Mistaken identity? Visual similarities of marine debris to natural prey items of sea turtles

Frontal processes as drivers of floating marine debris in coastal areas

The influence of floating marine debris (FMD) on coastal and marine communities and ecosystems is undeniable, and attention is increasingly focused on ecologically and biologically important coastal areas. To protect marine life and valuable resources from FMD pollution, identifying FMD accumulation zones is recognized as a priority. One of the coastal ocean processes found governing the distribution of FMD is water convergence (frontal zones). These fronts are driven by various oceanographical factors. To date, the transport and accumulation of FMD in relation to fronts in coastal areas is poorly understood. To address this knowledge gap, we reviewed various types of ocean fronts as well as FMD accumulation along frontal zones in coastal areas defined as the region between the coastline and the shelf break. Frontogenesis (physical processes related to frontal formation) were reviewed alongside studies on FMD accumulation in frontal zones to identify physical factors that drive the pathways and accumulation in these areas. This review will contribute to our understanding of accumulation hotspots of FMD within ocean fronts and identify gaps for further research on developing a proxy for FMD hotspot identification in ecologically important coastal areas.

Influence of trophic overlaps and trophic niche amplitude on microplastic intake of fish species in shallow areas of a neotropical coastal lagoon

Plastic pollution is a global challenge that affects all marine ecosystems, and reflects all types of uses and activities of human society in these environments. In marine ecosystems, microplastics and mesoplastics interact with invertebrates and become available to higher predators, such as fish, which can ingest these contaminants. This study aimed to analyze how ecological food interactions (diet overlap and trophic niche amplitude) among fish species contribute to the ingestion of plastic particles. The gastrointestinal contents of six fish species (Atherinella brasiliensis, Eucinostomus melanopterus, Eucinostomus argenteus, Genidens genidens, Coptodon rendalli, and Geophagus brasiliensis) were analyzed to identify prey items and plastic ingestion. Based on the ontogenetic classification, A. brasiliensis, E. melanopterus, and G. genidens were divided into juveniles and adults, and the six fish species analyzed were divided into nine predator groups. Most of the plastics ingested by the fish species were blue microplastic (MP) fibers (< 0.05 mm) classified as polyester terephthalate, polyethylene, and polybutadiene. Considering all the analyzed predators, the average number and weight of plastics ingested per individual were 2.01 and 0.0005 g, respectively. We observed that predators with a high trophic overlap could present a relationship with the intake of MP fibers owing to predation on the same resources. In addition, we observed the general pattern that when a species expands its trophic diversity and niche, it can become more susceptible to plastic ingestion. For example, the species with the highest Levin niche amplitude, E. argenteus juveniles, had the highest mean number (2.9) of ingested MP fibers. Understanding the feeding ecology and interactions among species, considering how each predator uses habitats and food resources, can provide a better understanding of how plastic particle contamination occurs and which habitats are contaminated with these polluting substances.

Closing the loop: A framework for tackling single-use plastic waste in the food and beverage industry through circular economy- a review

The escalating threat of plastic pollution necessitates urgent and immediate action, particularly within the food and beverage (F&B) industry, a significant contributor to single-use plastic waste (SUP). As the global population surges, so does the consumption of single-use plastics in the F&B sector, perpetuating a linear economy model characterized by a 'take, make, use, dispose' approach. This model significantly exacerbates plastic waste issues, with projections indicating an alarming increase in plastic outputs by 2050 if current practices continue. Against this backdrop, the circular economy presents a viable alternative, with its emphasis on resource retention, recovery, and the extension of product lifecycles. This study delves into the problems posed by single-use plastics, introduces the circular economy as a sustainable model, and explores effective strategies for the recycling and reuse of plastic waste within this framework. By examining the environmental impact of SUP in the F&B sector and advocating for the adoption of circular economy principles, this paper underscores a critical pathway towards sustainable solutions in the battle against plastic pollution. In conclusion, the transition to a circular economy, underpinned by global collaboration and the proactive implementation of supportive policies, is imperative for reducing the environmental footprint of single-use plastics and fostering a sustainable future.

Macroalgae Bioplastics: A Sustainable Shift to Mitigate the Ecological Impact of Petroleum-Based Plastics

The surge in global utilization of petroleum-based plastics, which notably heightened during the COVID-19 pandemic, has substantially increased its harm to ecosystems. Considering the escalating environmental impact, a pivotal shift towards bioplastics usage is imperative. Exploring and implementing bioplastics as a viable alternative could mitigate the ecological burden posed by traditional plastics. Macroalgae is a potential feedstock for the production of bioplastics due to its abundance, fast growth, and high cellulose and sugar content. Researchers have recently explored various methods for extracting and converting macroalgae into bioplastic. Some of the key challenges in the production of macroalgae bioplastics are the high costs of large-scale production and the need to optimize the extraction and conversion processes to obtain high-quality bioplastics. However, the potential benefits of using macroalgae for bioplastic production include reducing plastic waste and greenhouse gas emissions, using healthier materials in various life practices, and developing a promising area for future research and development. Also, bioplastic provides job opportunities in free enterprise and contributes to various applications such as packaging, medical devices, electronics, textiles, and cosmetics. The presented review aims to discuss the problem of petroleum-based plastic, bioplastic extraction from macroalgae, bioplastic properties, biodegradability, its various applications, and its production challenges.

The impact of chronic and acute problems on sea turtles: The consequences of the oil spill and ingestion of anthropogenic debris on the tropical semi-arid coast of Ceará, Brazil

Sea turtle mortality is often related to materials that reach the coast from different anthropic activities worldwide. This study aimed to investigate whether sea turtle mortality was related to older marine problems, such as solid waste, or one of the largest oil spill accidents on the Brazilian coast, that occurred in 2019. We posed three questions: 1) Are there solid residues in the digestive tract samples, and which typology is the most abundant? 2) Can meso‑ and macro-waste marine pollutants cause mortality? 3) Is the dark material found really oil? A total of 25 gastrointestinal content (GC) samples were obtained, of which 22 ingested waste of anthropogenic origin and 18 were necropsied. These 22 samples were obtained during or after the 2019 oil spill, of which 17 specimens were affected, making it possible to suggest oil ingestion with the cause of death in the animals that could be necropsied. Macroscopic data showed that the most abundant solid waste was plastic (76.05 %), followed by fabrics (12.18 %) and oil-like materials. However, chemical data confirmed only three specimens with oil levels ranging from remnants to high. It was possible to infer possible causes of death in 16 of the total 18 necropsied cases: Most deaths were due to respiratory arrest (62.5 %), followed by pulmonary edema (12.5 %), cachexia syndrome (12.5 %), circulatory shock (6.25 %), and head trauma (6.25 %), which may have been caused by contact with solid waste, oil, or both. The study showed that not all dark material found in the GCs of turtles killed in oiled areas is truly oil, and in this sense, a chemical analysis step to prove the evidence of oil must be added to international protocols.

