Western Peninsular Malaysia Research Articles

Exploring the Role of Organizational Culture on Job Performance in Western Peninsular Malaysia

Exploring the Role of Organizational Culture on Job Performance in Western Peninsular Malaysia

Ion adsorption-type rare earth element deposits in western Peninsular Malaysia: A case study in Bukit Enggang Granite, Kedah

This paper reports on the rare earth element (REE) deposit in Bukit Enggang Granite in Sik, Kedah, and its enrichment patterns. The granitic rock in the study area is porphyritic biotite granite with K-feldspar, quartz and biotite as the main minerals, with randomly arranged K-feldspar phenocrysts. The average REE content in rock samples is 340.9 ppm. The exposed weathered profiles are between 3 to 7 meters in thickness. The C horizon is thicker than the B horizon. The average REE content in soil samples taken from the weathered profiles is 943.9 ppm. Interpretations from laboratory results reveal that the REE deposit in the study area is of the ion adsorption-type, with the REE enrichment in the weathered profiles originating from easily weathered REE bearing minerals in the parent rock, rather than highly resistant minerals like monazite, xenotime and zircon.

Phytolith analyses of tropical plants and topsoil from western Peninsular Malaysia and their implications for paleoenvironmental reconstruction

The underrepresentation of many important rainforest species in pollen records still hinders accurate paleovegetation reconstructions in tropical Southeast Asia. In this study, we conducted a modern phytolith study of 141 plant and 15 surface soil samples around the forests of Jerai Hill in western Peninsular Malaysia to evaluate the potential of phytolith assemblages as a proxy for indicating tropical vegetation types. In the plant samples, including many Dipterocarpaceae species, tracheary annulate/helical phytoliths occur most commonly, followed by silicified epidermis, silicified stomata, elongate entire, sclereid, trichomes, irregular. A few diagnostic phytoliths with unique morphological features are found in dicotyledonous trees, palms, and ferns, such as spheroid ornate (sph_orn) and spheroid echinate (sph_ech). In contrast, the phytolith assemblage of surface sediment is dominated by sph_orn, sph_ech, and spheroid psilate. This suggests that similar to pollen, the contribution from dominating forest vegetation rich in Dipterocarpaceae species is obscure in phytolith deposits. However, phytolith analysis highlights the representation of monocotyledons and a few dicotyledonous trees. The more sensitive indication of Poaceae short-cell phytoliths than pollen for parent plants implies that their ratio to forest indicator phytoliths might be a valuable proxy of landscape openness. Additionally, the statistical analysis confirms that phytolith assemblages in the heath forest are slightly different from those in the lowland dipterocarp forest, exhibiting their potential to indicate various vegetation types.

Depositional Environment and Hydrocarbon Distribution in the Silurian–Devonian Black Shales of Western Peninsular Malaysia Using Spectroscopic Characterization

The present study aimed to evaluate the hydrocarbon functional groups, aromaticity degree, and depositional environment in the Silurian–Devonian Kroh black shales of western peninsular Malaysia. Fourier transform infrared spectroscopy (FTIR) was applied to measure the hydrocarbon functional groups in the sedimentary succession and associated organic matter of the black shale samples. The results showed that aromatic C=C stretching, aromatic C-H out-of-plane, aromatic C-H in-plane, and aliphatic =C–H bending are the major hydrocarbon functional groups in the Kroh shales. Also, ultraviolet-visible spectroscopy (UV-Vis) was used to evaluate the type of humic substance and analyze the sample extract ratios of E4/E6. It was revealed that the methanol-treated Kroh shale samples ranged from 0.00048 to 0.12 for E4 and 0.0040 to 0.99 for E6. The lower E4/E6 ratio (>5) indicates the dominance of humic acid over fulvic acid in the Kroh shales. The Kroh shale samples’ total organic carbon content (TOC) ranges from 0.33 to 8.5 wt.%, analyzed by a multi-N/C 3100 TOC/TNb analyzer. The comparison study revealed that the TOC content of the Kroh shale has close obtainable values for the Montney shales of Canada. Furthermore, both hydrocarbon functional groups from FTIR, and the E4/E6 ratio from UV-Vis show no correlation with TOC content. It is revealed that humic acid, aromatic, and aliphatic hydrocarbons are not the controlling factors of the enrichment of organic matter in the Kroh shales. Conversely, a positive correlation between aliphatic and aromatic hydrocarbons in the Kroh shales indicated that organic matter is thermally overmatured. The presence of humic acid and enrichment of aromatic hydrocarbons in the Kroh shales demonstrated that the organic matter in these shales contains plant-derived hydrophilic minerals, i.e., terrestrial in origin. These findings may provide clues on the depositional and thermal maturation of organic matter for the exploration efforts into the pre-Tertiary sedimentary successions of the peninsular.

