A review of ghost gear entanglement amongst marine mammals, reptiles and elasmobranchs

First report of plastic and non-plastic microparticles in stomach of slandertail lanternshark and shortspine spurdog from the edge of East China Sea

This study investigates the presence of plastic and non-plastic microparticles in the gastrointestinal tracts of two deep-sea sharks, Etmopterus molleri (n = 118) and Squalus mitsukurii (n = 6), bycatch from the East China Sea continental shelf. We found a total of 117 microparticles, predominantly fibres (67.52 %), with blue (31.62 %) and black (23.94 %) being the most prevalent colours. E. molleri contained 70 microparticles (0.63 ± 0.93 items/shark), 61.42 % non-plastics like viscose and cotton, while plastics included polyethylene, polyethylene terephthalate, and acrylic. Despite S. mitsukurii's limited sample size, the results show that it takes in a lot of microparticles (47 microparticles, 7.83 ± 2.64 items/shark), 57.44 % non-plastics (viscose, cotton, and ethyl cellulose), and 42.56 % plastics. A positive correlation between microparticle presence and total length was observed for E. molleri. These results provide initial data on microparticle ingestion by these species, highlighting potential ecological risks and trophic transfer implications in deep-sea ecosystems.

Tide of change: Urgency of a national marine litter policy in India

The rise of plastics in the 20th century revolutionized modern life but inadvertently exacerbated the marine litter crisis. The proliferation of wastes such as single-use plastics has escalated pollution along the coastline, demanding coordinated, decisive, and unified action. While the absence of specific national marine litter policies is concerning, there is growing recognition of urgency to address this issue. A group of experts and stakeholders was involved through a multi-staged workshop to assess the generated information based on scientific evidence and formulate a framework for the National Marine Litter Policy (NMLP). This paper proposes policy options (4 targets & 20 strategies) to address marine litter pollution, especially plastics, and aims to elucidate the urgency and significance of implementing an NMLP as a comprehensive strategy to combat plastics pollution. Implementing dedicated policies and action plans tailored to the unique challenges faced by each country is a vital step towards sustainable oceans.

Assessing the scale and ecological impact of derelict and discarded fishing gear across Thailand via the MARsCI citizen science protocol

South-East Asia is among the least studied regions for the growing issue of marine debris pollution, despite being a major contributor towards global marine debris. In the present study, we provide the preliminary results from the MARsCI project, a survey protocol designed to utilise citizen science to facilitate data collection on the ecological impact of discarded fishing gear (DFG) in Thailand. Over a three-year period, 103 surveys were carried out across Thailand, resulting in impact assessment of 606 pieces of DFG. Our findings indicate corals are regularly impacted by DFG in Thai waters and that isolated marine habitats may be more severely impacted than near-shore sites. We further identify crabs, muricid snails, and demersal fish to be among the most regularly entangled animals. We discuss our findings in the context of earlier work from Thailand, and conduct a critical review of the protocol itself, identifying improvements for future efforts.

Anthropogenic stressors and the marine environment: From sources and impacts to solutions and mitigation

Human-released contaminants are often poorly understood wholistically in marine ecosystems. This review examines the sources, pathways, impacts on marine animals, and mitigation strategies of five pollutants (plastics, per- and polyfluoroalkyl substances, bisphenol compounds, ethynylestradiol, and petroleum hydrocarbons). Both abiotic and biotic mechanisms contribute to all five contaminants' movement. These pollutants cause short- and long-term effects on many biological processes genetically, molecularly, neurologically, physiologically, reproductively, and developmentally. We explore the extension of adverse outcome pathways to ecosystem effects by considering known inter-generational and trophic relations resulting in large-scale direct and indirect impacts. In doing so, we develop an understanding of their roles as environmental stressors in marine environments for targeted mitigation and future work. Ecosystems are interconnected and so international collaboration, standards, measures preceding mass production, and citizen involvement are required to protect and conserve marine life.

Fishing plastic waste: Knowns and known unknowns

Plastics entering the marine environment primarily originate from land-based sources, prompting significant attention on single-use plastic packaging. However, fishing plastic waste also contributes substantially to marine plastic pollution, though it is often overlooked in the literature due to the challenges in pinpointing pollution sources. This study addresses this key knowledge gap by synthesizing existing literature to explore and document the knowns and known unknowns surrounding fishing plastic waste's environmental, health, and socio-economic impacts. Through the development of a causal loop diagram, the study offers a preliminary understanding of the issue, serving as a foundation for a deeper exploration of the complexities within the fishing industry's plastic waste dynamics. Finally, the study highlights that short-sighted views and approaches are likely to lead to systemic failures. Therefore, it advocates for strategic and meaningful measures to tackle marine plastic pollution, emphasizing the critical importance of a holistic and integrated understanding of the various plastic waste streams infiltrating and polluting our oceans.

Ingestion of fishing gear and Anisakis sp. infection in a beached Indo-Pacific finless porpoise (Neophocaena phocaenoides) in the Jeju Island, Republic of Korea: findings from post-mortem computed tomography and necropsy

BACKGROUND

Human fishing activities have significantly affect environmental concern for marine ecosystems, conservation of marine mammals, and human health. Coastal cetaceans are highly vulnerable to ingestion of fishing gear, bycatching, or entanglement, all of which can be fatal for these animals. In particular, certain coastal dolphins and porpoises are heavily impacted by fishing gear such as angling gear or stownet, as their food often overlap with the target fish species of human fisheries.

CASE PRESENTATION

This study presents a case of an Indo-Pacific finless porpoise (Neophocaena phocaenoides) beached on the coast of Jeju Island, Republic of Korea, with ingestion of fishing gear and severe Anisakis infection. Although this species inhabits waters ranging from the Persian Gulf to Taiwan, several stranded carcasses have been reported on Jeju Island in recent years. Post-mortem computed tomography revealed a bundle of four fishing hooks in the forestomach, along with nylon lines and steel lines with connectors, which were assumed to be angling gear for Jeju hairtail (Trichiurus lepturus). Further necroscopic investigation revealed that the forestomach contained a large number of Anisakis spp. (Nematoda: Anisakidae). Histological examination revealed a thickened forestomach wall with pinpoint and volcanic ulcerations, a thickened layer of stratified squamous epithelium, and infiltrated stroma in the squamous epithelium.

CONCLUSIONS

This study emphasizes the urgent need to address the impact of fishing activities on marine mammals, marine litter pollution, and the bycatch problem in Korean seawater. In addition, the occurrence of N. phocaenoides in seawater around Jeju Island should be raised in future geographical ecology or veterinary pathology studies and when its distribution is updated.

