Carcinoscorpius Research Articles

Morphometric and DNA-based identification of horseshoe crab Carcinoscorpius rotundicauda (Latreille, 1802) and Tachypleus gigas (Müller, 1785) from Bangladesh coast

Horseshoe crabs are the living fossils of xiphosurans that have survived for over 200 million years without morphological change and records fossil dating back 500 million years. A study was conducted on morphometric and molecular characterization of horseshoe crab Carcinoscorpius rotundicauda (Latreille, 1802) and Tachypleus gigas (Müller, 1785) from Bangladesh waters. A total of ten samples of C. rotundicauda and one sample of T. gigas were collected from Dublar Char, Sundarbans and Cox’s bazar from June 2016 to May 2017 and February 2024, respectively. Among them, four specimens were male and seven female. Morphometric measurements were taken from all the collected samples and differentiated male and female based on the second pair of legs, the pedipalps. The species were genetically identified using mitochondrial cytochrome c oxidase subunit I (COI) gene. An average length of about 670.5 bp nucleotide sequences were obtained. Average percentage of nucleotide frequencies were T (30.3), C (16.3), A (34.4) and G (19.0) for C. rotundicauda and T (34.45), C (22.01), A (27.91) and C (15.63) for T. gigas. GC content analysis showed that average GC 36.20% and AT 63.80%. The average GC content at the 1st, 2nd and 3rd codon position were 38.82%, 37.87% and 31.92% respectively. This is the first report of DNA barcoding of a living fossil C. rotundicauda and T. gigas from Bangladesh and will serve as baseline information for future research, conservation and management of this invaluable primitive creature. Bioresearch Commu. 10(2): 1489-1494, 2024 (July)

Abundance and morphometric variations of Carcinoscorpius rotundicauda (Mangrove Horseshoe crab) from Bhadrak coast of Odisha, India

Abundance and morphometric variations of Carcinoscorpius rotundicauda (Mangrove Horseshoe crab) from Bhadrak coast of Odisha, India

Modeling potential habitats of threatened horseshoe crabs in Indo-Pacific Asia: Suggestions for conservation management

Identifying critical habitats of threatened marine species is key to area-based management measures, while it can be of great challenge for those species that distribute continentally. Asian horseshoe crabs, including tri-spine horseshoe crab Tachypleus tridentatus, coastal horseshoe crab T. gigas, and mangrove horseshoe crab Carcinoscorpius rotundicauda, are globally threatened marine chelicerates, which are largely distributed in developing countries in Indo-Pacific Asia with limited baseline information. Here, we performed the maximum entropy model (MaxEnt), a widely used correlative species distribution model, to explore potential habitats of the Asian horseshoe crabs. Presence-only data of the adult Asian horseshoe crabs and the seven sea benthic environmental predictors, which included temperature, salinity, chlorophyll a concentration, dissolved oxygen, current velocity, bathymetry, and slope, were input into the MaxEnt. The Cloglog output format was adopted to estimate the presence probability of these three species under species-specific regularization multipliers. Our results showed that all three species have potential habitats in Southeast Asia. The range of potential habitats is the most widespread for T. tridentatus, but the most restricted for T. gigas. Bathymetry, temperature, and chlorophyll a concentration are the main contributing environmental predictors for the projected distribution of T. tridentatus, while for T. gigas and C. rotundicauda, temperature and bathymetry have contributed the most. Temperature of the potential habitats is the lowest for T. tridentatus (25.6 ± 4.4 °C), compared to the more tropically distributed T. gigas and C. rotundicauda (around 29 °C). Core habitats of the estuary-bound C. rotundicauda have shallower bathymetry of 5.8 ± 3.5 m in depth. Overall, Asian horseshoe crab species share similar niches, with the common characteristics of shallow bathymetry (<15 m in depth), high temperature (>25 °C), and relatively higher chlorophyll a concentration in coastal waters. We conclude that the projected habitats serve as a critical reference for the conservation management of threatened Asian horseshoe crabs under extensive baseline gaps. Generalized conservation strategies are suggested, depending on the sufficiency of baseline data, to facilitate the formation of specific decision-making.