Marine turtles as bio-indicators of plastic pollution in the eastern Mediterranean

The loggerhead turtle (Caretta caretta) has been suggested as a bio-indicator species for plastic pollution. However, detailed investigations in the eastern Mediterranean are limited. Here, we present data from loggerhead turtles (2012-2022; n = 131) of which 42.7 % (n = 57) had ingested macroplastic (pieces ≥ 5 mm). Frequency of occurrence (%) was not found to have changed over time, with body size (CCL cm), between stranded or bycaught turtles, or with levels of digesta present. The characteristics of ingested plastic (n = 492) were largely sheetlike (62 %), clear (41 %) or white (25 %) and the most common polymers identified were Polypropylene (37 %) and Polyethylene (35 %). Strong selectivity was displayed towards certain types, colours and shapes. Data are also presented for posthatchling turtles (n = 4), an understudied life stage. Much larger sample sizes will be needed for this species to be an effective bio-indicator, with the consideration of monitoring green turtles (Chelonia mydas) for the eastern Mediterranean recommended allowing a more holistic picture to be gathered.

Experimental study on color and texture as cues for plastic debris ingestion by captive sea turtles

Sea turtles face considerable risks from ingesting marine debris. They are primarily visual feeders, so color may be important for identifying food suitability or enhancing prey detection. Here, we investigated the impacts of color and texture on foraging behavior in relation to plastic consumption. We experimentally assessed the influences of color and texture as attractors for sea turtles using edible jellyfish. The findings showed that the colors of objects significantly affected selective preferences, as evidenced by different behaviors by sea turtles in response to different colors. They exhibited diet-related selectivity toward colors similar to common aquarium food, and texture had a significant impact on complete ingestion. The results suggest that plastic resembling natural prey is more likely ingested. Also, sea turtles were attracted by the color yellow, suggesting that visually distinctive items can attract them. Our results provide fundamental knowledge, helping mitigate the effects of plastic pollution on wildlife.

A macroplastic vulnerability index for marine mammals, seabirds, and sea turtles in Hawai'i

Plastic pollution is having devastating consequences for marine organisms across the planet. However, the population level effects of macroplastic pollution remain difficult and costly to quantify. As a result, there is a need for alternative approaches to evaluate species risk to plastic pollution and inform management needs. We apply a trait-based framework for macroplastic pollution to develop a relative vulnerability index-informed by three dimensions: likelihood of exposure, species' sensitivity, and population resilience-for marine mammals, seabirds, and sea turtles found in Hawai'i. This index ranks 63 study species based on their population level vulnerability to macroplastic pollution, with the highest scoring species being the most vulnerable. Our results indicate that ducks, waders, and noddies with large populations were the least vulnerable to macroplastics, while the most vulnerable were the Hawaiian monk seal, sea turtles, baleen whales, and some albatross and petrel species. This index can inform species in need of population monitoring in Hawai'i, and direct other management priorities (e.g., locations for clean-ups or booms). More broadly, this work exemplifies the value of qualitative risk assessment approaches for better understanding the population level effects of macroplastic pollution and showcases how vulnerability indices can be used to inform management priorities.

Solid waste ingestion by marine megafauna on Southeast Brazilian coast

The disparities in the ecology and behavior of marine megafauna may influence their susceptibility to solid waste ingestion; however, this relationship has been underestimated along the Brazilian coast. We analyzed a dataset of 7261 marine megafauna (45 species) necropsied to investigate the influence of their foraging strategies on solid waste ingestion. A total of 1240 specimens ingested solid waste with over 55 % (689) that ingested plastic. Sea turtles were the most impacted taxa, while cetaceans present the lowest frequency. Some characteristics such as regurgitation (e.g., Suliformes and Charadriiformes seabirds) or possess complex foraging strategies (e.g., cetaceans echolocation) may mitigate the negative effects of solid waste ingestion. Also, the variability over the monitoring program likely was influenced by the volume of pollutants transported to the ocean during flood periods, and level of staff training. This study serves as a valuable baseline for solid waste management actions and marine megafauna conservation efforts.

Marina Observation of Sea Turtles: Establishing a Database of Intracoastal Waterway Green Sea Turtles in Northeast Florida

As conservation efforts regarding green sea turtles, Chelonia mydas, continue, it is imperative to document behaviors and foraging habits/habitats of understudied populations. We have conducted an 18-month study dedicated to photographing the local population feeding alongside floating docks within the Guana Tolomato Matanzas estuary to determine the capability of matching head scale patterns efficiently through a pattern matching program: HotSpotter. To date, 195 unique sea turtles have been identified between two different marinas located in St. Augustine, FL. Of these, 98 were spotted more than once, with 39 of them being "tracked" for longer than a year. Temperature trends were also monitored in conjunction, showing that more individuals appeared during the warmer months of the year. The evidence, overall, indicates that these locations host a resident population of green sea turtles, leading to the need for a discussion on potential threats originating from the usage of these marinas by humans.

'Eye in the sky': Off-the-shelf unmanned aerial vehicle (UAV) highlights exposure of marine turtles to floating litter (FML) in nearshore waters of Mayo Bay, Philippines

Litter is a serious threat to the marine environment, with detrimental effects on wildlife and marine biodiversity. Limited data as a result of funding and logistical challenges in developing countries hamper our understanding of the problem. Here, we employed commercial unmanned aerial vehicle (UAV) as a cost-effective tool to study the exposure of marine turtles to floating marine litter (FML) in waters of Mayo Bay, Philippines. A quadcopter UAV was flown autonomously with on-board camera capturing videos during the flight. Still frames were extracted when either turtle or litter were detected in post-flight processing. The extracted frames were georeferenced and mapped using QGIS software. Results showed that turtles are highly exposed to FML in nearshore waters. Moreover, spatial dependence between FML and turtles was also observed. The study highlights the effectiveness of UAVs in marine litter research and underscores the threat of FML to turtles in nearshore waters.

