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Simple Summary: Plastic pollution presents a growing concern for marine biodiversity, and among these, anthropogenic particles (APs) are entering marine ecosystems at an alarming rate from land and sea sources. In this study, we quantify the ingestion of APs across fish, sea urchins, sea cucumbers (echinoderms), bivalves (molluscs), and jellyfish (cnidarians), identify biotic and abiotic factors that might influence the ingested items; and identify ingestion patterns based on taxonomic groups, trophic guilds, and habitats. Ingestion of APs was observed in the majority of the species analyses with occurrence ranging from 0% to 100%. The study results indicate that plastic pollution poses a threat to species found within the marine protected area of the Cabrera Marine-Terrestrial National Park despite their protection status. The multispecies approach provided a better understanding of the high level of AP exposure to species, highlighting the associated damage to marine biodiversity related to marine waste. We have applied a multispecies ecosystem approach to analyse the ingestion of anthropogenic particles (AP) in the gastrointestinal tract of 313 individuals (17 fish species and 8 invertebrate species) from pelagic, demersal and benthic habitats in a marine protected area off the Western Mediterranean (Cabrera National Park). We have quantified and characterized the ingestion at several taxonomic levels of fish, sea urchins, sea cucumbers, bivalves, and jellyfish in relation to biotic/abiotic factors based on taxonomic groups, trophic guilds (functional groups) and habitats. AP ingestion occurrence ranged from 26 to 100% with no significant differences among taxonomic groups. The fish within the MPA showed an overall ingestion occurrence ranging from 0 to 100%, the echinoderms from 29 to 100%, the bivalves from 72 to 96% and the jellyfish 36% ingestion. The ecosystem approach applied to evaluate overall AP ingestion within the species reported that for trophic guilds, the omnivorous species ingested the highest amounts of anthropogenic items, while herbivores ingested significantly fewer items than all other trophic guilds. Moreover, no significant differences were found amongst habitats, indicating a homogeneous spatial distribution of APs at all studied habitats. The multispecies approach provided insight into the high APs exposure to species within Cabrera MPA, highlighting the potential harm linked with marine litter that threatens marine biodiversity. [ABSTRACT FROM AUTHOR]

The Mediterranean Sea is one of the most polluted seas in terms of marine debris. To analyze the ingestion of anthropogenic particles in two areas, 197 gastrointestinal tracts from four fish species - Trachurus mediterraneus , Sardina pilchardus , Engraulis encrasicolus and Boops boops - were studied. 127 anthropogenic particles were identified in the gastrointestinal tract of 28% of the samples using visual sorting methods. Individuals from the peninsular coast showed higher ingestion occurrence (36%) than those from the Balearic Islands (12%). Significant differences in the ingestion of anthropogenic particles were found between species with Trachurus mediterraneus identified as the most affected species (43% of the individuals with mean values of 1.13 ± 0.16 particles/individual), and Engraulis encrasicolus , the least affected (2.56% and 0.03 ± 0.16 particles/individual). Moreover, the proportion of ingestion amongst species was similar in both areas, highlighting the importance of studying the same species at different locations as marine debris bioindicators. • Fishes from the western Mediterranean Sea are affected by marine debris. • 28% of sampled individuals (197) ingested anthropogenic particles. • Ingestion occurrence higher in peninsular coast (36%) than in Balearic Islands (12%). • The most and the least affected species have been the same in both areas. • The best fit GLM model is which considers the variable 'species'. [ABSTRACT FROM AUTHOR]

The Mediterranean Sea is one of the most polluted seas worldwide, especially with regard to plastics. The presence of this emerging man made contaminant in marine environments precludes large effects and interactions with species exposed to massive litter quantities. In this review, available data of floating and seafloor litter around Mediterranean sub-basins are reported. A review of scientific literature on the interaction of plastic with marine biota resulted in the identification of 134 species, several taxa and feeding strategies affected from 1986 to 2014. Data from 17,334 individuals showed different levels of ingestion and effects on catalogued IUCN species (marine mammals and sea turtles) in addition to several pelagic fish and elasmobranchs. Biodiversity is certainly under threat, and knowledge of the extent of taxa affected is of concern considering the increasing plastic loads in the Mediterranean Sea and worldwide. [ABSTRACT FROM AUTHOR]