Retrieval operations of derelict fishing gears give insight on the impact on marine life

Abandoned, lost and discarded fishing gear (ALDFG), significantly impacts marine ecosystems and biodiversity by incidental capture known as ghost fishing. Such impacts were quantified during the Norwegian Directorate of Fisheries' annual ALDFG cleanup operation in September 2023 by examining the characteristics of retrieved ALDFG and recording the taxonomically sorted catch abundance and biomass. A total of 307 specimens equaling 382 kg of biomass were caught in the recovered gillnets and king crab pots. Gillnets exhibited a 27.3 % greater catch abundance and 50.3 % higher biomass per ALDFG unit mass compared to king crab pots. Margalef, Menhinick, Simpson, Shannon, and Pielou diversity indices showed a more pronounced impact on species richness and biodiversity associated with recovered gillnets. This study introduces an approach to assess the impact of ghost fishing on ecosystems and biodiversity through ALDFG retrieval operations, instrumental in developing estimates of the total ghost fishing capture by ALDFG.

Revisiting Indonesia's governance and conservation of cetaceans

Over the past few decades, Indonesia's marine conservation governance has been criticized. This article analyzes the overlaps and gaps in domestic law and policy regimes for cetaceans or marine mammal management and examines issues of institutional arrangements and legal frameworks related to cetacean conservation in Indonesia. The legal framework's progress on cetacean governance shows three distinct phases: 1975-1985 (species-focused governance approach), 1990-2009 (area-based approach), and 2010-present (broader marine governance approach). This study reveals that the main shortcoming of the legal framework is unclear mandates and overlapping jurisdictions. This study suggests several urgent policies that should be accommodated in the current legal regime to strengthen cetacean conservation. In addition, this research also recommends creating a collaboration mechanism between institutions and encouraging Indonesia to join as a full member of the International Whaling Commission and the Conservation of Migratory Species of Wild Animals Convention to strengthen cetacean governance and conservation.

Conservation Genetics of the Loggerhead Sea Turtle, Caretta caretta, from the Central Mediterranean: An Insight into the Species' Reproductive Behaviour in Maltese Waters

Loggerhead sea turtle, Caretta caretta (Linnaeus, 1758), nestlings were investigated through specimens found dead either after hatching or unhatched (n = 120) from eight nests around the Maltese islands (Central Mediterranean). Molecular genetics was used to conduct maternity and paternity tests of the collected specimens utilizing expanded mitochondrial DNA sequences from the control region (858 bp) and 25 microsatellite loci (12 dinucleotide loci and 13 tetranucleotide loci). Mitochondrial data produced two haplotypes, CC-A2.1 and CC-A3.1, with the most common haplotype being present in seven nests. Microsatellite data revealed the identity of six different females that were involved in the deposition of the eggs in the eight turtle nests analysed. This confirms that two females laid multiple nests. Additionally, microsatellite data allowed for the determination of multiple paternity, with one clutch being sired by two fathers. These results are useful for monitoring the genetic diversity of loggerhead sea turtle nestlings and of the turtle mothers and fathers contributing to future turtle offspring, which rely on Maltese sandy beaches for their successful start to life. Effective conservation management benefits from merging scientific knowledge with effective measures at potential nesting sites to avoid losses of nestlings caused by human negligence.

Marine plastic pollution in Morocco: state of the knowledge on origin, occurrence, fate, and management

Plastic pollution presents a major challenge facing stakeholders and decision-making worldwide. Plastics in the ocean damage biodiversity and marine ecosystem services that the blue economy relies upon. The present work analyses and reviews the literature on plastic pollution and the background knowledge about marine plastic pollution in Morocco. The economy of Morocco depends mainly on marine activities, including fisheries, tourism, and maritime trade. These sectors were identified as the main in-situ sources of plastics entering Moroccan coastal waters. The analysis results showed that the increasing abundance of plastics in such marine systems causes substantial economic loss to blue economy activities. In contrast, the lack of data on the plastic waste quantity entering Moroccan water is a limiting factor for assessing plastic pollution. This highlights the need for a risk assessment and more field investigations to value the weight impacts of marine activities generators of plastics on biodiversity and the economy. In addition, implementing laws and rules forbidding the disposal of plastic waste (PW) in public spaces, mainly beaches, and streets, is urgently needed. Raising awareness of plastic waste management and prioritizing improved waste collection, sorting, and management would boost Morocco's establishment and adoption of circular economy strategies. It is worth noting that while implementing the management projects and regulatory frameworks of plastic waste, considering their source and usage purpose is mandatory.

Land-derived litter load to the Indian Ocean: a case study in the Cimandiri River, southern West Java, Indonesia

The first study related to the characteristics of the riverine litter was carried out at the mouth of the Cimandiri River in the southern West Java to provide a national database, as mandated in the Indonesian Presidential Regulation 83/2018 concerning the handling of marine debris. We examined floating riverine litter entering the South Java Sea at Cimandiri River outlets four times between December 2020 and October 2021 using a Thomsea 1 T trawl-net. The amount of litter collected tended to rise throughout the sampling period. Daily floating riverine litter released into the South Java Sea was estimated to be 285,931 ± 133.70 items or 307 ± 192.69 kg. Our monitoring data revealed no sampling period differences in litter release into the South Java Sea with no correlation with rainfall. Our data indicate that plastics are the most single abundant type of floating riverine litter entering the South Java Sea from the Cimandiri River, accounting for 99.92% of abundance (285,701 ± 133,464.75 items per day) or 97.78% in terms of weight (300 ± 181.99 kg per day) of the total litter collected. As the Cimandiri River is one of the major rivers with an outlet in the south of Java, this land-derived litter information could be an archetype for riverine ecosystems in the nation and region.

The fate of plastic-wearing sharks: Entanglement of an iconic top predator in marine debris

Plastic waste is currently a major threat to marine ecosystems, and the ever-growing production of plastic materials suggests that this scenario will not change soon. Understanding cryptic effects of plastic debris on keystone marine species is warranted to address ecosystem-level impacts caused by plastic pollution. This study reports on plastic entanglement in top predator tiger sharks, Galeocerdo cuvier, from the western South Atlantic Ocean. Circular plastic straps produced severe trauma in 3 % of all tiger sharks sampled and led to abnormal anatomical development, indicating worrisome incidence and consequences of plastic entanglement in this species. Removing the plastic strap from one shark which had been entangled for at least 9 months was probably the cause for the shark having experienced post-release mortality. This suggests that, in some circumstances, strap removal is not effective to promote the survival of entangled sharks. Eliminating the circular integrity of plastic materials at first use should contribute to mitigate some of the impacts of plastic pollution on marine megafauna since this shape might be determinant in the process of shark entanglement.

