Plastic Debris Research Articles

Prevention policies for the marine ecological environment in the South China Sea as a consequence of excessive plastic compound use in Vietnam.

Vietnam suffers from a distressing predicament: It ranks among the most heavily contaminated nations on earth. Its coastal and marine domains are plagued by an excess of plastic waste. Vietnam has consistently discharged a substantial amount of waste into the oceans, ranging from 0.28 to 0.73 million metric tons annually. Numerous areas have emerged as focal points of plastic pollution throughout its extensive seashore and marine areas. The escalating presence of marine litter poses an increasingly grave threat to the intricate equilibrium of Vietnam's marine ecosystems. This comprehensive policy study reveals that the mounting problem of ocean plastic pollution, characterized by the abundance of floating plastic debris, imperils both plant and animal life, placing various marine species such as seabirds, fish, turtles, and cetaceans at risk. The consumption of minuscule plastic particles and the harmful impact of chemical pollutants from plastic waste in the ocean not only endangers the vitality of marine life but also poses a substantial hazard to human well-being because plastic waste infiltrates the food chain. This research reveals that, despite the existence of numerous laws and policies-including the Law on Environmental Protection 2020, the Marine Plastic Waste Management Initiative for the Fisheries Sector 2020-2030, and the National Action Plan for Management of Marine Plastic Litter-a significant amount of plastic waste is infiltrating the river network and eventually infiltrating oceans as a result of improper monitoring and ineffective enforcement of these legislations. Relying primarily on existing data released by the government and other sources and a wide range of gray literature retrieved from reputable databases, this study aims to evaluate the role of Vietnam's legal framework for combating the critical issue of marine plastic pollution in the South China Sea. Integr Environ Assess Manag 2024;20:2088-2106. © 2024 SETAC.

Managing institutional interlinkages for the protection of marine environment in the East Asian seas region and beyond: The case of marine plastic pollution

The protection of the marine environment in the East Asian region (EAS region) faces a significant challenge from marine plastic pollution (MPP), highlighting the need for effective regulations and management by regional institutions. Employing empirical research methods, we examine the existing variation of institutional architectures and their regulatory measures regarding MPP in this region. Our study reveals regional institutions and initiatives established to address marine environmental protection against this issue, resulting in a variety of complex and overlapping regulations and policies. While these efforts show positive impacts, gaps in implementing regulations and policies remain significant. Managing institutional interlinkages is crucial to enhancing the effectiveness and accountability of efforts against MPP. In this context, we propose the concept of interplay management as a strategy to improve these efforts in the EAS region. Furthermore, our research highlights the necessity of implementing the concept of polycentric governance in future global agreements on plastic pollution, including marine environments. This approach aims to foster better cooperation and coordination among regions and institutions involved in marine environmental protection against MPP.

The assembly and ecological roles of biofilms attached to plastic debris of Ashmore reef

Plastic pollution in the ocean is a global environmental hazard aggravated by poor management of plastic waste and growth of annual plastic consumption. Microbial communities colonizing the plastic's surface, the plastisphere, has gained global interest resulting in numerous efforts to characterize the plastisphere. However, there are insufficient studies deciphering the underlying metabolic processes governing the function of the plastisphere and the plastic they reside upon. Here, we collected plastic and seawater samples from Ashmore Reef in Australia to examine the planktonic microbes and plastic associated biofilm (PAB) to investigate the ecological impact, pathogenic potential, and plastic degradation capabilities of PAB in Ashmore Reef, as well as the role and impact of bacteriophages on PAB. Using high-throughput metagenomic sequencing, we demonstrated distinct microbial communities between seawater and PAB. Similar numbers of pathogenic bacteria were found in both sample types, yet plastic and seawater select for different pathogen populations. Virulence Factor analysis further illustrated stronger pathogenic potential in PAB, highlighting the pathogenicity of environmental PAB. Furthermore, functional analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways revealed xenobiotic degradation and fatty acid degradation to be enriched in PABs. In addition, construction of metagenome-assembled genomes (MAG) and functional analysis further demonstrated the presence of a complete Polyethylene (PE) degradation pathway in multiple Proteobacteria MAGs, especially in Rhodobacteriaceae sp. Additionally, we identified viral population presence in PAB, revealing the key role of bacteriophages in shaping these communities within the PAB. Our result provides a comprehensive overview of the various ecological processes shaping microbial community on marine plastic debris.

