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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 ninth 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. The group was requested to implement mixed fisheries bio-economic models to run a number of scenarios up to 2030 with varying parameters, to evaluate a fishing effort reductions for trawlers, longliners and netters in association to vessel number reductions for trawlers, increase in mesh size for trawlers, existing closure areas and catch limits for deep water shrimps (ARA and ARS) through five scenarios and draft a mixed fisheries advice. For all mixed fisheries models applied during the EWG (TOR 3), the data from the DCF official data calls and from the western Mediterranean stock assessments, were updated using data from EWG 22-09 (Western Mediterranean stock assessments) and EWG 22-10 (FDI datacall). The same set of updated data were also used to answer TOR 1 and TOR 2. The exploration of effort data time series (TOR 1) highlighted that in GSA7 the French OTB fleet >18m showed a decrease in fishing days counteracted by an increase of the corresponding fleet segments of French OTT which could be potentially due to a shift in gear use, although experts did not suggest specific causes that would drive this shift. The comparison of fishing days for trawlers (OTB, OTM, OTT, PTB, PTM and TBB as per EU regulation 2019/2236) declared in the FDI official datacall and reported in the 2020 and 2021 regulations were reported this year as well. Discrepancies were found also between 2021 data and the 2021 regulation (as per 2020) with the values reported in the regulation being always higher (for all countries but not for all fleet segments) than the values declared in the FDI datacall. Results suggest that effort is decreasing faster than the regulation for most fleet segments and that the reference period 2015-2017 might not be representative anymore of the effort dynamics of the last few years. For Spain and Italy reductions by 2021 are suggested to be higher than the expected reduction by 2022, while this does not happen for France. From the data quality checks very minor issues were highlighted and there was no reporting in the DTMT of these issues. EWG 22-11 would like to ask for clarifications to MSs concerning the association of gear type with the upper level of aggregation fishing technique as it was observed that odd matching were found which could undermine the calculation of fishing days in the comparisons with the yearly regulations. Specifically the gear OTB was often found under the PGP fishing technique and experts present at the EWG were not able to explain this match. The estimated F by gear and GSA (TOR2) allowed updating the analysis of the linear relationship between F and E. As in previous years a linear relationship consistent across GSAs and stocks was not found. The HKE, MUT and ARA stocks showed a linear relationship with OTB in some cases. For HKE 1567 the relationship did not hold once observed by GSA (although this could be a modelling artefact from the assessment model) or in EMU 2. MUT showed a linear relationship in GSA 6 and 7 with OTB and OTT (but results for GSA 7 should be taken with caution as there is a very strong variation in F for a lower variation of effort). ARA in EMU 1 by GSA (and on the overall stock 6-7) showed a linear relationship with OTB. No relationship was found for gears as LLS, GTR (except for MUT in 9) or GNS, neither for the stocks of DPS or ARS. EWG 22-11 suggests that running the analysis at metier level would give more meaningful results, although it should be noted that the metier is a very unstable resolution of fisheries, therefore difficult to define as data sources. To the methodological section of models (Section 5) two subsections were added, one on the models behavior during mid and long term projections and one on the relationship between biomass increase and economic gain. All models at the moment are suggested to be used for mid-term projections but not for long-term projections as the population dynamics are led either by stock recruitment relationships (BEMTOOL), which are not robust at the moment due to the nature of the data or led by recruitment stochasticity (IAM, ISIS-Fish and SMART), based on a random resampling of the time series but not accounting for potential environmental effects. This year for EMU 1 new analytical assessments were available to EWG 22-11 such as ARA 5, DPS 1 and DPS 5-6-7. In EMU 2, instead, 2 stocks were lost as it was not possible to have an updated analytical assessment due to data issues for MUT 10 and ARA 8-9-10-11. As ARA is one of the stocks with a catch limit defined by the EU Regulation 2022/110, the limitations due to the lack of assessment for this species when running the models in EWG 22-11, should be noted. Based on the final draft report from EWG 22-09, stock assessment of Western Mediterranean, which will be presented to STECF in November 2022, but has not yet been endorsed by STECF, the EWG observed that in 2020, 94% and, in 2021, 79% of the stocks were not at MSY. In 2022, the EWG shows that 73% of the stocks are not at MSY and 53% remain severely overfished. Some of the stocks could be already responding positively to the MAP measures, although the MAP has been implemented only since 2020 and the data available are only up to 2021. 