Drivers of litter ingestion by sea turtles: Three decades of empirical data collected in Atlantic Europe and the Mediterranean

Sea turtles are considered as bio-indicators for monitoring the efficiency of restoration measures to reduce marine litter impacts on health. However, the lack of extended and standardised empirical data has prevented the accurate analysis of the factors influencing litter ingestion and the relationships with individual health. Historic data collected from 1988 and standard data collected from 2016 were harmonised to enable such analyses on necropsied loggerhead turtles (Caretta caretta) in eight Mediterranean and North-East Atlantic countries. Litter was found in 69.24 % of the 1121 individuals, mostly single-use and fishing-related plastics. Spatial location, sex and life history stage explained a minor part of litter ingestion. While no relationships with health could be detected, indicating that all individuals can be integrated as bio-indicators, the mechanistic models published in literature suggest that the high proportion of plastics in the digestive contents (38.77 % per individual) could have long-term repercussions on population dynamics.

Recent advances on the transport of microplastics/nanoplastics in abiotic and biotic compartments

Plastics enter the environment and break up into microplastics (MPs) and even nanoplastics (NPs) by biotic and abiotic weathering. These small particles are widely distributed in the environmental media and extremely mobile and reactive, easily suspending in the air, infiltrating into the soil, and interacting with biota. Current research on MPs/NPs is either in the abiotic or biotic compartments, with little attention paid to the fact that the biosphere as a whole. To better understand the complex and continuous movement of plastics from biological to planetary scales, this review firstly discusses the transport processes and drivers of microplastics in the macroscopic compartment. We then summarize insightfully the uptake pathways of MPs/NPs by different species in the ecological compartment and analyze the internalization mechanisms of NPs in the organism. Finally, we highlight the bioaccumulation potential, biomagnification effects and trophic transfer of MPs/NPs in the food chain. This work is expected to provide a meaningful theoretical body of knowledge for understanding the biogeochemical cycles of plastics.

Hidden problems in geological heritage sites: The microplastic issue on Saint Mary's Island, India, Southeast Arabian Sea

Microplastics (MPs) have become a dominant constituent of several oceanic islands. This study focuses on the occurrence and distribution of MPs present in the beach sediments of Saint Mary's Island (SMI), a geological heritage site located in the south-eastern part of the Arabian Sea. The average (standard deviation) abundance of MPs on this island was 97.18 (80.49) particles/kg. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy revealed that MPs are composed of high-density polyethylene (HDPE), low-density polyethylene (LDPE), polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyamide (PA). Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) highlighted the presence of Cr, As, Pb, and Cd (harmful pollutants) on MP surfaces. The MPs in the SMI are largely contributed by the nearby fishing harbour, touristic beaches and estuaries. The results of this study, act as a starting point for continuous environmental monitoring in this unique region of the world.

Multivariate analysis of biologging data reveals the environmental determinants of diving behaviour in a marine reptile

Diving behaviour of 'surfacers' such as sea snakes, cetaceans and turtles is complex and multi-dimensional, thus may be better captured by multi-sensor biologging data. However, analysing these large multi-faceted datasets remains challenging, though a high priority. We used high-resolution multi-sensor biologging data to provide the first detailed description of the environmental influences on flatback turtle (Natator depressus) diving behaviour, during its foraging life-history stage. We developed an analytical method to investigate seasonal, diel and tidal effects on diving behaviour for 24 adult flatback turtles tagged with biologgers. We extracted 16 dive variables associated with three-dimensional and kinematic characteristics for 4128 dives. K-means and hierarchical cluster analyses failed to identify distinct dive types. Instead, principal component analysis objectively condensed the dive variables, removing collinearity and highlighting the main features of diving behaviour. Generalized additive mixed models of the main principal components identified significant seasonal, diel and tidal effects on flatback turtle diving behaviour. Flatback turtles altered their diving behaviour in response to extreme tidal and water temperature ranges, displaying thermoregulation and predator avoidance strategies while likely optimizing foraging in this challenging environment. This study demonstrates an alternative statistical technique for objectively interpreting diving behaviour from multivariate collinear data derived from biologgers.

Polymer composition analysis of plastic debris ingested by loggerhead turtles (Caretta caretta) in Southern Tyrrhenian Sea through ATR-FTIR spectroscopy

The ingestion of anthropogenic plastic debris by marine wildlife is widespread in the Mediterranean Sea. The endangered status (in the IUCN Red List) of Loggerhead turtle (Caretta caretta, Linnaeus, 1758) is a consequence of its vulnerability. In this study, macro-/meso-plastics (5-170 mm) collected from faeces of twelve loggerhead turtles rescued (live) in the Aeolian Archipelago (Southern Tyrrhenian Sea, Italy) were analyzed by size, weight, shape, color and polymer type through Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR). The defecation rate during hospitalization (7-14 days) varied among turtles (from 0.08 to 0.58). The mean number of plastic expulsions (2.7 ± 1.8 items for turtle) was higher during the 5th day of hospitalization (Kruskal-Wallis test, P = 0.01). However, the mean number of plastic-like items defecated during the common days of hospitalization did not vary among turtles (Kruskal-Wallis test, P > 0.05). All turtles were found to have ingested plastic. A total of 114 debris items were recovered from their faeces, 113 of which were identified as plastic. Their color was mostly white-transparent (64.9%) and light (19.3%). Shape was mainly fragments (52.6%), sheets (38.6%), followed by nylon, net-fragments, elastic plastic, foamed plastic and industrial granules (8.8%). Meso-plastics (5-25 mm) represented 72% of the total number of debris and were found more frequently in turtle with Curved Carapace Length (CCL) ≤ 60 cm (CCL = 30-60 cm, n = 5) than those with CCL >60 cm (CCL = 60-71 cm, n = 7). Plastic items were composed mainly of polyethylene (48.2%) and polypropylene (34.2%). Polypropylene (R² = 0.95, P < 0.001) and polyisoprene (R² = 0.45, P = 0.017) were more common in meso-plastics while polyethylene (R² = 0.44, P < 0.01) in macro-plastics. Finally, high-density polyethylene, polyvinyl chloride, polyamide and polyurethane were also found in some turtles. This study reveals high spreads of plastic contamination in faeces of both turtles with CCL ≤60 cm and CCL >60 cm, particularly vulnerable to the increasing quantity of floating plastic into their foraging sites highlighting the need of further research to associate debris ingestion with turtle diet and their size.

Can we quantify the aquatic environmental plastic load from aquaculture?