Comparative putative metabolites profiling of Tachypleus gigas and Carcinoscorpius rotundicauda hemocytes stimulated with lipopolysaccharide

Horseshoe crabs are among the most studied invertebrates due to their unique, innate immune system and biological processes. The metabolomics study was conducted on lipopolysaccharide (LPS)-stimulated and non-stimulated hemocytes isolated from the Malaysian Tachypleus gigas and Carcinoscorpius rotundicauda. LC–TOF–MS, multivariate analyses, principal component analysis (PCA), and partial least squares-discriminant analysis (PLS-DA) were included in this study to profile the metabolites. A total of 37 metabolites were identified to be differentially abundant and were selected based on VIP > 1. However, of the 37 putative metabolites, only 23 were found to be significant with ANOVA at p < 0.05. The metabolites were identified using several databases, and the literature review of the metabolites was reported in the manuscript. Thus, this study has provided further insights into the putative metabolites' presence in the hemocytes of horseshoe crabs that are stimulated and non-stimulated with LPS and their abundance in each species. Several putative metabolites showed they have medicinal values from previous studies.

Saving the overlooked mangrove horseshoe crabs-A perspective from enhancing mangrove ecosystem conservation

Despite being widely distributed in Asia, Carcinoscorpius rotundicauda is often overlooked and, its population status remains unclear. Moreover, it is threatened by illegal harvesting and degradation of mangrove ecosystems. Protecting its habitat is essential for population and biodiversity conservation, as mangroves provide nursery grounds and food supply for C. rotundicauda. This review discusses the biological characteristics of C. rotundicauda, including ecology, nutrition, life history, toxicology, and immunology. It also presents information about its distribution and population status. The review emphasizes the challenges faced by C. rotundicauda and proposes a conservation framework that involves the participation of local residents to facilitate conservation efforts. Collaboration between local residents and communities is proposed to protect and monitor the mangrove ecosystem. Additionally, this framework can support field research, protect C. rotundicauda juveniles and other species, and ensure the livelihood of local residents through participation in carbon trading markets and eco-industries such as eco-farming and eco-tourism.

Population and spatial ecology of horseshoe crabs (Limulidae) in a nursery ground at Pulau Bedukang, Brunei Bay, Borneo

Abstract. Rozaini AF, Laurie KH, Marshall DJ. 2023. Population and spatial ecology of horseshoe crabs (Limulidae) in a nursery ground at Pulau Bedukang, Brunei Bay, Borneo. Biodiversitas 24: 4485-4492. Suitable nursery habitat to support populations of juvenile horseshoe crabs is becoming threatened globally. There are currently no formal studies on juvenile populations of the horseshoe crabs (Limulidae) for Brunei Darussalam (Brunei, Borneo). We investigated body size structure, population cohort and ecological distribution of juvenile horseshoe crabs associated with a mudflat on Pulau Bedukang, in Brunei Bay. Seventy juveniles were retrieved during four sampling days covering two seasons and four study sites. Carcinoscorpius rotundicauda and Tachypleus gigas were common, whereas only two individuals of Tachypleus tridentatus were found. Carapace width (size) was similar in the common species and there was no difference in juvenile size between the seasons and study sites. Body weight to carapace width relationships showed that the species grew at similar rates, although C. rotundicauda developed faster, producing 14 compared to the eight pre-migration mudflat instars produced by T. gigas. Species densities were similar, and there was no spatial separation of species or juvenile size across the mudflat or in relation to the mangrove forest edge. Nearest-neighbor (NN) analysis showed that individual crabs were generally dispersed. Their mudflat cohabitation suggests physiological and behavioral plesiomorphies for common optimal developmental salinity and temperature conditions. This study provides baseline information for comparison with other regional studies and for local conservation planning.

Central composite design‐based response surface methodology for optimization of tetrodotoxin extraction from the horseshoe crab Carcinoscorpius rotundicauda

