First record of microplastics ingestion by European hake MERLUCCIUS MERLUCCIUS from the Tyrrhenian Sicilian coast (Central Mediterranean Sea)

Microplastic contamination and biological alterations in Atlantic wild fish populations, and human health risks associated to fillet consumption

This study tested the hypothesis that long-term exposure to microplastics (MPs) is causing biological alterations in North Atlantic wild populations of Trisopterus luscus (pouting) and Merluccius merluccius (hake). It also estimated the human risk of MP intake (HRI) through fillet consumption, and combined the HRI and polymer health hazard in the Risk of Intake and Polymer Hazard Index (RIPHI). Fish (103) were analysed for MPs (gastrointestinal tract, gills, liver, brain, muscle), biomarkers (physical condition, neurotoxicity, energy production, oxidative stress and damage) and general stress (Integrated Biomarker Response - IBR). After particle analysis (Fourier Transform Infrared spectroscopy, Raman spectroscopy) and data correction for contamination, MPs accounted for 77 % of 311 particles. From 103 fish, 79 % contained MPs. The overall mean concentration ±SD was 0.09 ± 0.09 MP g-1 (2.32 ± 2.35 MPs ind-1) with no significant interspecific differences (p > 0.05). Among body sites, brain had the highest MP concentration (pouting: 0.6 MP g-1; hake: 0.5 MP g-1). Most abundant polymers were polyethylene (40 %), polypropylene (21 %) and polymethyl methacrylate (12 %). Fragments (<150 μm) predominated. MP profiles pointed to prey-predator transfer. Fish with MPs had higher stress levels (IBR, pouting: 0.317; hake: 0.200) than specimens without MPs (pouting: 0.0; hake: 0.062). Oxidative stress was the effect most clearly linked to MPs. Hake fillet poses lower HRI (e.g., 0.2 to 1.5 MPs day-1) than pouting fillet (e.g., 0.4 to 3.0 MPs day-1). RIPHI values showed the opposite trend (e.g., hake: 138 to 1038; pouting: 113 to 845), indicating medium to high risk to human consumers. Findings related long-term MPs exposure in the natural habitat with biological alterations in wild fish populations, highlight the importance of food diversification for a healthy alimentation, and stress the urgent need of reducing MPs pollution to promote ecosystem sustainability and global health.

Detection of fibrous microplastics and natural microfibers in fish species (Engraulis encrasicolus, Mullus barbatus and Merluccius merluccius) for human consumption from the Tyrrhenian sea

The occurrence of natural/artificial and synthetic microfibers was assessed in three commercial fish species (Engraulis encrasicolus, Mullus barbatus, Merluccius merluccius) from the Tyrrhenian Sea sold for human consumption. The gastrointestinal tracts of n. 150 samples were analyzed, the isolated microfibers were classified applying a morphological approach, based on the analysis of their morphological features, coupled with the identification of the chemical composition of a subsample of microfibers. All the species contained microfibers at levels ranging from 0 to 49 items/individual and the number of ingested microfibers significantly differed between pelagic and demersal fishes. The evaluation of fiber morphologies highlighted that natural/artificial microfibers were the most numerous among the isolated microfibers, while the dominant colors were blue, black, and clear in all the species. Chemical characterization confirmed the morphological identification and indicated cellulose and polyester as the most common polymer types. Considering the analytical issues that may affect the evaluation of microfiber pollution, the results pointed out the importance of an accurate morphological approach that allows the distinction between different fiber types, before the spectroscopic analyses. Moreover, the implementation of fast and accessible methods to identify microfibers in fish species intended for human consumption will be beneficial also to make an adequate risk assessment to consumer health.

Does the microplastics ingestion patterns and polymer composition vary across the oceanic zones? A case study from the Indian coast

This study explores microplastic (MP) presence in the gastrointestinal tracts of deep-sea fish from the Central Indian Ocean, off the Indian coast. Among the 27 species examined, 19 showed MP contamination, averaging 2.68 ± 0.30 (±SE) MPs per individual. Polymer analysis via FTIR and micro-Raman identified several types, including polyethylene terephthalate (PET), polyvinyl alcohol (PVA), polypropelene (PP), polyvinyl acetate (PVC), polyurethane (PU), polytetrafluoroethylene (PTFE), polyaniline (PANI), polymethyl methacrylate (PMMA), and polyethersulfone (PES), with PET being the most prevalent (33.33 %). MP ingestion was higher in benthopelagic fish and those at higher trophic levels, as indicated by comparisons across oceanic zones. Niche partitioning analysis suggests feeding behaviour as a primary influencer of MP ingestion in deep-sea fish rather than habitat or trophic level. The study proposes the potential use of deep-sea fish as indicators for assessing microplastic pollution across oceanic zones and deep-sea regions through bycatch monitoring.