9 out of 14 assessed stocks have decreasing fishing mortality, however, there are 4 stocks still behind transition to MSY of which two have declining biomass and increasing fishing mortality. Some stocks need particular attention for their low biomass level. EWG 22-09 identified as below the biomass reference point (Blim): Hake in GSAs 1-5-6-7, Hake in GSAs 8-9-10-11 and Blue and red shrimp in GSAs 1-2. In addition, five stocks are also below Bpa. Despite progress towards MSY, high levels of overfishing remains in particular for hake and deep-water shrimps. Models results (Section 6) showed that for EMU 1 (result only from IAM) none of the proposed scenarios (5 scenarios + status quo) achieved the objective of reaching FMSY by 2025. Red mullet in GSA 6 (MUT6) never reaches its Fmsy range during the simulation period (2022-2030) under any scenario, and hake in GSA 1-5-6-7 (HKE1567) is still above Fmsy in 2025. The other stock that is slightly behind the objectives is red mullet in GSA 1 (MUT1) with all scenarios. However, the other stocks (ARA12, ARA5, ARA67, NEP6, MUT7, DPS1 and DPS567) reach their FMSY range in 2025 with scenarios A to D. Only with the status quo scenario (scenario F) the FMSY range is not reached in 2025 for some of those stocks. Globally, all scenarios foresee some important negative economic impact for French and Spanish trawlers in the short and medium term with a decrease in their Gross Value Added. Even with scenario F (i.e. status quo), French trawler GVA is negative from 2022. This is due to the fuel price used in the simulation in 2022 and beyond from AER 2022 projections, where prices increased a lot compared to their initial values. Due to time constraints, it was not possible to have results from the ISIS-Fish model for EMU 1. For EMU 2 the setting of a maximum catch limit on ARA and ARS allows to approach FMSY for ARS, but not for HKE, even when in combination with other measures such as reduction of fishing days and number of vessels and change in selectivity. For ARS 8-9-10-11, NEP 9 and MUT 9 all scenarios implemented allow to reach FMSY in 2025 except for the status quo scenario (F). ARS, ARA and NEP stocks would benefit of all the scenarios, due to the re-allocation of the effort from the deep-water metier (OTB_DWS and OTB_DES) to the demersal (OTB_DES). This reallocation produces an increase in the fishing pressure on demersal fishing grounds, contributing to partly reduce the underutilization of red mullet in GSA 10, red mullet in GSA 9 and Norway lobster in GSA 9, but also increasing the F of hake. The total revenues and gross value added for the overall fleet are predicted to slightly increase with respect to the lowest values of the time series reached in 2020-2021. For scenarios A, B and D total revenues across all fleets will decrease compared to the SQ scenario (F), remaining above the recent values. A similar pattern is observed for gross value added. Simulations on fuel price increase of 120% (of the average fuel price in 2022) in 2023 onwards in EMU 1 showed an exacerbation on the GVA of fleet segments that already suffered from the management implementation. It should be highlighted that already with the "fuel option 1" (with fuel price in 2022 and onwards from AER projections), the economic performances are already negative, especially for French fleets, as the fuel price has strongly increased compared to 2021. Estimations of GVA in 2022, when effort reductions are still quite limited, are already negative suggesting that the negative GVAs are mainly due to the 2022 fuel price peak. In EMU 2 as well the main effect is to observe a lower GVA; specifically, the difference between the best performing scenario, that is B, and the status quo (F) is smaller. Here as well, the increase in fuel costs impacts more importantly on the GVA, compared to the decrease in fixed costs imposed by the effort limitations. For the application of the bio-economic models for the assessment of the development regarding the implementation of the West Med MAP it was decided to follow the methodology of the AER and, therefore, subsidies are not included in the calculations for income. The financial situation which the bio-economic models present for the year 2022 and beyond depend a lot on the assumptions regarding the development of fuel prices but include no mitigation measures for the fishing companies (like de minimis payments to cover parts of the increase in fuel