Evaluation of maximum catch limits and closure areas in the Western Mediterranean (STECF-22-01).
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AbstractCommission 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.
Publisher or UniversityPublications Office of the European Union
Series : NrSTECF-22-01;
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