Abandoned, lost or otherwise discarded fishing gear (ALDFG) as part of marine litter at the seafloor of the Baltic Sea - Characterization, quantification, polymer composition and possible impact

As an important part of marine litter at the seafloor "Abandoned, lost, discarded or otherwise lost fishing gear" (ALDFG) is gaining increasing attention in environmental assessments. Within this study marine litter at the seafloor of the Baltic Sea was quantified and characterized with special regard to fishery as source. Litter items (LI) were collected within fishery catches by bottom trawling during three cruises in 2020 and 2021. The resulting mean litter abundance was 9.2 LI/km2. Approximately 56 % of all LI were plastic, with PE as the most frequently identified polymer. ALDFG was present in considerable amounts with a mean value of 2.2 LI/km2 (22.2 %). However, the absolute counts of fishery nets were low (0.4 LI/km2; 4.2 %). Regarding weight, fishery nets are the dominant part of litter at the Baltic seafloor. Threshold values for marine litter at the seafloor are missing and might be developed using quantitative data on ALDFG.

A lesser known but emerging issue, recreational fishing debris and the anglers' opinions in South Korea

The abundance and characteristics of marine debris originating from recreational fishing were examined across 55 sites in four different regions in Korea. The result shows that the average abundance of debris was 4.3 ± 4.2 (n/m2) in terms of the number and 13.4 ± 18.1 (g/m2) in terms of the weight, and the most often found item was fishing lines (<1 m). Detrimental fishing debris such as fishing lines, hooks and weights comprised 50.9 % of the total debris, suggesting significant impacts on wildlife. A questionnaire survey was conducted with 374 anglers across all four regions to understand their behaviors, perceptions, and preferences regarding government policies. Most of the respondents were aware of the adverse impacts of recreational fishing debris on the environment, and >50 % agreed with the introduction of recreational fishing licenses. This study highlights the urgent need to raise awareness and address the undervalued problem of recreational fishing debris.

Evaluation of sea turtle morbidity and mortality within the Indian Ocean from 12 years of data shows high prevalence of ghost net entanglement

Anthropogenic activities can negatively affect sea turtle populations. Quantifying the effect of human actions on these threatened species can help guide management strategies to reduce adverse impacts. However, such assessments require extensive effort and resources and as such have not been carried out in many areas of important sea turtle habitat, including the Republic of the Maldives (Maldives). Here, we utilise 12 years of data (2010-2022) collected from marine turtle stranding and rehabilitation cases from across the Maldives to identify the key threats in this region. Olive ridley turtles were found stranded or injured most frequently (74.7% of total cases), along with hawksbill (15.2%), and green (10.1%) turtles. Anthropogenic factors were the primary cause of injury or stranding in 75.2% of cases with entanglement in ghost fishing gear being the most common (66.2% of all cases). Other causes of morbidity, such as from turtles being kept as pets (5.6%), boat strikes (<1%), bycatch (<1%), and poaching (<1%) were recorded less frequently. Olive ridley turtles were more likely to have injuries associated with entanglement than other species and showed a peak in admissions during the northeast monsoon, in the period following the known arribada nesting season in nearby India. Turtles admitted to rehabilitation following entanglement were released a mean of 70 days sooner and had 27.5% lower mortality rates than for other causes of admission. This study highlights the high prevalence of ghost net entanglement of sea turtles within the Maldives. The topic of ghost fishing is of global importance and international cooperation is critical in tackling this growing issue.

A new hotspot of macro-litter in the Rutland Island, South Andaman, India: menace from IORC

Supralittoral zones of 13 sandy beaches of remote Rutland Island were divided into three zones to identify the litter contamination, its source, pathway of plastic transport to determine the level of macro-litter contamination, and its impact on coastal biota. Owing to the floral and faunal diversity, apart of the study area is protected under Mahatma Gandhi Marine National Park (MGMNP). The supralittoral zones of each sandy beach (between low-tide and high-tide line) were individually calculated from 2021 Landsat-8 satellite imagery before conducting the field survey. The total area of the surveyed beaches was 0.52 km² (5,20,020.79 m²), and 317,565 litters representing 27 distinct litter types were enumerated. Two beaches in Zone-II and six in Zone-III were clean; however, all five in Zone-I were very dirty. The highest litter density (1.03 items/m²) was observed in Photo Nallah 1 and Photo Nallah 2, whereas the lowest (0.09 items/m²) was observed in Jahaji Beach. According to the Clean Coast Index (CCI), Jahaji Beach (Zone-III) is the very cleanest beach (1.74) while other beaches of Zone-II and Zone-III are clean. The findings of the Plastic Abundance Index (PAI) indicate that Zone-II and Zone-III beaches have a low abundance of plastics (< 1), while two beaches of Zone-I, viz., Katla Dera and Dhani Nallah, exhibited a moderate abundance of plastics (< 4) while a high abundance of plastics (< 8) was observed in the rest of three beaches of the same zone. The primary contributor of litter on Rutland's beaches was plastic polymers (60-99%), which were presumed to originate from the Indian Ocean Rim Countries (IORC). A collective litter management initiative by the IORC is essential in preventing littering on remote islands.

Entanglement in recreational fishing gear poses a threat to estuarine and coastal dolphins: Animal welfare and population level impacts should guide intervention decision making

Derelict and active fishing gear poses a threat to marine wildlife. This study details Indo-Pacific bottlenose dolphin entanglements in recreational fishing gear in the Peel-Harvey Estuary, Western Australia between 2016 and 2022. Eight entanglements were recorded, three resulted in death. While concerning from an animal welfare perspective, the impact of entanglements on the viability of the local dolphin population was low. This is as majority of affected individuals were juvenile males. Should entanglements result in the loss of reproductive females, or impact their reproductive success, the population trajectory could quickly change. As such, management decision making should consider population level impacts as well as the welfare of entangled individuals. Government agencies, together with relevant stakeholders, should work together to maintain preparedness to respond to entanglements and take preventative action that lowers the risk of interactions with recreational fishing gear.

Interactions between marine megafauna and plastic pollution in Southeast Asia

Southeast (SE) Asia is a highly biodiverse region, yet it is also estimated to cumulatively contribute a third of the total global marine plastic pollution. This threat is known to have adverse impacts on marine megafauna, however, understanding of its impacts has recently been highlighted as a priority for research in the region. To address this knowledge gap, a structured literature review was conducted for species of cartilaginous fishes, marine mammals, marine reptiles, and seabirds present in SE Asia, collating cases on a global scale to allow for comparison, coupled with a regional expert elicitation to gather additional published and grey literature cases which would have been omitted during the structured literature review. Of the 380 marine megafauna species present in SE Asia, but also studied elsewhere, we found that 9.1 % and 4.5 % of all publications documenting plastic entanglement (n = 55) and ingestion (n = 291) were conducted in SE Asian countries. At the species level, published cases of entanglement from SE Asian countries were available for 10 % or less of species within each taxonomic group. Additionally, published ingestion cases were available primarily for marine mammals and were lacking entirely for seabirds in the region. The regional expert elicitation led to entanglement and ingestion cases from SE Asian countries being documented in 10 and 15 additional species respectively, highlighting the utility of a broader approach to data synthesis. While the scale of the plastic pollution in SE Asia is of particular concern for marine ecosystems, knowledge of its interactions and impacts on marine megafauna lags behind other areas of the world, even after the inclusion of a regional expert elicitation. Additional funding to help collate baseline data are critically needed to inform policy and solutions towards limiting the interactions of marine megafauna and plastic pollution in SE Asia.