A study on textile microfiber contamination in the gastrointestinal tracts of Merluccius merluccius samples from the Tyrrhenian Sea

The increased demand and consumption of synthetic textiles have contributed to microplastic pollution in the form of microfibers. These particles are widely spread in the aquatic environment, leading to the exposure of marine biota, including edible species. The current study aimed to assess the extent of microfiber contamination in a commercially relevant fish species, Merluccius merluccius, which is considered a small-scale bioindicator for the monitoring of plastic ingestion in the Mediterranean coastal environment. The frequency of ingestion, abundance, and composition of textile microfibers isolated from the fish gut were characterized. Results showed the occurrence of microfibers in 75% of the samples, with a mean number of 10.6 microfibers/individual, of which 70% were classified as natural microfibers. The spectroscopic analyses confirmed both the visual identification of microfibers and the prevalence of cellulosic fibers. The obtained findings provided evidence of both natural/artificial and synthetic microfiber exposure in an important commercial fish species that, considering the consumption of small individuals without being eviscerated, may be a potential route of microfiber exposure in humans. Monitoring programs for fishery products from markets are needed to assess contamination levels and human health risks. In addition, measures to control microfiber pollution need to occur at multiple levels, from textile industries to international governments.

Impacts of microplastic on fisheries and seafood security - Global analysis and synthesis

This review paper collected, collated, analysed, interpreted, synthesised, and documented the research investigations conducted on microplastic (MPs) pollution impacts on seafood organisms (including fish, sharks, shrimps, lobsters, crabs, oysters, mussels, and seaweeds) during the last ten years (2012-2022) covering fifty-seven locations/countries in the world. MPs contaminated 926 seafood species comprising 895 finfish, 09 crustaceans, 20 molluscs and 02 seaweeds. Seafood from Asia was found to be most contaminated with MPs. High MP contamination/ingestion was revealed in several seafood organisms. The ingestion of MPs can reduce fish growth and fish fitness, leading to reduced yield/fish production. Fish and seafood play a significant role in supporting the economy, employment, food sources, and livelihoods of people across the globe, which can be threatened due to the contamination of seafood organisms with MPs. MPs have bioaccumulated in fish skin, gills, stomachs, liver, intestine, and muscles as well as dry fish and canned fish. Hence, the consumption of MP-contaminated fresh fish, whole fish, dried fish or canned fish poses risks as it may be a pathway of MP transfer to humans. MPs can increase the health risks to seafood fish consumers since there is a probability that high risks pollutants adsorbed on MPs (heavy metals, pesticides, and oil compounds) can transfer to humans via the food chain. Several of the chemicals (heavy metals, DDT, PAHs) adsorbed onto MPs are carcinogenic. MPs have also been detected in fish meals, therefore, farmed livestock such as aquaculture fish and chicken fed to fish meals can be exposed to MPs and ultimately to humans. Preventive and safety measures are suggested to reduce the exposure of MPs to humans. In addition, several policy strategies are recommended to reduce the impacts of plastic waste and plastic pollution on the environment, aquatic biota, wildlife, seafood and human health.

Application of Pattern Recognition and Computer Vision Tools to Improve the Morphological Analysis of Microplastic Items in Biological Samples

Since, in many routine analytical laboratories, a stereomicroscope coupled with a digital camera is not equipped with advanced software enabling automatic detection of features of observed objects, in the present study, a procedure of feature detection using open-source software was proposed and validated. Within the framework of applying microscopic expertise coupled with image analysis, a set of digital images of microplastic (MP) items identified in organs of fish was used to determine shape descriptors (such as length, width, item area, etc.). The edge points required to compute shape characteristics were set manually in digital images acquired by the camera coupled with a binocular, and respective values were computed via the use of built-in MotiConnect software. As an alternative, a new approach consisting of digital image thresholding, binarization, the use of connected-component labeling, and the computation of shape descriptors on a pixel level via using the functions available in an OpenCV library or self-written in C++ was proposed. Overall, 74.4% of the images were suitable for thresholding without any additional pretreatment. A significant correlation was obtained between the shape descriptors computed by the software and computed using the proposed approach. The range of correlation coefficients at a very high level of significance, according to the pair of correlated measures, was higher than 0.69. The length of fibers can be satisfactorily approximated using a value of half the length of the outer perimeter (r higher than 0.75). Compactness and circularity significantly differ for particles and fibers.

