This study aimed to assess the maternal offloading of metals in the Brazilian guitarfishPseudobatos horkelii through determining essential (Cr, Cu, Fe) and non-essential (Cd, Hg, Pb) metal concentrations along two generations of this species: pregnant females and offspring. The maximum transfer capacity (ECER) and offspring/mother ratio were calculated to estimate the extent of offloading, as well as the proportion of contaminants presented in offspring related to the maternal concentrations. Transfer efficiency was element-dependent. Chromium had the highest ECER (99.7%), followed by Hg (67.7%). Other essential metals were less transferred (9.6–35.6%) and Cd and Pb were not detected in uterine content samples. The relationships between maternal length and concentration, as well as transfer capacity were not significant, indicating that females might be continuously exposed, and that offloading might not excrete metals efficiently. On the other hand, embryos are exposed to these elements which could impair embryonic development.

Microplastic pollution in marine environment has been a growing public concern in recent years. This article analyzed the scientific literatures related to marine microplastics through a combination of social network analysis and bibliometrics. Researches related to microplastics have grown rapidly since 2011, with approximately two-thirds of the total number of articles published in the last three years. Researchers in United States and Europe have provided tremendous support, however, the efforts and progress of Chinese researchers cannot be ignored. Moreover, the international cooperation is getting closer, and related strategies are launched continuously. The results showed that Marine Pollution Bulletin is the most active journal. Through keyword analysis, we understand the development history and current hotspots of the whole microplastics researches, including ecological risks, interrelationship between microplastics and other pollutants, and detection methodology. Finally, some suggestions and perspectives for future microplastics research are provided.

In this study, we estimated the variety and distribution of macroplastics in the central part of Spitsbergen, Svalbard archipelago, Arctic. All marine litter photos were georeferenced, then identified using the OSPAR (2010) classification guide. The majority (90% of all objects) of marine debris was macroplastic with average number in the study area being 2.0 ± 0.4 objects per 100 m. It was determined that the full variety of macroplastic categories in the study area can be found after surveying approx. 8 km of coastline. Correlation analysis showed that the amount of macroplastic accumulated on the beaches decreases with distance from the open ocean and increases with wave fetch. When zoning the entire study area on the basis of a cluster analysis of the distribution of macroplastics, it was found that the geographical proximity of the sections is less important than the wave fetch.

Microplastic (MP) contamination is a serious threat to today's marine life. Therefore, this study investigates MP ingestion in three commercial fish species (European anchovy Engraulis encrasicolus, whiting Merlangius merlangus, and red mullet Mullus barbatus) from the Turkish coast of the Black Sea. Ninety-five MPs were detected in all examined fish (371). Fiber forms were detected in the majority of cases based on the MP morphology. Polyethylene and polypropylene were the most dominant polymer type. The mean of ingested MPs was found as 0.15 ± 0.04, 0.28 ± 0.06, 0.40 ± 0.07 in anchovy, whiting and red mullet, respectively. The size of the MPs ranged from 118 μm and 4854 μm. The MP waste was detected in each species, and the highest MP amount was determined in the red mullet, which was significantly higher than European anchovy. The present study's data might be a baseline on the ecological risk assessment of MPs in the fish and future experimental studies on the fish species living in the Black Sea.

The occurrence of the protozoan parasites Toxoplasma gondii and Cyclospora cayetanensis was molecularly investigated in the hemolymph, gills, stomach, hepatopancreas and gonads of the eleven invasive Atlantic blue crab Callinectes sapidus from the Lesina Lagoon (Mediterranean Sea). Out of 11 blue crabs, 6 (54.5%) and 4 (36.4%) were found positive to T. gondii and C. cayetanenis, respectively; parasites were found only in the six females analysed, while the remaining five males resulted negative. Moreover, out of 55 tissues samples, 7 (12.7%) and 8 (14.5%) were positive to T. gondii and C. cayetanensis, respectively with hemolymph and gills being the most infected tissues. This is the first report of the presence of protozoan pathogens in wild crab species collected from a Mediterranean lagoon. The present results may provide a baseline reference on microbial infection in the species for invaded Mediterranean waters, and on the potential health risks related with its consumption if eaten raw.