Material flow analysis of commercial fishing gears in Taiwan

Marine debris is an international environmental issue, and the growing amount of abandoned, lost, or otherwise discarded fishing gear (ALDFG) is a particular concern. Despite Taiwan's substantial fishing industry, there is a lack of comprehensive understanding of fishing gear. This work conducted a static material flow analysis to estimate the flows and the stocks of fishing gear in Taiwan in 2020, based on government statistics and interviews with fishing gears producing companies, fishermen, and recycling companies. Our findings reveal that the inflow, outflow, and stock of the fishing gears are 8,846 t/a, 4,271 t/a, and 4,575 t/a, respectively. Only 36 % of end-of-life fishing gear is recycled, while the rest is incinerated or landfilled. Additionally, the stock comprises 27 % in use, 23 % in ports, and 50 % entering the ocean. These results underscore the need to increase recycling capacity, prevent loss in oceans, and promote repairs to extend the lifespan of fishing gear.

Interactions between breeding gulls and monofilament lines at one of the main recreational fishing sites in Argentina

Monofilament fishing lines lost or discarded during recreational fishing activities often result in negative impacts on marine organisms. We assessed the interactions between Kelp and Olrog's gulls (Larus dominicanus and L. atlanticus, respectively) and recreational fishing at Bahía San Blas, Argentina. Monofilament lines constituted 61 and 29 % of total debris items recorded along beaches in the low and high fishing seasons, respectively. A total of 61 balls of tangled lines were also found within Kelp and Olrog's gull colonies. No Olrog's Gulls but nine Kelp Gulls were found tangled with monofilament lines within colony boundaries, seven of which were caught in vegetation. No Kelp or Olrog's gulls foraging in recreational fishing areas were observed tangled with lines. Monofilament lines did not negatively affect gull populations during the study period, but actions are needed to correctly manage their disposal given the relevance of Bahía San Blas as a recreational fishing area in the region.

A review on production and application of activated carbon from discarded plastics in the context of 'waste treats waste'

In the post-COVID scenario, the annual increase in plastic waste has taken an upsurge due to the disposal of plastic masks, gloves and other protective equipment. To reduce the plastic load ending up in landfills and oceans or dumped at roadsides, the potential of using plastic polymers in different sectors has been investigated over the years leading to their potential application in pavement laying, concrete industry, fuel generation and production of carbon-based compounds among which activated carbons (AC) is a prime example. As one of the most recommended adsorbents for removing contaminants from water and adsorbing greenhouse gases, AC creates a potential sector for using discarded plastic to further treat pollutants and approach closer to a circular economy for plastics. This paper analyses the production process, the effect of production parameters on AC characteristics and properties that aid in adsorption. The interdependence of these factors determines the surface area, porosity, relative micropore and mesopore volume, thereby defining the utility for removing contaminant molecules of a particular size. Furthermore, this work discusses the application of AC along with a summary of the earlier works leading to the existing gaps in the research area. Production costs, formation of by-products including toxic substances and adsorbate selectivity are the major issues that have restricted the commercial application of this process towards its practical use. Research aimed at valorization of plastic waste into ACs would minimize the solid waste burden, along with treating other pollutants.

A systematic review and risk matrix of plastic litter impacts on aquatic wildlife: A case study of the Mekong and Ganges River Basins

Plastic litter is a pollutant of aquatic environments worldwide, with some of the world's highest litter densities occurring in freshwater ecosystems. Little information about the risk that plastic litter poses to aquatic wildlife is available across the world's most polluted waterways. To help assess the risk to aquatic species where empirical data is lacking, our review presents i) a risk assessment methodology for predicting plastic litter impacts on aquatic wildlife in data poor environments, ii) a case study demonstrating this risk assessment methodology for wildlife across two heavily polluted river basins in Asia, the Mekong and Ganges River Basins; and iii) a broad review summarising common trends in litter interactions and risk to freshwater fish, aquatic birds, cetaceans and raptors. This risk analysis unites a systematic review approach with risk matrices following International Standards Organization's risk assessment criteria, evaluating the risk of plastic entanglement and ingestion and the potential for harm to the animal. In the Mekong and Ganges River Basins, we found that the risk of litter entanglement is higher than litter ingestion. Four species were forecast to be at high risk of entanglement: Ganges River dolphin, Gharial, Mekong giant catfish and Irrawaddy dolphin. The eastern imperial eagle and greater spotted eagle were noted to be at moderate risk of entanglement. Both the Ganges River dolphin and Irrawaddy dolphin were predicted to have a moderate risk of plastic ingestion. Interestingly, cranes, waterfowl and wading birds were deemed at low or negligible risk from plastic litter. This risk matrix methodology can be applied to other waterways and taxa to assess the risk posed by plastic. It can also be readily updated as more information becomes available. This review enables decision makers to bridge a data gap by providing a tool for conservation and management before comprehensive empirical data is available.

Quantifying the risk of plastic ingestion by ichthyofauna in the Balearic Islands (western Mediterranean Sea)

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.

Priorities to inform research on marine plastic pollution in Southeast Asia

Southeast Asia is considered to have some of the highest levels of marine plastic pollution in the world. It is therefore vitally important to increase our understanding of the impacts and risks of plastic pollution to marine ecosystems and the essential services they provide to support the development of mitigation measures in the region. An interdisciplinary, international network of experts (Australia, Indonesia, Ireland, Malaysia, the Philippines, Singapore, Thailand, the United Kingdom, and Vietnam) set a research agenda for marine plastic pollution in the region, synthesizing current knowledge and highlighting areas for further research in Southeast Asia. Using an inductive method, 21 research questions emerged under five non-predefined key themes, grouping them according to which: (1) characterise marine plastic pollution in Southeast Asia; (2) explore its movement and fate across the region; (3) describe the biological and chemical modifications marine plastic pollution undergoes; (4) detail its environmental, social, and economic impacts; and, finally, (5) target regional policies and possible solutions. Questions relating to these research priority areas highlight the importance of better understanding the fate of marine plastic pollution, its degradation, and the impacts and risks it can generate across communities and different ecosystem services. Knowledge of these aspects will help support actions which currently suffer from transboundary problems, lack of responsibility, and inaction to tackle the issue from its point source in the region. Being profoundly affected by marine plastic pollution, Southeast Asian countries provide an opportunity to test the effectiveness of innovative and socially inclusive changes in marine plastic governance, as well as both high and low-tech solutions, which can offer insights and actionable models to the rest of the world.

