Displaying publications 41 - 60 of 267 in total

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  1. Gabriel S, Khan NA, Siddiqui R
    J Water Health, 2019 Feb;17(1):160-171.
    PMID: 30758312 DOI: 10.2166/wh.2018.164
    The aim of this study was to determine the occurrence of free-living amoebae (FLA) in Peninsular Malaysia and to compare different methodologies to detect them from water samples. Water samples were collected from tap water, recreational places, water dispensers, filtered water, etc. and tested for FLA using both cultivation and polymerase chain reaction (PCR) via plating assays and centrifugation methods. Amoebae DNA was extracted using Instagene matrix and PCR was performed using genus-specific primers. Of 250 samples, 142 (56.8%) samples were positive for presence of amoebae, while 108 (43.2%) were negative. Recreational water showed higher prevalence of amoebae than tap water. PCR for the plating assays revealed the presence of Acanthamoeba in 91 (64%) samples and Naegleria in 99 (70%) of samples analysed. All samples tested were negative for B. mandrillaris. In contrast, the centrifugation method was less effective in detecting amoebae as only one sample revealed the presence of Acanthamoeba and 52 (29%) samples were positive for Naegleria. PCR assays were specific and sensitive, detecting as few as 10 cells. These findings show the vast distribution and presence of FLA in all 11 states of Peninsular Malaysia. Further studies could determine the possible presence of pathogenic species and strains of free-living amoebae in public water supplies in Malaysia.
    Matched MeSH terms: Fresh Water/parasitology*
  2. Muthukumaravel K, Priyadharshini M, Kanagavalli V, Vasanthi N, Ahmed MS, Musthafa MS, et al.
    Environ Monit Assess, 2022 Oct 21;195(1):10.
    PMID: 36269455 DOI: 10.1007/s10661-022-10554-2
    Phenol, an aromatic chemical commonly found in domestic and industrial effluents, upon its introduction into aquatic ecosystems adversely affects the indigenous biota, the invertebrates and the vertebrates. With the increased demand for agrochemicals, a large amount of phenol is released directly into the environment as a byproduct. Phenol and its derivatives tend to persist in the environment for longer periods which in turn poses a threat to both humans and the aquatic ecosystem. In our current study, the response of Labeo rohita to sublethal concentrations of phenol was observed and the results did show a regular decrease in biochemical constituents of the targeted organs. Exposure of Labeo rohita to sublethal concentration of phenol (22.32 mg/L) for an epoch of 7, 21 and 28 days shows a decline in lipid, protein, carbohydrate content and phosphatase activity in target organs such as the gills, muscle, intestine, liver and kidney of the fish. The present study also aims to investigate the toxic effects of phenol with special reference to the haematological parameters of Labeo rohita. At the end of the exposure period, the blood of the fish was collected by cutting the caudal peduncle with a surgical scalpel. And it was observed that the red blood corpuscle count (RBC), white blood corpuscle (WBC), haemoglobin count (Hb), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) values showed a decline after exposure to phenol for 7 days, while white blood corpuscle (WBC) shows an increased count. At 21 days and 28 days, all the haematological parameters showed a significant decrease.
    Matched MeSH terms: Fresh Water/chemistry
  3. Ahmad AK, Nur-Hazwani MNR, Aisyah Syed Omar S, Aweng ER, Taweel A
    Pak J Biol Sci, 2020 Jan;23(11):1374-1379.
    PMID: 33274864 DOI: 10.3923/pjbs.2020.1374.1379
    BACKGROUND AND OBJECTIVE: Malaysia reported experiencing serious invasive species intrusion in various rivers and threatening some local species to distinct. A study was undertaken to estimate and compare their composition and species richness in two pristine and two disturbed freshwater ecosystems.

    MATERIALS AND METHODS: Invasive and local species growth pattern was also estimated using length-weight analysis. Sampling was conducted using cast net and electric shock in each river twice in 12 months. Fish collected were identified, photo captured and measured for their weight and length. The growth pattern was also estimated using length-weight analysis.

