Microplastics (MPs) in the marine environment undergo complex weathering factors that can affect their ability to interact with different coexisting environmental contaminants (termed here co-contaminants). In this study, the influence of artificially aging using UV on the sorption of a complex mixture of co-contaminants onto MPs was investigated in order to provide meaningful hypotheses on their individual and combined toxicities on sea urchin embryos. A mixture of artificially aged MPs (PS particles and PA microfibers) combined with 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), or Cd or Cu, both alone and in a mix, were used to expose embryos of Paracentrotus lividus. The effects of polymer aging on co-contaminants bioavailability were assessed by measuring changes in the transcriptional profile of genes involved in oxidative-stress response and skeletogenic and endo-mesodermal specification. Changes in the sorption ability of MPs to co-contaminants in the aqueous phase highlighted that aging did not affect the sorption of BDE-47 and Cd on MPs, although a certain influence on Cu sorption was found. Despite no morphological effects in embryos at the gastrula stage after MPs/contaminants combinatorial exposure emerged, the greatest influence of the aging process was mainly found for combined exposures which included BDE-47. Finally, the exposure to multiple contaminants generated transcriptional profiles poorly related to those activated by single contaminant, at times suggesting a mixture-dependent different aging influence. These results open new scenarios on the controversial role of vector of co-contaminants for MPs, especially when complex and different types of mixtures were considered.

Estimated larval backward trajectories of three Tuna species, namely, Atlantic Bluefin Tuna (Thunnus thynnus, Linnaeus, 1758), Bullet Tuna (Auxis Rochei, Risso, 1801) and Albacore Tuna (Thunnus alalunga, Bonnaterre, 1788) in the central Mediterranean Sea, were used to characterize their spawning habitats, and to assess the impact of changes due to the major environmental parameters (i.e., sea surface temperature and chlorophyll-a concentration) on larval development during their advection by surface currents. We assumed that the environmental variability experienced by larvae along their paths may have influenced their development, also affecting their survival. Our results showed that the Tuna larvae underwent an accelerated growth in favorable environmental conditions, impacting on the notochord development. In addition, further updated information on spawning and larval retention habitats of Atlantic Bluefin Tuna, Bullet and Albacore Tunas in the central Mediterranean Sea were delivered.

Thunnus thynnus (Atlantic bluefin tuna, ABT) and other tuna species reproduce in the Mediterranean Sea during the summer period. Despite the Central Mediterranean Sea, the Strait of Sicily in particular, being a key spawning site for many tuna species, little is known on the effects of oceanographic variability on their larval distribution in this area. The abundance and presence-absence of larval specimens for three tuna species (ABT, bullet tuna and albacore) were modeled in order to examine their relationships with environmental factors, by analysing historical in situ information collected during seven annual surveys (2010–2016). The results revealed that most tuna larvae for the three species were found in the easternmost part of the study area, south of Capo Passero. This area is characterized by a stable saline front and warmer nutrient-poor water, and it has different environmental conditions, compared with the surrounding areas. The models used to investigate the presence-absence and abundance of the three species showed that ABT was the most abundant, followed by bullet tuna and albacore. The presence and abundance data collected are comparable with those of other spawning areas in the Mediterranean. Regarding biological and physical parameters, the results suggest that temperature, salinity, and day of the year are the key factors for understanding the ecological mechanisms and geographical distribution of these species in this area. Temperature affects the presence of ABT larvae and salinity, which, with a physical barrier effect, is a key factor for the presence-absence of bullet and albacore and for albacore abundance.

The European anchovy is an important fishing resource in the Sicilian Channel that supports a high recruitment success variability. The presence of two spawning areas, the drifting of the larvae along the currents and the different oceanographic conditions within the region suggest the presence of different larvae subpopulations. Morphometric and biochemical approaches have been used to analyze the differences among larvae collected. The amino acid composition discriminates two larval groups closely related to the spawning regions: Adventure Bank and the shelf between the South of Sicily and Malta. In addition, there are morphometric and growth differences between recently hatched larvae in these two regions, reinforcing the hypothesis of two larval subpopulations and suggesting differences in the parental reproduction effort. Between the South of Sicily and Malta there are growth and biochemical composition differences since larvae from the Maltese coast present a higher protein content and a bigger growth rate than those from Sicily, pointing out that Malta is an area with a better nutritional condition environment. No differences in the growth rate have been observed between the Adventure Bank area and the Maltese shelf, therefore, a diverse nutritional condition cannot be suggested between these two areas despite the Maltese larvae having a higher protein content present.

Marine protected area (MPA) implementation can lead to fishers’ displacement and opposition to conservation efforts. Yet, evidence on how MPAs affect fishing operations is limited, especially for the small-scale sector. Surveys and participatory mapping exercises (n=93) were carried out with small-scale fishers in four Mediterranean and one Black Sea MPA to investigate fishers’ behavioural responses and perceptions to MPA implementation. We found that MPAs had a significant impact on small-scale fisheries (SSF) leading to a reallocation of the small-scale fishing footprint, with most fishers choosing to displace their fishing activities to areas previously known to them. Multinomial logistic regression highlighted that the number of fishing gears and perceived impact of MPAs on access to productive fishing grounds were significant predictors of fishing displacement, with fishers using a greater number of gears (i.e. more diverse fishery portfolio) being more likely to reallocate elsewhere, and fishers who perceived increased access to productive areas being less likely to reallocate their fishing efforts to other grounds. MPA implementation did not affect the mean number of fishing gears used. Most fishers felt that they had not adapted their fishing activities following the MPAs’ implementation, and proportion odds models revealed that fishers perceiving higher involvement in decision-making perceived a higher level of adaptation. Our study contributes to fill the knowledge gap about the effect of MPAs on SSF footprint and perceived capacity to adapt, highlighting steps that can be taken to ensure MPAs better meet expectations and needs of local fishing communities.