costs 2022). Therefore, the modelling results show a lower level of gross value added compared to the real situation of the fishing companies. EWG 22-11 suggests that from an economic standpoint, it would make sense to conduct a detailed impact assessment (IA) for the further implementation of the West Med MAP. With such an assessment it would be possible to calculate possible scenarios (including possible mitigation and adaptation measures) regarding the implementation of effort reduction and the possible economic performance of the fishing fleets. The EU MSs affected by the management plan could then discuss possible mitigation and adaptation measures for the fishing sector. As such an IA is not requested by the West Med MAP it would have not follow the usual procedure within DG Mare and can be limited to assessments within the STECF context. EWG 22-11 concludes that the EWG chair and the STECF bureau should discuss with DG MARE how far such an impact assessment would be possible for the next EWG meeting in March 2023. Concerning economic indicators (Section 7), EWG 22-11 suggests that all the different bio- economic modules should report the same economic indicators and specific reference points should be defined in order to evaluate the economic results of the different simulated scenarios in a consistent way. The selected economic indicators should be harmonized with the ones applied by STECF for the assessment of the economic performance of the fleet (AER) and the “balance” indicators. Also, in the STECF report 18-15 (STECF 2018) indicators are proposed which could be possibly applied. Additionally EWG 22-11 highlights that there are no indicators on sociological characteristics in the bio-economic models so far. Some of the models give “social” indicators, but in general these are closely related to the economic ones (gross value added, crew share, employment) and they do not actually produce detailed results on the social impact of fisheries policies. Additional sections (Section 7) were added to review available information on technological creep in the western Mediterranean in the last ten years, but no information seems to be available now to account for this parameter within the models. A new section was dedicated to the development of a standardized ad hoc datacall for VMS and logbook data for MSs involved in the West Med MAP. The aim is to ease communication with MSs on the submission of these data and obtain a standardized format for all MSs that would fasten the work of experts in future EWGs. Due to time constraints, the two spatial modeling groups (SMART and ISIS-Fish) could not fulfill the scenarios requested in the TORs. The parameterization of such models is complex and time consuming, therefore to be able to respond to all TORs EWG 22-11 suggested that it would be very helpful to have scenarios at list a month before the beginning of the working group as it was done for EWG 22-01. Finally, in order to ease the work of EWGs concerned with the evaluation of effort and catch limit regime in the Western Mediterranean, catch at age matrices, F at age matrices and LFDs by GSA and gear for HKE and MUT stocks should be prepared in advance of the EWGs. This work could be held either during the western Mediterranean stock assessment EWG (to be evaluated with the chair of the EWG) or by a short ad hoc contract. 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 is the eighth 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 and 21-13. The group was requested to implement mixed fisheries bio-economic models to run a number of scenarios up to 2025 with varying parameters and up to 2030 with fixed parameters, to evaluate existing closure areas implemented since 2020 and 2022, maximum catch limits (MCLs) implemented since 2022 and draft a mixed fisheries advice. For all mixed fisheries models applied during the EWG, the data from the DCF official data calls and from the western Mediterranean stock assessments, were the same as the ones used during STECF EWG 21-13, as there were no updates since 2021. The non-spatially explicit mixed fisheries models, IAM (for EMU 1) and BEMTOOL (for EMU 2), focused on the scenarios evaluating MCLs on ARA, ARS and HKE. Reference MCLs for ARA and ARS where obtained from the Regulation EU 2022/110 and from STECF EWG 21-11, while for HKE were obtained solely from EWG 21-11. IAM was updated to differentiate between a coastal and a deep-water trawling within the Spanish fleet segments, as France does not have a deep-water fishery at present. As the model timescale has a yearly resolution, it was not possible to estimate the effect of a monthly MCL. The scenarios considered had a MCL for HKE, one for ARA, and one for both HKE and ARA. These scenarios were run for a decreasing MCL through time (forward scenario: aims at reaching catch at Fmsy by 2025) and an increasing MCL through time (inverse scenario: starting value is catch at Fmsy) accounting for the distribution of stocks by GSA, for a total of 10 scenarios alternative to the baseline. None of the scenarios allowed reaching Fmsy for all six species targeted by the MAP, except when applying a MCL on both ARA and HKE, simultaneously. The results for the HKE stock should be taken with caution as the MCL was applied only to trawlers in these scenarios, but this species can generally be targeted also by longliners and gillnetters. The economic consequences of scenarios accounting for a MCL on HKE, or both ARA and HKE, lead to a massive drop of GVA for the Spanish and French trawling fleets, while economic advantages are observed for longliners and gillnetters. BEMTOOL was updated and refined to consider the different types of fishing activity exerted by each fleet segment at metier level. The model timescale is set at a monthly resolution, so it was possible to run scenarios accounting for a monthly MCL (monthly flexibility was not considered). Only scenarios accounting for a MCL either for ARA or ARS where run, but never in combination (ARA+ARS), nor considering a MCL on HKE, for a total of eight scenarios: forward scenario, inverse scenario, monthly forward scenario, monthly inverse scenario, once with an MCL on ARA and once with an MCL on ARS. Implementing a MCL on the deep-water fisheries suggested an improvement for all stocks except for HKE. ARA and ARS would improve thanks to the control of the MCL, while MUT, DPS and NEP would stay within the upper and lower limits of Fmsy, despite the reallocation of fishing effort from deep to coastal fisheries. The implementation of a reverse MCL did not show a recovery of the stocks. Moreover, a MCL split by month seems to have a lower impact on the catches of ARA and ARS in the short term. The GVA shows an increase for the passive gears fleets (i.e., gillnetters and longliners) and a strong decrease for all trawling fleets in the first two years, with a stable trend over the following years. The spatially explicit mixed fisheries model ISIS-Fish also ran scenarios accounting for MCLs, but only for HKE in GSA 7, implementing a forward, an inverse and a monthly MCL for a total of four scenarios. The forward scenario led to fishing mortalities below Fmsy in 2025 because the value defined for MCL did not account for biomass rebuilding. On the other hand, the fishing mortality achieved using the HCR in the inverse scenario, never fell below Fmsy, because of the unrestricted catches of netters and long-liners. In terms of revenues, both MCL paths led to strong decreases for trawlers. The spatially explicit mixed fisheries models, ISIS-Fish (GSA 7) and SMART (EMU 2), focused on the evaluation of closure areas: existing closure areas, existing closure areas which were seasonal to become permanent, existing closure areas extended to all fishing gears, additional closure areas (only EMU 2), expansion of closure areas by 50% (only EMU 2) and expansion of closure areas by 100% (only EMU 2). ISIS-Fish was applied only for HKE in GSA 7 being the first time this model was used within this working group. The extension of closure areas to all fishing gears (passive gears on top of trawlers) in GSA 7 did not show any improvement, while shifting from a seasonal to a permanent closure showed a decrease in F and an increase in SSB. A decrease of catches of juvenile hake of 20% was observed both with seasonal and permanent closures. Catches of adults increased due to recovery of the stock and considering the low level of initial catches. It should be noted that revenues increased for passive gears but decreased for trawlers. SMART was updated, increasing the spatial resolution of the spatial grid of the model, to be in line with outputs of the ad-hoc contracts preceding the EWG and with ISIS-Fish. None of the scenarios considered for EMU 2 evaluating spatial closures allowed to reach Fmsy by 2025, except for MUT in 10 and NEP in 9 which remains underutilized. SSB shows, nevertheless, an increase across years. None of the scenarios allowed to reduce catches by 20% for all species. All scenarios are associated with a sharp decrease in revenues; spatial closures not widened or seasonal would involve lower decrease of the profits than widened and permanent closures. Loss of profits is more evident for VL12-18 and VL18-24, although the loss is evident for all fleet segments. During EWG 22-01 no explicit comparison between the implementation of an effort regime and a MCL regime was run. The group advices to do so accounting for the limitations encountered in the implementation of MCLs during EWG 22-01. It should be noted that the reduction of GVA is estimated in the short term (up to 2025), but further tests should be done to estimate the trend of GVAs in the mid- and long-term. It is highlighted that given the large number of other species exploited beyond the key ones included in the management plan and in the simulation models, the actual socio-economic impact of the plan remains uncertain. Also, the economic results are presented considering a constant number of vessels, and would differ if the number of vessels is reduced. Additionally, it is difficult to evaluate the socio-economic impact of the MAP on the fleets as at present no socio-economic reference points are used to compare the results against those. European Union Submitted Non Refereed

