Scylla Serrata Research Articles

Effect of Different Synthetic Substrates on the Growth, Survival and Molting of Mud Crab Instars (Scylla serrata) in Recirculatory Aquaculture System

Three species of land crab occur in The Bahamas; these are an important source of protein and income for Bahamian islanders. The crab harvesters represent an important and largely untapped knowledge source. We conducted surveys on the Bahamian islands of Andros, New Providence, and Eleuthera to document crabbing practices and catalogue this local ecological knowledge (LEK) of land crabs. The survey primarily employed close-ended questions targeting land crab harvesters; we also recorded general feedback from open-ended questions. Crab collection was primarily for self-consumption. Catch rates varied among islands, and were the highest on Andros. There was a preference for white land crabs (Cardisoma guanhumi) on Andros, whereas on Eleuthera and New Providence, there was no preference for either white or black crabs (Gecarcinus ruricola). The majority of respondents reported a decline in white and black crab numbers, with land development and overharvesting being consistently cited factors. On Andros, forest fires were also reported to account for the loss of crab habitat, whereas on Eleuthera, invasive raccoons were blamed for the population decline. Respondents identified broadleaf forests as critical refuges and food sources for black crabs. Birds were the major predator, confirming findings for other land crab species. Land crabs were not merely a food resource but represented a complex nexus of ecological knowledge, economic systems, cultural traditions, and community practices within Bahamian society. We demonstrated a substantial overlap between traditional and scientific knowledge systems, providing valuable insights into land crab behaviour, habitat use, and ecology that complements formal scientific research.

Increased awareness of healthy lifestyles has spurred the growth of functional food trends among communities. Iron deficiency causes anemia, a major nutritional problem in Indonesia. Mangrove crab shells are a local source of iron. In most cases, the edible portion of crabs is limited to the meat, while the shells are discarded, leading to their high potential as a source of waste. The purpose of this study was to determine the effect of adding mangrove crab shell powder on the iron content of cookies. This study employed an experimental design using a Complete Randomized Design (CRD), with treatments of adding different concentrations of mangrove crab shell powder (0%, 3%, 6%, 9%, 12%, 15%). The data were analyzed using ANOVA and Duncan’s multiple range test. Findings indicated that adding mangrove crab shell powder significantly affected the iron content of the cookies. The iron content of the modified cookies ranged from 64.13 to 187.54 mg. The higher the concentration of crab shell flour added, the higher the iron content of the cookies. It is recommended that further research be conducted, encompassing organoleptic evaluation, microbiological contamination analysis, and heavy metal contamination assessment, to ensure the product's safety and quality. It is hoped that this research can serve as a reference on the use of crab shell waste as a source of iron that is beneficial to health.

Exoskeletons of mud crabs, Scylla serrata, of different sizes: Body weight, surface morphology, internal tissue structure, and mechanical resistance

ABSTRACT Mariculture holds significant promise for enhancing food security, blue economy development and climate‐resilient livelihoods along Kenya's 640 km coastline. This review synthesises over two decades of empirical and grey literature to examine the current status, production trends, challenges and future prospects of commercially cultured mariculture species in Kenya. The review focuses on key species including milkfish ( Chanos chanos ), rabbitfish ( Siganus sutor ), seaweed ( Eucheuma spp.), mud crab ( Scylla serrata ), prawns ( Penaeus spp.), oysters ( Saccostrea cucullata ), Artemia franciscana and sea cucumbers ( Holothuria scabra ). Despite a favourable marine environment and policy recognition, the sector remains underdeveloped, with total production in 2023 reaching only 112 metric tons. Major constraints include limited hatchery capacity, weak technical knowledge, policy and regulatory fragmentation, infrastructural gaps and fragile market linkages. Nonetheless, emerging opportunities are evident: seaweed farming has shown rapid expansion with high female participation; integrated multi‐trophic aquaculture (IMTA) offers ecological and economic efficiencies; and strategic investments such as the National Mariculture Resource and Training (NAMARET) Center promise to improve seed and training access. The review identifies the potential for upscaling finfish and shellfish farming, diversifying species portfolios and strengthening mariculture value chains through policy alignment, climate adaptation and blue economy integration. Addressing key constraints through targeted investment, inclusive community participation, and sustainable technologies will be critical to unlocking the sector's growth. This synthesis provides a foundation for policymakers, researchers and stakeholders to develop resilient, inclusive and market‐oriented mariculture systems in coastal Kenya.