AbstractTetrodotoxin analogues (TTXs) used in research and development were originated from biological sources for the last decades. Among TTXs‐bearing aquatic animals, horseshoe crab Carcinoscorpius rotundicauda from Vietnam's Coast was reported to contain a high level of TTXs, indicating a promising source for extraction and purification of TTXs. In this work, horseshoe crab C. rotundicauda collected from Can Gio Coast, Vietnam was used for TTX extraction using homogenization‐assisted method with acetic acid solvent. The extraction process was analysed and optimized by single‐factor investigation and response surface methodology (RSM). Single‐factor investigation pointed out that the optimal conditions for TTX recovery yield from C. rotundicauda's soft tissues were homogenization time of 20 min, acetic acid concentration of 1.0%, solvent/matrix ratio of 4 mL/g, extraction temperature of 70°C, extraction time of 30 min and number of extraction of two times. The most significant factors including acetic acid concentration, solvent/matrix ratio and extraction temperature were utilized for constructing the RSM model to predict TTX recovery yield. The maximal TTX recovery yield predicted from RSM model was 97.3% under solvent/matrix ratio of 4 mL/g, extraction temperature of 70°C and acetic acid concentration of 1% (v/v). The RSM model displayed a high stability and precision for prediction of TTX recovery yield from experiments of 1–10 kg C. rotundicauda's soft tissues/batch extractions producing low errors (−1.95% to 1.85%). TTXs in C. rotundicauda's soft tissues were elucidated by HPLC‐MS/MS, revealing the presence of three analogues TTX, 4epi‐TTX and Anh‐TTX with their contents of 43.02, 22.54 and 45.07 μg/g, respectively.

Isolation, Identification, and Characterization of Tetrodotoxin Producing Bacillus amyloliquefaciens B1 Originated from Carcinoscorpius rotundicauda

This study isolated and identified Bacillus amyloliquefaciens B1 from Carcinoscorpius rotundicauda by carrying out the 16S rRNA sequence analysis, reconstructing the phylogenetic tree based on the Environment for Tree Exploration (ETE3) v3.1.1 belonging to the GenomeNet. By an indirect competitive enzyme-labeled immunoassay, B1 could produce tetrodotoxin (TTX) in MRS was more highly than LB media. After purification, TTX producing ability in B1 could be detected in ELISA assay, high performance liquid chromatography (HPLC). The gel permeation chromatography and gas chromatography were applied to determine the molecular weight of EPS and the concentration of glucose in EPS. The results indicated the highest molecular weight of exopolysaccharides (EPS) estimated 1.33 × 106 Da consisted of glucose (150.09 µg/g). TTX yield was proportional to EPS production in the bacterium. The antimicrobial activities of EPS were determined by agar well diffusion method. Diameter of inhibition zone (mm) of Bacillus amyloliquefaciens EPS on the test microorganisms. The EPS could inhibit against Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Vibrio parahaemolyticus ATCC 17802 and Micrococcus luteus ATCC 10240. In silico prediction, TTX might interact with Bacillus amyloliquefaciens via the extracellular domain of noncanonic ABC-type transporter from gram positive bacteria. TTX might also interact with peptidase S54, mistic, metal binding protein of Bacillus subtilis and tryptophan-rich sensory protein of Bacillus cereus. This study provides the understanding of TTX producing Bacillus amyloliquefaciens B1 isolated from Carcinoscorpius rotundicauda.

Local people perception on Carcinoscorpius rotundicauda and Tachypleus spp. in Banyuasin, Sumatera, Indonesia

The population decline in horseshoe crabs was increasingly revealed by various researchers in Asian countries, but there are still gaps in information regarding their population and ecological status. In data-poor situations, especially in the Banyuasin peninsula, collecting local knowledge was required because this approach was an easy, wide-scale, inexpensive, and rapid way to obtain data. This work aimed to assess the contributing local knowledge regarding the horseshoe crab's distribution, use, and threats to the existence of horseshoe crabs in the Banyuasin peninsula. Interviews using a questionnaire were conducted in five villages and one hamlet by visiting randomly selected households. The result revealed that most respondents (94%; n = 115) could correctly identify the species and shape between Carcinoscorpius rotundicauda and Tachypleus spp. Most respondents stated easily recognized C. rotundicauda by their rounded telson and smooth (without spines) whereas Tachypleus spp. was also easily recognized by their triangular telson with spines. The respondents avowed that Sembilang National Park Waters, especially Sembilang River (80%; n = 98), Cabe Island (71%; n = 87), Benawang River (56%; n = 68), and Sapi Island (52%; n = 64) were the most widespread location of horseshoe crabs. The C. rotundicauda was discovered more frequently than Tachypleus spp. in almost every distributing location around December (80%; n = 97), November (70%; n = 86), and October (57%; n = 69). The most horseshoe crabs benefit was for food (63%, n = 73). The main factors encouraged a decline in the horseshoe crab population, i.e. entangled in fishing nets (92%, n = 106). Respondents acknowledged that the Indonesian Government established the horseshoe crab as a protected animal. Fishermen's consciousness to reduce the horseshoe crab's bycatch and ensure it returned to the sea alive and safe was much needed to address the serious threat to its population decline.

