West Coast Of Peninsular Malaysia Research Articles

CHANGING EXTREME SEA LEVELS ALONG THE COAST OF MALAYSIA

This study examined extreme sea level (ESL) variations along the Malaysian coast using hourly sea level data from 17 tide gauge stations. The maximum observed ESLs varied from 1.26 m at Bintulu to 2.92 m at Port Klang, with tides playing a significant role in ESLs, especially along the west coast of Peninsular Malaysia. The spatial variation of seasonal ESLs showed a higher maximum of non-tidal residuals (0.8-1.1 m) along the east coast of Peninsular Malaysia during the northeast monsoon. This can be mainly attributed to the influence of the monsoon wind. Moreover, significant increases in ESLs were observed at 14 stations, largely due to rises in mean sea level. The interannual variability of ESL could be associated with the El Niño-Southern Oscillation at most sites except the northeast coast of Peninsular Malaysia. Interestingly, the interannual variability of the non-tidal residuals could be linked to the monsoon at sites located on the west coast of Peninsular Malaysia and East Malaysia. These findings provide valuable insights to relevant authorities for coastal planning, especially regarding flood risk management and the formulation of effective mitigation strategies.

The Coral Triangle and Strait of Malacca are two distinct hotspots of mangrove biodiversity

Knowledge of the biogeography of marine taxa has lagged significantly behind terrestrial ecosystems. A hotspot of marine biodiversity associated with coral reefs is known in the Coral Triangle of the Indo-West Pacific, but until now there was little data with which to evaluate broad patterns of species richness in the coastal fauna of ecosystems other than coral reefs. This data is critically needed for fauna with low functional redundancy like that of mangroves, that are vulnerable to habitat loss and rising sea levels. Here we show that the diversity of mangrove fauna is characterized by two distinct hotspots in the Indo-West Pacific, associated with two habitat types: fringe mangroves in the Coral Triangle, and riverine mangroves in the Strait of Malacca, between the west coast of Peninsular Malaysia and Sumatra. This finding, based on a family of slugs of which the systematics has been completely revised, illustrates an unexpected biogeographic pattern that emerged only after this taxon was studied intensively. Most organisms that live in the mangrove forests of Southeast Asia remain poorly known both taxonomically and ecologically, and the hotspot of diversity of onchidiid slugs in the riverine mangroves of the Strait of Malacca indicates that further biodiversity studies are needed to support effective conservation of mangrove biodiversity.

First evidence of microplastic ingestion by crescent perch (Terapon jarbua) in Malaysia

Microplastics are plastic debris smaller than 5 mm in size. In recent decades, the issue of microplastics contamination in marine organisms from the marine environment has gained more attention. This study focuses on the occurrence of microplastics in the gastrointestinal tract (GIT) of the crescent perch (Terapon jarbua). Sixty-two crescent perch were collected from four locations in Malaysia: Sungai Besar and Kuala Selangor on the west coast of Peninsular Malaysia, Kuantan on the east coast of Peninsular Malaysia, and Mukah in East Malaysia. Microplastics were found in the GIT in 82% of the samples with a mean value ranging from 1.46 ± 0.60 to 2.25 ± 1.26 particles/ind. Microplastics contamination in samples from Mukah was significantly higher than in samples from Kuala Selangor. The increased number of ingested microplastics could be attributed to the higher levels of microplastics contamination present in the coastal waters of Mukah due to the anthropogenic activities taking place there. The extracted particles were predominantly fibres, followed by fragment, and film. The microplastics ingested by crescent perch were primarily blue and black. μ-FTIR tests showed that the most common polymers found in crescent perch were rayon, polyethylene terephthalate, and polyethylene. The findings from this study provide initial evidence that microplastic contamination is emerging as a threat to crescent perch and the Malaysian water ecosystem. Further investigations into microplastics contamination in fish in Malaysia are required, as microplastics exposure to fish can induce adverse effects on the species and the food web.

Shell Deformities in the Green-Lipped Mussel Perna viridis: Occurrence and Potential Environmental Stresses on the West Coast of Peninsular Malaysia

The green-lipped mussel Perna viridis’ sensitive nature and characteristic as a benthos organism that filters the sediment in its environment make it one of the possible bioindicators for pollution in the aquatic ecosystem. The present study aimed to determine the percentages of total shell deformities in comparison to the past data in the coastal waters of Peninsular Malaysia. It was found that several types of discontinuous, continuous, and unexplained shell abnormalities contributed to the overall range of shell deformities of 15.8–87.5%, which was greater in comparison to that (0.0–36.8%). The present study showed that the highest overall proportion of shell abnormalities occurred in Teluk Jawa, whereas the lowest percentages were found in Kampung (Kg.) Pasir Puteh. The regulative mechanisms at the well-known polluted sites at Kg. Pasir Puteh could be the explanation. Further research should be conducted to determine the degree of heavy metal that may be the source of these malformations in the mussel shells.