Trophic transfer of microplastics in the aquatic ecosystem of Sundarbans mangrove forest, Bangladesh

Globally microplastics (MPs) contaminations have been widely reported across the large number of organisms in the marine ecosystem. Consequently, trophic transfer of MPs inferred to occur across the organisms of marine food webs. However, scientific evidence on trophic transfer of MPs across the marine organisms is very limited. Therefore, this study aimed to understand the transfer of MPs across the trophic levels in the marine ecosystem. We sampled individuals of different species of primary consumers, secondary consumers, tertiary consumers and quaternary consumers from the aquatic ecosystem of Sundarbans mangrove forest from June 2021 to December 2021. This study found that marine organisms in the aquatic ecosystem of Sundarbans mangrove forest are contaminated with MPs. The abundance of MPs in collected samples varied between 0.56 ± 0.25 items/individual and 6.06 ± 1.20 items/individual. Maximum MPs was recorded as 5.5 ± 1.21 items/individual in predators followed by 5.1 ± 0.85, 4.5 ± 0.39, 1.2 ± 0.26, 1.1 ± 0.28 and 1.01 ± 0.25 in filter feeders, browsers, deposit feeders, selective planktivores and variable feeders, respectively. Maximum MPs abundance was encountered in quaternary consumers (4.17 items/individual) followed by tertiary consumers (3.17 items/individual), secondary consumers (2.74 items/individual) and primary consumers (0.56 items/individual). We found that MPs abundance increases with the increase of trophic levels (R² = 0.64, p < 0.001) which indicates that transfer of MPs across different trophic levels and also showed the evidence of biomagnification of MPs in successive trophic levels. Our study is the first report of trophic transfer of MPs in sub-tropical mangrove ecosystem and will serve as a guideline to understand the MPs pollution in the coastal ecosystem of Bangladesh.

Industrialised fishing nations largely contribute to floating plastic pollution in the North Pacific subtropical gyre

The subtropical oceanic gyre in the North Pacific Ocean is currently covered with tens of thousands of tonnes of floating plastic debris, dispersed over millions of square kilometres. A large fraction is composed of fishing nets and ropes while the rest is mostly composed of hard plastic objects and fragments, sometimes carrying evidence on their origin. In 2019, an oceanographic mission conducted in the area, retrieved over 6000 hard plastic debris items > 5 cm. The debris was later sorted, counted, weighed, and analysed for evidence of origin and age. Our results, complemented with numerical model simulations and findings from a previous oceanographic mission, revealed that a majority of the floating material stems from fishing activities. While recent assessments for plastic inputs into the ocean point to coastal developing economies and rivers as major contributors into oceanic plastic pollution, here we show that most floating plastics in the North Pacific subtropical gyre can be traced back to five industrialised fishing nations, highlighting the important role the fishing industry plays in the solution to this global issue.

Properties and Recyclability of Abandoned Fishing Net-Based Plastic Debris

Plastics in marine environments undergo molecular degradation via biocatalytic and photocatalytic mechanisms. Abandoned, lost, or discarded fishing gear (ALDFG) damages marine and coastal environments as well as plant and animal species. This article reviews ghost fishing, ecological damage from marine plastics, recommended recycling practices and alternative usages of derelict fishing gear. Material mixing techniques are proposed to counteract the effect of biocatalytic and photocatalytic biodegradation within the context of plastic fish net recycling. There is a need for a new and rapid “multidimensional molecular characterization” technology to quantify, at a batch level, the extent of photocatalytic or biocatalytic degradation experienced on each recovered fishing net, comprising molecular weight alteration, chemical functional group polydispersity and contaminant presence. Rapid multidimensional molecular characterization enables optimized conventional material mixing of recovered fishing nets. In this way, economically attractive social return schemes can be introduced for used fishing nets, providing an economic incentive for fishers to return conventional fishing nets for recycling.

Spatial variation of plastic debris on important turtle nesting beaches of the remote Chagos Archipelago, Indian Ocean

We report Anthropogenic Marine Debris (AMD) in Chagos Archipelago in the Indian Ocean, globally amongst the most isolated island groups. AMD on 14 island beaches in five atolls were surveyed in 2019 using two techniques: Marine Debris Tracker (MDT) along littoral vegetation and photoquadrats in open beach. Over 60 % of AMD in both beach zones was composed of plastics, especially bottles and fragments (mean = 44.9 %, 27.2 %, range = 16.5-73.2 %, 4.8-55.9 % respectively in vegetation; mean = 28.7 %, 31.5 %, range = 17.7-40.7 %, 11.6-60.0 % respectively in open beach). The density of plastic debris in littoral vegetation (MDT data: 1995 bottles, 3328 fragments per 100 m²) was 10-fold greater than in open beach (photoquadrat data: 184 bottles, 106 fragments per 100 m²). Significant latitudinal variation in vegetation AMD occurred (8-fold greater in southern atolls, p = 0.006). AMD varied within island zones: most debris observed on oceanside beaches (oceanside vs lagoon, W = 365, p < 0.001; ocean vs island tip, W = 107, p = 0.034). Standardisation of surveys using the open-source MDT App is recommended. Debris accumulation hotspots overlapped with sea turtle nesting habitat, guiding future beach clean-up prioritisation.

Is the use of deep learning an appropriate means to locate debris in the ocean without harming aquatic wildlife?

With the global issue of marine debris ever expanding, it is imperative that the technology industry steps in. The aim is to find if deep learning can successfully distinguish between marine life and synthetic debris underwater. This study assesses whether we could safely clean up our oceans with Artificial Intelligence without disrupting the delicate balance of aquatic ecosystems. Our research compares a simple convolutional neural network with a VGG-16 model using an original database of 1644 underwater images and a binary classification to sort synthetic material from aquatic life. Our results show first insights to safely distinguishing between debris and life.

Ecosystem-Service Scaling Techniques to Evaluate the Benefits of Marine Debris Removal

While knowledge of the ecological impacts of marine debris is continually advancing, methods to evaluate the comparative scale of these impacts are less well developed. In the case of costly environmental restoration in marine and coastal environments, quantifying and comparing the ecological impacts of diverse forms of ecosystem injuries can facilitate a more efficient selection of restoration projects. This article proposes evaluating marine debris removal projects in an ecological service equivalency analysis framework that can be used to compare marine debris removal to other types of environmental restoration. Drawing on existing spatial and temporal data with respect to marine debris impacts on habitats and resources, we demonstrate how resource managers and organizations involved in marine debris removal can quantify the ecological service benefits of a removal project and use it to comparatively select between projects based on present value ecological benefits. This valuation can be useful in natural resource damage assessment restoration selection, and for directing limited funds to marine debris removal projects which produce the greatest gains in ecological services. This ecological scaling framework is applied to a seagrass injury case study to demonstrate its application for scaling marine debris removal as compensatory restoration.

