Setiu Wetlands Research Articles

Nereidid polychaetes (Annelida) inhabiting the inside of decaying fronds of the mangrove palm Nypa fruticans in a tropical estuary in Malaysia, with special reference to the life history of the dominant species, Namalycastis sp

ABSTRACT Since relatively dense assemblages of nereidid worms were discovered from a unique habitat within the decaying fronds of the mangrove palm Nypa fruticans, we conducted a one-year survey from September 2015 to September 2016 at six sites in Setiu Wetlands, Malaysia, to clarify the species composition of the nereidid assemblages and the life history of the dominant species. The majority of specimens collected from the plant body (507 out of a total 678 specimens) belonged to Namalycastis sp. with remaining specimens belonging to Namanereis sp. (n=168), Namalycastis rhodochorde (n=1), and Perinereis aibuhitensis (n=2). Specimens of P. aibuhitensis (n=2) and Dendronereis sp. (n=2) were also collected from sediments around the palm trees. The taxonomic accounts of two Namalycastis spp. and Perinereis aibuhitensis are provided here. The life history of the dominant species Namalycastis sp. is evaluated based on the population characteristics. This species is gonochoric, with the sex ratio close to 1:1. The ovigerous females were found throughout the year, with their body width (BW) ranging from 1.3 to 4.8 mm. The ovigerous rate (no. of ovigerous females/no. of worms larger than the minimum ovigerous female) was lowest in February and March 2016 (8–9%) and highest from July to November 2016 (23–29%), when the ovigerous females had the largest coelomic oocytes of 100–120µm in diameter. Probable epitokes with additional neuropodial sesquigomph spinigers occurred most abundantly in November 2015 (21% of adults), which was also the only month when a mature male with mature spermatozoa appeared. Few juveniles with BW of less than 1.3 mm occurred from February to July, whereas large adults with BW of more than 3.5 mm occurred from May to November. These results suggest semelparous reproduction with peak spawning in November, coinciding with low salinity during the north-east monsoon.

Antimicrobial and Enzymatic Activities of Mangrove-associated Actinomycetes

This study delves into the enzymatic and antimicrobial capabilities of actinomycetes isolated from the Setiu Wetland mangrove in Terengganu, Malaysia. A total of eighteen actinomycete bacteria were isolated and characterized from the site. These isolates underwent antimicrobial assessments targeting a representative range of Gram-positive bacteria, Gram-negative bacteria and a fungus were employed for the testing. The results of the antimicrobial evaluations demonstrated pronounced effectiveness of the majority of isolated actinomycetes against Gram-negative bacterial strains. Intriguingly, a notable observation was the inhibition against Streptococcus uberis on nutrient agar by 27.7% of the isolates. In conjunction with the antimicrobial investigations, an array of enzymatic assays encompassing amylase, protease, lipase, phosphate solubilization, urease, and cellulase were executed. The outcomes revealed that a substantial portion of the examined actinomycetes exhibited positive reactions in at least half of the conducted assays, with amylase and protease production being particularly prominent, were observed from 94% of the isolates. These findings, drawn from the amassed dataset, underscore the remarkable diversity of antimicrobial and enzymatic activities within the actinomycetes thriving in the mangrove environment. This diversity exemplifies the adaptability of these mangrove-associated actinomycetes, underscoring their capacity to generate a versatile spectrum of secondary metabolites and biochemical responses as a strategy for survival within this unique ecosystem.

Ecotoxicological impact of heavy metals on wild mud crabs (Scylla olivacea) in Malaysia: An integrative approach of omics, molecular docking and human risk assessment

Mud crab, one of the aquatic organisms found in estuary areas, has become a significant economic source of seafood for communities due to its delectable taste. However, they face the threat of heavy metal contamination, which may adversely affect their biological traits. This study explored the comparison of the mud crabs collected from Setiu Wetland as a reference site, while Kuala Sepetang is an area that contains a higher concentration of heavy metals than Setiu Wetlands. Heavy metal levels were quantified using inductively coupled plasma mass spectrometry (ICP-MS), while proteomes were assessed using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and 1H nuclear magnetic resonance (NMR)-based metabolomics, respectively. Heavy metal contamination affects the proteome, metabolome, and putative molecular targets in mud crabs (Scylla olivacea), leading to oxidative stress. Mud crabs collected from the metal-polluted area of Kuala Sepetang in Perak had considerably elevated concentrations of nickel (Ni), copper (Cu), zinc (Zn), lead (Pb), chromium (Cr), and cadmium (Cd) in comparison to the reference site of Setiu Wetlands in Terengganu. The proteome analysis revealed an upregulation of the stress-response protein Hsp70, which triggered superoxide dismutase (SOD) and increased arginine kinase expression (5.47 fold) in the muscle tissue, results in the alteration of metabolite regulation in the mud crab from Kuala Sepetang. Additionally, in the muscle tissues of mud crabs obtained from Kuala Sepetang, uncharacterized myosin-tail 1 domain proteins and sarcoplasmic calcium-binding proteins were downregulated. The metabolomic investigation identified changes in metabolites associated with energy metabolism and osmoregulation. Exploration of docking analysis suggests potential connections between methylarsonic acid and essential proteins in mud crabs. These findings suggest that the presence of heavy metals disrupts physiological processes and highlights potential molecular targets that warrant further investigation.