Strategic Environmental Assessment to Combating Marine Litter: an Analysis of Methodological Structures

Objective: Identify and analyze methodological structures that are appropriate and effective for the construction of a new Strategic Environmental Assessment (SEA) approach aimed at combating marine litter. Theoretical Framework: The fight against marine litter is understood as a context, that is, a set of elements that influence the choice of SEA approach. Its complexity is related to the sectoral profile, where solid waste management and coastal management are the key sectors. The literature does not present a SEA approach focused on this context, even given the ecological, socio-environmental relevance and challenges of the Decade of Ocean Science. Method: The methodology is qualitative and is divided into two stages: identification and selection of existing methodological structures; and analysis and selection of Elements of Methodological Frameworks. Methods such as Systematic Literature Review, Content Analysis, and Cross Comparison Analysis were used. Results and Discussion: It was possible to identify 5 methodological structures and select 13 elements of these structures that were significantly related to the participatory criteria of the priority actions of Brazilian public policies. Research Implications: The next step is to materialize the new SEA approach through the construction of a conceptual model that integrates all the elements of the selected methodological structures. Originality/Value: This study begins a process of developing a new methodological tool to contribute to efforts to combat marine litter in Brazil.

Uncovering the characteristics of plastic-associated biofilm from the inland river system of Mongolia

The occurrence and characteristics of plastic debris in aquatic and terrestrial environments have been extensively studied. However, limited information exists on the properties and dynamic behavior of plastic-associated biofilms in the environment. In this study, we collected plastic samples from an inland river system in Mongolia and extracted biofilms to uncover their characteristics using spectroscopic, isotopic, and thermogravimetric techniques. Mixtures of organic and mineral particles were detected in the extracted biofilms, revealing plastic as a carrier for exogenous substances, including contaminants, in the river ecosystem. Thermogravimetric analysis (TGA) indicated the predominant contribution of minerals primarily comprising aluminosilicate and calcite, representing approximately 80 wt% of the biofilms. Differential thermal analysis (DTA) coupled with Fourier transform infrared (FTIR) spectrometry operated at 25°C–600 °C enabled the detection of gaseous decomposition products, such as CO2, H2O, CO, and functional groups (O–H, C–H, C–O, CO, CC, and C–C), released from biopolymers in the extracted biofilms. Dehydration, dehydroxylation, and decarboxylation reactions explain the thermal properties of biofilms. The stable carbon (δ13C) and nitrogen (δ15N) isotope ratios of the biofilms demonstrated variable signatures ranging from −24.1‰ to −27.0‰ and 3.1‰–12.3‰, respectively. A significant difference in the δ13C value (p < 0.05) among the upstream, middle, and downstream research sites could be characterized by available organic carbon sources in the river environment, depending on the research sites. This study provides insights into the characteristics and environmental behavior of biofilms which are useful to elucidate the impact of plastic-associated biofilms on organic matter and material cycling in aquatic ecosystems.

Impacts of elevated temperature, decreased salinity and microfibers on the bioenergetics and oxidative stress in eastern oyster, Crassostrea virginica

Projected increases in temperature and decreases in salinity associated with global climate change will likely have detrimental impacts on eastern oyster, Crassostrea virginica, as these variables can influence physiological processes in these keystone species. We set out to determine how the interactive effects of temperature (20 °C or 27 °C) and/or salinity (27‰ or 17‰) impacted the energetic reserves, aerobic and anaerobic metabolism, and changes to oxidative stress or total antioxidant potential as a consequence of an altered environment over a 21-day exposure. Gill and adductor muscle were used to quantify changes in total glycogen and lipid content, Electron Transport System and Citrate Synthase activities, Malate Dehydrogenase activity, Protein Carbonyl formation, lipid peroxidation, and total antioxidant potential. A second exposure was performed to determine if these environmental factors influenced the ingestion of microfibers, which are now one of the leading forms of marine debris. Elevated temperature and the combination of elevated temperature and decreased salinity led to an overall decline in oyster mass, which was exacerbated by the presence of microfibers. Changes in metabolism and oxidative stress were largely influenced by time, but exposure to elevated temperature, decreased salinity, the combination of these stressors or exposure to microfibers had small impacts on oyster physiology and survival. Overall these studies demonstrate that oyster are fairly resilient to changes in salinity in short-term exposures, and elevations in temperature or temperature combined with salinity result in changes to the oyster energetic response, which can be further impacted by the presence of microfibers.