Global collision-risk hotspots of marine traffic and the world's largest fish, the whale shark

Marine traffic is increasing globally yet collisions with endangered megafauna such as whales, sea turtles, and planktivorous sharks go largely undetected or unreported. Collisions leading to mortality can have population-level consequences for endangered species. Hence, identifying simultaneous space use of megafauna and shipping throughout ranges may reveal as-yet-unknown spatial targets requiring conservation. However, global studies tracking megafauna and shipping occurrences are lacking. Here we combine satellite-tracked movements of the whale shark, Rhincodon typus, and vessel activity to show that 92% of sharks’ horizontal space use and nearly 50% of vertical space use overlap with persistent large vessel (>300 gross tons) traffic. Collision-risk estimates correlated with reported whale shark mortality from ship strikes, indicating higher mortality in areas with greatest overlap. Hotspots of potential collision risk were evident in all major oceans, predominantly from overlap with cargo and tanker vessels, and were concentrated in gulf regions, where dense traffic co-occurred with seasonal shark movements. Nearly a third of whale shark hotspots overlapped with the highest collision-risk areas, with the last known locations of tracked sharks coinciding with busier shipping routes more often than expected. Depth-recording tags provided evidence for sinking, likely dead, whale sharks, suggesting substantial “cryptic” lethal ship strikes are possible, which could explain why whale shark population declines continue despite international protection and low fishing-induced mortality. Mitigation measures to reduce ship-strike risk should be considered to conserve this species and other ocean giants that are likely experiencing similar impacts from growing global vessel traffic.

A Kettle of Fish: A Review of the Scientific Literature for Evidence of Fish Sentience

Simple Summary

Fish are traded, caught, farmed, and killed in their trillions every year around the world, yet their welfare is often neglected and their capacity for feelings is regularly disregarded. We have searched the scientific literature to determine what is known about fish sentience and relate our findings to the many uses of fish around the globe.

Abstract

Fish are traded, caught, farmed, and killed in their trillions every year around the world, yet their welfare is often neglected and their sentience regularly disregarded. In this review, we have sought to (1) catalogue the extent to which fish sentience has featured over the past 31 years in the scientific literature and (2) discuss the importance of fish sentience in relation to their commercial uses. We searched the journal database Science Direct using 42 keywords that describe traits or elements of sentience to find articles that were referring to or exploring fish sentience. Our review returned 470 results for fish sentience in 142 different species and subspecies of fish, and featured 19 different sentience keywords. The top four keywords were; ‘stress’ (psychological) (n = 216, 45.9% of total results), ‘anxiety’ (n = 144, 30.6%), ‘fear’ (n = 46, 9.7%), and ‘pain’ (n = 27, 5.7%). Our findings highlight an abundance of evidence for fish sentience in the published scientific literature. We conclude that legislation governing the treatment of fish and attitudes towards their welfare require scrutiny so that their welfare can be safeguarded across the globe.

The impact of marine debris on cetaceans with consideration of plastics generated by the COVID-19 pandemic

The accumulation of human-derived debris in the oceans is a global concern and a serious threat to marine wildlife. There is a volume of evidence that points to deleterious effects of marine debris (MD) on cetaceans in terms of both entanglement and ingestion. This review suggests that about 68% of cetacean species are affected by interacting with MD with an increase in the number of species reported to have interacted with it over the past decades. Despite the growing body of evidence, there is an ongoing debate on the actual effects of plastics on cetaceans and, in particular, with reference to the ingestion of microplastics and their potential toxicological and pathogenic effects. Current knowledge suggests that the observed differences in the rate and nature of interactions with plastics are the result of substantial differences in species-specific diving and feeding strategies. Existing projections on the production, use and disposal of plastics suggest a further increase of marine plastic pollution. In this context, the contribution of the ongoing COVID-19 pandemic to marine plastic pollution appears to be substantial, with potentially serious consequences for marine life including cetaceans. Additionally, the COVID-19 pandemic offers an opportunity to investigate the direct links between industry, human behaviours and the effects of MD on cetaceans. This could help inform management, prevention efforts, describe knowledge gaps and guide advancements in research efforts. This review highlights the lack of assessments of population-level effects related to MD and suggests that these could be rather immediate for small populations already under pressure from other anthropogenic activities. Finally, we suggest that MD is not only a pollution, economic and social issue, but also a welfare concern for the species and populations involved.

Impact of plastic bags on the benthic system of a tropical estuary: An experimental study

Plastic bags are among the most discarded waste items as they are generally only used once and are often improperly eliminated and transported by rivers and estuaries to the ocean. We developed an experimental design to mimic the effect of plastic bag deposition in a tropical estuary and investigated its short-term impact on benthic community structure. We observed a significant influence of the presence of plastic bags on the abundance, richness and diversity of benthic fauna after an eight-week exposure period. Plastic bags acted as a barrier and interfered in processes that occur at the water-sediment interface, such as organic matter and silt-clay deposition. Our results indicate that plastic bags, in addition to directly affecting benthic fauna, may alter processes such as carbon burying, known as "blue carbon", thus making its storage in the sediment more difficult.

Entanglement of Steller sea lions (Eumetopias jubatus) in man-made marine debris on Tyuleniy Island, Sea of Okhotsk

The present report provides data on entanglement of Steller sea lions (SSL) in marine debris on Tyuleniy Island, Sea of Okhotsk. The frequency of entanglement depending on the material, sex, and age of animals was estimated. A total of 133 SSL were recorded as having debris on their bodies, or an average of 22.2 individuals per year. The relative rate of entanglement over the observation years ranged from 1.48 to 1.97% of their total number. The entangled individuals were both males and females of all ages, but young males constituted the largest proportion among them (5.2%). The entangled SSL most frequently (43.2%) had neck collars (the material is not defined) and, less frequently, packaging bands (23.4%), nets (17.7%), and other debris. Most of marine litter found on SSL is associated with commercial fishing activities. On Tyuleniy Island, the rate of SSL entanglement is higher than in the eastern part of the species' range.

