Search

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 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, 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

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

This study aimed to test the effectiveness of a “guarding net”, a device placed at the bottom of a trammel net, for reducing unwanted catches in the caramote prawn trammel net fishery of the Ligurian Sea. This specialized and profitable fishery is affected by unwanted catches that generate high discard rates and damage to the nets, with environmental impacts and costs for fishermen. The experimental study consisted in comparing the catches of a standard trammel net (STN) with those of two “experimental” trammel nets, e.g. STNs provided with a guarding net of 19 cm (TGN20) and 24 cm height (TGN25), respectively. The guarding net, a strip of gillnet placed at the bottom of the net, can be considered a by-catch reducer device (BRD). Some fishermen of the investigated fishery have been using this device for several years. The results of the 15 experimental fishing trials performed from June to July 2016 indicate that the guarding nets significantly reduce discards (e.g. crabs and other invertebrates); the biomass of the unwanted species caught was 75% lower than that produced by the STN. The catch rates of the target species obtained with TGN20 and TGN25 were also significantly lower than those of the STN, though of a lesser amount. Nonetheless, this economic loss can be compensated by the decrease in sorting time and material and labour costs that can be achieved using the guarding net.

This study aimed to test the effectiveness of a “guarding net”, a device placed at the bottom of a trammel net, for reducing unwanted catches in the caramote prawn trammel net fishery of the Ligurian Sea. This specialized and profitable fishery is affected by unwanted catches that generate high discard rates and damage to the nets, with environmental impacts and costs for fishermen. The experimental study consisted in comparing the catches of a standard trammel net (STN) with those of two “experimental” trammel nets, e.g. STNs provided with a guarding net of 19 cm (TGN20) and 24 cm height (TGN25), respectively. The guarding net, a strip of gillnet placed at the bottom of the net, can be considered a by-catch reducer device (BRD). Some fishermen of the investigated fishery have been using this device for several years. The results of the 15 experimental fishing trials performed from June to July 2016 indicate that the guarding nets significantly reduce discards (e.g. crabs and other invertebrates); the biomass of the unwanted species caught was 75% lower than that produced by the STN. The catch rates of the target species obtained with TGN20 and TGN25 were also significantly lower than those of the STN, though of a lesser amount. Nonetheless, this economic loss can be compensated by the decrease in sorting time and material and labour costs that can be achieved using the guarding net.