Spatial risk analysis of floating marine macro litter along the Western Sicilian coast: Overlap with bottlenose dolphin and seabird hotspots.

Marine litter is known to be a major stressor in coastal marine habitats. Therefore, the aim of this study was to identify the areas where species could be most threatened by floating marine macro-litter (FML) The composition and density distribution of FML along the waters of the Agrigento province was monitored from 2019 to 2021, together with the density distribution for the protected species Tursiops truncatus, Hydrobates pelagicus melitensis, Calonectris diomedea, and Puffinus yelkouan.. The areas where marine litter poses the biggest threat to these species were identified by overlapping the core areas of their distribution with that of FML. The results showed that FML’s was mainly composed of plastics (90 %). There was a high degree of overlap between FML’s core area and focal species: 65 % for bottlenose dolphins, 76,3 % for the European storm-petrel, and 85,1 % for the shearwaters. Our findings highlight a key area of about 54 km2, within the 25–70 m depth, where the highest presence of protected species and FML was observed. The high degree of overlap of the species and FML core-areas underlines the need to enact specific management measures.

Prevalence of plastic debris in nests of two cormorant species in Peru

The guanay cormorant (Leucocarbo bougainvilliorum) and red-legged cormorant (Poikilocarbo gaimardi) are known for their prolific nest-building behavior, utilizing a diverse array of materials, including anthropogenic debris, thereby serving as valuable indicators of ocean plastic pollution. To elucidate inter-specific variations in nest plastic occurrence between these two cormorant species, we conducted a comprehensive examination of nests at 12 colonies along the Peruvian coast in 2018–2019. Our findings revealed a significantly higher occurrence of plastic in red-legged cormorant nests (mean 50 ± 27 %, N = 100 nests in 7 colonies) compared to guanay cormorant nests (mean 10 ± 20 %, 3497 nests in 8 colonies). Furthermore, the prevalence of plastic waste varied across colonies within both species. Off-white/clear plastic bags were the predominant color and type of debris found in both cormorant nests. This study is a baseline of plastic marine pollution occurrence along the Peruvian coast.

Exploring the Ecotoxicological Effects and Mitigation Strategies for Microplastics Pollution in Aquatic Ecosystems

&lt;p&gt;Microplastics pollution poses a significant threat to aquatic ecosystems globally, originating from various sources such as plastic debris breakdown and microbeads. This study investigates the ecotoxicological impacts of these pollutants on marine plants and evaluates mitigation strategies. Field surveys assess their distribution, sources, and fate in rivers, lakes, estuaries, and coastal waters. Sampling methods include sediment cores, water samples, and biological specimens to quantify abundance, size distribution, polymer types, and spatial variability. Source apportionment techniques aid in identifying major contributors to pollution. Laboratory experiments simulate environmental conditions to study their behavior, including sedimentation, resuspension, aggregation, and bioaccumulation. Mathematical models predict dispersal and deposition patterns over varying time scales. Ecotoxicological studies investigate impacts on organisms across trophic levels, including fish, invertebrates, and phytoplankton, considering acute and chronic effects. Mitigation strategies like filtration systems, policy interventions, and public awareness campaigns are evaluated for efficacy in reducing pollution and safeguarding ecosystems. This research contributes to developing sustainable solutions essential for environmental preservation and human health.&lt;/p&gt;