    RESULTS: A total of 188 fishes were caught, comprises of 8 families and 15 species (ten local species with 119 individuals and five alien species with 69 individuals). Sistomus binotatus was the most dominant local species, whereas Tilapia nilotica was the most dominant alien species. There is no significant difference in composition between local and invasive species occur indicates the raise of alien species in those ecosystems even local species still dominated. The growth pattern for Sistomus binotatus and Clarias batrachus is isometric in the pristine ecosystem but negative isometric in disturbed rivers. Contrary, Tilapia nilotica has isometric for both ecosystems.

    CONCLUSION: This study concluded the capability and potential of colonization of alien species in stress ecosystem especially Tilapia nilotica. Thus, there is potential colonization of alien in Malaysia freshwater systems and a threat to local species due to food competition, site preferences and survival ability.

    Matched MeSH terms: Fresh Water*
  4. Chan KG, Tan WS, Chang CY, Yin WF, Mumahad Yunos NY
    Genome Announc, 2015;3(2).
    PMID: 25767237 DOI: 10.1128/genomeA.00100-15
    Aeromonas hydrophila has emerged worldwide as a human pathogen. Here, we report the draft whole-genome sequence of a freshwater isolate from Malaysia, A. hydrophila strain M062, and its N-acylhomoserine lactone genes are also reported here.
    Matched MeSH terms: Fresh Water
  5. Martin-Smith KM, Laird LM, Bullough L, Lewis MG
    Philos Trans R Soc Lond B Biol Sci, 1999 Nov 29;354(1391):1803-10.
    PMID: 11605623
    Community resistance to, and resilience from, perturbation will determine the trajectory of recovery from disturbance. Although selective timber extraction is considered a severe disturbance, fish communities from headwater streams around Danum Valley Field Centre, Sabah, Malaysia, showed few long-term changes in species composition or abundance. However, some species showed short-term (< 18 months) absence or decrease in abundance. These observations suggested that both resistance and resilience were important in maintaining long-term fish community structure. Resistance to perturbation was tested by monitoring fish communities before and after the creation of log-debris dams, while resilience was investigated by following the time-course of recolonization following complete removal of all fish. High community resistance was generally shown although the response was site-specific, dependent on the composition of the starting community, the size of the stream and physical habitat changes. High resilience was demonstrated in all recolonization experiments with strong correlations between pre- and post-defaunation communities, although there was a significant difference between pool and riffle habitats in the time-course of recovery. These differences can be explained by the movement characteristics of the species found in the different habitats. Resilience appeared to be a more predictable characteristic of the community than resistance and the implications of this for ensuring the long-term persistence of fish in the area are discussed.
    Matched MeSH terms: Fresh Water
  6. Tan WT, Tan GS, Nather Khan IS
    Environ Pollut, 1988;52(3):221-35.
    PMID: 15092608
    Chemical forms of copper and lead in river water of the Linggi River Basin have been fractionated into ASV labile, moderately labile, slowly labile, and inert metal species, based on a previously proposed scheme. Free (hydrated) metal ions were identified by a potentiometric method using an ion selective electrode. Speciation results showed that the soluble copper and lead species occurred mainly in the moderately labile and slowly labile fractions. The speciation results are primarily interpreted in terms of organic interaction due to agricultural based and light industries, and urban discharges. The measured metal complexing capacity (MCC) of the samples reveals consistency of the results with the nature of the discharge. MCC correlates reasonably well with the value from the permanganate test on the river water. In general, the speciation pattern was found to be consistent with the findings of other workers.
    Matched MeSH terms: Fresh Water
  7. Belton B, Little DC, Zhang W, Edwards P, Skladany M, Thilsted SH
    Nat Commun, 2020 11 16;11(1):5804.
    PMID: 33199697 DOI: 10.1038/s41467-020-19679-9
    Recent literature on marine fish farming brands it as potentially compatible with sustainable resource use, conservation, and human nutrition goals, and aligns with the emerging policy discourse of 'blue growth'. We advance a two-pronged critique. First, contemporary narratives tend to overstate marine finfish aquaculture's potential to deliver food security and environmental sustainability. Second, they often align with efforts to enclose maritime space that could facilitate its allocation to extractive industries and conservation interests and exclude fishers. Policies and investments that seek to increase the availability and accessibility of affordable and sustainable farmed aquatic foods should focus on freshwater aquaculture.