Aquaculture provides livelihoods for hundreds of millions of people, but it also forms a significant source of plastic litter that poses a serious hazard to aquatic ecosystems. How to assess and subsequently manage plastic loads from aquaculture is a pending and pressing issue for aquaculture sustainability, and an important concern for water environment monitoring and management. In this study, we developed the first framework for estimating plastic litter from aquaculture by combining data from satellite remote sensing, drones, questionnaires, and in situ measurements. By acquiring multidimensional (human and nature) and multiscale (centimeter to basin scale) data, this framework helped us understand the aquaculture farming patterns and its spatial and temporal evolution, and thus estimate the plastic load it generates and suggest effective management approaches. Applying this framework, we assessed the marine plastic load from oyster floating raft farming in the Maowei Sea, a typical mariculture bay in China, with an increasing farming area. Approximately 3840 tons of plastic waste is expected to be discharged into the sea in the next four years (the average service life of a floating raft) without improvements in aquaculture waste management. Strengthening governance, timely plastic removal, innovative replacement, and transforming farmers' behavior patterns are recommended as the subsequent measures for plastic management. This framework can be extended to other regions and other aquaculture patterns, and is applicable to local, regional, and global aquaculture plastic litter assessments. It is a source-based method for evaluating plastic pollution that is more conducive to subsequent plastic management than traditional post-contamination environmental monitoring. In the context of the global expansion of mariculture and the global commitment to action to combat plastic pollution, this approach could play a critical role in the investigation and management of plastic waste in aquatic environments.

Phthalate esters (PAEs) concentration pattern reflects dietary habitats (δ13C) in blood of Mediterranean loggerhead turtles (Caretta caretta)

Phthalic acid esters (PAEs) are classified as endocrine disruptors, but it remains unclear if they can enter the marine food-web and result in severe health effects for organisms. Loggerhead turtles (Caretta caretta) can be chronically exposed to PAEs by ingesting plastic debris, but no information is available about PAEs levels in blood, and how these concentrations are related to diet during different life stages. This paper investigated, for the first time, six PAEs in blood of 18 wild-caught Mediterranean loggerhead turtles throughout solid-phase extraction coupled with gas chromatography-ion trap/mass spectrometry. Stable isotope analyses of carbon and nitrogen were also performed to assess the resource use pattern of loggerhead turtles. DEHP (12-63 ng mL^-1) and DBP (6-57 ng mL^-1) were the most frequently represented PAEs, followed by DiBP, DMP, DEP and DOP. The total PAEs concentration was highest in three turtles (124-260 ng mL^-1) whereas three other turtles had concentrations below the detection limit. PAEs were clustered in three groups according to concentration in all samples: DEHP in the first group, DBP, DEP, and DiBP in the second group, and DOP and DMP in the third group. The total phthalates concentration did not differ between large-sized (96.3 ± 86.0 ng mL^-1) and small-sized (67.1 ± 34.2 ng mL^-1) turtles (p < 0.001). However, DMP and DEP were found only in large-sized turtles and DiBP and DBP had higher concentrations in large-sized turtles. On the other hand, DEHP and DOP were found in both small- and large-sized turtles with similar concentrations, i.e. ~ 21.0/32.0 ng mL^-1 and ~ 7^.1/9.9 ng mL^-1, respectively. Winsored robust models indicated that δ¹³C is a good predictor for DBP and DiBP concentrations (significant Akaike Information criterion weight, AIC_wt). Our results indicate that blood is a good matrix to evaluate acute exposure to PAEs in marine turtles. Moreover, this approach is here suggested as a useful tool to explain the internal dose of PAEs in term of dietary habits (δ¹³C), suggesting that all marine species at high trophic levels may be particularly exposed to PAEs, despite their different dietary habitats and levels of exposure.

Polymer composition assessment suggests prevalence of single-use plastics among items ingested by loggerhead sea turtles in the western mediterranean sub-region

The ingestion of plastic is becoming a major concern for various species and particularly for marine turtles across the globe. The loggerhead sea turtle (Caretta caretta) was recently chosen by the European Commission as a bio-indicator for plastic pollution within the Mediterranean basin. We further investigated which items this key species is more prone to ingest, following the standardised Marine Strategy Framework Directive protocols. Moreover, we integrated to this protocol the Fourier Transform Infrared Spectroscopy, which allowed us to determine the polymer type of each item. We analysed samples from 226 sea turtles from 2008 to 2017 in two areas of the western Mediterranean sub-region (sensu MSFD). In the Lazio area we found a frequency of occurrence of plastic ingestion of 78.33%, while in Sardinia 41.79%. The analysis of the litter categories, among all individuals, highlights a prevalence of user-sheet (Use-She; 69.13%) and user-fragment plastics (Use-Fra; 20.84%). In addition, the polymer analysis showed a dominance of polyethylene (65.98%) and polypropylene (26.23%). As a result, by looking at other works that have investigated polymer types and items sources, we are able to infer that 77.25% of the objects ingested by the C. caretta individuals are attributable to disposable daily-life objects managed in an improper way. Therefore, C. caretta apart from being an efficient bio-indicator for plastic pollution, highlighting spatial and temporal concentration differences, it could also be used to verify the effectiveness of the Single-use Plastic Directive (EU 2019/904).

Junk food: A preliminary analysis of ingested marine debris by hawksbill Eretmochelys imbricata and olive ridley Lepidochelys olivacea sea turtles (Testudines: Cheloniidae) from the eastern coast of the United Arab Emirates

For the first time, the qualitative and quantitative characteristics of marine debris ingested by six hawksbill (Eretmochelys imbricata) and seven olive ridley (Lepidochelys olivacea) sea turtles from the Gulf of Oman coast of the United Arab Emirates were investigated. The numeric and gravimetric proportions of ingested marine debris obtained from the esophagus, stomach and intestines were quantified following categories of presumed sources, Marine Strategy Framework Directive (MSFD), rigidity, color and plastic polymer types. Marine debris was observed in 28.6% of olive ridley (x̅: 2.00 items; 4.83 g) and 83.3% of hawksbill specimens (x̅: 6.00 ± 2.32 items; 0.32 ± 0.24 g). Overall, the results of this preliminary study suggest that hawksbill sea turtles were ingesting marine debris at higher frequencies and that plastics were observed to be the most predominant debris ingested. However, non-plastic rubbish, particularly metallic fishing gear (fish hooks and fish traps), were observed to present lethal hazards for both species.