This study aims to investigate the diversity and distribution of brachyuran crabs living in the mangrove swamps of Kalibhanjadia Island, located within the Bhitarkanika National Park in Odisha, India. The research spanned two years, from January 2018 to December 2019. A total of twelve species of crabs from six distinct families were recorded. The families represented include Sesarmidae (Episesarma versicolor, Episesarma mederi, and Parasesarma plicatum), Varunidae (Metaplax dentipes, M. distincta, and Varuna litterata), Grapsidae (Metapograpsus latifrons, also known as M. maculatus, and M. messor), Ocypodidae (Uca annulipes and U. rosea), along with one species each from Gecarcinidae (Cardisoma carnifex) and Portunidae (Scylla serrata). The results reveal a clear distribution pattern of brachyuran crabs across varying salinity gradients, underscoring their ecological adaptability. Specifically, grapsid, sesarmid, and ocypodid crabs mostly inhabit riverbank regions with low to moderate salinity, while varunid crabs, with the exception of Varuna litterata, are predominantly found in areas characterized by medium to high salinity within the upper tidal zones.

Mangrove crab (Scylla serrata) as one of the crustacean species, has a variety of bioactive compounds that can be utilized in the field of pharmacology. Antioxidant compounds act as therapeutic agents against degenerative diseases. Banyuasin waters have mangrove vegetation with associated marine organisms that have the potential to be studied for bioactive compounds. This study aims to identify the phytochemical profile quantitatively and qualitatively, samples were collected from mud flats near mangrove ecosystems in Banyuasin waters, South Sumatra. Samples were tested for antioxidant activity using the DPPH test, and IC50 values, qualitative phytochemical identification, and phytochemical profiles were calculated using Gas Chromatography-Mass Spectrometry (GC-MS) analysis. Based on the results of antioxidant testing, the IC50 value of S. serrata extract is 2.25 ppm, the sample is included in the category of very strong antioxidants. Phytochemical test results showed that the compound is thought to contain antioxidant activity from flavonoids and triterpenoids. GC-MS analysis detected major compound groups of alkaloids, purines, and vitamins. Minor compound groups detected amines, terpenoids, monosaccharides, amino acids, fatty acids, silanes, formamides, heterocycles, carboxylic acids, aminoglycosides, naphthalene derivatives, nitriles, amides, glycosides, and peptides. S. serrata extract shows very strong antioxidant activity, with major compounds such as alkaloids, purines, and vitamins. S. serrata extract detected compounds that have been reported as anti-inflammatory, anticancer, antimicrobial, and antiviral. These findings highlight the pharmaceutical potential of S. serrata as a source of bioactive compounds. The results of this study provide valuable information for the development of alternative medicines derived from marine organisms.

Viral load differences associated with infection outcomes and resistance to white spot syndrome virus (WSSV) infection in mud crab, Scylla serrata.

Effective management of Mud crab Reovirus (MCRV) infection in mud crab, Scylla serrata (Forskal, 1775) culture, using an individual compartmentalized system.

IntroductionPesticides can be transported into estuaries via spray drift, ground water contamination and surface runoff. Increasing climatic variability and global pesticide use are likely to increase the exposure of harvested estuarine species, and therefore seafood consumers, to agrichemicals. Post-harvest processing strategies present opportunities to reduce pesticide residues in seafood and so mitigate consumer exposure.Materials and methodsWe evaluated the efficacies of thermal processing (cooking) and depuration (holding individuals in clean flow-through seawater) for reducing pesticide residues in wild-caught giant mud crab (Scylla serrata) edible tissues (flesh and brown meat (i.e. hepatopancreas and gonads)). Pesticide residues were detected in 82% of assessed crabs, with five analytes quantified (cyprodinil, diuron, imidacloprid, propargite and triazophos).ResultsCorrelative analyses revealed cooking at ~82°C for 2 min 100-g–1 body mass reduced all pesticide concentrations (and the total residues) in both tissues by 7–99%—except for cyprodinil (51% increase). Imidacloprid residues in crab flesh were reduced (by 81%) after six days of depuration, with complete elimination after 12 days. While a human health-risk assessment identified that the concentrations of pesticide residues in crab tissues posed no negative health effects to seafood consumers, the data support post-harvest processing methods for mitigating consumer exposure.DiscussionThese findings do not constitute health advice regarding post-harvest possessing methods for reducing contaminants in seafood, but rather highlight the potential utility of the methods assessed for achieving this objective and the broader need for ongoing pesticide surveillance of Australian seafood. Food safety regulation should consider establishing maximum residue limits for seafood, with consideration of consumption preferences.