Low morphological and genetic variation within the glass-perchlet Parambassis siamensis (Teleostei: Ambassidae) in Peninsular Malaysia.

We compare several populations of the glass-perchlet Parambassis siamensis (Fowler 1937) (Teleostei: Ambassidae) sampled throughout Peninsular Malaysia to determine their degree of differentiation, using both morphological and molecular characters. Our morphological analyses do not show evidence for the presence of more than one species, with the range of morphometric and meristic characters overlapping among populations. Our genetic analysis using partial sequences of the mitochondrial gene coding for the protein cytochrome c oxidase I (COI) reveals the existence of two clades that diverge from each other by a minimum uncorrected p-distance of 2.2%. The first clade comprises of specimens from south-eastern Peninsular Malaysia (Pahang and Endau-Rompin River basins) along with those from Cambodia (lower Mekong River). The second clade comprises of specimens from western Peninsular Malaysia (Selangor, Kurau, Perak, Muda and Kerian River basins) and north-eastern Peninsular Malaysia (Terengganu River basin), along with those from Chao Phraya River basin nearby Bangkok (type locality of P. siamensis). The presence of specimens with numerous melanophores on body sides in each of these two clades indicates that body marking pattern is not a valuable taxonomic character. This finding supports the conclusion that Chanda punctulata Fraser-Brunner 1955 is a junior synonym of P. siamensis. Altogether, our results support the hypothesis that all populations of P. siamensis in Peninsular Malaysia (along those from Chao Phraya and lower Mekong basins) are conspecific, comprising two genetically distinct, although close lineages. We further discuss the phenotypic plasticity within P. siamensis in relation to lotic and lentic habitats. Finally, we briefly discuss some implications for biogeography and possible causes explaining the distribution pattern.

Inorganic geochemical, mineralogical and methane sorption capacities of Paleozoic shale formations from Western Peninsular Malaysia: Implication of shale gas potential

An experimental study comprising methane sorption capacity (MSC), inorganic geochemical and mineralogical analysis was conducted to assess the shale gas potential, depositional environments, and tectonic settings in the Western Peninsula (WP) Malaysia. Here, we report 146 shale samples from seven Paleozoic formations in WP Malaysia, divided into four groups based on their ages. The results indicate MSC ranging between 0.054 and 0.065, 0.034 and 0.109, 0.032 and 0.069 and 0.021 and 0.100 mmol/g rock for Silurian-Devonian (S-D), Devonian, Carboniferous, and Permian shales, respectively. By comparison, the MSC of the WP Malaysia shale is close to obtainable values for Longmaxi (China) and Barnett (USA) shales. Geochemical characterization reveals that the studied Paleozoic shales were deposited mainly in continental island arc and active continental margin (ACM) under a reducing marine depositional environment. Sr/Cu, Rb/Sr,Sr/Ba ratios, and C-values reveal warm, humid to hot arid paleoclimate for the S-D and Carboniferous shale samples, and warm, humid paleoclimate for the Devonian and Permian shales. The PIA, CIW, and CIA values indicate the source rocks have been subjected to moderate to strong chemical weathering. Al2O3/TiO2, Zr/TiO2, and LREE/HREE ratio, Eu anomalies, and the binary plot of Zr/Sc and Th/Sc denote that the shales from WP Malaysia are derived from intermediate to felsic igneous source rock. Mineralogical analysis reveals that S-D and Permian shales generally possess less clay and more siliceous minerals than the Devonian and Carboniferous shales. Comparatively, the mineral content of the Paleozoic shales is close to the mineralogy of Niutitang and Longmaxi shales. The geochemical analysis indicates that the pyrobitumen reflectance of Paleozoic shale samples is overmatured. Overall, based on the derived geological data and comparative analysis with hot gas shale reservoirs around the world, high, moderate and low shale gas potentials were obtained for the Devonian and Permian shales, S-D shales and Carboniferous shales in WP Malaysia, respectively.