    Matched MeSH terms: Fresh Water
  8. Md. Sadek Uddin Chowdhury, Faridah Othman, Wan Zurina Wan Jaafar, Nuzaima Che Mood, Md. Ibrahim Adham
    Sains Malaysiana, 2018;47:457-469.
    Sungai Selangor is very important from the viewpoint of water supply and multipurpose water use in Malaysia. The
    water quality of this river is degrading due to point and non-point sources of pollution. This study, focus on the water
    quality assessment and simulation the effect of the pollution sources from urbanization to the Sungai Selangor basin.
    Water quality Index (WQI) is used to define the status of river water quality and the QUAL2K was used as a simulation
    model. Water quality parameters DO, BOD and NH3
    -N have been chosen for modeling. In addition, five different model
    scenarios were simulated to observe the impacts of pollution sources on the Sungai Selangor water quality. WQI results
    showed that most of the stations in this river basin recorded water inferior to Class III. The water quality model presented
    different scenarios for changes of Sungai Selangor water quality. Simulation results for different scenarios showed
    that reduced levels of BOD and NH3
    -N at 51.10% and 66.18%, respectively, can be obtained if Scenario-5 is employed.
    The river water quality issue in the Rawang sub- basin within the study area is considered crucial to create significant
    improvement within the sub basin and in the downstream area of Sungai Selangor basin.
    Matched MeSH terms: Fresh Water
  9. Seena S, Bärlocher F, Sobral O, Gessner MO, Dudgeon D, McKie BG, et al.
    Sci Total Environ, 2019 Apr 15;661:306-315.
    PMID: 30677678 DOI: 10.1016/j.scitotenv.2019.01.122
    Global patterns of biodiversity have emerged for soil microorganisms, plants and animals, and the extraordinary significance of microbial functions in ecosystems is also well established. Virtually unknown, however, are large-scale patterns of microbial diversity in freshwaters, although these aquatic ecosystems are hotspots of biodiversity and biogeochemical processes. Here we report on the first large-scale study of biodiversity of leaf-litter fungi in streams along a latitudinal gradient unravelled by Illumina sequencing. The study is based on fungal communities colonizing standardized plant litter in 19 globally distributed stream locations between 69°N and 44°S. Fungal richness suggests a hump-shaped distribution along the latitudinal gradient. Strikingly, community composition of fungi was more clearly related to thermal preferences than to biogeography. Our results suggest that identifying differences in key environmental drivers, such as temperature, among taxa and ecosystem types is critical to unravel the global patterns of aquatic fungal diversity.
    Matched MeSH terms: Fresh Water
  10. Vilizzi L, Copp GH, Hill JE, Adamovich B, Aislabie L, Akin D, et al.
    Sci Total Environ, 2021 Sep 20;788:147868.
    PMID: 34134389 DOI: 10.1016/j.scitotenv.2021.147868
    The threat posed by invasive non-native species worldwide requires a global approach to identify which introduced species are likely to pose an elevated risk of impact to native species and ecosystems. To inform policy, stakeholders and management decisions on global threats to aquatic ecosystems, 195 assessors representing 120 risk assessment areas across all six inhabited continents screened 819 non-native species from 15 groups of aquatic organisms (freshwater, brackish, marine plants and animals) using the Aquatic Species Invasiveness Screening Kit. This multi-lingual decision-support tool for the risk screening of aquatic organisms provides assessors with risk scores for a species under current and future climate change conditions that, following a statistically based calibration, permits the accurate classification of species into high-, medium- and low-risk categories under current and predicted climate conditions. The 1730 screenings undertaken encompassed wide geographical areas (regions, political entities, parts thereof, water bodies, river basins, lake drainage basins, and marine regions), which permitted thresholds to be identified for almost all aquatic organismal groups screened as well as for tropical, temperate and continental climate classes, and for tropical and temperate marine ecoregions. In total, 33 species were identified as posing a 'very high risk' of being or becoming invasive, and the scores of several of these species under current climate increased under future climate conditions, primarily due to their wide thermal tolerances. The risk thresholds determined for taxonomic groups and climate zones provide a basis against which area-specific or climate-based calibrated thresholds may be interpreted. In turn, the risk rankings help decision-makers identify which species require an immediate 'rapid' management action (e.g. eradication, control) to avoid or mitigate adverse impacts, which require a full risk assessment, and which are to be restricted or banned with regard to importation and/or sale as ornamental or aquarium/fishery enhancement.