KELIMPAHAN MAKRO DEBRIS DI EKOSISTEM MANGROVE MUARA TUKAD MATI, BALI

Macro debris refers to waste materials ranging in size from 2.5 cm to 1 m, commonly found both on the water's surface and on the seabed. The accumulation of such large debris in coastal and marine environments can lead to various consequences, including disturbances to ecosystem stability and threats to the survival of organisms. Additionally, it diminishes the aesthetic quality of the environment. Among the ecosystems most susceptible to becoming repositories for this waste is the mangrove ecosystem. This study aims to quantify the amount, types, and abundance of macro debris scattered in the Tukad Mati Estuary Mangrove Area, Badung Regency, Bali. The research methodology involved several steps, starting with the selection of research stations. Transects measuring 5 x 5 meters were established. Within these designated areas, samples of macro debris were collected and categorized according to their composition, including materials such as plastic, fabric, glass, metal, and rubber. The results revealed that the total mass of macro debris collected in the Tukad Mati Estuary area amounted to 42,630 grams. The types of macro debris found in the Tukad Mati Estuary mangrove ecosystem consist of plastic, fabric, glass, metal, and rubber. Based on their quantity, the composition of macro debris is dominated by plastic at 87.02%, followed by fabric at 4.24%, rubber at 4.17%, glass at 2.67%, and metal being the least at 1.89%. Based on their weight, the composition of macro debris is highest for plastic at 32.33%, followed by rubber at 27.29%, fabric at 20.23%, glass at 14.36%, and metal being the lowest at 5.78%. The abundance of macro debris in the Tukad Mati Estuary mangrove ecosystem ranges from 0.85 items/m² to 10.68 items/m². Keywords: Marine Debris; Pollution; Tukad Mati Estuary; Mangrove

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.

Spatiotemporal variation in marine litter distribution along the Bulgarian Black Sea sandy beaches: amount, composition, plastic pollution, and cleanliness evaluation

The threat of anthropogenic marine litter, particularly plastic pollution, to marine ecosystems and human health, has spurred mitigation initiatives and global scientific research. Following the Marine Strategy Framework Directive guidelines, this study evaluated marine litter distribution, cleanliness, and plastic pollution indices along Bulgarian Black Sea beaches in 2023. The survey integrates visual assessment, manual sampling, and drone mapping, distributing the beaches along the coastline to encompass a broader range, totaling 45, including 28 remote/natural, 10 semi-urban, and 7 urban beaches. Results indicate a 48% decrease in marine litter distribution on beaches from 1462 ± 147 items/100 m in 2021 to 753 ± 97 items/100 m in 2023, with Artificial polymer materials/plastic materials constituting 88.62% of the total litter amount. A comprehensive plastic macro litter pollution assessment was carried out along Bulgarian beaches using PAI for the first time. In 2023, the average cleanliness status of Bulgarian beaches was classified as “moderate” (CCI: 7.61 ± 1.00), with clean northern and central beaches contrasting with dirty southern beaches. Urbanized beaches were assessed with the highest level of pollution (PAIAV,23: 5.51; CCIAV,23: 18.16). In the long term, cleanliness and plastic pollution maintain “moderate” values with CCIAV,18-23: 8.81 ± 0.89, and PAIAV,18-23: 2.35 ± 0.32, persisting throughout the period, necessitating ongoing monitoring and intervention strategies. Despite identifying a significant number of clean beaches, none meet the EU threshold value of 20 litter items/100 m. This study highlights the urgent need for effective interventions to combat litter accumulation and plastic pollution, particularly in urban or semi-urban beaches, emphasizing multi-stakeholder collaboration for sustainable solutions and coastal ecosystem preservation.

Abandoned, Lost and Otherwise Discarded Fishing Gear in the Eastern Caribbean: Barriers, Challenges, and Opportunities for Improved Governance

Abstract In recent years there has been a growing focus on filling critical knowledge gaps on the challenge of abandoned, lost, and discarded fishing gear (ALDFG) in the global ocean. While not the biggest contributor to the world’s marine debris problem, ALDFG has been shown to be a particularly deadly form of marine litter due to its ability to entangle, entrap, and ensnare marine wildlife, damage coastal habitats, and result in negative economic impacts to the fishing sector. In the Eastern Caribbean region, fisheries play a crucial role in ensuring livelihood and food security for vulnerable coastal communities. Therefore effective management interventions that are geared towards eliminating anthropogenic threats to the marine environment, including ALDFG are considered of paramount importance. This article aims to gain insight into challenges associated with the governance of ALDFG within the small-scale fisheries of the Eastern Caribbean with a view to outlining opportunities for improvement. A qualitative approach was utilized and interviews were conducted with fisheries and conservation experts from both national and regional-level institutions. The participants revealed that ALDFG was of significant concern for their country or the region and each advocated for the establishment of improved management infrastructure. Identified barriers that could impede this critical goal include limited human and financial capacity, lack of knowledge and understanding of ALDFG generally, lack of trust, and policy incoherence across sectors and between regional and national agencies. To overcome barriers, a multi-faceted approach is required, including regulatory and institutional improvements.