Lithofacies, mineralogy, and pore types in Paleozoic gas shales from Western Peninsular Malaysia

An experimental study including Fourier Transform Infrared (FTIR), thin section petrography, scanning electron microscope (SEM) imaging, and low-pressure nitrogen adsorption analysis has been conducted to assess the mineralogy, lithofacies, pore types, and pore properties of the potential Paleozoic gas shales from Western Peninsula (WP) Malaysia. In WP Malaysia, shale samples from seven Paleozoic Formations were investigated and classified into four age categories. FTIR analysis documented the presence of aromatic out of plane and in plane bending, aliphatic CH bending, OH functional group, and presence of quartz, carbonates, kaolinite, and illite minerals. Four lithofacies identified from the petrographic analysis of the Paleozoic shale include silica-rich argillaceous mudstone (SAM), clay-rich siliceous mudstone (CSM), silica dominated lithofacies mudstone (SD), and mixed carbonate mudstone (MCM). In comparison, the mineral content and lithofacies found in Paleozoic shales are close to the Niutitang, Longmaxi, Marcellus, and Eagle Ford shales. Furthermore, with high organic matter content, laminated fabric, and with more brittle mineralogy, SD lithofacies would be a highly promising type of lithofacies in WP Malaysia. FESEM studies show that organic matter pores, interparticle pores, and intraparticle pores are the main pore types. Pore sizes analyze through N2 adsorption reveal radii of lesser than 25 nm contribute mainly to porosity and total pore volume. Micropore volume of the WP Malaysia shale was found to be greatly similar to hot shales from USA and China, while surface area values of only older Paleozoic shales, i.e., S-D and Devonian, are close to USA shales.

Diversity and Distribution of Microbial Communities Associated with Reef Corals of the Malay Peninsula.

Coral-associated bacteria play critical roles in the regulation of coral health and function. Environmental perturbations that alter the bacterial community structure can render the coral holobiont more susceptible and less resilient to disease. Understanding the natural variation of the coral microbiome across space and host species provides a baseline that can be used to distinguish shifts in community structure. Using a 16S rRNA gene metabarcoding approach, this study examines bacterial community structure across three scleractinian coral hosts. Our results show that corals of three regions-eastern and western Peninsular Malaysia and Singapore-host distinct bacterial communities; despite these differences, we were able to identify a core microbiome shared across all three species. This core microbiome was also present in samples previously collected in Thailand, suggesting that these core microbes play an important role in promoting and maintaining host health. For example, several have been identified as dimethylsulfoniopropionate (DMSP) metabolizers that have roles in sulfur cycling and the suppression of bacterial pathogens. Pachyseris speciosa has the most variable microbiome, followed by Porites lutea, with the composition of the Diploastrea heliopora microbiome the least variable throughout all locations. Microbial taxa associated with each region or site are likely shaped by local environmental conditions. Taken together, host identity is a major driver of differences in microbial community structure, while environmental heterogeneity shapes communities at finer scales.

Multi-Drug Resistance Bacteria: A Case Study in Western Peninsular Malaysia Freshwaters

The emergence of antibiotic resistant bacteria in aquatic environment has led to an increase in waterborne health risks to an alarming extent. This study attempts to investigate the population of certain antibiotic resistant strains in Peninsular Malaysia. From the samples of 14 rivers from 7 different states in Peninsular Malaysia, a total of 203 isolates were successfully isolated. These are from rivers in Negeri Sembilan, Melaka, Selangor, Kuala Lumpur, Kedah, Kelantan and Terengganu with 35, 15, 37, 39, 24, 26 and 27 isolates, respectively. The isolates were tested for their susceptibility towards 6 broad spectrum of antibiotics which are gentamicin, ampicillin, rifampicin, chloramphenicol, tetracycline, and ciprofloxacin. A total of 117 isolates were identified to have more than 20% MAR index value with 47 of the isolates possess minimum MAR index value of 50%. Based on MAR index value, 59% of isolates are high risk threats indicating a serious emergence of antibiotic resistant bacteria in the rivers in Peninsular Malaysia. Isolates with MAR index value of more than 50% were selected for 16S rRNA gene sequencing for further identification.Based on 16s rRNA gene sequencing, the isolates are a mixture of pathogenic and commensals bacteria. This also implies that the environment especially rivers can be a reservoir for genetic jugglery

