Catch and discard composition including solutions for limitation and possible elimination of unwanted by-catches in trawl net fisheries in the Mediterranean.

An evaluation of national discards programs has been done by identifying all potential loopholes in methodology. Different technical and environmental factors that influence discard rates have been identified and summarized. Furthermore, selective properties of demersal and pelagic trawls have been summarized in relation with the MLS and landing obligation Regulation, in order to assess the efficacy of these technical measures. Finally, the stakeholder's perceptions on the discard issue and their opinions and options have been integrated. The main results achieved have been: - Discard amount fluctuates among fisheries and areas, usually from < 20 % to 70 %, due to a biological, technical, environmental, legal and socio-economic factors. - The complexity of the fishing activity in the Mediterranean basin is influenced by many factors: multi-target species, the geographical peculiarities, the multi-gear use, the seasonality etc. - The Mediterranean onboard national discard programmes seem to have low levels of bias in the sampling protocols, with the higher level of risk of bias linked to low sampling coverage and landings and effort statistics. - Discarding in the Mediterranean is affected by numerous reasons and several factors which is difficult to disentangle (commercially unimportant invertebrate and fish species, commercially important but undersized species (under MLS), commercially important species which fishermen could not sell on the market or have very low market price). - High regional, seasonal and interannual fluctuations are observed even within the same fishing gear. - Increased discarding of some species has been reported during the recruitment period when they migrate from shallow waters to off-shore areas accessible to bottom trawling. - Fishing depth has been greatly related to patterns in discarding, obviously due to varying catch composition and the relative biomass of target species in the different depth strata even if there doesn't seem to be a constant pattern related to the depth stratum for the whole basin. - The availability of resources, sometimes affected by the status of the stocks, has been shown to affect fluctuations of market demands and associate discarding practices. - Fishers' attitude, approaches practiced and experience, both the captain's and the crews have been also shown to affect discards. - Nutritional habits of the community affect fishing and discarding practices. At small scale, some species may be marketable only in some areas. - At larger scale, discards ratios for trawls are generally lower in the easternmost and southern basin. - The low level of discarding of MLS-regulated species in certain Mediterranean trawl fisheries may be a consequence of a quota-independent management system of demersal trawl fisheries and, even more importantly, a consequence of low compliance by fishermen and weak control and enforcement in certain areas. - Market demands rather than fish size (legal reason) determines what is discarded in Mediterranean fisheries. - The existing MLSs are ecologically inefficient for sustainable management and MCRS should be redefined for several species. - Mediterranean trawling produces the bulk of discards and this is the reason why most studies focus on trawling activities. In general, fisheries targeting fish or mixed categories presented higher discard ratios compared to the ones targeting shrimps. Several shrimp fisheries operate throughout the Mediterranean with varying generation of discards according to the species targeted and the depth stratum that they operate - The majority of selectivity studies were focused on the species that have highest commercial values; some studies show that a simple change from a 40 mm diamond to a 40 mm square mesh improves the selectivity for some target species, it also results in economic losses due to escapement of some accompanying species; - The MLS of species commonly caught in Mediterranean trawl fisheries are not harmonised with the species length at first maturity, indicating that most of the species that are caught are not allowed to spawn at least once in their life time. - All these suggest that current codends used in Mediterranean trawl fisheries are not adequate and that some additional improvements in selectivity are needed. The deliverable D 0.2. A working document on factors affecting the selective behaviour related to discarding offered the opportunity to contribute further to our understanding of factors that drives fishers' behaviours to a higher or lower discard level and also towards exploring effective discard mitigation measures. The main results achieved have been: - At the level of the fisher, the act of discarding involves a short term economic decision - Economic, regulatory and environmental/natural factors, as well as individual characteristics related to the fisher, fishing operations and vessel seem to have a synergistic effect in the decision-making process of discarding, which is sometimes difficult to disentangle. - The efficacy of technical measures (eg. Minimum Mesh Sizes (MMSs), Minimum Conservation reference Sizes (MCRSs), closed areas and seasons) mainly depend on the level of rule compliance and enforcement effort, on the collaboration between fishermen and