Morphometry of Limulidae (Oscar E. Brown) in Leidong, Sei Berombang, and Tanjung Tiram, North Sumatera

Limulidae (Horseshoe crab), or Mimi in the local name, are known; there are four species, namely Limulus polyphemus in North America and Asia, namely Tachypleus tridentatus, T. gigas, and Carcinoscorpius rotundicauda. In Indonesia, these species are protected by the Decree of the Minister of Forestry Number 12/KPTS-II/1987; meanwhile, illegal fishing still occurs. This study aims to identify Limulidae species and analyze Mimi's morphometric characteristics and distribution in North Sumatra to conserve the species. This research was conducted using a quantitative descriptive method in Leidong, Sei Berombang, Tanjung Tiram - North Sumatera, from September to December 2021. Biometric measurements were performed on 98 Mimi, and the data were statistically analyzed using the Kruskal Wallis test, Mann-Whitney test, and Multinomial logistics. The results showed that Mimi in the study area was identified as Tachypleus tridentatus, T. gigas, and Carcinoscorpius rotundicauda. The most commonly caught was T. tridentatus at the Tanjung Tiram. Based on the maximum width of the prosoma and body length, the largest to most petite sizes are T. tridentatus at Leidong (10.31 cm), T. gigas at Leidong, and Sei Berombang (10 cm) and C. rotundicauda at Sei Berombang (7.56 cm) respectively. The cluster analysis based on 27 morphometric characters showed that T. tridentatus had almost the same characteristics as T. gigas, while C. rotundicauda had its features. It can be concluded that the largest to most petite sizes of Mimi in the study area were T. tridentatus, T. gigas, and C. rotundicauda, respectively.

COI Gene Analysis of Asian Horseshoe Crab in Banyuasin Estuarine Waters, Sumatra, Indonesia

There is limited study on DNA barcoding of horseshoe crabs in South Sumatra, Indonesia. The present study was the first to record horseshoe crabs' COI DNA barcoding in three localities of Banyasin estuarine waters. The nucleotide composition was in a strong adenine thymine bias (AT = 63.90%) with high haplotypic diversity (Hd = 0.858) relative to low nucleotide diversity (π = 0.0534). A total of 16 haplotypes were recorded, of which two were in Carat Cape, 4 in Makati Jaya, and 12 in the Banyuasin river estuary (BRE), and Hap 1 was a dominant type (62.5%). The population differentiation (FST) value was varied, and only in the comparison of BRE-Carat Cape was significant (FST = 0.637), while the gene flow (Nm) value in Makati Jaya-BRE was high (6.563). The neutrality test, Tajima's D (0.4142), and Fu's Fs values were negative (-0.492), suggesting these populations have experienced a current bottleneck or multiplication. Analysis of molecular variation (AMOVA) suggested that 68% was distributed within populations. The haplotype network, PCoA, and phylogenetic of COI DNA sequences clustered in three groups correspond to Carcinoscorpius rotundicauda, Tachypleus gigas, and Tachypleus tridentatus. This finding is a matter of concern for managing and conserving horseshoe crab species in Banyuasin estuarine waters.

Specifications of bioinspired material structural foam prosoma of Tachpleus gigas and Carcinocorpius rotundicaud using acoustic impulse response

Renewable material innovation has shifted from inorganic materials to biological materials. Especially due to the demands of modern applications in food, biomedicine, and environmental sustainability. The peculiarity of the horseshoe crab is in the prosoma with a hollow structure (foam). The development of structural specifications also leads to non-destructive modern measurements using acoustic response impulse. This study aimed to determine the specifications foam material (shape and size) of the prosoma Tachypleus gigas and Carcinoscorpius rotundicauda using acoustic impulse responses. The research includes the characterization of the components and structure of the foam material prosoma using acoustic impulse response The prosoma components of T. gigas and C. rotundicauda have high protein and crude fiber, as well as functional groups according to chitin. The weight of T. gigas and C. rotundicauda ranges 484.33 ± 5.13 g and 493.33 ±15.28 g and densities of 1206.45 ± 148.01 kg/m3 and 1264.60 ± 120.01 kg/m3, but have differences in pore diameter and strut, 431.39μm ± 166.22 and 153.30μm ± 33.62 for pore diameter and strut, 120.09μm ± 57.83 and 98.0881μm ± 26.75 and compressive strength of 220.68 kPa and 285.88 kPa, and elasticity of 17.85 and 38.12.