A comparative study on the antennae morphology and ultrastructure of three mud crab species of the genus Scylla from Setiu Wetlands, Terengganu, Malaysia.

Crustaceans possess a range of sensory organs crucial in sensory perception, communication, and various ecological functions. Understanding morphological and functional differences in antennae among species could validate taxonomic differentiation and ecological adaptations. The antennae morphology and ultrastructure of mud crab species within the Scylla genus are poorly understood, and their role in ecological adaptation and species differentiation remains unexplored. This study aimed to describe and compare the morphology and ultrastructure of antennae in Scylla olivacea, Scylla tranquebarica, and Scylla paramamosain. Antennae were carefully excised from each crab and subjected to morphological, morphometric, and ultrastructural analysis. The study revealed that the antennae of Scylla species exhibit similar overall morphology, with a series of segments that tapered toward the upper end. All species possess non-branched single setae on the upper end of each segment. The number of antennae segments varied between species, with S. paramamosain having significantly more segments than S. olivacea. Additionally, the length and width of antenna segments differed among the species, with S. tranquebarica having a rougher antenna surface compared to S. olivacea and S. paramamosain. Our findings suggest that Scylla's antennae are distinct between species, especially in the number of segments and setae size. Such difference might be related to ecological adaptation. The role of antennae in sensory perception and social behavioral cues in mud crabs warrants further investigation. This study serves as a foundational reference for future research on the taxonomy, ecological adaptation, and sensory behaviors in the Scylla genus. RESEARCH HIGHLIGHTS: Variations and similarities in morphology and ultrastructure of three Scylla species can be found in the antennae. Scylla paramamosain had significantly higher number of segments than Scylla olivacea in morphology feature. The antennae surface of Scylla tranquebarica was rougher than that of S. olivacea and S. paramamosain. Antennae of three Scylla species possess non-branched single setae.

MORPHOLOGICAL MEASUREMENT AND ABUNDANCE OF MANGROVE CLAM (Geloina expansa) AND ITS SEDIMENT GRAIN SIZE PREFERENCES AT PULAU SUTUNG AND PULAU BUSUNG, SETIU WETLANDS, TERENGGANU

Geloina expansa is an infaunal filter-feeding clam species found in mangrove forest. They are important for humans and aquatic ecosystem. Not much information about morphological measurement, abundance and sediment grain size at Pulau Sutung and Pulau Busung. This study aims to determine the shell size measurements, the abundance and the composition of sediment grain size in these sites. Line transects were used for samples and sediment collection in a plot at Pulau Sutung and Pulau Busung. Twenty samples from each site were measured. The grain size and total carbon percentage were obtained using sieve shaker and ignition method. Independent t-test was conducted using SPSS for abundance density and measurements between two sites. 155 specimens (Pulau Sutung = 90; Pulau Busung = 65) were collected. However, abundance density between the two sites were insignificant. The most dominant grain size in Pulau Sutung is C500 whereas VC1000 is dominant in Pulau Busung. Mean shell length (= 55.35mm ± 6.39) and height (= 52.51mm ± 6.14) in Pulau Busung were greater than in Pulau Sutung (= 53.21mm ± 6.39; = 51.10mm ± 6.49), respectively. But mean shell width in Pulau Sutung, (= 31.30 mm ± 3.20) is greater than in Pulau Busung (= 31.19mm ± 4.05) but measurements were insignificantly different between the sites. This result will be useful to establish a baseline of data and also for the management and sustainability of the species. Future studies must be done by considering water parameter and collecting more samples from more site in Setiu Wetlands.