High microplastics concentration in liver is negatively associated with condition factor in the Benguela hake Merluccius polli

Microplastics (MPs) affect both marine and terrestrial biota worldwide for their harmful effects, which range from physical cell damage to physiological deterioration. In this research, microplastics were quantified from gills, liver and muscle of demersal Benguela hakes Merluccius polli (n = 94), caught by commercial trawling from northwest African waters. Plastic polymers were identified using Fourier Transformed-infraRed spectroscopy (FT-iR). Fulton's k condition factor and the degree of DNA degradation in liver were measured. None of the individuals were free of MPs, whose concentration ranged from 0.18 particles/g in muscle to 0.6 in liver. Four hazardous polymers were identified: 2-ethoxyethylmethacrylate, polyester, polyethylene terephthalate, and poly-acrylics. MP concentration in liver was correlated negatively with the condition factor, suggesting physiological damage. Positive association of MP concentration and liver DNA degradation was explained from cell breakage during trawl hauls during decompression, suggesting an additional way of MPs harm in organisms inhabiting at great depth. This is the first report of potential MPs-driven damage in this species; more studies are recommended to understand the impact of MP pollution on demersal species.

Microplastics in Sepia officinalis caught on the central Adriatic coast: preliminary results

Microplastics (μPs) represent an emerging problem for the marine environment given their wide bioavailability for all aquatic organisms, from zooplankton to top predators. This work aimed to evaluate a method of extracting microplastics from the gastrointestinal tract of 122 Sepia officinalis caught from the Adriatic Sea (along Abruzzo region coasts) to measure its quantity in a poorly investigated species. The extraction method used for gastrointestinal content was performed using 10% potassium hydroxide. In 98/122 (80.32-95% CI=73.27-87.37%) wild animals microplastics were detected with a mean concentration of 6.82±5.52 μPs/subject. Among the fragments, as supported by various authors, those of black color were the most represented ones; however, also blue fibers and transparent spheres were isolated. This study, in agreement with previous ones, poses further attention to the wide microplastic diffusion in the marine environment (surface, columns, sediments, and animals). The obtained results provide the basis for future investigations on this public health concern.

Revealing the capability of the European hake to cope with micro-litter environmental exposure and its inferred potential health impact in the NW Mediterranean Sea

Prevalence, abundance, concentration, size and composition of anthropogenic items (AIs) (synthetic and non-synthetic) ingested by Merluccius merluccius juvenile specimens and from near-bottom water samples from different localities off the Catalan coast (NW Mediterranean), were characterized. The potential effect of AIs on fish condition was assessed through different health indicators. Virtually all AIs found in fish and near-bottom water samples were fibres. A mean of 0.85 fibres/m³ from the surrounding water was observed. Fish ingested a mean of 1.39 (SD = 1.39) items/individual. Cellulosic fibres were predominant (77.8% of samples), except for Barcelona. No differences in ingested AIs abundance and composition off Barcelona between 2007 and 2019 were found. Small AIs from the environment matched ingested AIs composition. Hakes did not ingest large fibres despite being present in the environment, probably due to their feeding behaviour. No adverse health effects or parasites aggregations were detected to be potentially related to AIs ingestion.

Occurrence of nano/microplastics from wild and farmed edible species. Potential effects of exposure on human health

The occurrence of nano/microplastics (N/MPs) has become a global concern due to their risk on the aquatic environment, food webs and ecosystems, thus, potentially affecting human health. This chapter focuses on the most recent evidence about the occurrence of N/MPs in the most consumed wild and farmed edible species, the occurrence of N/MPs in humans, the potential impact of N/MPs on human health as well as future research recommendations for assessing N/MPs in wild and farmed edible species. Additionally, the N/MP particles in human biological samples, which include the standardization of methods for collection, characterization, and analysis of N/MPs that might allow evaluating the potential risk of the intake of N/MPs in human health, are discussed. Thus, the chapter consequently includes relevant information about the content of N/MPs of more than 60 edible species such as algae, sea cucumber, mussels, squids, crayfish, crabs, clams, and fishes.

Microbial engineering strategies for synthetic microplastics clean up: A review on recent approaches

Microplastics are the small fragments of the plastic molecules which find their applications in various routine products such as beauty products. Later, it was realized that it has several toxic effects on marine and terrestrial organisms. This review is an approach in understanding the microplastics, their origin, dispersal in the aquatic system, their biodegradation and factors affecting biodegradation. In addition, the paper discusses the major engineering approaches applied in microbial biotechnology. Specifically, it reviews microbial genetic engineering, such as PET-ase engineering, MHET-ase engineering, and immobilization approaches. Moreover, the major challenges associated with the plastic removal are presented by evaluating the recent reports available.