White shrimp (P. merguiensis) is the dominant catch caught in Demak waters and has high economic value. The fishing gear used by fishermen is wangkong fishing gear. This research aims to determine the composition and size structure of the catch, as well as the relationship between length and weight and sex ratio. The research was carried out in April and May 2024. The research method used was a survey method. The shrimp sampling method used is the census method. The target catch of fishermen from Menco Village, namely Penaeus merguiensis, was 87.10% and fishermen from Babalan Village, namely Penaeus merguiensis, amounted to 66.63%. The non-target catches were Mugil spp, Plotosuscanius, Rastrelliger spp, Scylla serrata, Oratosquilla oratoria, and Anguilla bicolor. The length class mode for white shrimp in Menco Village is 74.4 – 79.2 mm and Babalan Village is 96.6 – 106.5 mm. The relationship between length and weight of male white shrimp from Menco Village was obtained as W= 0.000353293L2.724 and female white shrimp from Menco Village was obtained as W= 0.000244543L2.837. The relationship between length and weight of male white shrimp from Babalan Village was obtained as W= 0.001095644L2.402 and female white shrimp from Babalan Village was obtained as W= 0.000167463L2.960. The sex ratio for white shrimp showed that the ratio between males and females in Menco Village was 1:1.10 and Babalan Village was 1:1.36. The growth pattern of P. merguiensis is negative allometric and more female shrimp are caught than male shrimp. Keywords: Catch; Demak Waters; Wangkong; WhiteShrimp (P. merguiensis)

Abstract Microplastic pollution significantly impacts both marine and freshwater ecosystems, posing a growing concern for aquatic organisms and food safety. This research focuses on comparing microplastic contamination in the hepatopancreas of three edible crab species: two marine—the giant mud crab (Scylla serrata) and the blood-spotted swimming crab (Portunus sanguinolentus)—and one freshwater species (Parathelphusa convexa). These crabs are widely consumed and play an important role in local fisheries and diets. Thirty adult crabs were collected from three sites in the coastal areas of North-East Bay of Bengal and nearby freshwater ponds. Analysis of the hepatopancreas showed average microplastic counts of 0.97 for Scylla serrata, 0.93 for Portunus sanguinolentus, and 3.84 for Parathelphusa convexa. Confocal Raman spectroscopy identified nine different types of microplastics, likely including polyphenylene sulfide (PPS), polyurethane (PUR), polyethylene terephthalate (PET), polypropylene (PP), polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), polyvinyl chloride (PVC), polystyrene (PS), and poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) , which pose risks to aquatic life and human health. These pollutants, which persist in the environment, can disrupt ecosystems and may cause immune system damage and chronic diseases in humans. The Pollution Load Index (PLI) showed that the giant mud crab is most vulnerable to microplastic pollution, with a PLI of 2.31—significantly above the threshold of 1, indicating considerable pollution. This study highlights the urgent need for strategies to mitigate microplastic contamination, considering the health risks linked to consuming contaminated crabs.

Polyethylene Terephthalate (PET) microplastics are among the primary contaminants in aquatic environments and pose potential risks to human health. Coagulation is an effective method for reducing microplastics; however, conventional coagulants such as alum may leave harmful residues. This study aims to evaluate the effectiveness of chitosan synthesized from crab shell waste (Scylla serrata) as an eco-friendly biocoagulant in the coagulation of PET microplastics. Chitosan synthesis was carried out through three stages: demineralization, deproteinization, and deacetylation. The coagulation process was conducted under varying pH conditions (3, 5, 7, 9, and 11), with a chitosan dosage of 500 mg/L and a sedimentation time of 45 minutes. The results show that optimal conditions were achieved at pH 7, with microplastic removal efficiency reaching 98.4%. Characterization using Fourier Transform Infrared Spectroscopy (FTIR), Particle Size Analyzer (PSA), and stereo microscopy confirmed successful floc formation and active interaction between chitosan and microplastics. The study concludes that chitosan derived from crab shell waste has strong potential as an effective and environmentally friendly alternative coagulant for treating water contaminated with microplastics.