    Matched MeSH terms: Fresh Water
  11. Ruppert N, Mansor A, Sah SA
    Trop Life Sci Res, 2017 Jan;28(1):33-44.
    PMID: 28228915 MyJurnal DOI: 10.21315/tlsr2017.28.1.3
    Rattans (subfamily Calamoideae) are an important component of the forests of the Old World. However, few studies have been conducted on the distribution of these abundant palms within different habitats, specifically in Peninsular Malaysia. This study was aimed at assessing rattan diversity, abundance and biomass change across two different habitat types, namely, dipterocarp forests and fresh-water swamps within the Segari Melintang Forest Reserve, Perak, within two years. All rattan stems within five 100 m × 100 m sized study plots (A-E) of the two habitat types were counted in 2011 and 2013, and Shannon-Wiener diversity indices (H') and Bray-Curtis dissimilarity indices were calculated. A total of 11 species from 5 genera (161 stems ha(-1)) were sampled. Rattan abundance was higher in all swamp plots; however, rattan diversity (H') was highest in the dipterocarp plot (D: H' (2011)1.79; H' (2013)1.84). Bray-Curtis indices of rattan abundance (highest similarity in swamp: plot BC(2011) 0.484, BC(2013) 0.262) and biomass were highest for study plots with the same vegetation types in both years. For rattan biomass, the most similar plot pairs changed during the years: dipterocarp plots A and D were most similar in 2011 (0.509), and swamp plots B and C were most similar in 2013 (0.282). This study helped contribute information regarding the distribution and dynamics of rattans in a primary rainforest of Peninsular Malaysia.
    Matched MeSH terms: Fresh Water
  12. Wan Mohd Hafezul Wan Abdul Ghani, Che Salmah Md Rawi, Suhaila Abd. Hamid, Al-Shami, Salman Abdo
    Trop Life Sci Res, 2016;27(1):115-133.
    MyJurnal
    This study analyses the sampling performance of three benthic sampling tools
    commonly used to collect freshwater macroinvertebrates. Efficiency of qualitative D-frame
    and square aquatic nets were compared to a quantitative Surber sampler in tropical
    Malaysian streams. The abundance and diversity of macroinvertebrates collected using
    each tool evaluated along with their relative variations (RVs). Each tool was used to
    sample macroinvertebrates from three streams draining different areas: a vegetable farm,
    a tea plantation and a forest reserve. High macroinvertebrate diversities were recorded using the square net and Surber sampler at the forested stream site; however, very low
    species abundance was recorded by the Surber sampler. Relatively large variations in the
    Surber sampler collections (RVs of 36% and 28%) were observed for the vegetable farm
    and tea plantation streams, respectively. Of the three sampling methods, the square net
    was the most efficient, collecting a greater diversity of macroinvertebrate taxa and a
    greater number of specimens (i.e., abundance) overall, particularly from the vegetable
    farm and the tea plantation streams (RV
    Matched MeSH terms: Fresh Water
  13. Arguelles ED
    Trop Life Sci Res, 2019 Jan;30(1):1-21.
    PMID: 30847030 DOI: 10.21315/tlsr2019.30.1.1
    Taxonomic study on the composition of epiphytic algae living on submerged leaf and root tissues of macrophyte Eichhornia crassipes (Mart.) Solms-Loubach, found at Laguna de Bay, Philippines was conducted. In total, 21 algal taxa were identified: seven Cyanophyceae, six Euglenophyceae, five Chlorophyceae, two Trebouxiophyceae and one Klebsormidiophyceae. Of these taxa, the occurrence of two rare cyanobacteria, Pseudanabaena minima (G.S. An) Anagnostidis and Synechococcus nidulans (Pringsheim) Komárek are reported for the first time in the Philippines. Two species are also reported here for the first time in the Philippines based on current taxonomic nomenclature and these are Pseudopediastrum boryanum (Turpin) E. Hegewald, Phormidium granulatum (Gardner) Anagnostidis which were based on the former names of Pediastrum boryanum (Turpin) Meneghini and Oscillatoria granulata Gardner, respectively. These taxonomic records are considered important basal information in enriching the knowledge about the diversity and habitat distribution of cyanobacteria and microalgae on macrophytes found in freshwater habitats in the Philippines.