Detection of microplastic fibers tangle in deep-water rose shrimp (Parapenaeus longirostris, Lucas, 1846) in the northeastern Mediterranean Sea

Microplastic (MP) pollution in marine environments has been a major global concern in recent years. Microplastic particles pose a threat in aquatic animals by accumulating in their digestive system, acting like a pollution vector, and they can also transfer to upper trophic levels. For that reason, commercially important deep-water rose shrimp Parapenaeus longirostris were employed in this study to examine the MP pollution status of two different regions (Samandağ and Mersin offshore waters) of the northeastern Mediterranean Sea. MPs were detected in all examined specimens (average of 18.8 MPs ind-1), and fiber tangle-shaped like balls were observed by 22% and 9% at Samandağ and Mersin, respectively. P. longirostris individuals from Samandağ showed higher occurrence (100%) and higher accumulation (29.7 ± 24.4 MPs ind-1). MP abundance extracted from the shrimp individuals from Samandağ region was higher than that of previously reported shrimp species. The majority of extracted microplastics were fiber (100%), black (46%) in color and 1-2.5 mm in size. Polyethylene was identified as the most common polymer type by Fourier transform infrared spectroscopy (FTIR). This study is the first report to evaluate microplastic occurrence and fiber tangles in P. longirostris from northeastern Mediterranean Sea. Results obtained in this study will enhance the understanding of MP pollution among different trophic levels.

Is Wild Marine Biota Affected by Microplastics?

The present review provides detailed information on the adverse effects of MPs on wild marine organisms, including tissue damage, fish condition, oxidative stress, immune toxicity, and genotoxicity. A bibliometric analysis was carried out on CiteSpace (version 6.1.R3) (Drexel University, Philadelphia, PA, USA) to verify how many papers studied the effects on wild marine species. The results showed a total of 395 articles, but only 22 really presented data on the effects or impacts on marine biota, and of these, only 12 articles highlighted negative effects. This review shows that the observed effects in wild organisms were less severe and milder than those found in the experimental conditions. The knowledge of negative effects caused by direct ingestion of microplastics in wild animals is still limited; more efforts are necessary to fully understand the role of MPs and the adverse effects on wild marine organisms, the ecosystem, and human health.

Microplastics in fish and sediments from the Montenegrin coast (Adriatic Sea): Similarities in accumulation

The accumulation of microplastics (MPs) in the biotic and abiotic components of the marine environment poses a major threat to marine ecosystems worldwide. The objective of this study was to document, for the first time, differences in MP accumulation in the gastrointestinal tract of two commercially important fish species and to evaluate the possible correlation between MP accumulation in the biotic (fish) and abiotic (sediment) components of the marine environment of the Montenegrin coast (Adriatic Sea). Samples were collected from two areas of the Montenegrin coast, Boka Kotorska Bay and the coastal part of the open sea. The frequency of MP ingestion was 58.6 % for Mullus barbatus and 54 % for Merluccius merluccius, while the average number of ingested MPs was 2.9 ± 0.5 and 3.2 ± 1.0 items/individual, respectively. Average MP abundance in surface sediments from Boka Kotorska Bay and the coastal part of the open sea was 315 ± 45 and 435 ± 258 MPs/kg of dry sediment, respectively. Most MPs identified were filaments, followed by fragments and films, while the most abundant polymers found in fish and sediments samples were polypropylene and polyethylene. The present results indicate that MP pollution in the study area is reflected in the accumulation of MPs in the biotic (fish) and abiotic (sediment) components of the marine environment. Measures need to be taken to reduce the input of plastics/MPs into the marine environment.