Macroplastic and Microparticle Pollution in Beach Sediments from Urias Coastal Lagoon (Northwest Mexico).

This study investigates the occurrence and characteristics of macroplastic and polymer microparticles in the Urias coastal lagoon's beach sediments, in northwest Mexico. Coastal lagoons, productive and vulnerable ecosystems, are impacted significantly by anthropogenic activities, leadings to their pollution by various contaminants, including plastics. Our research involved sampling sediments from four sites within the lagoon that were influenced by different human activities such as fishing, aquaculture, thermoelectric power plant operations, industrial operations, and domestic wastewater discharge. Our methodology included collecting macroplastics and beach sediment samples, followed by laboratory analyses to identify the plastic debris' size, shape, color, and chemical composition. The results indicated a notable presence of macroplastic items (144), predominantly bags, styrofoam, and caps made of polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). The polymer microparticles were mainly fibers, with cotton and polyester as the most common polymers, suggesting a significant contribution from clothing-related waste. The dominant colors of the microparticles were blue and transparent. High densities were observed in areas with slower water exchange. Our findings highlight the urgent need for better waste management practices to mitigate plastic pollution in coastal lagoons, preserving their ecological and economic functions.

ANALYZING THE PROPERTIES OF A COMPOSITE OF PCL-GRAPHITE BY THE INJECTION MOLDING

Coral reefs are vulnerable to several natural phenomena such as ocean warming, acidification, coral diseases, and plastic pollution. In order to tackle these problems, scientists are now working on the development of biocomposites utilizing biodegradable polymers such as polycaprolactone (PCL). Graphite can be used in conjunction with PCL to enhance its characteristics. The work is centered around conducting water absorption experiments on a composite material consisting of PCL and graphite. The investigation employs PCL granular and graphite powdered materials. The materials undergo heating, crushing, and weighing processes to ascertain weight ratios. Next, the mixture is shaped into specimens. The product's shape and distribution of chemical constituents are analyzed using water absorption, hydrophobicity, FTIR, and SEM testing. The findings indicate that the water absorption diminishes as the concentration of graphite powder increases. An alloy containing 10% graphite had the highest water absorption rate. The hydrophobicity test assesses the ability of a specimen's surface to repel water by introducing NaCl droplets and observing droplet production. The contact angle value exhibits a direct correlation with the increase in graphite content. The FTIR study indicates that there are no changes in the functional groups, resulting in a limited connection between the PCL matrix and the graphite filler. The temperature during the injection molding process affects the microstructure of the polymer. Lower temperatures lead to reduced crystallization, whereas higher temperatures result in denser molecular groupings. Graphite is a highly suitable choice for use as a filler in a PCL matrix because of its layered structure, large surface area, and excellent capacity to effectively fill voids within the matrix.

Proof of concept for a new sensor to monitor marine litter from space

Worldwide, governments are implementing strategies to combat marine litter. However, their effectiveness is largely unknown because we lack tools to systematically monitor marine litter over broad spatio-temporal scales. Metre-sized aggregations of floating debris generated by sea-surface convergence lines have been reported as a reliable target for detection from satellites. Yet, the usefulness of such ephemeral, scattered aggregations as proxy for sustained, large-scale monitoring of marine litter remains an open question for a dedicated Earth-Observation mission. Here, we track this proxy over a series of 300,000 satellite images of the entire Mediterranean Sea. The proxy is mainly related to recent inputs from land-based litter sources. Despite the limitations of in-orbit technology, satellite detections are sufficient to map hot-spots and capture trends, providing an unprecedented source-to-sink view of the marine litter phenomenon. Torrential rains largely control marine litter inputs, while coastal boundary currents and wind-driven surface sweep arise as key drivers for its distribution over the ocean. Satellite-based monitoring proves to be a real game changer for marine litter research and management. Furthermore, the development of an ad-hoc sensor can lower the minimum detectable concentration by one order of magnitude, ensuring operational monitoring, at least for seasonal-to-interannual variability in the mesoscale.