Validation of GPM IMERG Extreme Precipitation in the Maritime Continent by Station and Radar Data

AbstractThe Maritime Continent (MC) is a region subject to high impact weather (HIW) events, which are still poorly predicted by numerical weather prediction (NWP) models. To improve predictability of such events, NWP needs to be evaluated against accurate measures of extreme precipitation across the whole MC. With its global spatial coverage at high spatio‐temporal resolution, the Global Precipitation Measurement (GPM) data set is a suitable candidate. Here we evaluate extreme precipitation in the Integrated Multi‐Satellite Retrieval for GPM (IMERG) V06B product against station data from the Global Historical Climatology Network in Malaysia and the Philippines. We find that the high intragrid spatial variability of precipitation extremes results in large spatial sampling errors when each IMERG grid box is compared with individual co‐located precipitation measurements, a result that may explain discrepancies found in earlier studies in the MC. Overall, IMERG daily precipitation is similar to station precipitation between the 85th and 95th percentile, but tends to overestimate above the 95th. IMERG data were also compared with radar data in western Peninsular Malaysia for sub‐daily timescales. Allowing for uncertainties in radar data, the analysis suggests that the 95th percentile is still suitable for NWP evaluation of extreme sub‐daily precipitation, but that the rainfall rates diverge at higher percentiles. Hence, our overall recommendation is that the 95th percentile be used to evaluate NWP forecasts of HIW on daily and sub‐daily time scales against IMERG data, but that higher percentiles (i.e., more extreme precipitation) be treated with caution.

Ozone Trends from Two Decades of Ground Level Observation in Malaysia

We examine the change in surface ozone and its precursor behavior over 20 years at four locations in western Peninsular Malaysia which have undergone urban-commercial development. Trend and correlation analyses were carried out on ozone and oxides of nitrogen observation data over the periods of 1997–2016 as well as the decadal intervals of 1997–2006 and 2007–2016. Diurnal variation composites for decadal intervals were also plotted. Significant increasing ozone concentrations were observed at all locations for the 20-year period, with a range between 0.09 and 0.21 ppb yr−1. The most urbanized location (S3) showed the highest ozone trend. Decadal intervals show that not all stations record significant increasing trends of ozone, with S1 recording decreasing ozone at a rate of −0.44 ppb yr−1 during the latter decade. Correlation analysis showed that only oxides of nitrogen ratios (NO/NO2) had significant inverse relationships with ozone at all stations corresponding to control of ozone by photostationary state reactions. The diurnal composites show that decadal difference in NO/NO2 is mostly influenced by change in nitric oxide concentrations.

Comparison of characteristics and geochemical behaviors of REEs in two weathered granitic profiles generated from metamictized bedrocks in Western Peninsular Malaysia

