The rapid, global spread of COVID-19, and the measures intended to limit or slow its propagation, are having major impacts on diverse sectors of society. Notably, these impacts are occurring in the context of other anthropogenic-driven threats including global climate change. Both anthropogenic stressors and the COVID-19 pandemic represent significant economic challenges to aquaculture systems across the globe, threatening the supply chain of one of the most important sources of animal protein, with potential disproportionate impacts on vulnerable communities. A web survey was conducted in 47 countries in the midst of the COVID-19 pandemic to assess how aquaculture activities have been affected by the pandemic, and to explore how these impacts compare to those from climate change. A positive correlation between the effects of the two categories of drivers was detected, but analysis suggests that the pandemic and the anthropogenic stressors affect different parts of the supply chain. The immediate measurable reported losses varied with aquaculture typology (land vs. marine, and intensive vs. extensive). A comparably lower impact on farmers reporting the use of integrated multitrophic aquaculture (IMTA) methods suggests that IMTA might enhance resilience to multiple stressors by providing different market options under the COVID-19 pandemic. Results emphasize the importance of assessing detrimental effects of COVID-19 under a multiple stressor lens, focusing on areas that have already locally experienced economic loss due to anthropogenic stressors in the last decade. Holistic policies that simultaneously address other ongoing anthropogenic stressors, rather than focusing solely on the acute impacts of COVID-19, are needed to maximize the long-term resilience of the aquaculture sector.

Anthropogenic litter, such as plastic, is investigated by the global scientific community from various fields employing diverse techniques. The goal is to assess and finally mitigate the pollutants' impacts on the natural environment. Plastic litter can accumulate in different matrices of aquatic and terrestrial ecosystems, impacting both biota and ecosystem functioning. Detection and quantification of macroplastics, and other litter, can be realized by jointly using visual census and remote sensing techniques. The primary objective of this research was to identify the most effective approach for monitoring macroplastic litter in riverine and marine environments through a comprehensive survey based on the experiences of the scientific community. Researchers involved in plastic pollution evaluated four litter occurrence and flux investigation methods (visual census, drone-based surveys, satellite imagery, and GPS/GNSS trackers) through a questionnaire. Traditional visual census and drone deployment were deemed as the most popular approaches among the 46 surveyed researchers, while satellite imagery and GPS/GNSS trackers received lower scores due to limited field validation and short performance ranges, respectively. On a scale from 0 to 5, visual census and drone-based surveys obtained 3.5 and 2.0, respectively, whereas satellite imagery and alternative solutions received scores lower than 1.2. Visual and drone censuses were used in high, medium and low-income countries, while satellite census and GPS/GNSS trackers were mostly used in high-income countries. This work provides an overview of the advantages and drawbacks of litter investigation techniques, contributing i) to the global harmonization of macroplastic litter monitoring and ii) providing a starting point for researchers and water managers approaching this topic. This work supports the selection and design of reliable and cost-effective monitoring approaches to mitigate the ambiguity in macroplastic data collection, contributing to the global harmonization of macroplastic litter monitoring protocols.

Marine pollution is a growing global issue, impacting both marine ecosystem and human health. High quantities of debris, mainly composed by plastic items, have been identified both in the coastal area and in the sea environment. Remote sensing techniques represent an useful tool (complementary to the in-situ campaigns) to monitor litter in the coastal environment, especially if the spectral signatures of the debris are known. In this framework, harvested beach litter (plastic items especially) were collected from two sandy beaches. The samples were spectrally characterised by implementing two indoor laboratory experiments with the aim to infer the best wavelengths to be used for beach litter detection via the spectral angle mapper index. Due to lack of a scientific protocol concerning the spectral data acquisition, two experimental setups were carried out to simulate the direct and diffuse illumination conditions. For around 30% of the samples, the spectral signatures are influenced by the two experimental setups. Outcomes suggest that for the majority of the samples green, blue, red-edge and some infrared bands are suitable for the beach litter detection.

Marine litter is a globally recognized issue that impacts the environment and has significant negative effects on both human health and socio-economic activities. Mainly composed of plastic items, marine litter can be dispersed in the ocean by surface currents, sink to the seafloor, and/or be deposited on coastal areas. Monitoring, quantifying, and characterizing beach litter can be time-consuming but can be conducted using established monitoring protocols (both European and international) and supported by citizen science. Here, we present and discuss the main outcomes from in situ monitoring campaigns covering sandy beaches in both an urban area and a Marine Protected Area. Both macro- and meso-litter were quantified and identified by material, size, shape, and color. The quantity and heterogeneity of items (classified using the Joint List of Litter Categories for Macrolitter Monitoring) were highest in areas with the greatest user presence (e.g., refreshment areas, shops, and restaurants). Free-access beaches showed the highest density of macro-litter items compared to beaches where entrance was regulated by three levels of subscription. Artificial polymers/plastics, particularly plastic caps and lids, dominated, followed by paper and cardboard fragments. A database has been created allowing to highlight hotspots and patterns of occurrence that can inform local management measures, urging municipalities to improve waste management.

Marine plastic pollution is a global issue affecting ecosystems and various aspects of human life. The scientific community is exploring new monitoring and containment approaches. Because in-situ sampling campaigns are time and resource demanding, there is a focus on integrating different approaches for marine litter monitoring. Data of two in-situ surveys (using a manta net) were compared to sea surface currents data and derived products with the aim to find a proxy variable of the plastic occurrence. Sea surface currents data were provided by the CALYPSO HF network (operating in the Sicily Channel since 2012). Notably, the occurrence of fragment items is inversely correlated with the total kinetic energy (r² ~ 0.85). This result was confirmed by a Lagrangian tracking model considering the deployment of virtual drifters around each in-situ measurement point. The proposed method applied to a wider domain using Copernicus Marine Service (CMS) data revealed that high plastic accumulation areas could be located at the centre of eddies often occurring in the winter period. However, uncertainties arise by the moderate-low correlation found between HF CALYPSO and CMS sea current data.