Microplastics in beluga whale (Delphinapterus leucas) prey: An exploratory assessment of trophic transfer in the Beaufort Sea

Microplastics (MPs, <5 mm in length) have been identified as emerging contaminants in marine environments, with ingestion by a variety of biota being of increasing concern. Few studies exist on MP ingestion in Arctic fish, and there are currently no such data from the Beaufort Sea. We investigated MP abundance in five ecologically valuable species from three sampling sites in the Eastern Beaufort Sea to evaluate possible trophic-level pathways of MPs from prey to beluga whales. Polymer analysis confirmed that 21% of fish gastrointestinal tracts (n = 116) contained microplastic particles. Fish that contained MPs had a mean abundance of 1.42 ± 0.44 particles per individual and an overall mean abundance of 0.37 ± 0.16 particles. No plastic particles >5 mm were found, and 78% of the particles observed were fibers. Based on energetic needs, we estimate that individual beluga may ingest between 3800 and 145,000 microplastics annually through trophic transfer, with uncertain health implications.

Abandoned, lost and discarded fishing gear 'ghost nets' are increasing through time in Northern Australia

The remote Gulf of Carpentaria (GoC) represents 10% of Australia's coastline. This large, shallow sea supports high-value fishing activities and habitat for threatened species, and is a sink for abandoned, lost and discarded fishing gear (ALDFG) 'ghost nets', most originating from fishing activities outside of Australia's Exclusive Economic Zone. With growing concerns about the plastic waste along the world's coastlines, we retrospectively analyzed ghost net sighting information from four aerial surveys across 15 years, to investigate whether densities of ghost nets are changing through time or in space. We found an increase in ghost nets, despite more than a decade of illegal fishing countermeasure and clean-up efforts in the broader region. This demonstrates that the input of ALDFG into the system currently overwhelms the substantial net removal activities. We make recommendations for improving monitoring and consider the underlying drivers of nets being lost to improve ghost gear management on land and at sea.

Dangerous traps: Macroplastic encounters affecting freshwater and terrestrial wildlife

Encounters (or interactions) between plastic debris and wildlife can cause great harm to individuals and populations. The most common encounters are ingestion, entanglement and plastic usage (plastic as nesting material, vector for biota transport and refuge/shelter). Hundreds of plastic-encounters have been reported for marine species. However, there is a lack of studies reporting encounters in other ecosystems, such as freshwater and terrestrial ones. Based on a citizen science approach, we documented and analyzed 90 different cases of macroplastic-fauna encounters for 44 freshwater and terrestrial species. Herein, we provided evidence (photographically documented) of the negative consequences of macroplastic debris discarded in freshwater and terrestrial environments. Birds were by far the taxon most frequently reported in encounters (72.2% of the encounters, 30 different species). The dominant type of plastic-fauna encounter was the use of plastic as nesting material (42% of the total cases) and the second one was entanglement (33%). Most of the entanglements had lethal consequences for the organisms involved (almost 60%). Entanglement in ghost fishing gear and bottle (security) rings were particularly dangerous and comparatively frequent in this study. Some invasive species could benefit from the encounters to the detriment of the environment's health, using plastics as settlement substrata. Finally, we lay the foundation for creating worldwide lists of non-marine species impacted by encounters with plastic debris.

Stranded marine debris on the touristic beaches in the south of Bali Island, Indonesia: The spatiotemporal abundance and characteristic

Stranded marine debris (MD) has become a hot topic on Bali Island because it threatens coastal tourism sustainability. This study aims to investigate the spatiotemporal abundance and characteristics of MD on 14 touristic beaches in Bali Island. Sampling is carried out twice every season by adapting methods from NOAA's MD program. We found that the average MD abundance and weight were 0.356 ± 0.366 items/m² and 4.057 ± 3.892 g/m², respectively. Plastic dominated the MD based on abundance (86.9%) and weight (40.1%). Plastic bags, straws, and plastic cups are the most common items among plastics. The MD is originated from Indonesia and is dominated by land-based sources. The beaches are categorized as dirty in the rainy seasons and clean in the dry seasons. Statistically, the MD based on abundance, weight, category, source, and level of cleanliness varied significantly between seasons.

Ghost nets: A poorly known threat to Brazilian freshwater biodiversity

Ghost nets constitute a serious threat to aquatic biodiversity, because they entangle animals as long as they persist in the environment. However, scientific literature in Brazil is virtually silent about this issue in inland ecosystems. Concerned with this gap, we conducted searches on YouTube BR to gather information about ghost nets in Brazilian freshwaters. Through our search, we compiled 33 independent videos showing ghost nets in different aquatic environments. In several cases, we identified entangled animals (i.e., fishes, reptiles, and birds). In this work we also provide recommendations to better understand and mitigate this problem in Brazilian freshwater ecosystems.

Digital media reveal negative impacts of ghost nets on Brazilian marine biodiversity

Abandoned, lost, or otherwise discarded fishing gear (ALDFG) is responsible for the entanglement of several marine species. Based on a search of digital media (i.e., Google and YouTube^BR), we assessed the negative impacts of ghost nets-a type of ALDFG-on Brazilian marine biodiversity. We found that ghost nets negatively affected crustaceans, fishes, reptiles, birds, and mammals in different parts of the Brazilian coast. Our reports include marine megafauna, such as the Bryde's whale and Guiana dolphin. In addition, we found that ghost nets impacted seven threatened species and had negative effects on animals within marine protected areas. Here, we provide an update on the negative impacts of ghost nets on Brazilian marine biota, but the real situation remains underestimated and somewhat obscure.

Marine-dumped waste tyres cause the ghost fishing of hermit crabs

Poorly managed waste tyres pose serious environmental and health risks, ranging from air pollution caused by fire, leaching of heavy metals and outbreaks of mosquitos, to destruction of vegetation and coral reefs. We report a previously unrecognized ecological risk to marine organisms from waste tyres. Over 1 year, we made monthly counts of hermit crabs (n = 1278) invading and/or being trapped within six tyres anchored to the seabed at 8 m depth in Mutsu Bay, Japan. A complementary aquarium experiment in which hermit crabs were released into a tyre confirmed that they could not escape. We report marine-dumped waste tyres to ghost fish in a manner analogous to discarded fishing gear. Because hermit crabs play important roles in coastal food webs as both prey and scavengers, declines in their numbers as a consequence of this ghost fishing might affect coastal ecosystems.

Characteristics of Plastic Pollution in the Environment: A Review

Plastics are ubiquitous in the environment and have become a hot topic in academic circles. Extensive studies have focused on analytical methods, source, abundance, transport, fate, degradation of plastics in the environment and threats to natural surroundings, wildlife or even human health. However, characteristics of plastic pollution, which are critical to understand this emerging problem, remain unknown up to now. Here, this paper reviews the major characteristics of plastic pollution in the environment to enhance present understanding of this issue. These characteristics, including diversity, persistence, global issues, combined pollution and threats to organisms and human health, are critically summarized in this work. Further, "plastic cycle" in the environment, namely, aquatic, atmospheric, and terrestrial system, is also discussed in this review. Finally, we highlight current challenges of plastic pollution posed to the public and also recommend the research trends in future work.