The present study was aimed to purify, characterize and quantify vitellin from the mature ovaries of the mud crabs, Scylla serrata. Vitellin was purified using saturated ammonium sulfate method followed by dialysis. Analysis on SDS-PAGE revealed two subunits of 105 kDa and 85 kDa. To analyse the peptide profile of vitellin, the bands obtained were digested with trypsin and the tryptic peptides were sequenced by liquid chromatography-mass spectroscopy and MALDI-TOF analysis. The peptides identified from 105 kDa were spread along the entire sequence of vitellogenin corresponding to the full length of the protein. Purified vitellin was used to raise polyclonal antisera with which an enzyme linked immunosorbent assay method was developed. Typical standard curve using ELISA showed a detectable vitellin sensitivity range between 5.0 ng and 1.0 μg (linear regression analysis: R2= 0.991). Quantification of vitellogenin during natural reproductive cycle of mud crabs, revealed a significant increase (p< 0.001) in vitellogenin levels as compared to crabs at immature stage. To conclude, we demonstrated the isolation, purification, characterization and quantification of ovarian yolk protein from mud crabs, S. serrata which could be used as an aquaculture tool to identify and assess the signalling molecules that promote seed in hatchery industry.

L-asparaginase is a vital antineoplastic drug. The side effects of the current formulations intrigued researchers to explore novel candidates. The study evaluated a novel type-II L-asparaginase from Chryseomicrobium amylolyticum from marine crab, Scylla serrata. Statistical optimization enhanced production to 281.6 from 115.69 IU/ml. The purified enzyme had 173.69 IU/mg protein specific activity. The Km, Vmax, and Kcat were 6.364 µM, 909.09 µM/min, and 222.82 /sec. The enzyme didn't react with L-glutamine, D-glutamine, L-glutamic acid, and urea, a clinically desirable feature. In vitro trypsin and serum half-life were ~ 39h and ~ 27min. The study enlisted ions, protein-modifying agents, and surfactants influencing its activity. The detailed in silico analyses of the functional gene predicted its physicochemical and structural features. The low sequence identity with the commercial enzymes and the predicted nonallergenic and nontoxic features suggested its clinical suitability. Molecular docking revealed a higher binding affinity for L-asparagine than L-glutamine and urea. The IC50 against MCF7, MOLT4 and THP-1 cell lines were 0.043, 0.041, and 0.05 IU/ml, respectively. Phase contrast microscopy confirmed its cytotoxicity. Flow cytometry demonstrated 81.4% apoptotic cells in MOLT-4 cells at IC50, signifying potent anticancer activity. The enzyme did not affect normal human fibroblast cells and was non-haemolytic. The results underscore the therapeutic potential of C. amylolyticum type-II L-asparaginase and support further in vivo studies to advance L-asparaginase-based cancer therapies.

Comparative analysis of the microbiota in wild mud crab (Scylla serrata) intestine, sediment, and water in Koggala Lagoon, Sri Lanka

The study assessed heavy metal accumulation (As, Cd, Cr, Pb, Hg) in mud crabs (Scylla serrata) and soils from four municipalities in Northern Samar, Philippines. Although environmental conditions like pH, salinity, and temperature were suitable for crab farming, both crab meat and soil showed heavy metal levels exceeding FAO/WHO safety limits. Several factors may have contributed to the alarming issue of heavy metal levels in mud crab meat exceeding FAO/WHO standards, despite favorable environmental conditions. One of the major concerns is poor water quality particularly in farms located near polluted water bodies. These water sources are often plagued by industrial and agricultural runoff, which can seep into the farms and introduce heavy metals into the environment where the crabs live. Another concern is the use of low-quality feed, such as trash fish, which may contain high levels of heavy metals. Farmers who use this type of feed have reported foul odors, a clear indication of potential contamination. Additionally, natural environmental factors like saltwater intrusion and rising water temperatures may also contribute to the heavy metal contamination. The findings suggest that while the water conditions in the fish ponds are suitable for mud crab cultivation, the presence of heavy metals poses significant health risks to consumers and environmental concerns. The study highlights the need for further investigation and mitigation strategies to address the issue of heavy metal contamination in mud crab cultivation in Northern Samar.