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No abstract available

Marine recreational fishers accumulate a vast amount of local ecological knowledge (LEK) during their fishing activity that can be of paramount importance for monitoring how climate change affects fish assemblages. We assessed LEK of recreational fishers to investigate the increase in the abundance of 5 northward-expanding indigenous thermophilic fish species in 2 Mediterranean subregions. We accessed LEK through an online survey completed by 794 re- creational fishers (386 from the Adriatic/Ionian subregion and 408 from the Tyrrhenian/Ligurian subregion). The species perceived to have increased most in abundance were Pomatomus salta- trix (71% of replies) followed by Sphyraena viridensis (58%). The remaining species (Sparisoma cretense, Balistes capriscus and Coryphaena hippurus) ranged between 17 and 25%. Recreational fishers have a stable system of beliefs about meridionalization, which is perceived homogeneously between recreational anglers and recreational spearfishers. Our results indicate that latitude is negatively correlated with meridionalization in the Adriatic/Ionian, but not in the Tyrrhenian/ Ligurian Seas, suggesting that meridionalization of the Adriatic/Ionian Seas could be a process that has temporally lagged with respect to the Tyrrhenian/Ligurian Seas. Our study demonstrates that LEK of recreational fishers can be easily accessed on a large geographical scale and can be useful to monitor changes in the distributions of data-limited species such as those studied here.

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 reportdeals with the revision of the EU-MAP and Work Plan template. The Expert Group report was reviewed during the 2019 STECF November plenary meeting during the 2019 STECF November plenary meeting.

Climate change and biological invasions are rapidly reshuffling species distribution, restructuring the biological communities of many ecosystems worldwide. Tracking these transformations in the marine environment is crucial, but our understanding of climate change effects and invasive species dynamics is often hampered by the practical challenge of surveying large geographical areas. Here, we focus on the Mediterranean Sea, a hot spot for climate change and biological invasions to investi- gate recent spatiotemporal changes in fish abundances and distribution. To this end, we accessed the local ecological knowledge (LEK) of small-scale and recreational fish- ers, reconstructing the dynamics of fish perceived as "new" or increasing in different fishing areas. Over 500 fishers across 95 locations and nine different countries were interviewed, and semiquantitative information on yearly changes in species abun- dance was collected. Overall, 75 species were mentioned by the respondents, mostly warm-adapted species of both native and exotic origin. Respondents belonging to the same biogeographic sectors described coherent spatial and temporal patterns, and gradients along latitudinal and longitudinal axes were revealed. This information pro- vides a more complete understanding of the shifting distribution of Mediterranean fishes and it also demonstrates that adequately structured LEK methodology might be applied successfully beyond the local scale, across national borders and jurisdic- tions. Acknowledging this potential through macroregional coordination could pave the way for future large-scale aggregations of individual observations, increasing our potential for integrated monitoring and conservation planning at the regional or even global level. This might help local communities to better understand, manage, and Email: eazzurr@gmail.com Funding information European Regional Development Fund, Grant/Award Number: MPA-Adapt 1MED15_3.2_M2_337; Albert II of Monaco Foundation 1 | INTRODUCTION The redistribution of Earth's species is among the most evident con- sequences of global warming (Parmesan & Yohe, 2003; Poloczanska et al., 2016) and a critical aspect for the health of both natural eco- systems and human populations worldwide (Pecl et al., 2017). These changes are usually greater for marine environments, because of their high environmental connectivity (Burrows et al., 2011) and because of the pivotal role of water temperatures, which strongly influence growth, survival, and reproduction in marine animals (Crozier & Hutchings, 2014; Reusch, 2014). In fact, even apparently