Rare earth elements (REEs), an important group of non-energy minerals, are vital to industrialized societies worldwide. Southeast Asian granitic belts are potential sources of ion-adsorption REE clays comprising large weathered granitic crusts that often have high-grade ion-adsorbed REEs. Characterization studies were conducted on representative samples from two sites, namely Lumut (LU) and Telok Murok (TM), located within the Malaysian Western granite belt. In both profiles, parent rocks were documented as medium-grained mica (phlogopite)-rich, S-type, peraluminous, ilmenite-series granite with metamict texture. Quartz, K-feldspar, and mica were major minerals, while REE-bearing accessory minerals were apatite, allanite, monazite, xenotime, and zircon. Al2O3 and LOI contents increased with depth in both weathered profiles, whereas P2O5 tended to be constant. Long-tube halloysite and kaolinite are abundant clays in the upper portions of the profiles, whereas the lower parts were rich in short-tube halloysite with smectite. Moreover, the depletion of REE + Y (REY) content in horizon A (B1) was clear, whereas REY was abundant in horizon B and/or C. The maximum content of REY could reach up to approximately 850 and 2350 ppm in horizon B2 and/or C in the LU and TM sites, respectively. Total REE content of the weathered crust was relatively elevated compared with that of the parent rocks (3–7 times) in the lower portions of both sites due to “high adsorption capacity” of abundant clay minerals in the deep profiles. Enrichment in LREE and HREE was indicated in the LU and TM sites, respectively. Trial leaching experiments with high-grade samples from both sites were conducted using ammonium sulfate. High recovery in the results proved REE adsorption by the clays in the lower parts of the profiles.

The Role of Local Orography on the Development of a Severe Rainfall Event over Western Peninsular Malaysia: A Case Study

AbstractSevere rainfall events are common in western Peninsular Malaysia. They are usually short and intense, and occasionally cause flash floods and landslides. Forecasting these local events is difficult and understanding the mechanisms of the rainfall events is vital for the advancement of tropical weather forecasting. This study investigates the mechanisms responsible for a local heavy rainfall event on 2 May 2012 that caused flash floods and landslides using both observations and simulations with the limited-area high-resolution Met Office Unified Model (MetUM). Results suggest that previous day rainfalls over Peninsular Malaysia and Sumatra Island influenced the development of overnight rainfall over the Strait of Malacca by low-level flow convergence. Afternoon convection over the Titiwangsa Mountains over Peninsular Malaysia then induced rainfall development and the combination of these two events influenced the development of severe convective storm over western Peninsular Malaysia. Additionally, anomalously strong low-level northwesterlies also contributed to this event. Sensitivity studies were carried out to investigate the influence of the local orography on this event. Flattened Peninsular Malaysia orography causes a lack of rainfall over the central part of Peninsular Malaysia and Sumatra Island and produces a weaker overnight rainfall over the Strait of Malacca. By removing Sumatra Island in the final experiment, the western and inland parts of Peninsular Malaysia would receive more rainfall, as this region is more influenced by the westerly wind from the Indian Ocean. These results suggest the importance of the interaction between landmasses, orography, low-level flow, and the diurnal cycle on the development of heavy rainfall events.

Future projections of Malaysia daily precipitation characteristics using bias correction technique

Abstract The quantile mapping (QM) bias correction algorithm was applied to bias-correcting the daily rainfall over the Malaysia based on the APHRODITE gridded observed dataset. The quality of the bias correction in reducing the biases of regional climate models in frequency (FREQ), mean intensity (SDII) and 90th percentile (Q90) of the daily rainfall was assessed. The result shows that QM performs well in correcting the rainfall statistics. The QM bias correction method was then applied to seven Regional Climate Models (RCMs) projection output from the CORDEX Southeast Asia (CORDEX-SEA) dataset, to obtain high resolution rainfall change scenarios over the Malaysia, based on the IPCC's representative concentration pathways (RCP) 4.5 and 8.5 scenarios. The ensemble mean of seven RCMs suggests that the future projection expected a decrease in the rainfall frequencies over the Malaysia toward the 21st century for both RCP scenarios. Meanwhile, the rainfall intensity and extremes over the Peninsular Malaysia (East Malaysia) is likely to decrease (increase) especially during the winter (summer and autumn) months by the end of the century. A remarkable decrement of rainfall frequency and extremes was found in western Peninsular Malaysia, with changes of around −4 to −8% with respect to the historical period driven by the RCP4.5 and RCP8.5 scenario respectively.

