Inês Cardoso

Raising awareness on marine environmental issues is crucial to deepen students’ knowledge on ocean sustainability. Nonetheless, ocean-related topics have not been adequately addressed through formal education curricula, thus non-formal learning activities were developed to promote Ocean Literacy among students. These include visits to the local fish market and hands-on activities of fish biological sampling. A mixed methodology with closed and open-self questionnaires and interviews, was used to assess the activities’ effect in student’s learning and to evaluate their implementation and importance. Results showed the activities contribution to the increased learning while promoting a more active citizenship regarding ocean conservancy.

Aim: We present the first global biogeographical regionalization of estuaries, assessing how dispersal limitation and/or environmental filtering mechanisms drive the patterns of fish assemblage composition among and within biogeographical regions.Location: Estuaries worldwide.Methods: A bootstrapped hierarchical cluster analysis was applied to define biogeographical regions based on pairwise beta diversity (βsim) of fish assemblages among 393 estuaries worldwide. Variables representing dispersal limitation and environmental features were used to disentangle the possible effects of assembly processes acting among and within biogeographical regions, through hierarchical partitioning of variation. Finally, we assessed the contribution of species to beta diversity through a method newly developed in this article.Results: Estuaries were grouped into seven major biogeographical regions explained by geographical dispersal variables. Dissimilarity in species composition within each biogeographical region was mainly determined by ecosystem‐connectivity dispersal variables, with a minor influence of environmental variables (chiefly sea surface temperature). Marine species contributed highly to beta diversity between estuaries but less than expected by chance, whilst freshwater species had low contributions yet also less than expected. Estuarine (i.e. brackish) and diadromous species had low contributions to beta diversity but higher than expected by chance.Main conclusions: Fish assemblage composition in estuaries seems to be driven by dispersal limitation processes both among and within biogeographical regions, with only a minor role of environmental filtering evident within biogeographical regions. These findings contrast with the acknowledged importance of environmental variables as drivers of species richness patterns. Irrespective of biogeographical region, the ecosystem affinity of a species determined its contribution to beta diversity between estuaries. The new method presented here offers new opportunities for assessing the effects of taxonomic and functional aspects on beta diversity (βsim) across taxa and ecosystems, and thus contributes to improving knowledge of assembly processes.

The term “mixed fisheries” refers to fishing activities where more than one species are caught simultaneously and one species may be fished by different gears. Therefore, mixed fisheries present a harder challenge for fisheries management than single-species fisheries and the uncertainty can start at the definition of the target species. In these particular fisheries, we have a large group of species that are caught, being target or not, species with large landing values that are actually not target, and species with a high economic value that can fall in the bycatch category. Although the dynamics of such fisheries is poorly understood, they are known to have a relevant contribution to Portuguese fishers' revenue. The present demand on sustainable fishing activities to ensure marine ecosystem preservation has led towards an ecosystem approach where effort is being made to take into account biological and technical interactions on management measures and advice. In this work, logbooks data of the Portuguese multi-gear fleet were used to identify different fisheries based on catch composition and gears through cluster analysis (CLARA). Two identified fisheries were used to explore the impact of these fishing activities on the ecosystem scale. This approach was achieved by a productivity and susceptibility analysis and through foodweb analysis. The relation between species vulnerability and their functional role in the ecosystem were highlighted. Technical interactions among fishing gears, and species biological interactions, were explored within and among fisheries. We found and illustrated that these interactions go beyond the fleets and fisheries considered in the present work. This approach allows us to identify key elements that can, ultimately, be relevant to an ecosystem-based approach towards mixed fisheries management.

Summary: Knowledge of global patterns of biodiversity and regulating variables is indispensable to develop predictive models. The present study used predictive modelling approaches to investigate hypotheses that explain the variation in fish species richness between estuaries over a worldwide spatial extent. Ultimately, such models will allow assessment of future changes in ecosystem structure and function as a result of environmental changes. A comprehensive worldwide data base was compiled of the fish assemblage composition and environmental characteristics of estuaries. Generalized Linear Models were used to quantify how variation in species richness among estuaries is related to historical events, energy dynamics and ecosystem characteristics, while controlling for sampling effects. At the global extent, species richness differed among marine biogeographic realms and continents and increased with mean sea surface temperature, terrestrial net primary productivity and the stability of connectivity with a marine ecosystem (open vs. temporarily open estuaries). At a smaller extent (within a marine biogeographic realm or continent), other characteristics were also important in predicting variation in species richness, with species richness increasing with estuary area and continental shelf width. The results suggest that species richness in an estuary is defined by predictors that are spatially hierarchical. Over the largest spatial extents, species richness is influenced by the broader distributions and habitat use patterns of marine and freshwater species that can colonize estuaries, which are in turn governed by history contingency, energy dynamics and productivity variables. Species richness is also influenced by more regional and local parameters that can further affect the process of community colonization in an estuary including the connectivity of the estuary with the adjacent marine habitat, and, over smaller spatial extents, the size of these habitats. In summary, patterns of species richness in estuaries across large spatial extents seem to reflect from global to local processes acting on community colonization. The importance of considering spatial extent, sampling effects and of combining history and contemporary environmental characteristics when exploring biodiversity is highlighted.

Estuaries are among the most productive environments in the coastal zone that may act as sink of pollutants. In this study we evaluated how levels of heavy metal contamination can be reflected in the macroinvertebrate communities of six Tagus Estuary mudflats, inferring their consequences to upper trophic levels. We used Shannon-Wiener’s diversity, Pielou’s evenness and Simpson’s dominance indices, and macroinvertebrate densities to characterize benthic communities at the sites that presented different metal contamination loads. Those stations with high levels of contamination presented a lower diversity but also the highest prey density. This study indicated that unhealthy areas can still perform their ecosystem function with costs that remain to be evaluated. The biodiversity can be impoverished compared with other less contaminated sites, but with regard to their utilization as feeding areas by birds and fishes this is not a limiting factor. For this particular function of the mudflats, prey availability is the main characteristic determining the choice of one particular site as a bird and fish feeding area that may not be affected by heavy metal contamination.

The suitability of using four bivalve molluscs (Sanguinolaria acuminata, Anadara granosa, Meretrix meretrix, and Pelecyora trigona) in biomonitoring of heavy metals (Cu, Pb, Cd, Zn, and Hg) collected from intertidal regions of the Sunderban mangrove wetland, northeastern part of the Bay of Bengal, were evaluated. Both speciesdependent variability and temporal variations were pronounced. A high degree of organ specificity was evident in the bivalves where gill and mantle exhibited higher metal accumulation due to ion exchange property of the mucous layer covering these organs while shells represent very poor accumulation. Elevated values of Zn and Cu reflect high potential for biomagnification through marine food chain. Metal concentrations in different body size groups of the bivalves do not follow uniform trend. Correlation coefficient between different metal couplings as tested statistically revealed significant coupling for Pb–Zn, Pb–Cu, Zn–Cu, and Hg–Cu. Concentrations of all the metals in specific organs (visceral mass, mantle and gill) of the bivalves exceeded the safe levels according to the international standards for metals compiled by Food and Agricultural Organization of the United Nations and would be of great risk for human consumption. It is concluded that the mussel and clam are suitable biomonitors to employ in programs designed to assess changes in metal pollution in the Sunderban mangrove wetland.