Anthropogenic pollutants in Nephrops norvegicus (Linnaeus, 1758) from the NW Mediterranean Sea: Uptake assessment and potential impact on health

Anthropogenic pollution is considered one of the main threats to the marine environment, and there is an imperious need to assess its potential impact on ecologically and economically relevant species. This study characterises plastic ingestion and tissue levels of potentially toxic metallic elements in Nephrops norvegicus and their simultaneous levels in abiotic compartments from three locations of the Catalan coast (NW Mediterranean Sea). A multidisciplinary assessment of the health condition of N. norvegicus through condition indices, enzymatic biomarkers and histological techniques is provided, and its relationship with anthropogenic pollutant levels explored. Plastic fibres were commonly found in stomachs of N. norvegicus (85% of the individuals), with higher abundances (13 ± 21 fibres · ind^-1) in specimens captured close to Barcelona. The presence of long synthetic fibres in near-bottom waters, as well as the mirroring trends in abundance among locations for water and ingested plastics, suggest that uptake from water may be occurring potentially through suspension feeding. The spatial variability in the levels of metallic elements in N. norvegicus was poorly correlated to the variability in sediments. In any case, present levels in abdominal muscle are considered safe for human consumption. Levels of ingested plastics only showed significant, yet weak, correlations with glutathione S-transferase and catalase activities. However, no other health parameter analysed showed any trend potentially associated to anthropogenic pollutant levels. Neither the condition indices nor the histopathological assessment evidenced any signs of pathologic conditions affecting N. norvegicus. Thus, it was concluded that presently there is no evidence of a negative impact of the studied pollutants on the health condition of N. norvegicus in the studied grounds.

Microplastics in seawater and marine organisms: Site-specific variations over two-year study in Giglio Island (North Tyrrhenian Sea)

Geographical and temporal differences of microplastic occurrence were documented in water and fish collected in 2017 and 2019 from the Giglio Island (North Tyrrhenian Sea) close to the area where the Costa Concordia sank in January 2012. Results on water samples showed a site-dependent difference, suggesting the role of surface current dynamics in the microplastic local distribution, while tested Neuston nets (200 μm and 330 μm mesh size) did not influence microplastic retention efficiency. Fish exhibited in 2019 a higher frequency of specimens positive to microplastic ingestion with respect to 2017, with an occurrence higher than those typically observed in other Mediterranean areas. Both in water and fish, fragments were the dominating shape, polypropylene and polyethylene were the prevalent polymers, without particular difference between sites and years. This study highlights the importance of applying microplastic investigation in biotic and abiotic matrices for an effective monitoring of this pollution in the marine environment.

Embryotoxicity of Polystyrene Microspheres of Different Sizes to the Marine Medaka Oryzias melastigma (McClelland, 1839)

Polystyrene microplastics (PS-MPs) are potentially harmful to marine organisms, especially during the early developmental stages, although the underlying mechanism remains unclear. The present study evaluated the growth and morphological characteristics of marine medaka Oryzias melastigma (McClelland, 1839) embryos exposed to PS-MP. PS-MPs of three different sizes (0.05, 0.5, and 6.0 μm with a concentration of 106 particles/L) were subjected to waterborne exposure for 19 d. The hatching time and rate of embryos exposed to 0.5 and 6.0 μm PS-MPs were significantly lower than those of the control, while no significant difference was observed in the 0.05 μm treatment. No significant differences were observed in the mortality rate of the embryos, embryo diameter, and relevant gene expression levels, including il6, il8, il-1β, jak, stat-3, nf-κb, hif-1α, epo, cyp1a1, ahr, sod, cat, and gpx, but with the exception of vtg. Fluorescent PS-MPs were found on the embryo surfaces when the embryos were exposed to 0.5 and 6.0 μm PS-MPs, but no signals were detected inside embryos using confocal microscopy. Therefore, the results indicate that PS-MPs having a diameter of 6.0 μm can only attach to the surface or villus of embryos and not enter the embryos through the membrane pores, whereas PS-MPs with diameters of 0.05 and 0.5 μm cannot enter the embryos.

Microplastic occurrence in the gastrointestinal tract and gill of bioindicator fish species in the northeastern Mediterranean

Microplastic pollution is an extremely emerging problem and its potential threats to the aquatic organisms were investigated worldwide. In this study, four different commercial fish species (Mullus barbatus (Linnaeus, 1758), Mullus surmuletus (Linnaeus, 1758), Mugil cephalus (Linnaeus, 1758), Saurida undosquamis (Richardson, 1848)) were used as a bioindicator to assess the microplastic pollution in the northeastern Mediterranean. The frequency of occurrence in the gastrointestinal tract (GIT) and gill was varied between 66-100% and 68-90%, respectively. The highest microplastic abundance was detected at the GIT of M. cephalus sampled from Asi River estuary. The majority of extracted microplastics were fiber, black in color and less than 1 mm in size. Fourier Transform Infrared Spectroscopy (FTIR) indicated the most common polymer type as polyethylene. This study is the first study examining the microplastic existence in gill and results obtained in this study improve the knowledge about the relationship of microplastic ingestion in fish and environmental conditions in the Northeastern Mediterranean Sea.