Microplastics in Russian Freshwater Systems: a Review

Contamination of environment by plastic debris has already become a worldwide problem due to the global production of polymers and the further accumulation of waste. Microplastic particles (&lt;5 mm) have been found almost everywhere. Despite the significant number of publications devoted to the microplastic pollution in freshwater and marine environments, in the review articles around the world freshwater systems the Russian territory is a white spot. The article provides the summary of studies investigating microplastics (MP) in Russian lakes and rivers, the determination of concentrations, type and composition of polymer particles and also possible sources of plastic contamination. The map of the MP distribution in Russian freshwater systems is presented. The concentration of microplastics in freshwater system varies greatly, e.g., in lakes from 0,27 items/m3 in Lake Baikal to (4-26)∙103 items/m3 in the Altai lakes of Western Siberia; in large Russian rivers measured polymer content varies by three orders of magnitude, from parts of items/m3 in the Volga River to hundreds of items/m3 in the Upper Ob. Significantly higher concentrations of MP are found in the bottom sediments of rivers and lakes, exceeding polymer concentrations in surface water by several orders of magnitude. Thus, bottom sediments are able to accumulate significant amounts of MP.

Microplastic identification in marine environments: A low-cost and effective approach based on transmitted light measurements

Microplastics have become a significant concern for the well-being of marine ecosystems. Small fragments of plastic debris are released into the environment from both the direct disposal of plastic products and the deterioration of larger items. Ingestion of microplastics by marine life can result in detrimental effects, including physical harm and the accumulation of toxic chemicals in their tissues. The aim of this research is to design a compact and cost-effective measurement system for effectively detecting and quantifying microplastics in marine environments. The proposed system uses a 2.4-inch liquid-crystal display (LCD) panel and a digital USB microscope, both of which are connected to a single-board computer, with a dedicated python-based graphical user interface (GUI). Specifically, the light transmitted through plastic and organic samples was measured in order to identify and classify them. Various types of materials, such as polypropylene, polyvinyl chloride, polycarbonate, polyethylene, and organic algae samples, were tested and the metrological performance of the system has been estimated. The transmittance of the samples analyzed was primarily influenced by their opacity and thickness. In general, thicker materials exhibited significantly lower transmittance values. This trend was particularly evident in organic components and opaque plastic samples, where transmittance was significantly low. In addition, the experimental results suggest that the colour of the material also affects transmittance, although as a secondary factor. The employed technique could be used to identify and distinguish samples based on material properties, thereby allowing the proposed system to be a valuable tool for further research on microplastics in marine environments.

Development of an onboard waste-to-energy process for disposing marine plastics debris

Development of an onboard waste-to-energy process for disposing marine plastics debris

Assessing the ecological impact of beach tourism on crustacean abundance: a case study from West Coast of India

Sandy beaches are vulnerable to natural and anthropogenic disturbances like coastal hydrological disasters, coastal erosion, sea-level rise, pollution, and land degradation. Apart from these, at the habitat level, tourism and recreation activities impact the sandy beach ecosystem in countless ways. Several studies indicate that trampling caused due to human visitation negatively impacts the macrobenthic communities. In this study, along with the trampling effect, we assessed the impact of human visitation on the sandy beach ecosystem using factors like littering and human-induced predation pressure. The study was conducted on three sandy beaches in the Udupi district of Indian coastal state, Karnataka. We used human presence, predation pressure, and total litter as response variables; against sand crabs and ghost crabs as indicator species. The results indicated a significant correlation between response variables. Sand crabs were less affected by the human presence (r = 0.07, p = 0.14); however, ghost crab abundance was negatively influenced by human presence (r = − 0.36, p < 0.05), predation pressure (r = − 0.28, p < 0.05), and by litter presence (r = − 0.28, p < 0.05) at the beaches. We observed that human presence impacts sand crabs and ghost crabs directly (trampling) and indirectly (attracting human commensal predators through beach litter). We highlight the impacts of tourism on often neglected crab assemblages and emphasise the importance of deriving appropriate conservation measures for sandy beach ecosystems.