    Matched MeSH terms: Fresh Water
  14. Jumaat AH, Hamid SA
    Trop Life Sci Res, 2021 Mar;32(1):91-105.
    PMID: 33936553 DOI: 10.21315/tlsr2021.32.1.6
    Abundance and distribution of aquatic insects respecting to several water chemical parameters from six rivers were studied in order to determine the performance of biological index in monitoring the water quality. A total of 960 individuals of aquatic insects from nine orders were recorded using kick and drag sampling techniques. Lubok Semilang had the greatest number of aquatic insects with 250 individuals, followed by Telaga Tujuh (181 individuals) and Sungai Durian Perangin (171 individuals). EPT (Ephemeroptera, Plecoptera and Trichoptera) order were the most dominant order recorded in all six rivers. Lata Kekabu had more diverse and richer aquatic insect assemblages based on ecological indices compared to the other five rivers. In order to evaluate the water quality of recreational rivers in Malaysia, Family Biotic Index (FBI), Malaysian Family Biotic Index (MFBI) and Biological Monitoring Working Party (BMWP) were used and compared with Water Quality Index (WQI) to determine the water quality at the study areas. Results demonstrated that the biotic indices were more sensitive towards changes in water parameters than the WQI. Among all the biological indices, MFBI was the most suitable index to be adopted in Malaysian river water assessment as it is more reliable in assessing the status of water quality.
    Matched MeSH terms: Fresh Water
  15. Hamli H, Hamed NA, Azmai SHS, Idris MH
    Trop Life Sci Res, 2020 Jul;31(2):145-158.
    PMID: 32922672 DOI: 10.21315/tlsr2020.31.2.7
    Pachychilidae is one of the freshwater gastropod family which was previously known under the Potamididae and Thiaridae families. Studies on freshwater gastropods especially on conchcology examinantions are still inadequate compared to marine gastropods. Morphological and morphometric studies of gastropods are practically used to identify and differentiate between species and necessary to complement molecular studies due to its low cost and tolerable resolving power of discrimination. The aim of the current study is to provide information on morphological and morphometric characteristics of Pachychilidae in Bintulu, Sarawak stream. A total of 20 individuals from each species of Sulcospira testudinaria, Sulcospira schmidti, Brotia siamensis, and Tylomelania sp. from Pachychilidae familiy were collected at three different sites from a small stream within the Bintulu area. Fourteen measurement of shell morphometrics were converted into proportioned ratios and analysed for univariate and multivariate analysis. Three shell morphometric (Aperture width, AW; Whorl width, WW2; and, Interior anterior length, AINL) of Pachychilidae indicated significant differences (P < 0.05) between species. However, multivariate analysis revealed that these shell morphometrics are pre-eminent factors to discriminate genus Sulcospira, Brotia and Tylomelania, as well as between Sulcospira species. This current study also suggests that these three characteristics are unique to Sulcospira species due to strong distinction among species. Findings on these three characteristics are significant for Sulcospira spp. as this study is the first shell morphometric report on the Pachychilidae species in Sarawak.