A new species and new records of Onchidium slugs (Gastropoda, Euthyneura, Pulmonata, Onchidiidae) in South-East Asia

A new species, Onchidium melakense Dayrat & Goulding, sp. nov., is described, bringing the total to four known species in the genus Onchidium Buchannan, 1800. Onchidium melakense is a rare species with only nine individuals found at three mangrove sites in the Andaman Islands and the Strait of Malacca (western Peninsular Malaysia and eastern Sumatra). The new species is delineated based on mitochondrial (COI and 16S) and nuclear (ITS2 and 28S) DNA sequences as well as comparative anatomy. Each Onchidium species is characterized by a distinct color and can easily be identified in the field, even in the Strait of Malacca where there are three sympatric Onchidium species. An identification key is provided. In addition, Onchidium stuxbergi (Westerlund, 1883) is recorded for the first time from eastern Sumatra, and Onchidium pallidipes Tapparone-Canefri, 1889, of which the type material is described and illustrated here, is regarded as a new junior synonym of O. stuxbergi.

Anadromy and heterogenous population of a tropical shad Tenualosa ilisha in Malaysia, as revealed by otolith microchemistry and molecular evidence.

Tenualosa ilisha was found recently in the Perak River in western Peninsular Malaysia. Molecular phylogenetic and haplotype network analyses suggest that T. ilisha has two genetically distinct populations/groups: (i) Peninsular Malaysia (Malaysia population), and (ii) Peninsular Malaysia, Thailand, India and Bangladesh (Indian Ocean population). The results also suggest that the T ilisha population in Peninsular Malaysia is genetically heterogeneous with a typical anadromous migration pattern.

Effects of Seasonal Variability on the Physicochemical, Biochemical, and Nutritional Composition of Western Peninsular Malaysia Gracilaria manilaensis.

This study evaluated the effect of seasonal variation on the physicochemical, biochemical, and nutritional composition of Gracilaria manilaensis. Sampling was designed during the main monsoon seasons in Malaysia—the Southwest monsoon (SWM) and Northeast monsoon (NEM)—to understand the intraspecific variation (p < 0.05). Carbohydrates, protein, and dietary fiber were found to be higher in NEM–G. manilaensis, whereas a higher ash content was quantified in SWM–G. manilaensis. No significant differences were found in crude lipid and moisture content (p > 0.05). Vitamin B2 was calculated as (0.29 ± 0.06 mg 100 g−1) and (0.38 ± 0.06 mg 100 g−1) for the NEM and SWM samples, respectively (p < 0.05). The fatty acid profile showed the dominance of saturated fatty acids (SFAs)—palmitic acids, stearic acid, and myristic acid—while the mineral contents were found to be good sources of calcium (1750.97–4047.74 mg 100 g−1) and iron (1512.55–1346.05 mg 100 g−1). Tryptophan and lysine were recorded as the limiting essential amino acids (EAAs) in NEM G. manilaensis, while leucine and phenylalanine were found to be the limiting EAAs in the SWM samples. None of the extracts exhibited antibacterial properties against the screened strains. The study concluded that seasonal changes have a great effect on the biochemical composition of G. manilaensis.

Structural controls on polyphase hydrothermal dolomitization in the Kinta Valley, Malaysia: Paragenesis and regional tectono-magmatism

In the eastern side of the Malay Peninsula, thick successions of limestone formations preserve important records of the Mesozoic and Cenozoic tectonic events. Here we investigate the strata- and fracture-bound hydrothermal dolomites in the Palaeozoic carbonates of the Kinta Valley, western Peninsular Malaysia. Based on their textural and morphologic characteristics, structural relationships with the host rock, different facies types, and associations with hydrothermal calcite and low-grade metamorphic marble, we attempt to trace their polyphase origin and relationship with thermo-tectonic events of the region. A detailed evaluation of the nature of brecciation and crystallization of polyphase dolomites, dolomitic limestones, limestones and marble, under the influences of episodic faulting, is associated with the regional structural geology with emphasis on pre-existing fault reactivations, granitic emplacement and progressive thermal influence. Supply of Mg2+ from the host rock for dolomitization, limited and episodic influx of circulating fluids and cessation of thermo-tectonic evolution with progressive cooling are also inferred. Correlating the geological events in western Peninsular Malaysia with regional structural dynamics reveals that the major deformation episodes exerted first order controls on the loci of dolomite occurrences. The occurrence, geometry and structural relationships of the dolomites were controlled by successive magmatic events, whereas, the intensity of replacement dolomitization was controlled by host rock texture and varied bulk chemistry, together with the nature of circulating fluids.