In this study, we examine anthropogenic particles (APs) in the zooplankton aggregation layer and in fish species along the continental Catalan shelf. APs in the zooplankton aggregation layer were found in 100% of the net tows. Fibres of textile origin dominated the types of AP found in the zooplankton aggregation layer (96%). APs were found ingested in all species of fish at each sampling site, with an overall ingestion occurrence of 21%, with the most abundant fragments (62%). Significant differences in ingestion occurrence were found between species and hierarchal cluster analysis identified two feeding groups, S. pilchardus , T. trachurus and P. erythrinus almost exclusively ingested fibres while T. mediterraneus , S. colias and S. cantharus almost exclusively ingested fragments. The results indicate that the ingestion of APs in the first group of species occurs through indirect ingestion, whereas, in contrast, the second group is composed of more predatory and selective feeders, possibly through accidental predation. In general, our findings indicate that the fate of APs in fish on the Catalan continental shelf depends on the combination of feeding ecology and the availability of APs in the water column. [Display omitted] • The zooplankton aggregation layer was between 25 and 64 m depth. • Fibers (96%) were dominant in the zooplankton aggregation layer. • A 5–69% occurrence of anthropogenic particles (fibers and fragments) was found in 7 pelagic fish species. • The prevalence of fragments was more common in predatory feeders and fibers in filter and generalist feeders. [ABSTRACT FROM AUTHOR]

This study investigates the risk plastic debris ingestion poses to coastal marine taxa in the Balearic Islands in the western Mediterranean Sea. Here, we use species observations and environmental data to model habitat maps for 42 species of fish. For each species, we then match estimates of habitat suitability against the spatial distribution of plastic debris to quantify plastic exposure, which we further combine with species-wise ingestion rates to map the risk of plastic ingestion. The results indicate that the risk of plastic ingestion is particularly high in the north-west and south-east regions and the risks varied strongly between species, with those at higher trophic levels being the most vulnerable overall. Extending this work to other coastal regions within the Mediterranean Sea and beyond will allow managers and policymakers to target the most appropriate areas and types of interventions for mitigating plastic pollution on coastal diversity in the marine environment. • The exposure of marine biodiversity to plastic pollution is high across all coastal areas of the Balearic Islands. • The risk of plastic ingestion is most severe in the north-western and south-eastern regions of the archipelago. • Marine species in higher trophic levels are more vulnerable to plastic ingestion. [ABSTRACT FROM AUTHOR]

During the last years, ingestion of microplastics (MPs) has been quantified in marine species both with an ecological and commercial interest at sea and under experimental conditions, highlighting the importance to assess MP ingestion in commercially and aquaculture important species such as gilthead seabream (Sparus aurata) fish. In order to study the ingestion of MPs in a commercially valuable species, gilthead seabreams were exposed to an enriched diet with virgin and weathered low-density polyethylene (LDPE) pellets for three months followed by a detoxification period of one month of no exposure to MP enriched diets. Our results indicate that MP ingestion in these fishes increased with exposure time, and differences were found between treatments, showing the highest ingestion values after three months of exposure to MP enriched diets and in the weathered treatment. However, after one month of detoxification, no MPs were found in the gastrointestinal tracts of fish, reflecting no long-term retention of MPs in Sparus aurata digestive system. According to results from this study, exposure of fish to MP enriched diets does not affect fish size neither the Fulton's condition index as both parameters increased with time in all treatments (control, virgin and weathered). Both carbon and nitrogen isotopic signatures decreased with fish size in all treatments which could be related to an increase of nitrogen deposition efficiency in fish muscle with a high protein assimilation during the first months of Sparus aurata. [Display omitted] • Highest microplastic ingestion with time of exposure and in the weathered treatment. • Fish size is not affected by microplastic ingestion during three months of exposure. • No long-term retention of microplastics in gastrointestinal tracts of Sparus aurata. • Stable isotopic signatures are not indicating differences in microplastic intake. Microplastic ingestion in Sparus aurata increases with time of exposure, with highest values in fish exposed to MP weathered enriched diets but fish size was not seen to be affected. [ABSTRACT FROM AUTHOR]