Battling the known unknowns: a synoptic review of aquatic plastics research from Australia, the United Kingdom and China

Plastic pollution is a global environmental and human health issue, with plastics now ubiquitous in the environment and biota. Despite extensive international research, key knowledge gaps ("known unknowns") remain around ecosystem-scale and human health impacts of plastics in the environment, particularly in limnetic, coastal and marine systems. Here we review aquatic plastics research in three contrasting geographic and cultural settings, selected to present a gradient of heavily urbanised (and high population density) to less urbanised (and low population density) areas: China, the United Kingdom (UK), and Australia. Research from each country has varying environmental focus (for example, biota-focussed studies in Australia target various bird, fish, turtle and seal species, while UK and China-based studies focus on commercially important organisms such as bivalves, fish and decapods), and uses varying methods and reporting units (e.g. mean, median or range). This has resulted in aquatic plastics datasets that are hard to compare directly, supporting the need to converge on standardised sampling methods, and bioindicator species. While all the study nations show plastics contamination, often at high levels, datasets are variable and do not clearly demonstrate pollution gradients.

Selectivity of marine-debris ingestion by juvenile green turtles (Chelonia mydas) at a South American World Heritage Listed area

Beaches in southern Brazil have substantial marine debris and strandings of dead juvenile green turtles (Chelonia mydas). This study investigates associations by quantifying marine debris (1) ingested among new (<40 cm curved carapace length; CCL) and older (≥40 cm CCL) juvenile C. mydas recruits; (2) concentrations on beach transects; and then (3) selective ingestion by C. mydas. Among 40 C. mydas (2014-2015), 93% had ingested debris, with smaller individuals having proportionally more. Sheet-like and hard plastics were the most frequently ingested, and commonly concentrated on beach transects. Estuarine beach transects had more debris than those facing the ocean. Selectivity analyses revealed all C. mydas avoided white miscellaneous debris and straws, while smaller conspecifics selected clear sheet-like plastics and avoided coloured ones. The results reiterate a need for long-term reforms to regional waste disposal and short-term initiatives encouraging social awareness to avoid key plastics and reduce ingestion by C. mydas.

Plastic additive oleamide elicits hyperactivity in hermit crabs

Numerous studies have estimated the abundance of plastics in our oceans and warned of its threat to wildlife. However, mechanisms underlying its attractiveness to marine life remain unclear. Though visual similarities to food sources have been suggested, recent studies show that biofouled plastics release dimethyl sulfide which marine fauna mistake for food whilst foraging. Our study shows that the plastic additive oleamide (9-octadecenamide) attracts hermit crabs (Pagurus bernhardus). Respiration rate increases significantly in response to low concentrations of oleamide, and hermit crabs show a behavioral attraction comparable to their response to the feeding stimulant betaine. Oleamide has a striking resemblance to the necromone oleic acid, a chemical released by arthropods during decomposition. As scavengers, hermit crabs may misidentify oleamide as a food source, creating an olfactory trap. As such, our short communication demonstrates that additive leaching may play a significant role in the attraction of marine life to plastic.

Comparison of the polarization contrast of gelatinous zooplankton and a transparent single-use plastic bag-Implications for marine animals

Plastic pollution in the ocean is an increasingly detrimental issue for marine organisms. As a form of polarized light pollution, transparent plastic debris may be more visible and pose additional threats to organisms that can detect and interpret polarized light. Plastic can mimic the visual features of common marine prey items, such as transparent gelatinous zooplankton, which may lead to more significant plastic ingestion. We measured, in situ, the polarization and radiance contrast between a transparent plastic bag and gelatinous zooplankton with an underwater video polarimeter. The plastic bag had significantly higher polarization contrast than the gelatinous zooplankton, yet both shared similar radiance contrasts. This higher polarization contrast may contribute to the observed high ingestion rates of transparent plastic by marine organisms. Further study into the connection between polarization-sensitive organisms and plastic ingestion is recommended.

First record of plastic debris in the stomach of a hooded seal pup from the Greenland Sea

Plastic debris is globally found around the world and the remote Arctic is no exception. Arctic true seals are sentinel species of marine pollution and represent the link between marine food webs and Arctic apex predators like polar bears and humans. With regard to true seals, ingested macroplastics have never been reported in an Arctic species. We harvested 10 harp seals Pagophilus groenlandicus and 8 hooded seals Cystophora cristata from the breeding grounds in the pack ice of the Greenland Sea. The digestive tract was inspected exclusively for the presence of macroplastics (>5 mm). Two pieces of single-use plastic were found in the stomach of a weaned hooded seal pup. This study indicates that young Arctic marine predators may ingest macroplastics, and therefore may be at risk during their early stages of life due to human caused plastic pollution even in the remote Arctic pack ice.

Plastic ingestion by juvenile green turtles (Chelonia mydas) off the coast of Southern Brazil

Five of the seven extant sea turtle species in the world forage on the coast of Southern Brazil at least in some stage of their life cycle. The green turtle Chelonia mydas frequently strands on beaches of Rio Grande do Sul State. The species is currently classified as vulnerable to extinction in the region, and pollution by marine debris is one of the most conspicuous threats to its conservation. In this study, we quantified and characterized plastic ingestion by juvenile green turtles in waters off the southern Brazilian coast between 2013 and 2016. We analysed the gastrointestinal content of 17 beached carcasses and registered debris ingestion in 15 individuals (88%). On average, each green turtle ingested 38.4 ± 88.5 plastic fragments. White and transparent plastic bags and plastic sheets were predominant. Our results indicate a high interaction between juvenile green turtles and marine debris off the coast of Southern Brazil.

The nexus of macroplastic and microplastic research and plastic regulation policies in the Philippines marine coastal environments

The Philippines was reported as one of the top plastic polluters (macroplastics and microplastics (MPs)) to the marine coastal environment, which necessitated the development and enforcement of plastic regulation policies. However, the nexus between the growing research on macroplastic/MP and the plastic regulation policies in the country is unexplored. Current review suggests that macroplastic/MP research in the Philippines is still in its infancy owing to methodological and technological constraints to apportion the sources and fluxes, characterize macroplastics/MPs, and identify influencing socio-environmental factors. While government efforts are underway, it is also unclear if local researches on macroplastics/MPs were the basis in institutionalizing the existing plastic regulation policies. Therefore the nexus between the researches carried out on this problem and the policies enforced cannot be concluded. Overall, this review presents gaps on the macroplastic/MP research needing more work on the problem to establish a sound science plastic regulation policy.

