sardinian Seas. The use of a generalized additive model, in which standardized biomass indices (kg km–2) were analysed as a function of environmental variables, explained how ecological factors could affect the spatio-temporal distribution of European hake biomass in the basin. High biomass levels predicted by the model were observed especially at 200 m depth and between 14°C and 18°C, highlighting the preference of the species for colder waters. A strong reduction of biomass was observed since the year 2009, probably due to the strengthening of the seasonal thermocline that had greatly reduced the availability of food. The general decrease in biomass of several stocks of anchovy and sardine, preys of European hake, might be indirectly connected to the decreasing biomass detected in the present study. The length analysis shows me- dian values lower than 200 mm total length of most of the investigated areas., Sí

130 pages, Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report is the fourth of a suite of STECF EWG reports dedicated to the fishing effort regime in the Western Mediterranean Sea, following EWG reports 18-09, 18-13 and 19-01. The group wasrequested toprogress on an operational mixed-fisheries model for Effort Management Unit 1 (i.e. GSAs 1-2-5-6-7), to update mixed fisheries models and F-E analyses with the most recent data and the most recent stock assessments., and to draft amixed-fisheries advice including relevant scenarios and displays. In EMU 1, good progresses were achieved in combining effort and catch data from both France and Spain into the bioeconomic multifleet model IAM. The model is now able to run and perform management simulations on the stock of hake (combined assessment in GSAs 1-2-5-6-7). Time did not allow to include additional stocks at this stage, but the required elements are now in place and adding these should be fairly straightforward in the future.The updates of the F-E analyses performed in EWG 18-09 and 18-13 with the most recent time series did not change the perception of the lack of relationship between fishing effort and fishing mortality. For many stocksand fleet segments, the relationship using effort expressedas fishing days has no obvious slope, indicating that the limited reduction of effort observed in the recent years did not have any visible effect on reducing fishing mortality yet.Supplementary analyses were performed using effort expressed in hours instead of days, which improved the relationship to some extent. This is consistent with previous statements in previous reports that fishing effort would be best expressed and managed in terms of fishing hours than fishing days:Extended simulation work was performed regarding management scenarios, especially in EMU 2 (GSAs 8-9-10-11). The multi-fleet BEMTOOL model was updated and extended, and 6 scenarios involving effort reductions, sometimes combined with spatial closures, were simulated in a stochastic approach. Also, the individual-based spatial model SMART was updated, and the outcomes of the spatial closures scenarios was used to parameterise the spatial scenarios in BEMTOOL. Finally, the simpler NIMED model was also updated and run, but its results were not compared to the two other models. In EMU 1, the IAM model (hake alone) was used to perform 3 runs of effort reduction, one of them including a French proposal for a spatial closure in the Gulf of Lion. Finally, a 3-pages synthetic advice is proposed, summarising the key findings of the simulations. A key outcome is that the proposed closure of the coastal zone down to 100 m deep, max 6nm from the shore, is unlikely to contribute to reducing hake catches. Rather, it can have an adverse effect if the fleets reallocate their effort further away where important concentrations of juvenile exists. In the light of the F-E relationships analyses, all results presented in this report are considered to be overoptimistic since they assume a true reduction in F if effort decreases, which may in reality be limited during the first years of effort reductions

The second Workshop on Tradeoffs Scenarios between the Impact on Seafloor Habitats and Provisions of catch/value (WKTRADE2) was established to provide input on trade-offs aspects to the Working group on Fisheries Benthic Impact and Trade-offs (WGFBIT). As such, the workshop was tasked to: 1) demonstrate the applicability of a set of approaches to better estimate fisheries revenue; 2) establish ways to assess effort reduction scenarios; and 3) explore how to (better) incorporate social factors associated with fisheries. The workshop suggests that to improve estimates of the “value” of an area to fisheries that the contribution margin (income from landings minus variable costs) should be calculated. To do this two complementary approaches (disaggregation and mechanistic) are presented and can be developed using the current ICES VMS and logbook data, supplemented with economic data layers. A modular workflow to integrate the variables into the assessment is also presented. Furthermore, the workshop found that redistribution of total revenue among individual fishers and fishers’ communities will need to be considered to accurately predict displacement effects and impact evaluation on fisheries economics. Applying predictive modelling techniques adds to assessing a static picture (current fishing activity) because it considers displacement effects which may elucidate increased pressure on essential fish habitats, sensitive vulnerable habitats, or previously untrawled areas. To better identify trade-offs between ecological, economic and social factors for use by the ICES working group WGFBIT, the workshop recommends also using integrative approaches (e.g. bioeconomic models, stakeholder engagement) that account for direct linkages between fish, fisheries and benthos dynamics to address issues related to MSFD, CFP and spatial management plans in a consistent way. When considering the effects of displacement the contribution margin should be accounted for as the fishing closures are likely to have indirect (positive or negative) effects. For example, protecting part of the fish stocks might lead to better catch rates and therefore fuel savings, etc. The workshop also found static models to be operational and more easily used to identify impacted fishing fleets. While, dynamic modelling approaches allow for the adaptation of fishing fleets (e.g. displacement, gear modifications), potentially mitigating the estimated impact of spatial and temporal restrictions. Static approaches are easy to use in stakeholder processes, and can facilitate stakeholder engagement. Future development of static and dynamic models will need to account for the influence of other activities (e.g. closures due to wind farm) on fisheries activities. Running scenarios using dynamic models will indicate which areas are most valuable to fisheries after spatial management scenarios are proposed. This elicits the socio-economic valuable fisheries areas. The workshop’s focus was on the spatial management scenarios so far identified by the working group WGFBIT, but the suggested workflow can also be used to address other scenarios, e.g. technical measures aimed at reducing gear penetration depths, disturbance effects and improving selectivity, habitat credits approaches that define credits related to the sensitivity of habitat and convey credits to the fishing industry to manage either collectively or individually. The workshop also identified some follow-up work that working group WGFBIT could take on to both to improve the current scenario testing on spatial restrictions, as well as how to deal with fleet adaptation/effort displacement in reaction to the spatial restrictions. This work would benefit by stronger links to ICES working groups WGECON and WGSOCIAL to ensure the required fisheries economic expertise.

The uncertainty in age estimation by otolith reading may be at the root of the large variability in red mullet (Mullus barbatus) growth models in the Mediterranean. In the MEDITS survey, red mullet age data are produced following the same sampling protocol and otolith reading methodology. However, ageing is assigned using different interpretation schemes, including variations in theoretical birthdate and number of false rings considered, in addition to differences in the experience level of readers. The present work analysed the influence of these variations and the geographical location of sampling on red mullet ageing using a multivariate approach (principal component analysis). Reader experience was the most important parameter correlated with the variability. The number of rings considered false showed a significant effect on the variability in the first age groups but had less influence on the older ones. The effect of the theoretical birthdate was low in all age groups. Geographical location had a significant influence, with longitude showing greater effects than latitude. In light of these results, workshops, exchanges and the adoption of a common ageing protocol based on age validation studies are considered fundamental tools for improving precision in red mullet ageing., Sí