This study aims to evaluate the catch performance and socio-economic relevance of traditional stick dip nets, by comparing two types, Rakkang-A in Muara Kintap and Rakkang-B in Bawah Layung, Tanah Laut Regency, Indonesia. The fieldworks were conducted between September and October 2024. A total of 580 Rakkang were deployed in the mangrove areas, with sample size: Rakkang-A (n = 73 lifts, 10.43±0.04) and Rakkang-B (n = 71 lifts, 10.14±2.89). The crab catch data on Scylla serrata and S. olivacea were collected, and statistical analysis was performed to determine significant differences in catch rates. Results showed that the two Rakkang types effectively captured both S. serrata and S. olivacea, but with species-specific preferences. Rakkang-A was more effective for S. olivacea, while Rakkang-B yielded higher catches of S. serrata. Catch per unit effort (CPUE) analysis revealed that Rakkang-A had a higher CPUE for S. olivacea (0.14 ind/trap) compared to Rakkang-B (0.05 ind/trap). Conversely, both Rakkang types performed equally for S. serrata (0.16 ind/trap). Overall, CPUE of Rakkang-A (0.30±0.03) was approximately 1.34 times greater than that of Rakkang-B (0.22±0.05). The bait selection played a crucial role, with S. olivacea being more attracted to fish bait, whereas S. serrata preferred crab bait. These findings highlight the importance of selecting the appropriate Rakkang type and bait for optimizing crab fishing efficiency. Further research on environmental factors and gear modifications could enhance sustainability and economic viability for local fishers.

Mangrove crab, (Scylla serrata) in the shell contains chitosan which can be used for anti-hypercholesterolemia. Chitosan synthesis procedures include demineralization, deproteination, and deacetylation. The resulting chitosan is then evaluated. The results of chitosan evaluation include organoleptic (powder, white to pale yellow, and odorless), deacetylation degree test (77.89±0.81%), yield (69.92%), ninhydrin (purple), ash content (0.2±0.09%) and water content (4.6±3.05%). This study aims to formulate Effervescent Granule Suspension using xanthan gum (F1) and CMC-Na (F2) as variations of suspending agents. The evaluation results of effervescent granules before reconstitution include the angle of repose test F1=22.31±1.53 ° and F2=24.51±1.85°, flow rate test F1=21.12±2.62 g/sec and F2=23.27±0.89 g/sec. % fines test F1=6.95±9.03% and F2=6.86±2.11%. Water content test F1=4.3±2.10% and F2=9.2±1.03%. The evaluation results after reconstitution include the foam height test F1=5±1 cm and F2=4.6±1.15 cm; dispersion time test F1=2.03±0.15 minutes and F2=3.2±0.25 minutes; Viscosity F1=1.97±0.19 mPa.S and F2=1.94±0.14 mPa.S and pH test F1=5.82 and F2=8.31. The results were then analyzed statistically. The conclusion in this study is that there is an effect of different suspending agents on the evaluation of water content, dispersion time and pH. The best Effervescent Granule Suspension Formulation is F1 with Xanthan gum suspending agent

Alat tangkap bubu lipat merupakan salah satu alat tangkap yang dioperasikan untuk menangkap kepiting bakau di Desa Pangkal Babu, Penangkapan kepiting bakau (Scylla serrata) menggunakan alat tangkap bubu lipat diperlukan umpan dalam upaya untuk meningkatkan hasil tangkapan secara efektif. Penelitian ini bertujuan untuk mengetahui Perbedaan hasil tangkapan kepiting bakau menggunakan umpan ikan pari dan ikan tembakul Menggunakan bubu lipat. Penelitian ini dilakukan di Desa Pangkal Babu, Tanjung Jabung Barat pada tanggal l7 Maret -7 April 2024. Metode yang digunakan adalah experimental fishing. Data yang dihimpun meliputi jumlah, berat dan lebar hasil tangkapan kepiting bakau, Jumlah, berat, dan lebar karapas hasil tangkapan ditabulasikan dalam bentuk tabel dan grafik. Data yang diperoleh kemudian dilakukan analisis uji T. Hasil penelitian yang didapatkan bahwa jumlah hasil tangkapan kepiting bakau sebanyak 27 ekor dengan rata-rata berat total 407,8gr dan rata-rata lebar karapas yaitu sebanyak 198,4 mm. Sedangkan hasil tangkapan kepiting bakau dengan perlakuan ikan tembakul mendapatkan 34 ekor dengan rata-rata berat 602,4gr, dan rata-rata lebar 267,6 mm. Dari hasil analisis uji T menunjukkan bahwa perlakuan jenis umpan berpengaruh tidak nyata (P > 0,05) terhadap jumlah hasil tangkapan kepiting bakau, namun berpengaruh nyata (P < 0,05) terhadap berat dan lebar karapas kepiting bakau, Dari penelitian ini, dapat disimpulkan bahwa penggunaan umpan ikan tembakul pada alat tangkap bubu lipat di Desa Pangkal Babu menghasilkan berat dan lebar karapas yang lebih tinggi dibandingkan dengan penggunaan umpan ikan pari.