modest changes in water temperature might trigger a rapid cascade of multiple pressures over marine organisms. Some species, unable to cope with these environmental alterations, or benefit from them, may change their abundances accordingly. However, mobile marine organisms also have another option: they can move to new areas where they were formerly absent (Cheung et al., 2009; Fogarty, Burrows, Pecl, Robinson, & Poloczanska, 2017). These two dynamics are not mutually exclusive, as they can be considered as different be- havioral and demographic responses that might coexist in the same species or population. Specifically, in the northern hemisphere, seawater warming has been associated with both the northward expansion of species and their increasing abundances (Fossheim et al., 2015; Perry, Low, Ellis, & Reynolds, 2005; Pörtner & Knust, 2007; Sabatés, Paloma, Lloret, & Raya, 2006). Yet, many studies provided evidence for the causal relationship between temperature, species distribution, and abun- dance (Cheung, Watson, & Pauly, 2013; Pinsky, Worm, Fogarty, Sarmiento, & Levin, 2013; Poloczanska et al., 2013) as well as their interplay with other global drivers, such as biological invasions, ma- rine overexploitation, and pollution (Stergiou, 2002; Walther et al., 2009). These changes, which are taking place across many differ- ent taxa and through different regions of the globe, have significant implications for biodiversity, ecosystems, and society (McGeoch & Latombe, 2016) and are considered to be particularly apparent in the Mediterranean, a semi-enclosed sea, which is warming faster than any other marine region in the world (Schroeder, Chiggiato, Bryden, Borghini, & Ben Ismail, 2016; Vargas-Yáñez et al., 2008). In addition, maritime traffic, mariculture, aquarium trade and above all, entries through the Suez Canal (Edelist, Rilov, Golani, Carlton, & Spanier, 2013; Parravicini, Azzurro, Kulbicki, & Belmaker, 2015) contribute to the introduction of a large number of nonindigenous species (hereafter referred as NIS) to this basin (Galil, Marchini, Occhipinti- Ambrogi, & Ojaveer, 2017; Golani et al., 2018; Zenetos et al., 2017), reshaping the structure of biological communities (Albouy et al., 2013, 2015, 2014; Katsanevakis et al., 2017) and impacting biodi- versity and fishery resources (Edelist et al., 2013). Despite the magnitude of these changes and their relevance for conservation and adaptation policy (Givan, Parravicini, Kulbicki, & Belmaker, 2017; Marras et al., 2015), observational studies are often fragmented in space (Elmendorf et al., 2015) and methodologically heterogeneous (Coll et al., 2010). This also applies to the northward expansions of warmwater species, a phenomenon that has been mostly described in the northwestern sectors of the Mediterranean basin, probably due to the uneven distribution of research ef- forts (Boero et al., 2008; Lejeusne, Chevaldonné, Pergent-Martini, Boudouresque, & Pérez, 2010; Marbà, Jordà, Agustí, Girard, & Duarte, 2015; Sabatés, Martín, & Raya, 2012). This fragmentation, together with the lack of coherent depictions of change, hampers the availability of reliable information to stakeholders and decision-mak- ers (Grafton, 2010; Pauly & Zeller, 2016). Indeed, in light of profound impacts that have already affected both people and the ecosystems they depend on, many national and transnational authorities and agencies are engaged in efforts to build adaptive capacity, seeking reliable information to enable people to anticipate and appropriately respond to the ongoing change (Coulthard, 2012). This explains the growing need of integrated monitoring and assessment systems to capture the ongoing transformations of marine ecosystems (includ- ing the effects of a changing climate) and to bring them into the pol- icy agendas (Creighton, Hobday, Lockwood, & Pecl, 2016). Certainly, our observational potential grew steadily during the last few years and increasing efforts are devoted to conceive global observation systems for up-to-date information on the state of biodiversity and the threats it faces (Tittensor et al., 2014). To achieve this, the use of standardized and cost-effective procedures is needed to underpin a large-scale observation strategy that can accommodate countries across a range of baseline knowledge levels and capabilities (Bélisle, Asselin, LeBlanc, & Gauthier, 2018; Latombe et al., 2017). These are key principles for collecting and integrating information from stake- holders across national boundaries. In this, fishers are a particularly interesting group of stakeholders, as they spend a considerable proportion of their lives in close contact with the marine environ- ment and they become familiar with local species. Therefore, their personal experience gained through individuals' observations over adapt to the ongoing biotic transformations driven by climate change and biological invaders.