Abundance and characteristics of microplastics in retail mussels from Cape Town, South Africa

With the increased occurrence of plastics in the marine environment, ingestion of microplastics (MPs) by marine invertebrates such as mussels is increasing globally. This study investigated the occurrence of microplastics in mussels sold at supermarkets and wholesalers in Cape Town, South Africa. Soft tissue was extracted from mussels, digested and identified by microscopy and FTIR-ATR. MP filaments (70%) and fragments (30%) were the only types of MPs identified and an average of 0.04 MPs/g soft tissue and 3.8 MPs/mussel recorded. Blue/green (44%) and black/grey (40%), smaller than 2000 μm were the most prominent MPs recorded and the main polymer type was filamentous polyethylene terephthalate (PET). Our results suggest that retail mussels in Cape Town do not contain as high concentrations of MPs when compared to other investigations and routine monitoring of seafood in the country is suggested.

Disposal Behavior of Used Masks during the COVID-19 Pandemic in the Moroccan Community: Potential Environmental Impact

The spread of coronavirus disease-2019 (COVID-19) levied on the Moroccan authorities to increase their mask production capacity, which reached up to 12 million facemask units produced per day. This increase in personal protective equipment (PPE) production and consumption is an efficient tool to address the spread of COVID-19. However, this results in more plastic and microplastic debris being added into the land and marine environments, which will harm the ecosystem, wildlife, and public health. Such a situation needs deep individual behavior observation and tracking, as well as an assessment of the potential environmental impact of this new type of waste. For this reason, we assessed the Moroccan population's behavior regarding the use and disposal of facemasks and gloves. An exploratory survey was prepared and shared via social media and email with the population of Rabat-Salé-Kénitra and Casablanca-Settat regions. Additionally, we calculated the estimated number and weight of daily and weekly PPE used and generated by the studied regions. The survey showed that 70% of the respondents threw their discarded masks and gloves in house trash or trash bins after their first use, whereas nearly 30% of respondents admitted that they did not wear masks because they did not leave their homes during the lockdown, while from the 70% of facemask users, more than five million (equivalent to 40,000 kg) of facemasks would be generated and disposed of daily by the community of these regions, which presents 35% of the total engendered facemask waste in Morocco. Accordingly, the environment impact of facemasks showed that the greenhouse gas footprint is about 640 kT CO2 eq./year for the whole of Morocco, while the energy footprint is around 60,000 GWh/year. Furthermore, an urgent multidisciplinary environmental assessment of the potential impact of PPE must be conducted among the 12 Moroccan regions. This study demonstrated the real impact of the COVID-19 PPE on human behavior and the environment and suggests a need for providing new didactic management of facemasks and gloves.

Exploiting common senses: sensory ecology meets wildlife conservation and management

Multidisciplinary approaches to conservation and wildlife management are often effective in addressing complex, multi-factor problems. Emerging fields such as conservation physiology and conservation behaviour can provide innovative solutions and management strategies for target species and systems. Sensory ecology combines the study of 'how animals acquire' and process sensory stimuli from their environments, and the ecological and evolutionary significance of 'how animals respond' to this information. We review the benefits that sensory ecology can bring to wildlife conservation and management by discussing case studies across major taxa and sensory modalities. Conservation practices informed by a sensory ecology approach include the amelioration of sensory traps, control of invasive species, reduction of human-wildlife conflicts and relocation and establishment of new populations of endangered species. We illustrate that sensory ecology can facilitate the understanding of mechanistic ecological and physiological explanations underlying particular conservation issues and also can help develop innovative solutions to ameliorate conservation problems.

Understanding individual and population-level effects of plastic pollution on marine megafauna

Plastic pollution is increasing rapidly throughout the world’s oceans and is considered a major threat to marine wildlife and ecosystems. Although known to cause lethal or sub-lethal effects to vulnerable marine megafauna, population-level impacts of plastic pollution have not been thoroughly investigated. Here, we compiled and evaluated information from peer-reviewed studies that reported deleterious individual-level effects of plastic pollution on air-breathing marine megafauna (i.e. seabirds, marine mammals, and sea turtles) worldwide, highlighting those that assessed potential population-level effects. Lethal and sub-lethal individual-level effects included drowning, starvation, gastrointestinal tract damage, malnutrition, physical injury, reduced mobility, and physiological stress, resulting in reduced energy acquisition and assimilation, compromised health, reproductive impairment, and mortality. We found 47 studies published between 1969 and 2020 that considered population-level effects of plastic entanglement (n = 26), ingestion (n = 19), or both (n = 2). Of these, 7 inferred population-level effects (n = 6, entanglement; n = 1, ingestion), whereas 19 lacked evidence for effects (n = 12, entanglement; n = 6, ingestion; n = 1, both). However, no study in the past 50 yr reported direct evidence of population-level effects. Despite increased interest in and awareness of the presence of plastic pollution throughout the world’s oceans, the extent and magnitude of demographic impacts on marine megafauna remains largely unassessed and therefore unknown, in contrast to well-documented effects on individuals. Addressing this major assessment gap will allow researchers and managers to compare relative effects of multiple threats—including plastic pollution—on marine megafauna populations, thus providing appropriate context for strategic conservation priority-setting.

Ocular ultrasonography of sea turtles

BACKGROUND

Environmental changes contribute to the development of ophthalmic diseases in sea turtles, but information on their eye biometrics is scarce. The aim of this study was to describe ophthalmic ultrasonographic features of four different sea turtle species; Caretta caretta (Loggerhead turtle; n = 10), Chelonia mydas (Green turtle; n = 8), Eretmochelys imbricata (Hawksbill turtle; n = 8) and Lepidochelys olivacea (Olive ridley; n = 6) under human care. Corneal thickness, scleral ossicle width and thickness, anterior chamber depth, axial length of the lens, vitreous chamber depth and axial globe length were measured by B-mode sonography with a linear transducer. Carapace size and animal weight were recorded. A sonographic description of the eye structures was established.

RESULTS

The four species presented an ovate eyeball, a relatively thin cornea, and a small-sized lens positioned rostrally in the eye bulb, near the cornea, resulting in a shallow anterior chamber. The scleral ossicles did not prevent the evaluation of intraocular structures, even with a rotated eye or closed eyelids; image formation beyond the ossicles and measurements of all proposed structures were possible. B-mode sonography was easily performed in all animals studied. The sonographic characteristics of the eye were similar among the four species. Since there was a correlation between the size of the eye structures and the size of the individual, especially its carapace size, the differences found between E. imbricata and Caretta caretta are believed to be due to their overall difference in size.