Identification and Morphology of the Two Horseshoe Crab Species, Tachypleus tridentatus (Leah, 1819) and Carcinoscorpius rotundicauda (Latreille, 1802) (Merostomata: Limulidae) from Honda Bay, Palawan, Philippines

There were reports of the existence of horseshoe crabs in Palawan, Philippines, but there is a need to identify and confirm these species. A total of 128 adult horseshoe crabs were collected from Honda Bay, Palawan, Philippines. These were identified as Tachypleus tridentatus (68 males, 40 females) and Carcinoscorpius rotundicauda (2 males, 18 females). Morphology, morphometric measurements, and ratios of male and female of each species were described. Morphological characteristics in differentiating a male from a female crab involve examination of the appearance of the genitalia. Morphological characteristics in identifying the species include the presence or absence of notches in the frontal margin, arching in the frontal view, appearance of the chelae of the 2nd and 3rd prosomal appendages, number of lateral spines and the immovable spines in the opisthosoma, the presence of spinnerets on the surface of the telson, and shape of the telson and its cavity in cross-section. This study confirmed the identification of the two species found in Palawan, Philippines, and the morphological characteristics of the male and female of each species. In addition, a comparison was made of the size of the horseshoe crab species in Palawan with those found in other locations in the Asia-Pacific region.

Transcriptomic Signature of Horseshoe Crab Carcinoscorpius rotundicauda Hemocytes' Response to Lipopolysaccharides.

Carcinoscorpius rotundicauda (C. rotundicauda) is one of the four species of horseshoe crabs (HSCs). The HSC hemocytes store defense molecules that are released upon encountering invading pathogens. The HSCs rely on this innate immunity to continue its existence as a living fossil for more than 480 million years. To gain insight into the innate mechanisms involved, transcriptomic analysis was performed on isolated C. rotundicauda hemocytes challenged with lipopolysaccharides (LPS), the main components of the outer cell membrane of gram-negative bacteria. RNA-sequencing with Illumina HiSeq platform resulted in 232,628,086 and 245,448,176 raw reads corresponding to 190,326,253 and 201,180,020 high-quality mappable reads from control and LPS-stimulated hemocytes, respectively. Following LPS-stimulation, 79 genes were significantly upregulated and 265 genes were downregulated. The differentially expressed genes (DEGs) were related to multiple immune functional categories and pathways such as those of the cytoskeleton, Toll and Imd, apoptosis, MAP kinase (MAPK), inositol phosphate metabolism, phagosome, leucocyte endothelial migration, and gram-negative bacterial infection, among others. This study provides important information about the mechanisms of response to LPS, which is relevant for the understanding the HSCs' immune response.

Discarded Species in Artisanal Fisheries South Sumatra, Indonesia: Case Study on Crab Gill Nets

This study identified the discard species generated by the crab gillnet for targeting the blue swimming crab Portunus pelagicus (Linnaeus 1758) in the Banyuasin estuarine of South Sumatra, Indonesia. The fishing gear yielded the discarded catch about 12% (25.68 kg) of the total catch in weight (212.68 kg). For the discarded catch, 703 individuals represented 18 species from 3 phyla (Arthropoda, Chordata, and Mollusca). The crustaceans Charybdis helleri (Milne-Edwards 1867), Clibanarius spp., Matuta planipes(Fabricius 1798), and Libinia dubia(Milne Edwards 1834) were the majority components of these discards accounted for 90% of the total discards. Results of ecological classification rare, i.e., Chiloscyllium indicum(Gmelin 1789), and occasional, i.e., Chiloscyllium punctatum(Müller &amp; Henle 1838), and Maculabatis macrura(Bleeker 1852) included in the International Union for Conservation of Nature (IUCN) red list as Vulnerable (C. indicum), Near Threatened (C. punctatum), and Endangered (M. macrura) category. Based on the IUCN status, two species of crustaceans i.e., Carcinoscorpius rotundicauda (Latreille 1802) and Tachypleus gigas (Müller 1785) listed as ‘Data Deficient’. Discarded on crab gillnet fishing in Banyuasin waters is a challenge for species that need to be conserved (shark, ray, and horseshoe crabs). Species with IUCN red list status ranging from Data Deficient to Endangered were found dead, except for horseshoe crabs. Mitigation options offered include captive breeding of horseshoe crabs, the release of protected species when caught, and fishing gear modification. These findings can help design suitable mitigations for discarding crab gill nets.