Sustainable Resilient Design Challenges for Ecotourism Education in Setiu Wetland

Sustainable Resilient Design Challenges for Ecotourism Education in Setiu Wetland

Anthropogenic trace metals in Setiu Wetland: Spatial and seasonal distribution and implications for environmental health

The growing urban wastewater volume poses a major global environmental challenge, especially in developing nations where inadequate treatment and discharge impact clean water availability. This study focused on Setiu Wetland, aiming to analyze seasonal and spatial variations of trace metals in particulate form from anthropogenic and pathogenic sources. Surface water samples were collected from multiple stations, measuring physical parameters like salinity, temperature, pH, dissolved oxygen (DO), and dissolved organic carbon (DOC). Samples were filtered using ultrafiltration and analyzed with inductively coupled plasma mass spectrometry (ICP-MS). Correlations between trace metals and other parameters were examined to understand their dynamics in the area. The study found that particulate trace metals were influenced by anthropogenic sources, including municipal, industrial, agricultural, and domestic wastewater discharge. The measured concentrations for Cd, Cu, Pb, Fe, and Zn were 10.9 ± 5.1, 31.8 ± 16.8, 72.5 ± 28.5, 20,206 ± 17,929, and 46,742 ± 30,898 μg/g, respectively, indicating their significant presence. To gain deeper insights, a model incorporating principal component analysis (PCA) analyzed the relationships between trace metals, dissolved oxygen levels, and factors like pH, temperature, salinity, and DOC. Regression techniques predicted Cd, Zn, and Fe concentrations based on salinity, with pH serving as an additional predictor for Cu. Moreover, Pb concentration was influenced by temperature, dissolved oxygen, and dissolved organic carbon. These findings emphasize the importance of regular monitoring and assessment of trace metals in protected tropical areas and wetlands, helping mitigate environmental risks associated with wastewater discharge and preserving these ecosystems.

Commercially important mangrove crabs are more susceptible to microplastic contamination than other brachyuran species

Brachyuran crabs are ecologically and economically important macrofauna in mangrove habitats. However, they are exposed to various contaminants, including plastics, which bioaccumulate in relation to their feeding modes. Setiu Wetlands is a unique place on the east coast of Peninsular Malaysia where different ecosystems such as mangroves, lagoon, beaches, etc., are duly connected and influencing each other. In recent years, the shifted river mouth has threatened these wetlands, causing severe hydrodynamic changes in the lagoon, especially in the core mangrove zone. The present study tested microplastics (MPs) contamination in the mangroves through brachyuran crabs as indicators. Three sampling sites, namely Pulau Layat, Kampung Pengkalan Gelap, and Pulau Sutung were chosen. The four abundant crab species Parasesarma eumolpe, Metaplax elegans, Austruca annulipes, and Scylla olivacea, which display different feeding behaviours were collected from all sites covering the dry (Feb–Mar 2021) and the wet (Dec 2021–Jan 2022) seasonal periods. There were significant differences in the seasonal abundance of MPs among crab species. The highest accumulation of MPs in the crab stomachs in the dry season could be linked to subdued water circulation and poor material dispersion. Besides the lower MPs in the wet period due to improved water exchange conditions, its significant presence in the stomachs of S. olivacea indicates the role of its feeding behaviour as a carnivore. In addition, the micro-Fourier transform infrared spectroscopy (micro-FTIR) revealed the widespread occurrence of polymers such as rayon and polyester in all species across the sites. Given the fact that crabs like S. olivacea are commercially important and the ones contaminated with MPs can cause detrimental effects on the local community's health, further managerial actions are needed to assure sustainable management of the Setiu Wetlands.

An evaluation of spatial and seasonal distributions of dissolved trace metals in the water of the natural wetlands

The spatial and temporal distributions of trace metals in dissolved forms mainly result from anthropogenic and lithogenic contributions. Surface water samples (∼0.5 m) were collected monthly at respective stations from Setiu Wetland. In this study, the behaviour of trace metals in the dissolved phases along the water column from sampling sites in the Setiu Wetland, Malaysia was investigated. In addition, dissolved organic carbon (DOC) and physical parameters such as salinity, temperature, pH and dissolved oxygen (DO) of the surface water were measured in order to evaluate the relationship between trace metals fractionation with different water quality parameters. Size fractionation study of dissolved trace metals using ultrafiltration technique were also carried out and analysed using inductively coupled plasma mass spectrometry (ICP-MS). Correlation of trace metals with other measured parameters was made to furthermore understand the dynamics of trace metals and its fractionated components in this area. The concentration of dissolved trace metals was in the range of 0.001–0.16 μg/L for Cd, 0.12–2.81 μg/L for Cu, 0.01–1.84 μg/L for Pb, 3–17 μg/L for Fe and 1–34 μg/L for Zn, suggesting the input of anthropogenic sources for trace metals such as municipal, industrial, agricultural and domestic discharge. The periodic monitoring and evaluation of trace metals in wetlands and protected tropical areas is highly recommended.

