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Despite the crucial role of herbivory in shaping community assembly, our understanding on biogeographical patterns of herbivory on seagrasses is limited compared to that on terrestrial plants. In particular, the drivers of such patterns remain largely unexplored. Here, we used a comparative-experimental approach in Cymodocea nodosa meadows, across all possible climate types within the seagrass distribution, 2000 km and 13° of latitude in two ocean basins, to investigate biogeographical variation in seagrass herbivory intensity and their drivers during July 2014. Particularly, the density and richness of herbivores and their food resources, seagrass size, carbon and nitrogen content, as well as latitude, sea surface temperature, salinity, chlorophyll, and sediment grain size, were tested as potential drivers. We found that shallow meadows can be subjected to intense herbivory, with variation in herbivory largely explained by fish density, seagrass size, and annual sea temperature range. The herbivorous fish density was themost important determinant of such variation,with the dominant seagrass consumer, the fish Sarpa salpa, absent atmeadows from regionswith lowherbivory. In temperate regionswhere herbivorous fish are present, annual temperature ranges drive an intense summer herbivory, which is likelymediated not only by increased herbivore metabolic demands at higher temperatures, but also by higher fish densities. Invertebrate grazing (mainly by sea urchins, isopods, amphipods, and/or gastropods) was the dominant leaf herbivory in some temperate meadows, with grazing variation mainly influenced by seagrass shoot size. At the subtropical region (under reduced annual temperature range), lower shoot densities and seagrass nitrogen contents contributed to explain the almost null herbivory.We evidenced the combined influence of drivers acting at geographic (region) and local (meadow) scales, the understanding of which is critical for a clear prediction of variation in s

This work is the result of an international research effort to determine the main impacts of the COVID-19 pandemic on marine recreational fishing. Changes were assessed on (1) access to fishing, derived from lockdowns and other mobility restrictions; (2) ecosystems, because of alterations in fishing intensity and human presence; (3) the blue economy, derived from alterations in the investments and expenses of the fishers; and (4) society, in relation to variations in fishers’ health and well-being. For this, a consultation with experts from 16 countries was carried out, as well as an international online survey aimed at recreational fishers, that included specific questions designed to capture fishers’ heterogeneity in relation to behavior, skills and know-how, and vital involvement. Fishers’ participation in the online survey (5,998 recreational fishers in 15 countries) was promoted through a marketing campaign. The sensitivity of the fishers’ clustering procedure, based on the captured heterogeneity, was evaluated by SIMPER analysis and by generalized linear models. Results from the expert consultation highlighted a worldwide reduction in marine recreational fishing activity. Lower human-driven pressures are expected to generate some benefits for marine ecosystems. However, experts also identified high negative impacts on the blue economy, as well as on fisher health and well-being because of the loss of recreational fishing opportunities. Most (98%) of the fishers who participated in the online survey were identified as advanced, showing a much higher degree of commitment to recreational fishing than basic fishers (2%). Advanced fishers were, in general, more pessimistic about the impacts of COVID19, reporting higher reductions in physical activity and fish consumption, as well as poorer quality of night rest, foul mood, and raised more concerns about their health status. Controlled and safe access to marine recreational fisheries during pandemics would provide b

The Multiannual Management Plan embedded in Regulation EU 2019/1022 of the European Parliament and of the Council of June 20, 2019, envisages to reform Mediterranean demersal fisheries to restore stocks to maximum sustainability yields by 2025. This paper leverages a bioeconomic model based on a specific case study of the Western Mediterranean Sea to analyze the objectives of this new EU reform. We complement this analysis with simulations based on alternative management strategies: the reduction of fishing effort of 1–2 days-per-week and changes to selectivity patterns. Effects on artisanal fleets are also analyzed in order to assess scenarios that could achieve sustainability for all demersal fishing fleets. The results reveal that it is not possible to achieve the plan’s aims for all stocks. Furthermore, the fishing time established is insufficient, although it would increase economic, and biological indicators for medium- and long-term periods. The best scenarios would be achieved by applying selective changes that provide for faster recovery of biological and economic indicators for trawler and artisanal fleets. The results also reveal that the reduction in the number of fishing days per week complemented with selectivity changes would have a lower socioeconomic impact than a reduction in fishing effort based entirely on fishing days or number of boats. In any case, Mediterranean demersal fisheries require a significant and well-planned reduction in fishing mortality levels over the next several years to recover and maintain sustainable exploitation

Desalination of seawater has become an important and growing industry due to the present water shortage in some Mediterranean countries. This activity may result in some environmental impacts, mainly generated by the discharge into the sea of the brine produced, which can affect marine benthic communities. Posidonia oceanica (L.) Delile is an endemic seagrass of the Mediterranean Sea, where its meadows represent a relevant ecosystem susceptible to being affected by these desalination effluents. The present study was planned in order to investigate the effects of hypersaline discharges on P. oceanica and its main associated organisms, and to provide adequate knowledge to help managers in the taking of decisions related to hypersaline discharges potentially affecting Posidonia meadows, particularly in the Spanish Mediterranean. The research included three different approaches conducted by distinct research teams whose results indicate that P. oceanica is very sensitive to salinity increases. Laboratory and field experiments showed significant effects on seagrass structure and vitality at salinities of 39.1 and 38.4, respectively. Due to this high sensitivity of P. oceanica to salinity increases, we recommend to avoid design and construction of brinedischarges in areas where these ecosystems or others that are potentially sensitive occur. However, when this option is not possible, we suggest not to exceed neither 38.5 psu of salinity in any point of the meadow for more than 25% of the observations (on an annual basis) nor 40 psu of salinity in any point of the meadow for more than 5% of those observations.

[EN] The cepholopod founo collecled in 24 houls corried out in the upper continentol slope off Aliconte (Western Mediterroneon) by commerciol irowlers is onolysed. Somples were ioken ot depths between 237 ond ól I m from April 1998 to December I999. Eighteen species in 8 fomilies were coptured . Todarodes sogittotus, Todoropsis eblonoe, Rossio mocrosomo, Sepielta oweniono, Eledone cirrhoso ond Oclopus so/ufii were lhe mosl obundont species. Cepholopods represented 3.9 % oÍ the totol cotch (94 kg). Averoge cepholopod biomoss estimoted wos 89.2 g,/hectore. The known depth ronge lor Octopus defilippi in the Mediterroneon is exponded up to 320 m. Observed seosonol chonges in biomoss of moin species ore discussed., [ES] En el presente trobojo se onolizon los cefolópodos copfurodos por orrosfreros comercioles en 24 lonces reolizodos en el tolud superior de lo provincio de Aliconie {Mediterróneo occidentol). Los muesiros fueron tomodos enfre los 237 y 61,l m de profundidod, entre obril de 1998 y diciembre de 1999. Se copturoron I8 especies pertenecientes o 8 fomilios. Todorodes sagitfotus, Todoropsis eblonoe, Rossio mocrosomo, Sepietlo oweniona, Eledone cirrhoso y Octopus so/utii fueron los mós obundonles. Los cefolópodos representoron un 3,9 % de lo copturo rotol (94 kg.). Lo biomoso de cefolópodos medio esiimodo fue de 89,2 gr./hecl6reo. El rongo.de profundidod conocido poro Octopus defilippi en el Mediterróneo fue ompliodo hosto los 320 mehos. Se discuten los combios eslocionoles de biomoso de los especies mós importontes.