First evidence of in vitro cytotoxic effects of marine microlitter on Merluccius merluccius and Mullus barbatus, two Mediterranean commercial fish species

Marine litter is composed mainly of plastics and is recognized as a serious threat to marine ecosystems. Ecotoxicological approaches have started elucidating the potential severity of microplastics (MPs) in controlled laboratory studies with pristine materials but no information exists on marine environmental microlitter as a whole. Here, we characterized the litter in the coastal Northern Tyrrhenian sea and in the stomach of two fish species of socio-economic importance, and exposed primary cell cultures of mucosal and lymphoid organs to marine microlitter for evaluating possible cytotoxic effects. An average of 0.30 ± 0.02 microlitter items m^-3 was found in water samples. μFT-IR analysis revealed that plastic particles, namely HDPE, polyamide and polypropylene were present in 100% and 83.3% of Merluccius merluccius and Mullus barbatus analyzed, which overall ingested 14.67 ± 4.10 and 5.50 ± 1.97 items/individual, respectively. Moreover, microlitter was confirmed as a vector of microorganisms. Lastly, the apical end-point of viability was found to be significantly reduced in splenic cells exposed in vitro to two microlitter conditions. Considering the role of the spleen in the mounting of adaptive immune responses, our results warrant more in-depth investigations for clarifying the actual susceptibility of these two species to anthropogenic microlitter.

Occurrence of microplastics in the gastrointestinal tract of benthic by-catches from an eastern Mediterranean deep-sea environment

Concern about microplastic pollution little is known about levels in deep-sea species; to fill this knowledge gap, levels of microplastics in the gastrointestinal (GI) tracts of 34 fish from eight different deep-sea by-catches: blackmouth catshark, lesser spotted dogfish, and velvet belly, armless snake eel, hollowsnout grenadier, phaeton dragonet, royal flagfin, and slender snipe eel were measured. All were collected at the same site (east Sardinia, Mediterranean Sea; 40°10'12.49″N, 9°44'12.31″E) using a bottom gillnet at depths between -820/250 and -1148 ft./350 m. Microplastics (MPs) were retrieved in 16 out of 34 fish. At least one microplastic item was found in 48% (33%, E. spinax - 75%, G. melastomus) of the samples. The most frequent was polyethylene (PE), with nine items (filaments, films, fragments) found in five specimens. This preliminary study of by-catches adds new data on MPs ingestion by species inhabiting a deep-sea environment of the Mediterranean.

Microplastic contamination of fish gills and the assessment of both quality assurance and quality control during laboratory analyses

Microplastic pollution has received substantial international attention in terrestrial and marine environments and in the atmosphere. In this study, we assessed microplastic pollution and analyzed the accumulation of microplastics in the gills of fish caught in the Zhoushan fishing ground from September 2017 to March 2018. The average abundance of microplastics was 0.49 ± 0.54 particles/gill and frequently found chemical polymers was polyethylene terephthalate. We also conducted experiments on microplastic pollution in the water and the working solutions used during the analytical process and found that the source of microplastic contamination was the solutions used. Moreover, we evaluated and scored experimental quality control and quality assurance adapted from the 'Total Accumulated Score' method. Valuable steps are recommended in order to produce reliable results and improve the quality of results in microplastic analyses.

Walleye Pollock Gadus chalcogrammus, a Species with Continuous Range from the Norwegian Sea to Korea, Japan, and California: New Records from the Siberian Arctic

The first records of walleye pollock Gadus chalcogrammus Pallas, 1814 in the seas of the Siberian Arctic (the Laptev Sea, the Kara Sea, the southeastern Barents Sea), are documented. Information about the external morphology (morphometric and meristic characters), photos of sagittal otoliths and fish, and data on the sequences of the CO1 mtDNA gene are presented. The results of a comparative analysis indicate that walleye pollock caught in the Siberian Arctic do not differ in principle from North Pacific and North Atlantic individuals. Previous conclusions about the conspecificity of the walleye and Norwegian pollock Theragra finnmarchica are confirmed. New captures of walleye pollock in the Siberian Arctic allow us to formulate a hypothesis about its continuous species’ range from the coasts of Norway in the North Atlantic to the coasts of Korea, Japan, and California in the North Pacific. The few records of walleye pollock in the North Atlantic originate from the North Pacific due to the transport of early pelagic juveniles to the Arctic by currents through the Bering Strait and further active westward migrations of individuals which have switched to the bentho-pelagic mode of life.