Species Diversity and Assemblage of Mangroves at Setiu Wetland, Terengganu, Malaysia

Mangroves in wetland ecosystems are diverse and play significant role in the adjacent communities on which they are dependent for their livelihoods. It is also important for fishery resources and nutrient inputs in marine and brackish water ecosystems. However, little is known about the tropical wetland lagoon ecosystems, particularly mangrove diversity and assemblages. Therefore, this present study was initiated to observe the mangrove species diversity and assemblages together with the conservation status in an important tropical wetland ecosystem in Setiu, Terengganu, Malaysia. In a variety of landward and small fringe island areas, three zones of square plots were selected (zones 1, 2 and 3) to address the objectives of this study. As a result, a total of 20 true mangrove species belonging to 11 genera from nine families were documented, of which, Avicennia rumphiana was listed as vulnerable (VU) by the IUCN. Twelve species of mangrove associates from 11 genera and nine families were also found in the investigated zones at Setiu. One of the mangrove associates, Intsia bijuga, was designated as vulnerable (VU) by the IUCN. The Shannon diversity index (H') of mangroves was found to be 1.08 at Setiu Wetland. Rhizophora mucronata was found to be well-expanded (H' = 1.05) followed by A. rumphiana, A. officinalis, Heritiera littoralis, A. corniculatum. Excoecaria agallocha, Lumnitzera racemosa, and A. ebracteatus (H' = 0.0) as the lowest. The findings of the present study revealed that mangroves in the Setiu Wetland are diverse and healthy compared to other mangrove ecosystems in the region. To maintain the health and function of the mangrove ecosystem in Setiu Wetland, proper monitoring is required.

Erratum: Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs.

Erratum: Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs.

Weight Prediction for Fishes in Setiu Wetland, Terengganu, using Machine Learning Regression Model

Predicting fish weight holds several essential implications in ecology, such as population assessment, trophic interactions within ecosystems, biodiversity studies of fish communities, ecosystem modelling, habitat evaluation for different fish species, climate change research, and support fisheries management practices. The objective of the studies is to analyse the prediction performance of machine learning (ML) regression models by applying different statistical analysis techniques. This study collected biometric measurements (total length and body weight) for 19 fish families from three locations in Setiu Wetland, Terengganu, captured between 2011 and 2012. The study adopts two regression types: Linear Regression (i.e., Multiple Linear, Lasso, and Ridge model) and Tree-based Regression (i.e., Decision Tree, Random Forest, and XGBoost model). Mean absolute error (MAE), root-mean-square error (RMSE), and coefficient of determination (R2) were used to evaluate performance. The results showed that the proposed ML regression models successfully predicted fish weight in Setiu Wetlands, and the Tree-based Regression model provides more accurate prediction results than the Linear Regression model. As a result, Random Forest is the best predictive model out of the six suggested ML regressions, with the highest accuracy at 96.1% and the lowest RMSE and MAE scores at 3.352 and 0.880, respectively. In conclusion, the use of machine learning is crucial for rapid, precise, and cost-effective fish weight measurement. By incorporating weight prediction into ecological research and management practices, we may make informed decisions supporting the conservation and sustainable use of fish populations and their habitats.

Species Composition, Diversity, and Biomass Estimation in Coastal and Marine Protected Areas of Terengganu, Peninsular Malaysia