CONCLUSIONS

Sonography is a valuable tool in ophthalmic evaluation of these species. Only minor differences were found between the species in this study, reinforcing their phylogenetic proximity and their similar functions and habitats.

Reporting Guidelines to Increase the Reproducibility and Comparability of Research on Microplastics

The ubiquitous pollution of the environment with microplastics, a diverse suite of contaminants, is of growing concern for science and currently receives considerable public, political, and academic attention. The potential impact of microplastics in the environment has prompted a great deal of research in recent years. Many diverse methods have been developed to answer different questions about microplastic pollution, from sources, transport, and fate in the environment, and about effects on humans and wildlife. These methods are often insufficiently described, making studies neither comparable nor reproducible. The proliferation of new microplastic investigations and cross-study syntheses to answer larger scale questions are hampered. This diverse group of 23 researchers think these issues can begin to be overcome through the adoption of a set of reporting guidelines. This collaboration was created using an open science framework that we detail for future use. Here, we suggest harmonized reporting guidelines for microplastic studies in environmental and laboratory settings through all steps of a typical study, including best practices for reporting materials, quality assurance/quality control, data, field sampling, sample preparation, microplastic identification, microplastic categorization, microplastic quantification, and considerations for toxicology studies. We developed three easy to use documents, a detailed document, a checklist, and a mind map, that can be used to reference the reporting guidelines quickly. We intend that these reporting guidelines support the annotation, dissemination, interpretation, reviewing, and synthesis of microplastic research. Through open access licensing (CC BY 4.0), these documents aim to increase the validity, reproducibility, and comparability of studies in this field for the benefit of the global community.

Quantifying impacts of plastic debris on marine wildlife identifies ecological breakpoints

Quantifying sublethal effects of plastics ingestion on marine wildlife is difficult, but key to understanding the ontogeny and population dynamics of affected species. We developed a method that overcomes the difficulties by modelling individual ontogeny under reduced energy intake and expenditure caused by debris ingestion. The predicted ontogeny is combined with a population dynamics model to identify ecological breakpoints: cessation of reproduction or negative population growth. Exemplifying this approach on loggerhead turtles, we find that between 3% and 25% of plastics in digestive contents causes a 2.5-20% reduction in perceived food abundance and total available energy, resulting in a 10-15% lower condition index and 10% to 88% lower total seasonal reproductive output compared to unaffected turtles. The reported plastics ingestion is insufficient to impede sexual maturation, but population declines are possible. The method is readily applicable to other species impacted by debris ingestion.

Debris ingestion and nutritional niches in estuarine and reef green turtles

Little attention has been drawn toward the effects of marine debris ingestion in relation to nutrient acquisition and fitness consequences. We tested whether anthropogenic debris ingestion influence the nutritional niches of endangered green turtles (Chelonia mydas) in estuarine and reef habitats on the Brazilian coast. Our results showed that estuarine turtles consumed diets with lower proportional wet mass composition of protein (P) and water (W) than their reef conspecifics. The amounts of debris, mostly plastics, retrieved from the digestive tracts of estuarine turtles were higher compared with those individuals from reefs. The realized nutritional niche from estuarine turtles was subject to the debris density in the environment, lack of benthic food resources available and the surface foraging behavior, likely preventing them from reaching their nutritional goals and resulting in lower fitness. The study provides critical information for the management and conservation of ecologically threatened individuals, populations, and their natural habitats.

Micro- and nano-plastics in marine environment: Source, distribution and threats - A review

Plastic litters have become the predominant components of marine debris due to extensive consumption plastics and mismanagement of plastic wastes. As part of the problem, microplastics (MPs) and nanoplastics (NPs) have generated special concerns due to their unique features that make them easy to transfer among oceans in the marine ecosystem, across different trophic levels inside the food web, and even across different tissues inside contaminated animals. Studies have demonstrated the almost omnipresence of MPs in the marine ecosystem, which present serious threats to the health of marine animals, causing symptoms such as malnutrition, inflammation, chemical poisoning, growth thwarting, decrease of fecundity, and death due to damages at individual, organ, tissue, cell, and molecule levels. The information on NPs in the marine ecosystem has been scarce due to the challenges in sampling and detecting these nano-scaled entities. In vitro and in vivo experiments have demonstrated that NPs have the potential to penetrate different biological barriers including the gastrointestinal barrier and the brain blood barrier and have been detected in many important organs such as brains, the circulation system and livers of sampled animals.

Ingestion of macroplastics by odontocetes of the Greek Seas, Eastern Mediterranean: Often deadly!

Plastic pollution is an omnipresent problem that threatens marine animals through ingestion and entanglement. Marine mammals are no exception to this rule but their interaction with plastic remains understudied in the Mediterranean Sea. Here we highlight this problem by analyzing the stomach contents of 34 individuals from seven odontocete species stranded in Greece. Macroplastic (>5 mm) was found in the stomachs of nine individuals from four species (harbour porpoise Phocoena phocoena, Risso's dolphin Grampus griseus, Cuvier's beaked whale Ziphius cavirostris and sperm whale Physeter macrocephalus) with the highest frequency of occurrence in sperm whales (60%). Gastric blockage from plastic was presumably lethal in three cases, with plastic bags being the most common finding (46%). Plastic ingestion is of particular conservation concern for the endangered Mediterranean sperm whales. A regular examination of stranded cetaceans with a standardised protocol is critical for allowing spatiotemporal comparisons within and across species.

Diet-related selectivity of macroplastic ingestion in green turtles (Chelonia mydas) in the eastern Mediterranean

Understanding the drivers of key interactions between marine vertebrates and plastic pollution is now considered a research priority. Sea turtles are primarily visual predators, with the ability to discriminate according to colour and shape; therefore these factors play a role in feeding choices. Classification methodologies of ingested plastic currently do not record these variables, however here, refined protocols allow us to test the hypothesis that plastic is selectively ingested when it resembles the food items of green turtles (Chelonia mydas). Turtles in the eastern Mediterranean displayed strong diet-related selectivity towards certain types (sheet and threadlike), colours (black, clear and green) and shapes (linear items strongly preferred) of plastic when compared to the environmental baseline of plastic beach debris. There was a significant negative relationship between size of turtle (curved carapace length) and number/mass of plastic pieces ingested, which may be explained through naivety and/or ontogenetic shifts in diet. Further investigation in other species and sites are needed to more fully ascertain the role of selectivity in plastic ingestion in this marine vertebrate group.