In the framework of the Plastic Busters MPAs project, a harmonization exercise on two methods of microplastic extraction from biological samples i.e. 15% H 2 O 2 digestion and 10% KOH digestion was carried out. The two methods were tested in four laboratories on fish gastrointestinal tracts and mussel tissues spiked with polyethylene, polypropylene and polyethylene terephthalate. The recovery percentage of microplastics for each method, species and polymer tested were overall similar among laboratories, and interlaboratory coefficient of variation was less than 11% for the majority of samples. Microplastic recovery rates for the two methods were similar for each sample tested, but overall mean interlaboratory recovery rate using KOH (96.67%) was higher than H 2 O 2 (88.75%). Results validate the use of both methods for extracting microplastics from biota tissues. However, when comparing the two methods in terms of microplastic recovery rate, time consumed, technical difficulties and cost, digestion with 10% KOH is considered optimal. Unlabelled Image • H 2 O 2 and KOH are effective for microplastic extraction from fish and mussel samples. • Mean interlaboratory recovery rate of microplastics using KOH is higher than H 2 O 2. • Considering microplastic recovery, time, technical issues and cost, KOH is optimal. [ABSTRACT FROM AUTHOR]

In order to have a wider understanding of the impacts of plastics on marine ecosystems, studies should approach different environmental compartments, such as seafloor and biota, at the same time. The aim of this research is to study the relation between microplastic ingestion in species and the amount of seafloor plastics caught in the same bottom trawls hauls of the western Mediterranean Sea to describe a potential overlap between these two indicators of plastic pollution. According to results, 15% of the sampled individuals ingested microplastics with a mean value of 0.30 ± 0.40 microplastics/individuals. Regarding seafloor plastics, these were present in 58% of the hauls with a mean value of 1.31 ± 0.09 kg/km2. The highest overlap between ingestion of microplastic in species and seafloor plastics was observed in the bay of Palma, the most urbanized area, but also in areas close to Marine Protected Areas (MPAs). • 15% individuals ingesting microplastics with mean value of 0.30 ± 0.40 MPs/individual • Seafloor plastics present in 58% of hauls with mean abundance of 1.31 ± 0.09 kg/km2 • In 40% hauls both MP ingestion in species and seafloor plastics were quantified • Overlap between ingestion and seafloor plastics highest in the bay of Palma [ABSTRACT FROM AUTHOR]

• The ingestion of MPs alters the behavior of the individuals. • MPs treatment groups are more active than control group. • Significant differences were found for all biomarkers except for MDA in liver. • Weathered group presented significantly higher values for CAT and SOD in brain. • Additional pollutants in MPs trigger higher physiological responses than virgin MPs. Increasing global research has identified microplastics (MPs) to be impacting marine organisms. The present work aimed at investigating the physiological and behavioral effects of thirty-six juvenile Sparus aurata exposed to control, virgin and weathered MPs enriched diets during a 21-day period under controlled conditions. Physiological effects were assessed in liver and brain using the following biomarkers: activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GRd), the detoxifying enzyme glutathione S-transferase (GST) and malondialdehyde (MDA) as indicative of lipid peroxidation. Individuals were recorded for behavior analysis (i.e. social interactions and feeding behavior). Results revealed an increase in cellular stress from control to weathered fish groups, with the virgin group showing intermediate levels in all quantified biomarkers. Significant differences were found in the liver for all biomarkers except for MDA, suggesting that exposure time to MPs in this experiment is long enough to trigger the activation of antioxidant enzymes but not to produce cell damage by lipid peroxidation. In brain tissue samples, fish from the weathered group presented significantly higher values for CAT and SOD, highlighting its function as primary antioxidants. Regarding behavioral effects, results showed that the two MPs enriched groups were significantly bolder during social interactions and, although no significantly, tended to be more active during feeding. In conclusion, MPs which have been weathered in marine environmental conditions produces a higher physiological response than virgin MPs but also, a physiological response is variable depending on the tissue analyzed. In addition, a short period to MP exposure seems to affect overall social and feeding behavior but, further research is needed to assess long-term effects of MP ingestion and its potential consequences on fish populations. [ABSTRACT FROM AUTHOR]