We investigated and compared the tree species composition and diversity of different forest types in Setiu Wetlands and on the three major islands of Terengganu. A total of 24 plots of 25 m × 25 m with four plots in each study site were established, viz. Melaleuca swamp forest in Kampung Fikri, freshwater swamp forest in Kampung Gong Batu, mangrove forest in UMT Setiu research station, and the islands, namely Pulau Bidong, Pulau Redang, and Pulau Perhentian. We calculated the basal area, stand density, Importance Value Index, species diversity, and above-ground biomass in the designated study areas. We assessed 139 tree species from 96 genera and 50 families based on a total of 2608 tree samples of 5 cm DBH and above. The freshwater swamp forest harbored the highest number of species with 20 species in Setiu Wetlands, and among the islands, Pulau Redang had the highest with 56 species. Melaleuca cajuputi was the most dominant species in the Melaleuca swamp forest, while Alstonia spatulata and Rhizophora apiculata are expected in the freshwater swamp and mangrove forest, respectively. Pulau Bidong, Pulau Redang, and Pulau Perhentian are mostly represented by Licania splendens, Shorea glauca, and Vatica sp., respectively. All the dominant species but Licania splendens contributed to the highest amount of above-ground biomass. Our current study indicated that different forest types vary in composition and structure, which may contribute to their unique ecological roles within their specific environment.

Developing and application to the fishing industry with the internet of thing (IoT)

Abundance of three coexisting gastropod species (Cerithidea cingulata, Cerithium coralium and Batillaria zonalis) in the lagoon area of Setiu Wetlands, Terengganu, Malaysia

Abundance of three coexisting gastropod species (Cerithidea cingulata, Cerithium coralium and Batillaria zonalis) in the lagoon area of Setiu Wetlands, Terengganu, Malaysia

Abundance of three coexisting gastropod species (Cerithidea cingulata, Cerithium coralium and Batillaria zonalis) in the lagoon area of Setiu Wetlands, Terengganu, Malaysia

Mangrove Propagule Dispersal in a Shallow and Narrow Coastal Lagoon: A Simulation-Based Assessment of the Setiu Wetlands, Malaysia

The short- to long-distance dispersal (SDD and LDD) of propagules is critical for the regeneration of mangrove forests. Mark–recapture experiments are considered to be a good tool for assessing such dispersal patterns. However, dense mangrove roots, exposed mudflats, shallow water, etc. often limit the number of recaptured propagules and their implication studies. Therefore, a combination of hydrodynamic and particle tracking models, together with a mark–recapture experiment, were applied to identify the dispersal behavior of Rhizophora mucronata Lamk. propagules in a coastal lagoon of Setiu Wetlands, Malaysia. The transport trajectories revealed that the dispersal of propagules is leptokurtic, with majority of them confined to very-short-distance dispersal (VSDD; 3–5 m) to SDD (1400 m). While higher obstacle density (e.g., mangrove roots) constrained the propagule dispersal, weaker tidal currents that coupled with less upstream discharge increased their retention time and settlement closer to the point of release. Under this scenario, the chances for propagules to exit from the lagoon mouth and their entry into the open waters for LDD are very limited. These results can explain the abundance of Rhizophora spp. in the northern sector of the Setiu Wetlands and be useful for species-level conservation/management.

Species composition, abundance, size distribution, sex ratios, and movement of Scylla mud crabs within the mangrove ecosystem at Setiu Wetland, Terengganu, Malaysia

The aim of the present study was to determine the movement patterns of mud crabs, genus Scylla, within the mangrove area of the Setiu Wetland in Terengganu, Malaysia. Mark-release-recapture technique were conducted during 24 sampling trips. A fluorescent visible implant elastomer (VIE) tag was inserted within the crab’s shell and they were released at the same capture stations over an interval of two weeks before the next sampling. A total of 288 crabs of various sizes, sex and species were identified, measured, tagged and recorded. The numbers of male crabs were higher than females. Three species were present, dominated by S. olivacea at 54.2% and S.tranquebarica at 26.4%, with S. paramamosain in third place at 19.4%. Among the 288 crabs that were tagged and released, 26.38% were recaptured. The tagged crabs did not move very far from the release station based on the recapture data. The greatest mean chance of being recaptured within 24 h was 44.5%, and there were no tagged crabs recaptured after 48 h even on sampling trips at several points from the release site. Knowledge of movement patterns is essential to understand migration and population dynamics and the relationship between reproduction and local distribution.