The Proposal and Necessity of the Numerical Description of Nano- and Microplastics' Surfaces (Plastisphere)

The constantly growing amount of synthetic materials < 5 mm, called microplastics (MPs), is fragmented in the environment. Thus, their surface, Plastisphere, is substantially increasing forming an entirely new ecological niche. It has already been extensively studied by microbiologists observing the biofilm and by material scientists interested in the weathering of polymer materials. This paper aims to construct a bridge between the physical and chemical description of the Plastisphere and its microbiological and ecological significance. Various algorithms, based on the analysis of pictures obtained by scanning electron microscopy (SEM), are proposed to describe in detail the morphology of naturally weathered polymers. In particular, one can study the size and distribution of fibres in a standard filter, search the synthetic debris for mapping, estimate the grain size distribution, quantitatively characterize the different patterns of degradation for polymer spheres and ghost nets, or calculate the number of pores per surface. The description and visualization of a texture, as well as the classification of different morphologies present on a surface, are indispensable for the comprehensive characterization of weathered polymers found inside animals (e.g., fishes). All these approaches are presented as case studies and discussed within this work.

Do Polystyrene Beads Contribute to Accumulation of Methylmercury in Oysters?

To clarify whether microplastics contribute to elevated bioaccumulation of methylmercury (MeHg) in aquatic organisms, we studied the sorption pattern of MeHg on polystyrene beads (PBs) and evaluated MeHg accumulation, via uptake of MeHg-adsorbed PB, in the oyster Crassostrea gigas. MeHg-cysteine conjugates were added to seawater at 10, 100, and 1000 µg/L as Hg. Polystyrene beads (φ = 0.02, 0.2, and 2 µm) were immersed in the seawater for 24 h. The concentrations of total mercury (T-Hg) adsorbed onto the PBs were then measured using the reduction vaporization method. T-Hg concentrations for the PBs with diameters of 0.02, 0.2, and 2 µm were 10.6 ± 0.4, 1.8 ± 0.1, and 1.3 ± 0.1 ng/mg-PBs, respectively, when immersed in 2 mL of MeHg-added seawater (100 µg/L as Hg). Thus, the adsorption efficiency of MeHg onto PBs was higher in the presence of smaller diameter PBs. Next, 1 mg of PBs immersed in 2 mL of seawater containing 100 µg/L of MeHg for 24 h was added to an oyster tank containing 1 L of seawater. The T-Hg concentration of the oysters was measured after 6 h of exposure. No significant difference was found in the T-Hg concentration of oysters in the presence of PBs (0.30 ± 0.01 to 0.37 ± 0.05 ng/mg as dry weight) with MeHg and in the absence of PBs (0.36 ± 0.03 ng/mg as dry weight). Our results suggest that the presence of PBs in seawater has little effect on MeHg uptake by oysters.

Plastic pollution: A focus on freshwater biodiversity

Plastics are dominant pollutants in freshwater ecosystems worldwide. Scientific studies that investigated the interaction between plastics and freshwater biodiversity are incipient, especially if compared to the marine realm. In this review, we provide a brief overview of plastic pollution in freshwater ecosystems around the world. We found evidence of plastic ingestion by 206 freshwater species, from invertebrates to mammals, in natural or semi-natural ecosystems. In addition, we reported other consequences of synthetic polymers in freshwater ecosystems-including, for instance, the entanglement of animals of different groups (e.g., birds). The problem of plastic pollution is complex and will need coordinated actions, such as recycling programs, correct disposal, stringent legislation, regular inspection, replacement of synthetic polymers with other materials, and ecological restoration. Current information indicates that the situation in freshwater ecosystems may be as detrimental as the pollution found in the ocean, although highly underappreciated.

Managing multiple pressures for cetaceans' conservation with an Ecosystem-Based Marine Spatial Planning approach

Despite the recognized important ecological role that cetaceans play in the marine environment, their protection is still scarcely enforced in the Mediterranean Sea even though this area is strongly threatened by local human pressures and climate change. The piecemeal of knowledge related to cetaceans' ecology and distribution in the basin undermines the capacity of addressing cetaceans' protection and identifying effective conservation strategies. In this study, an Ecosystem-Based Marine Spatial Planning (EB-MSP) approach is applied to assess human pressures on cetaceans and guide the designation of a conservation area in the Gulf of Taranto, Northern Ionian Sea (Central-eastern Mediterranean Sea). The Gulf of Taranto hosts different cetacean species that accomplish important phases of their life in the area. Despite this fact, the gulf does not fall within any area-based management tools (ABMTs) for cetacean conservation. We pin down the Gulf of Taranto being eligible for the designation of diverse ABMTs for conservation, both legally and non-legally binding. Through a risk-based approach, this study explores the cause-effect relationships that link any human activities and pressures exerted in the study area to potential effects on cetaceans, by identifying major drivers of potential impacts. These were found to be underwater noise, marine litter, ship collision, and competition and disturbance on preys. We draw some recommendations based on different sources of available knowledge produced so far in the area (i.e., empirical evidence, scientific and grey literature, and expert judgement) to boost cetaceans' conservation. Finally, we stress the need of sectoral coordination for the management of human activities by applying an EB-MSP approach and valuing the establishment of an ABMT in the Gulf of Taranto.

Biofilm development of Bacillus siamensis ATKU1 on pristine short chain low-density polyethylene: A case study on microbe-microplastics interaction

A low-density polyethylene (LDPE) degrading bacterial strain (ATKU1) was isolated (99.86% similar with Bacillus siamensis KCTC 13613^T) from a plastic dumping site to study interactions between microplastics (< 5 mm) and microorganisms. The strain was found (by scanning electron microscopy) to form biofilm on the microplastic surface after its interaction with LDPE (avg. M_w~4,000 Da and avg. M_n~1,700 Da) as a sole carbon source. Atomic force microscopy (AFM) showed the biofilm's 3-D developmental patterns and significantly increased Young's modulus of the LDPE surface after microbial treatment. Most of the viable bacteria attached to biofilms rather than media, which suggested their ability to utilize LDPE. Absorption bands of carbonyl, alkenyl, acyl, ester, primary-secondary alcohol, alkene groups and nitric oxides were found on the treated LDPE particles using Fourier-transform infrared spectroscopy. Fourier transform-ion cyclotron resonance mass spectrometry of the media indicated compositional shifts of the compounds after treatment (i.e., increase in the degree of unsaturation and increment in oxygen-to-carbon ratio) and presence of unsaturated hydrocarbons, polyketides, terpenoids, aliphatic/peptides, dicarboxylic acids, lipid-like compounds were hinted. The plastic degrading abilities of Bacillus siamensis ATKU1 suggest its probable application for large scale plastic bioremediation facility.