Plant produced endotoxin binding recombinant proteins effectively remove endotoxins from protein samples

Lipopolysaccharides (LPS) are highly toxic compounds, even at a trace amount. When recombinant proteins are produced in E. coli, it is inevitable that LPS contaminates. However, LPS removal is still technically challenging and costly due to the high degree of solubility in a wide range of solvents. In this study, we explored the possibility of using the N-terminal region containing cysteine-rich, EGF-like, and sushi1–3 domains (CES3) of Factor C from the horseshoe crab Carcinoscorpius rotundicauda to develop a platform to remove LPS from recombinant proteins. We expressed CES3 as part of a recombinant protein, BiP:NT:CBM3:SUMO:CES3:His:HDEL, in Nicotiana benthamiana and found that purified or microcrystalline cellulose (MCC) bead-immobilised CES3 showed strong binding to LPS-containing E. coli. To produce CES3:CBM3 in an LPS-free environment, we generated Arabidopsis transgenic plants harbouring a recombinant gene, BiP:NT:SUMO:CES3:CBM3:HDEL, and found that transgenic plants mainly produce CES3:CBM3:His:HDEL, a truncated version of BiP:NT:SUMO:CES3:CBM3:HDEL via endogenous protease-mediated proteolytic processing in vivo. CES3:CBM3:HDEL purified from Arabidopsis plant extracts and immobilised onto MCC beads removed LPS contamination from protein samples. We propose that the CES3:CBM3 fusion protein produced in plants and immobilised on MCC beads can be a robust and easy platform for LPS removal from recombinant proteins.

Influence of Tidal Cycles on Embryonic Rotation, Hatching and Emergence of Mangrove Horseshoe Crab, Carcinoscorpius rotundicauda

Influence of Tidal Cycles on Embryonic Rotation, Hatching and Emergence of Mangrove Horseshoe Crab, Carcinoscorpius rotundicauda

Population Characteristic of Carcinoscorpius Rotundicauda in The Northern Coast of Rangsang Island, Riau

Carcinoscorpius rotundicauda is often found in mangrove areas and is known as mangrove horseshoe crab. The crab is a common species that was abundantly caught by fishermen but currently, it has been said to be declining. The study aimed to estimate the population density and sex ratio of C. rotundicauda. In addition, it is necessary to know the local community’s perception of the horseshoe crab. The study was conducted from March to April 2021 in the northern coast of Rangsang Island of Riau Province. Sampling was carried out using 100x1m nets at 5 selected stations. The crabs were enumerated, marked, and released. People’s perception of C. rotundicauda was obtained by using a questionnaire method. The population density of the crabs in the northern coast of Rangsang Island is 0.026/m2. The sex ratio is 1.67. Public perception of horseshoe crabs is low so it is necessary to socialize the conservation of horseshoe crabs there.

Carcinoscorpius rotundicauda (mangrove horseshoe crab)

The mangrove horseshoe crab, Carcinoscorpius rotundicauda, is one of the four extant species of horseshoe crabs. Mangrove horseshoe crabs have an important ecological role in the marine food chain, besides providing nutrient-rich eggs to migratory birds. However, their populations have been declining rapidly due to loss of habitat and irresponsible fishing. Hence, there is a need to understand their population-genetic structure and genetic diversity, which are essential for designing effective conservation strategies.

Abandoned, lost, or discarded fishing gear at urban coastlines

Abandoned, lost, or discarded fishing gear (ALDFG) is considered a major threat to ocean biodiversity. Yet, little is known of the interactive impacts of ALDFGs and urban nearshore biodiversity and habitats, especially in Southeast Asia where fisheries efforts are increasing. We identified ALDFG hotspots around Singapore–where 80% of coastal areas are urbanized or anthropogenically modified. Fishing lines and nets were the most common ALDFGs recovered; with strong correlations between ALDFG presence and beaches, intertidal, mangroves, as well as sites with significant coastal modifications. Plastic polymer nets trapped the highest organism diversity and abundance. A total of 1052 trapped individuals comprising 124 species were recovered, the majority in classes Merostomata, Actinopterygii and Malacostraca. The most abundant trapped species was Carcinoscorpius rotundicauda and the highest mortality presentation was in Class Actinopterygii. This study demonstrates that ALDFGs remain a threat to marine biodiversity within urban coastal habitats and at heavily modified shorelines.