ARCOTHERES SP., A NEW REPORT ON PEA CRABS (CRUSTACEA: PINNOTHERIDAE) IN BIVALVES FROM THE SETIU WETLAND LAGOON, MALAYSIA

Pea crab infestations reduce the quality of bivalves, decreasing their market value and may result in consignment rejection during exportation in the bivalve aquaculture industry. This study investigates the prevalence of pea crabs in four different species of bivalves collected in habitats in the Setiu Wetland Lagoon, Terengganu. A total of 771 samples of bivalves including Geloina expansa (Mousson, 1849), Meretrix meretrix (Linnaeus, 1758), Anadara cornea (Reeve, 1844) and Magallana bilineata (Röding, 1798) were collected during low tide, with shell length measurements of 5.44 ± 1.3, 2.67 ± 0.6, 3.96 ± 0.6 and 0.00 ± 0.0, respectively. No length measurement was recorded for M. bilineata due to the unequal sizes of the shells. A total of 30 pea crabs were harboured with single colonisation and all of them were females. The pea crabs were identified to be from the genus Arcotheres sp. Manning, 1993 with carapace subcircular and invisible eyes in the dorsal view, chela slender, half of the palm length dactylus, palm slender, dactylus and pollex straight, propodus spatulate with apex rounded, dorsally and distally setose, slender exopod, dorsally and ventrally unarmed ambulatory legs, and relative length of meri P3>P2=P4>P5, P2 and P3 dactyl less than half of the propodal length. The prevalence of pea crabs was higher in G. expansa (P: 9.73%), followed by M. bilineata (P: 1.59%) and M. meretrix (P: 1.12%) which were highly influenced by the host size. No pea crab infestation was found in A. cornea probably due to muddy and strong waves area. Overall, the present study revealed that host size and habitat were the main factors affecting the colonisation of pea crabs in bivalves from the Setiu Wetland Lagoon, Terengganu.

Utilizing Pyrolysis-Gas Chromatography/Mass Spectrometry for Monitoring and Analytical Characterization of Microplastics in Polychaete Worms.

Microplastics (the term for plastics at sizes of <5 mm) might be introduced into the environment from domestic or agricultural activities or from the breakdown of plastic pieces, particles, and debris that are bigger in size. Their presence in the aquatic environment has caused accumulation problems, as microplastics do not easily break down and can be digested by some aquatic organisms. This study was conducted to screen and monitor the level of microplastic pollution in polychaete worms using pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS). The study was conducted in Setiu Wetlands, Malaysia from November 2015 to January 2017 at five-month intervals and covered all monsoon changes. Results from physical and visual analyses indicated that a total number of 371.4 ± 20.2 items/g microplastics were retrieved from polychaete for all seasons, in which, the majority comprised transparent microplastics (49.87%), followed by brown with 138.3 ± 13.6 items/g (37.24%), 21.7 ± 1.9 items/g for blue (5.84%), and 12.9 ± 1.1 items/g for black (3.47%), while the remaining were green and grey-red colors. Statistical analysis using Kruskal–Wallis showed insignificant differences (p > 0.05) between the sampling station and period for the presence of a microplastics amount. Most of the microplastics were found in fiber form (81.5%), whereas the remaining comprised fragment (18.31%) and film (0.19%) forms. Further analysis with Py-GC/MS under a selective ion monitoring mode indicated that pyrolytic products and fragment ions for a variety of polymers, such as polyvinyl chloride, polypropylene, polyethylene, polyethylene terephthalate, polyamide, and polymethylmethacrylate, were detected. This study provides an insightful application of Py-GC/MS techniques for microplastics monitoring, especially when dealing with analytical amounts of samples.

Water flow velocity influence the gonad maturation, glucose and energy levels of mud crab, Scylla olivacea

Environmental factors affect the biological functions of aquaculture species both in the wild and in captivity. Therefore, optimization of the husbandry conditions under captivity can improve the production performance of an aquaculture species. In this study, the effect of water velocity on the glucose concentration, energy level of different body parts (i.e., hepatopancreas, gonad, muscle, and feces), and gonadal maturation of the Mud crab Scylla olivacea was evaluated. Immature crab samples of both sexes were collected from the Setiu Wetland and reared for 60 days in different water velocities (0, 20, 40, and 60 cm/s). The results of this study suggested that rearing the mud crab in 20 cm/s and 0 cm/s elicited the least stress as revealed by the glucose concentration of male and female crabs respectively when compared to other flow velocities. The trend of energy reserved in the hepatopancreas, and feces of both sexes however showed a significant decrease with the increasing flow velocity. A similar trend was also observed in the muscles of male S. olivacea. The energy in the muscle and gonad of the female mud crab on the other hand was higher in 20 cm/s and declining thereafter (with least recorded in 0 cm/s). This study also noticed that the 20 cm/s flow velocity advanced the stages of gonadal development (i.e., stages 3 and 4 for males and females respectively) of the crabs better than other flow velocities. It was therefore concluded that the 20 cm/s flow velocity is optimum to induce gonadal maturation and lessen the stress encountered by S. olivacea in captivity.