the willingness of fleets to share information. - Stakeholder engagement showed that cost compensation, commercialising species caught in a sustainable manner and overall economic incentives have been seen positively as potential interventions. - Concerns have been expressed about providing discards to the fishmeal industry and aquaculture, needed facilities and infrastructure and control/fines, which are already strict. The main concern was that if the landed discards can be re-used for other purposes, (fishmeal for instance), fishermen will be stimulated to catch more fish. - Reducing discarding is a complex issue which involves combinations of management measures (e.g., use of avoidance and gear selective strategies along with campaigns to increase awareness) or a single method/tool. - Reducing discards should be designed for specific fisheries and fleet characteristics and may differ between regions. - Reducing discards should incorporate stakeholders' knowledge and in particular fishers since they have unique knowledge concerning local features, needs and better understanding of impacts of measures. - Reducing discards should take human behaviour into account as an important source of variability. In the deliverable D 0.3. Report on the management options for the discard reduction different combinations of scenarios developed in each study area/fleet that will advise on the effects of selectivity-related management measures have been reviewed together with the results obtained from the two stakeholders meetings. - Approaches contributing to discards mitigation in the Mediterranean mainly comprise technical measures, which are related to improvement of selectivity and/or avoidance of potential hot spots of discards. - Technical measures may be gear- and fishery-specific and their application should be tested in different areas - Trawl selectivity indicator graphs provide a good opportunity to compare MLS and lengths at first maturity. The results show that the Lengths at first maturity for the investigated DISCATCH species for the majority of species show that MLSs are well below the size at first maturity. - This goal can be achieved by promoting bottom trawl replacement with more selective fishing gears or promoting changes to the selective performance of bottom trawling through technical changes (square mesh codend, sorting grids etc.). - Many studies highlight the advantages of the use of a square mesh instead of a diamond shaped due to the fact that square mesh tends to keep shape and stay open, better than diamond mesh. - The existing MLSs are ecologically inefficient for sustainable management; thus, the selective performance of bottom trawls in the Mediterranean Sea should be improved in order to fulfil ecological and biological targets. - Spatio-temporal closures for specific fishing gears exist and they usually aim to protect juvenile fish - The designation of spatio-temporal closures in the GFCM area is not always based on scientific criteria and they often try to satisfy social demands. A more targeted designation, based on scientific results may prove more effective in by-catch reduction and fisheries management in general - The results of stakeholders meeting show that there is not a clear trend of the topics that stakeholders consider as having a paramount importance. - The costs to shift from the traditional to more selective gears is the most important topic for stakeholders, who consider any modification of the gear needed to reduce discarding should be funded by the national authorities or by the EU. - Stakeholders seem to be not available to pay for more selective gears; on the other hand they also consider that retaining and selling undersize fish shall not increase their income, mainly because the undersized fish products are not effectively utilized. - Stakeholders consider the current design of bottom trawl gears as highly unselective and they seem to be well aware of the potential positive effects of improving selective form an ecological (discards reduction, positive effects on the biodiversity) as well as technological (better catch quality and marketing opportunities, reduction of time devoted to sorting the catch ecc.) point of view. - The stakeholders consider the maintaining of a safe level of reproductive potential as one of the main management objectives while the discards reduction is perceived as a minor issue. - As regards the ecological indicators the most important issue seems to be the "mean size of the spawners". - Considering the economic indicators, the stakeholders gave their preference to "revenue" in comparison to "production" and to "fuel costs" in comparison to "crew costs". - Stakeholders consider the "fleet withdrawal" (scraping) as the worst option for the management strategies to achieve a sustainable fishery management in the long term - The combination of three measures is considered as the best option: Spatial fishing ban (Protection of nursery and spawning areas), seasonal fishing ban, improved gear selectivity. - Overall, the stakeholders do not consider the discards ban implemented in the framework of EU Reg. No 1380/2013 as a proper management measure to improve the status of the commercial stocks since: 1) there is uncertainty on the long term gains; 2) the retaining and selling of undersized fish will not increase their income; 3) the compliance with the EU provision will not easily be achieved.