The Influence of Polystyrene Microspheres Abundance on Development and Feeding Behavior of Artemia salina (Linnaeus, 1758)

In the present study, it has been evaluated how 10 µm of polyethylene microspheres can be ingested by Artemia salina (Linnaeus, 1758) larvae within the first 7 days of the life cycle, and the impact on their health. Twelve A. salina larvae (instar I) groups were exposed to different microplastics (MPs) concentrations (0-1-10-102-103-104 MPs/mL), with and without Dunaliella salina as a food source. The results highlighted that A. salina larvae ingest MPs in relation to the exposure times in a dose-dependent manner and are significantly influenced by food availability. The highest contamination found was 306.2 MPs/individual at 104 MPs/mL exposure without a food source. No MPs were found in the presence of the food source from 1 to 102 MPs/mL, while contamination was detected at all concentrations of MPs without a food source. The worst effect on the developmental stages was evaluated at 168 h with a food source, with a delay compared to the control of I and II instars at 103 and 104 MPs/mL, respectively. Furthermore, microalgal feeding was significantly reduced for about 50% in the presence of 104 MPs/mL. These results highlight that aquatic microplastics pollution could affect the A. salina’s feeding behavior and life cycle.

Comparative Analysis of Neurotoxicity of Six Phthalates in Zebrafish Embryos

The effects and underlying mechanisms of phthalates on neurotoxicity remain unclear as compared with the potentials of these substances as endocrine disruptors. The locomotor activities of zebrafish embryos were investigated upon exposure to six phthalates: dimethyl phthalate (DMP), diethyl phthalate (DEP), benzyl butyl phthalate (BBzP), di-2-ethylhexyl phthalate (DEHP), di-n-octyl phthalate (DnOP), and diisononyl phthalate (DiNP). Moreover, changes in fluorescence intensity in the green fluorescent protein (GFP) transgenic (Tg) lines Tg(HuC:eGFP), Tg(sox10:eGFP), and Tg(mbp:GFP) were measured after exposure to six phthalates, and changes in the expression profiles of genes involved in the cholinergic (ache) and dopaminergic systems (dat, th, and drd1b) were assessed. Exposure to BBzP, DEHP, and DiNP affected larval behaviors, whereas exposure to DMP, DEP, and DnOP revealed no alterations. A reduced expression of Tg(HuC:eGFP) was observed upon exposure to BBzP, DEHP, and DiNP. The expression of Tg(sox10:eGFP) and Tg(mbp:GFP) was reduced only in response to BBzP and DiNP, respectively. Further, exposure to DiNP upregulated ache and drd1b. The upregulation of ache and downregulation of drd1b was observed in DEHP-exposed groups. Exposure to BBzP suppressed th expression. These observations indicate that exposure to phthalates impaired embryogenesis of the neurological system and neurochemicals in zebrafish embryos, although the detailed mechanisms varied among the individual phthalates. Further mechanistic studies are needed to better understand the causality between phthalate exposure and neurotoxicity.

Testicular leiomyoma and spermatogenic failure syndrome in a seabass from broodstock

Testicular leiomyomas and gonadal dysfunctions are not commonly reported in teleost and particularly in broodstock fish. In the present work, a testicular leiomyoma related to an unusual case of spermatogenic failure syndrome, in a broodstock seabass coming from an Italian aquaculture farm, is reported. At gross pathology, the circumscribed neoplasia showed several white nodular masses, originating from the gonad, deforming the anatomo-physiological shape. From light microscopy, the presence of neoplastic tissue islands with spindle cells with a whirling pattern and the low presence of connective tissue were evident and originated from smooth muscle cells. Seminiferous tubules showed severe azoospermia with the absence of sperm cells even closer to the neoplastic area. Immunohistochemical analysis was positive for alpha-SMA, desmin and vimentin but negative for S-100, confirming a diagnosis of leiomyoma. This is the first report of spermatogenic failure syndrome associated with a testicular leiomyoma in fish from broodstock. More efforts should be made in studying broodstock fish pathologies related to fish maintenance and hormonal treatments that could economically affect aquaculture production.