Fishing of Nassarius mutabilis is by far the most important activity carried out by artisanal fisheries in the central and northern Adriatic Sea, accounting for more than 35% of total fishing effort and yielding from 2000 to 3000 t of landings each year. This gastropod is targeted from the beginning of autumn to the end of spring using basket traps. Despite its importance under a socioeconomic point of view, the scientific studies on the biology and ecology of this species are very scarce and the failure of the current management measures could also be attributed to the scarce knowledge on the biology of this species in the area. Taking this statement into consideration, the results of the present study contribute to fill a few existing gaps and may be useful to improve the management measures currently in force. Samples were collected from March 2006- March 2008 during monthly fishing surveys and carried out using basket traps in the central Adriatic Sea. A total of 383 males (size range 7-29 mm SH) and 504 females (size range 15-32 mm SH) were caught. Mean SH (± SD) of males was 15.84±3.57 mm and mean SH of females was 25.31±3.06 mm. A significant difference in the biometric characteristics between the two sexes was discovered. The condition index (CI) showed similar seasonal trends for both sexes, with a decrease from late winter to spring followed by an increase from summer to fall - early winter. The minimum values were recorded in summer and the maximum ones in winter, following an opposite trend in respect to water temperature. In the males this trend was observed starting from size classes larger than 11 mm SH, hence this size might be very close to the size at first sexual maturity. The size at first maturity hypothesized for females (16-20 mm SH) agrees with the minimum landing size (MLS) currently established for this species (20 mm SH). The absence of small females (SH < 15 mm) and large males (SH > 23 mm) leads to suppose a sex reversal from male to female at around 20 mm SH. On this basis, the management measure of MLS leads to the selective retention of females and, hence, to a sexual gap between the two sexes with possible consequences on the biology of the species and the resilience of the stock. The peaks of CI observed for males and females confirmed that the spawning season of this gastropod occurs in late winter - early spring, according to the abundant presence of egg capsules attached to submerged substrates in that period at sea. Consequently, from a management point of view, it would be advisable to shorten the fishing season that at present extends from fall to later spring.

The western coastal area of the Adriatic Sea is seat of several human activities, including fishery and aquaculture. Small-scale fishery, otter and pelagic trawling, hydraulic dredges for clams, mussel harvesting on wild banks, recreational fisheries and intensive and extensive mussel culture play an important socio-economic role for the coastal communities but often interfere each other for space and/or resources. The study area has not a dedicated national coastal management plan and the spatial administration of fisheries and aquaculture is often carried out at regional level. An important management tool adopted by Regional Authorities to mitigate these conflicts is the deployment of medium-scale artificial reefs along the 3 nm boundary of the coastal strip. The main goals of these artificial reefs are to create physical obstacles against illegal trawling, create suitable habitats for reef-dwelling species, improve small-scale fisheries diversifying target species and catches, and create new extensive mussel cultures to sustain harvesting of mussels on wild banks. Indirect possible effects of these structures include the revitalization of artisanal fisheries, the conversion of high-impact fishing techniques in more selective gears and the creation of appropriate fishing ground for recreational fisheries. This paper will show the potential socio-economic effects of artificial reefs on fisheries and aquaculture in a coastal study area (Marche Region) of the western Adriatic Sea. The evolution of potential future scenarios characterised by an increasing number of artificial reefs will be analysed taking into account all the above mentioned aspects.