    Matched MeSH terms: Fresh Water
  16. Sinha, P.C., Jena, G.K., Rao, A.D., Mohd Lokman Husain, Jain, Indu
    MyJurnal
    A depth-averaged numerical model was developed to study tidal circulation and suspended sediment transport in the gulf of Khambhat along the west coast of India. The spatial resolution of the model is 750m x 750m. A 2-D fine resolution (150 m x 150 m) model for the lower part of the Narmada estuary is coupled with the coarser gulf model to simulate the flow features in the lower estuary. The model dynamics and basic formulation remain the same for both the gulf model and the estuary model. The models are barotropic, based on the shallow water equations and neglect horizontal diffusion and wind stress terms in the momentum equations. The models are fully non-linear and use a semi-explicit finite difference scheme to solve mass, momentum, and advection- diffusion equation for suspended sediments in a horizontal plane. The erosion and deposition have been computed by an empirically developed source and sink term in the suspended sediment equation. The tide in the gulf is mainly represented in the model by the semi-diurnal M2 constituent. Meanwhile, fresh water discharge from the rivers joining the gulf had also been considered. Numerical experiments were carried out to study the circulation and suspended sediment concentrations in the gulf and estuarine region.
    Matched MeSH terms: Fresh Water
  17. Nazli Zainuddin, Nair, Prenav, Farid Razali
    Malays Fam Physician, 2016;11(23):33-34.
    MyJurnal
    Leech is an uncommon nasal foreign body, which can cause epistaxis. It is an aquatic segmental
    worm living in fresh water most commonly in tropical areas. Once it is attached in the nose, it will
    secrete an anticoagulant enzyme named hirudin, and that will result in continuous bleeding more
    than from a normal wound even after it is removed. We present a case of a live leech in the nose
    that caused unilateral epistaxis in a patient with a recent history of jungle trekking.
    Matched MeSH terms: Fresh Water
  18. Zainuddin N, Nair P, Razali F
    Malays Fam Physician, 2016;11(2-3):33-34.
    PMID: 28461857
    Leech is an uncommon nasal foreign body, which can cause epistaxis. It is an aquatic segmental worm living in fresh water most commonly in tropical areas. Once it is attached in the nose, it will secrete an anticoagulant enzyme named hirudin, and that will result in continuous bleeding more than from a normal wound even after it is removed. We present a case of a live leech in the nose that caused unilateral epistaxis in a patient with a recent history of jungle trekking.
    Matched MeSH terms: Fresh Water
  19. Akazawa, Noriaki, Eguchi, Mitsuru
    MyJurnal
    Microcosm experiments simulating the occurrence of early mortality syndrome/acute hepatopancreatic necrosis disease (EMS/AHPND) in white shrimp production ponds were performed in 30-L aquariums. Healthy white shrimp, Litopenaeus vannamei, were reared in aquariums containing EMS/AHPND-free hatchery or pond water. Raw pond sludge, collected from shrimp ponds where EMS/AHPND had occurred, was added to some test aquariums, while others were treated with sterilized pond sludge. In some aquariums, water pH was increased from 7.5 to 8.8. Microcosms with stable pH (around 7.5) and/or autoclaved sludge served as controls. The combination of raw sludge and increased pH induced EMS/AHPND and killed white shrimp, whereas raw sludge/stable pH and autoclaved sludge/increased pH combinations did not affect healthy shrimp. Thus, EMS/AHPND outbreaks are due not only to the causative agent but also to environmental stresses such as pH fluctuation. These findings contribute to improved management in shrimp production farms.
    Matched MeSH terms: Fresh Water
  20. Ng PKL, Ng PYC
    Zookeys, 2018.
    PMID: 29872365 DOI: 10.3897/zookeys.760.24787
    Seven species of freshwater crabs from three families are recorded from and around the Danum Valley Conservation Area in Sabah, Malaysian Borneo: Thelphusula capillodigitussp. n., Thelphusula dicerophilus Ng & Stuebing, 1990, Arachnothelphusa terrapes Ng, 1991, Terrathelphusa secula Ng & Tan, 2015, Parathelphusa valida Ng & Goh, 1987 (new record) (Gecarcinucidae); Isolapotamon ingeri Ng & Tan, 1998 (Potamidae); and Geosesarma danumense Ng, 2002 (Sesarmidae). The new species of Thelphusula Bott, 1979, can be distinguished from all congeners by a unique combination of morphological features, most notably the presence of dense patches of short setae on the fingers of the adult male chelipeds, as well as the structure of the male first gonopod. Arachnothelphusa terrapes is confirmed to be a phytotelm species. A key to all species in the conservation area is provided.
    Matched MeSH terms: Fresh Water
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