Plastics occurrence in juveniles of Engraulis encrasicolus and Sardina pilchardus in the Southern Tyrrhenian Sea

We report the presence of microplastics on the external surface and in the gastrointestinal tract of white late-larval and juvenile stages (fry) of clupeid fishes caught in the Southern Tyrrhenian Sea. The average highest number of plastics debris was recorded on Sardina pilchardus (0.53 items/specimen); a lower average number of items was observed for Engraulis encrasicolus (0.26 items/specimen). The plastics were characterized by fibers that differed in shape, colour and composition. Polyester, polypropylene, polyacrylonitrile, polyethylene, polyamide, nylon, rayon and polyurethane segments were detected by Raman and FTIR spectroscopies. Traces of organic components and dyes, compounds that are generally included in the polymer matrix to modify its base properties, were also identified on microplastics. Our results raise concerns for the potential transfer of synthetic materials through the marine food web and into humans, given the prominent role of S. pilchardus and E. encrasicolus within the food web as main food source for many marine species.

Gastric leiomyoma in a sea bass Dicentrarchus labrax broodfish

This report describes a spontaneously arising non-infiltrative neoplasm of gastric tunica muscularis in a broodstock sea bass Dicentrarchus labrax from an Italian aquaculture farm. Microscopically, the mass was circumscribed and non-encapsulated and was composed of spindle cells arranged in parallel interlacing bundles or, occasionally, a whirling pattern. Cells had a small quantity of eosinophilic cytoplasm with distinct cell borders. Neoplastic cells were immuno-reactive with smooth muscle actin, vimentin and desmin; S100 was negative. The mucosal epithelium was intact with no neoplastic involvement. A gastric leiomyoma was diagnosed based on the findings. More efforts should be made to study the possible etiology of leiomyoma affecting fish from aquaculture.

Quali-quantitative analysis of plastics and synthetic microfibers found in demersal species from Southern Tyrrhenian Sea (Central Mediterranean)

This study highlights plastics occurrence in five demersal fish species from the Southern Tyrrhenian Sea: the Red mullet Mullus barbatus barbatus, the Piper gurnard Trigla lyra, the Blackmouth catshark Galeus melastomus, the Lesser spotted dogfish Scyliorhinus canicula and the Brown ray Raja miraletus. Overall, 125 fish were examined: 21 Red mullets, 16 Piper gurnards, 75 Blackmouth catsharks, 72 Dogfish and 1 Brown ray. The percentage of fish with ingested plastics was 14.4% with 0.24 items per specimen. The majority of the debris were fibers and the application of infrared and Raman spectroscopy allowed the identification and discrimination of plastic and non-plastic fibers. The plastic debris isolated were mainly microplastics (94.1%), while macroplastics occurrence was very low (5.9%). The plastics were identified as polypropylene, Teflon, nylon, kraton G (triblock copolymer) and polyethylene. Also cellulose was detected. S. canicula was the species with the highest number of plastic pollutants.

Detection of artificial cellulose microfibers in Boops boops from the northern coasts of Sicily (Central Mediterranean)

Pollution deriving from textile wastes, including industrial and household waste, is recently of great interest due to their environmental impacts. Anthropogenic and synthetic fibers are responsible for negative effects on the quality of water and soil, and, also, their presence damages plant and animal health. In this work, the authors revealed the occurrence of man-made cellulose fibers in specimens of Boops boops from the Northern Sicilian coasts. Bogue was chosen as target species as it has been used as an indicator within the European Marine Strategy Framework Directive (MSFD 2008/56/EC) in order to value the "microplastics status" in the stomach contents. Of the 30 specimens examined, 63.3% of these had ingested fibers items. The number of fibers ranged from 1 to 10 per specimens with an average of 2.7 items/specimen. Fibers length ranged from 0.5 to 30 mm, most of them were black (95%), and a small percentage was red (5%). The ingestion of man-made cellulose fibers, observed for the first time, in Boops boops in the Mediterranean Sea wake-up call and it should attract the attention of the EU for new guidelines where this new type of contaminant is classified harmful as well as plastics.

Plastics occurrence in the gastrointestinal tract of Zeus faber and Lepidopus caudatus from the Tyrrhenian Sea

The present study investigates the occurrence of plastic pollution in two commercially important marine teleosts (Zeus faber and Lepidopus caudatus) from the northern coasts of Sicily (Tyrrhenian Sea). Plastics occurrence in the gastrointestinal tract was higher in Lepidopus caudatus (78.1%) than Zeus faber (51.4%). Debris characterization, carried out by micro-Raman spectroscopy, allowed identified the main types of found polymers as: polypropylene (PP), polyamide (PA), nylon and, to a lesser extent, polyethylene (PE). Of the two fish species studied, the silver scabbardfish appeared to be the more vulnerable to plastic ingestion. Our study represents a starting point that may pave the way for future investigation of the fate, accumulation and transfer of plastic debris to upper trophic levels, to verify their potential toxicity and to better understand strategies to mitigate this phenomenon.