Study on the capability and characteristics of heavy metals enriched on microplastics in marine environment

In this study we examined the adsorption characteristics of heavy metals on microplastic through laboratory test and field test. We demonstrated that polyvinyl chloride, polypropylene, polyethylene, polyamides and polyformaldehyde could adsorb lead, copper and cadmium in the simulating solution, and the heavy metals showed higher adsorbance on PVC and PP particles compared with PA, PE and POM. In the field experiment, the adsorption rate and concentration of heavy metals varied significantly among different plastic types and locations. The adsorbability of PP and PVC toward Pb and Mn was strongly correlated with the metal concentration in seawater. We also compared the adsorption quantity of PP to heavy metals and polycyclic aromatic hydrocarbons which resulted in an order of magnitude within one month. During the adsorption, the surface morphology of the microplastics which were washed and corroded by seawater underwent a rough-smooth-rough changing process, and different materials had great differences.

Debris ingestion by carnivorous consumers: Does the position in the water column truly matter?

The hypothesis that carnivorous consumers associated with the seabed are more likely to ingest marine debris was tested based on stomach content analysis of fish (Trichiurus lepturus and species of Ariidae) and cetaceans (Sotalia guianensis and Pontoporia blainvillei). Among 596 stomach contents, only 22 (3.7%) contained debris. The debris was flexible plastic, nylon yard, paper, latex, styrofoam and cigarette filter. The proportion of stomach contents with debris varied among species: P. blainvillei (pelagic demersal consumer) presented the highest frequency of ingestion (15.7%), while T. lepturus (pelagic consumer), S. guianensis (pelagic consumer) and Ariidae (demersal consumer) presented similar frequencies (1.3-1.8%). Therefore, a feeding site in the water column does not predict the probability of debris ingestion. Concerning these species, this probability seems to be more associated with prey-capture strategies (or feeding behavior), regardless of debris availability in the environment.

Scavenging as a pathway for plastic ingestion by marine animals

Plastic pollution is prevalent worldwide and affects marine wildlife from urbanized beaches to pristine oceanic islands. However, the ecological basis and mechanisms that result in marine animal ingestion of plastic debris are still relatively unknown, despite recent advances. We investigated the relationship between scavenging behavior and plastic ingestion using green turtles, Chelonia mydas, as a model. Diet analysis of C. mydas showed that sea turtles engaging in scavenging behavior ingested significantly more plastic debris than individuals that did not engage in this foraging strategy. We argue that opportunistic scavenging behavior, an adaptive behavior in most marine ecosystems, may now pose a threat to a variety of marine animals due to the current widespread plastic pollution found in oceans.

Microplastic exposure and effects in aquatic organisms: A physiological perspective

The impact of microplastics (MPs) on aquatic life, given their ubiquitous presence in the water compartment, represents a growing concern. Consistently, scientific knowledge is advancing rapidly, although evidence on actual adverse effects is still highly fragmented. This paper summarizes the recent literature on MP impacts on aquatic organisms in an attempt to link routes of uptake, possible alterations of physiological processes, and outcomes at different levels of biological organization. Animal feeding strategies and MP biodistribution is discussed, alongside with relevant effects at molecular, cellular, and systemic level. Pathways from animal exposure to apical physiological responses are examined to define the relevance of MPs for animal health, and to point out open questions and research gaps. Emphasis is given to emerging threats posed by leaching of plastic additives, many of which have endocrine disruption potential. The potential role of MPs as substrates for microorganism growth and vehicle for pathogen spreading is also addressed.

Can plastics affect near surface layer ocean processes and climate?

Plastics in the ocean are of great concern nowadays, and are often referred to as the apocalyptic twin of climate change in terms of public fear and the problems they pose to the aquatic and terrestrial environment. The number of studies focusing on the ecological effects and toxicity of plastics has substantially increased in the last few years. Considering the current trends in the anthropogenic activities, the amount of plastics entering the world oceans is increasing exponentially, but the oceans have a low assimilative capacity for plastics and the near-surface layer of it is a finite space. If loading of the oceans with plastics continues at the current rate, the thin sea surface microlayer can have a substantial amount of plastics comparable to the distribution of phytoplankton, at least in the major oceanic gyres and coastal waters in the future. Also, processes like biofouling can cluster microplastics in dense fields in the near-surface layer. Plastics can contribute to the warming or cooling of the water column by scattering and attenuating incoming solar radiation, leading to a potential change in the optical and other physico-chemical properties of the water column. We propose a new notion that changes in solar radiation in the water column due to the plastics have the potential to affect the physical processes in the ocean surface and near-surface layers, and can induce climate feedback cycles. The future can be very different, if plastics evolve as one of the key players affecting the ocean physical processes and hence this is the time to tackle this puzzle with appropriate strategies or let the genie out of the bottle.

Social media as a novel source of data on the impact of marine litter on megafauna: The Philippines as a case study

Marine litter is a global threat to marine biodiversity. However, there is a key knowledge gap on the impacts of marine litter in the Philippines - a country of high marine biodiversity and large exclusive economic zone. This gap is addressed here by using information shared on the internet by citizen scientists and conservation groups to assess the impacts of marine litter on megafauna. Facebook, presently the largest social media platform, was scanned for posts concerning the interaction between litter and marine species in the Philippines. Results showed thirty-two individuals from 17 species were affected by marine litter in the country. Furthermore, ingestion (61%) was the most frequent interaction reported. Mindanao was also identified as a hotspot for marine litter interactions. The study highlights the utility of social media in providing data to create an inventory of marine species adversely affected by litter and the spatial distribution of these interactions.

Interaction of the Atlantic ghost crab with marine debris: Evidence from an in situ experimental approach

Sandy beaches pollution by marine debris imposes arguably threats for the biodiversity, but interaction of beach bioindicators (e.g., ghost crabs) with debris has been rarely assessed. We aimed to test whether the Atlantic ghost crab Ocypode quadrata (Fabricius, 1787) misidentifies marine debris as food sources. Cigarette butts, straws, popsicle sticks, paper napkins and styrofoams were mixed into solutions with odour of natural and industrialized food. The debris were placed around burrows on beaches with distinct human pressures (low, medium and high-impact). The species interacted with marine debris more frequently in situations of lower human impact, lower prey abundance and larger burrow diameter. These results indicate that in areas with low prey availability and larger individuals, interactions between ghost crabs and debris left by beach visitors and/or transported by winds and currents to low-impact beaches are more likely to occur, mainly near to urbanized areas.