A low-cost solution for documenting distribution and abundance of endangered marine fauna and impacts from fisheries.

Fisheries bycatch is a widespread and serious issue that leads to declines of many important and threatened marine species. However, documenting the distribution, abundance, population trends and threats to sparse populations of marine species is often beyond the capacity of developing countries because such work is complex, time consuming and often extremely expensive. We have developed a flexible tool to document spatial distribution and population trends for dugongs and other marine species in the form of an interview questionnaire supported by a structured data upload sheet and a comprehensive project manual. Recognising the effort invested in getting interviewers to remote locations, the questionnaire is comprehensive, but low cost. The questionnaire has already been deployed in 18 countries across the Indo-Pacific region. Project teams spent an average of USD 5,000 per country and obtained large data sets on dugong distribution, trends, catch and bycatch, and threat overlaps. Findings indicated that >50% of respondents had never seen dugongs and that 20% had seen a single dugong in their lifetimes despite living and fishing in areas of known or suspected dugong habitat, suggesting that dugongs occurred in low numbers. Only 3% of respondents had seen mother and calf pairs, indicative of low reproductive output. Dugong hunting was still common in several countries. Gillnets and hook and line were the most common fishing gears, with the greatest mortality caused by gillnets. The questionnaire has also been used to study manatees in the Caribbean, coastal cetaceans along the eastern Gulf of Thailand and western Peninsular Malaysia, and river dolphins in Peru. This questionnaire is a powerful tool for studying distribution and relative abundance for marine species and fishery pressures, and determining potential conservation hotspot areas. We provide the questionnaire and supporting documents for open-access use by the scientific and conservation communities.

Mafic microgranular enclaves (MMEs) in amphibole-bearing granites of the Bintang batholith, Main Range granite province: Evidence for a meta-igneous basement in Western Peninsular Malaysia

Mafic microgranular enclaves (MMEs) with varying sizes are a common occurrence in porphyritic amphibole-bearing granite of the Bintang batholith, which is part of the Main Range granite province. The MMEs of the amphibole-bearing granite are significant as they are related to the I-type granitoids within the Main Range granite province. Petrographic observations indicate the MMEs are mantled with coarse mafic crystals on the rim and contain similar minerals to the host (biotite+plagioclase+K-feldspar+pyroxene+amphibole), but in different proportions. Geochemical analyses indicate the MMEs are shoshonitic with mg# comparable to the granite host. Substantial similarities exist between the MMEs and granite with regards to the normalized rare earth element patterns and trace elements variation diagrams. The MMEs and granite are not completely coeval as the MME zircon U-Pb age (224.3±1.2Ma) is slightly older than its granite host zircon U-Pb age (216.2±1.0Ma). The age difference is also observed from the unusual 500m-long Tiak MME and another amphibole-bearing granite sample from the south of the pluton, which yield 221.8±1.1Ma and 217.4±1.0Ma respectively. The oldest inherited zircons found in the MME and granite are 2.0Ga and 1.3Ga respectively, while the oldest xenocrystic zircons found in the MME and granite are 2.5Ga and 1.5Ga respectively. Identical negative εHf(t) values from zircon U-Pb and Lu-Hf analysis for a MME-granite pair indicates the rocks were generated from a similar, ancient source in the basement. Combining the results, we suggest that incongruent melting of an ancient protolith played an important part in the evolution of the MMEs and granite and the MMEs characteristics are best explained as restite. The zircon Hf model age (two-stage) and the I-type peritectic and restitic mineral assemblages in the MMEs further describe the protolith as Early Proterozoic-Late Archean (≈2.5Ga) meta-igneous rock. This shows the Western Peninsular Malaysia basement does not consist entirely of meta-sedimentary rocks. As the amphibole-bearing granite and MMEs ages both falls within the suggested period of Late Triassic Sibumasu and Indochina-East Malaya collision and the calculated melt temperature for the amphibole-bearing granite is much higher than melt generated from a sedimentary source, the high heat flow required for protolith melting is best explained by episodes of lithosphere attenuation during the collision. The age of the MME and Tiak MME (∼221–224Ma) can be taken to indicate the time of such an event.