To explore the impact of microplastic (MP) pollution on planktivorous fish, we examined the uptake and retention of MPs by Japanese anchovy (Engraulis japonicus) under laboratory conditions. MP uptake was size selective in adult anchovy—0.3-mm MPs were taken up in significantly larger amounts than 0.85-mm MPs—but not in juveniles. There were no significant differences in the uptake of MPs of three different colors, suggesting that anchovy do not select for MP coloration. More than 90% of the MPs were excreted within 20 h of ingestion, indicating that MP retention time is similar to the processing time of food items. Our findings suggest that Japanese anchovy tend to take up MPs that are equivalent in size to prey items, but that the impacts of MP ingestion are likely to be limited under the current state of oceanic MP contamination.

Oil emulsions can harm marine and coastal environments for extended periods. Timely identification and quantification of oil emulsions are essential for oil spill response. Although SAR is the most commonly used technique in detecting oil presence, it has limits in oil quantification. In contrast, optical remote sensing can fill this gap with more spectral bands. Hyperspectral remote sensing is capable of achieving this purpose. However, it is challenging to use multi-band coarse-resolution imagery due to the fewer bands and mixed pixel effect. Through laboratory measurements, numerical simulation, and Hue-Saturation-Value (HSV) model, we illuminate the multispectral mixed characteristics of oil emulsions and demonstrate Hue's role in characterizing the mixture features and oil concentration trends. Hue-based oil emulsion classification and oil concentration segmentation (OCS) methods are proposed and applied to Landsat-5 images under quantified uncertainties. This approach is expected to expand its application in multispectral remote sensing.

The present research aimed to investigate the concentrations and patterns of six potentially toxic elements (PTEs) in three common sponge species collected along the Moroccan Mediterranean coast, as well as their levels in ambient seawater and sediments. Distinct inter-species variability in PTEs bioaccumulation was observed among the three species, suggesting that sponges have distinct selectivity for assimilating PTEs from the surrounding environment. C. crambe had a higher enrichment capacity for Cu, As, Cr and Ni, while P. ficiformis and C. reniformis exhibited the highest concentration of Cd and Pb, respectively. Interestingly, a similar spatial distribution patterns of PTEs was observed in the three media, with high values occurring in Tangier and Al-Hoceima locations. Overall, our results confirm that sponges reliably reflect the bioavailability of PTEs in their immediate environment, especially C. crambe, whose PTE tissue contents were highly and positively correlated with the contents of all PTEs in the sediments.

Microplastics (MPs) are widely distributed in marine ecosystems, and their ubiquitous presence is raising concern, particularly about possible impacts on fisheries resources. In tropical regions, shellfish fisheries represent an essential source of income and subsistence for traditional communities, and adverse effects on these resources may have severe consequences on human health. In the present study, bivalve molluscs of the species Anomalocardia flexuosa, captured in the region of the Itapessoca estuary in Pernambuco, Brazil, were analysed. A total of 90% of the individuals presented MP particles in their tissue. We observed an average of 5.15 ± 3.80 MP particles per individual, and for each gram of soft tissue, 3.66 ± 2.59 MP particles were found. Our results showed that MPs are present in clams captured on the Pernambuco coast and that the species studied proved to be suitable for monitoring the levels of microplastic pollution.

Total mercury (THg) concentrations were measured in muscle and liver of two placental viviparous sharks, the Pacific sharpnose shark (Rhizoprionodon longurio) and the brown smooth-hound (Mustelus henlei); as well as in the muscle, liver, and yolk of the yolk-sac viviparous speckled guitarfish (Pseudobatos glaucostigmus) in Baja California Sur. The aim was to determine which factors could be involved in maternal transfer and resultant maternal and embryonic THg concentration. Higher THg concentrations were found in pregnant females compared to embryos paired tissues. THg concentrations of embryo tissues decreased with total length (TL), except for the muscle of the Pacific sharpnose shark. THg concentrations of embryo muscle was positively related to THg concentration in the muscle of pregnant females. Embryos TL, muscle THg concentration of pregnant females, percentage of THg concentration in embryos, along with the reproductive strategy are relevant factors required to improve our understanding of THg concentration in embryo tissues.