Trend Analysis of Tides Level and Projection Sea Level Rise On the West Coast of Peninsular Malaysia

Globally, sea levels are rising due to climate change caused by humans. Current and future sea level rise will have a variety of effects, particularly on coastal infrastructure. This study analysed the tidal level trend and projected sea level rise along the western coast of peninsular Malaysia using tide level records collected between 1986 and 2012. The seasonal Mann-Kendall test and linear trend were used to determine the tide level trend over time and to predict sea level rise for 2050 and 2100. Based on a confidence interval of 95%, the results of the analysis indicated a rising trend at all stations. Tau values for the Mann-Kendall test range between 0.16 and 0.33, while seasonal Mann-Kendall values range between 0.18 and 0.41. Based on the sea level projection analysis, the mean sea level will rise between 8.77 cm and 14.29 cm in 2050, and between 20.44 cm and 33.20 cm in 2100. In conclusion, the sea level trend at all stations on the west coasts of peninsular Malaysia exhibits an upward trend.

Does age matter? Unravelling the effects of replanted mangrove forests on the total ecosystem carbon stocks

Mangrove replanting is a fundamental approach for restoring the ecosystem services in the mangrove ecosystems. This study assesses and compares the total ecosystem carbon stock (TECS) in different stand ages of replanted mangrove forests (1, 2, 5, 9, 10 and 21 years old and an Intact/Undisturbed Forest as the control) in the west coast of Peninsular Malaysia. The preferred species for planting are Rhizophora mucronata, R. apiculata and Bruguiera parviflora, while the Intact Forest only has one species, Avicennia marina. Most sites recorded additional species recruits after a few years. The study determines the total ecosystem carbon stock (TEC) based on the above-ground standing trees, below-ground, dead wood and soil, uses the established allometric equations to calculate the biomass and carbon stock in vegetation, and determines the soil carbon using the LI method. In general, the results showed a linear relationship between the TECS and stand age (R=0.86, y=70.993x + 353.51). The ten-year-old stand had the highest TECS (875.79 Mg C ha −1), the one-year-old had the lowest (376.91 Mg C ha −1), and the Intact Forest was moderate at 530.57 Mg C ha −1. In all cases, soil contributed the highest percentage of 75%–98% to the TECS. The Principal Component Analysis (PCA) revealed that the primary determiners of the TECS are the stand age, followed by mangrove tree structure and soil carbon accumulation capacity.

Biomonitoring of Benthic Organisms for Coastal Protection: A Checklist Study from Pantai Remis and Blue Lagoon on the West Coast of Peninsular Malaysia

The objective of the study was to provide an updated checklist of benthic marine organisms in Pantai Remis (Selangor) and Blue Lagoon (Negeri Sembilan) in November 2022. The research areas comprised a total of 26 species of marine benthic organisms, which were divided into 12 orders, 18 families, and 22 genera. Benthic macrophytes formed the largest group (11 species), followed by other benthic macrofauna (molluscs, with eight species). In addition, three coral species, two gastropods, and two crabs were also recorded. The findings revealed that both sites are fertile and suitable habitats for marine benthic organisms. The established checklist of benthic organisms can serve as an ongoing basis for future reference as part of our efforts to develop coastal marine ecosystem management and conservation on the west coast of Peninsular Malaysia. In summary, the checklist of benthic organisms provides the basic information that is much needed for the protection of coastal ecosystems.

Global Terrapin Character-Based DNA Barcodes: Assessment of the Mitochondrial COI Gene and Conservation Status Revealed a Putative Cryptic Species.

Technological and analytical advances to study evolutionary biology, ecology, and conservation of the Southern River Terrapin (Batagur affinis ssp.) are realised through molecular approaches, including DNA barcoding. We evaluated the use of COI DNA barcodes in Malaysia's Southern River Terrapin population to better understand the species' genetic divergence and other genetic characteristics. We evaluated 26 sequences, including four from field specimens of Southern River Terrapins obtained in Bota Kanan, Perak, Malaysia, and Kuala Berang, Terengganu, Malaysia, as well as 22 sequences from global terrapins previously included in the Barcode of Life Database (BOLD) Systems and GenBank. The species are divided into three families: eight Geoemydidae species (18%), three Emydidae species (6%), and one Pelomedusidae species (2%). The IUCN Red List assigned the 12 species of terrapins sampled for this study to the classifications of critically endangered (CR) for 25% of the samples and endangered (EN) for 8% of the samples. With new haplotypes from the world's terrapins, 16 haplotypes were found. The intraspecific distance values between the COI gene sequences were calculated using the K2P model, which indicated a potential cryptic species between the Northern River Terrapin (Batagur baska) and Southern River Terrapin (Batagur affinis affinis). The Bayesian analysis of the phylogenetic tree also showed both species in the same lineage. The BLASTn search resulted in 100% of the same species of B. affinis as B. baska. The Jalview alignment visualised almost identical sequences between both species. The Southern River Terrapin (B. affinis affinis) from the west coast of Peninsular Malaysia was found to share the same haplotype (Hap_1) as the Northern River Terrapin from India. However, B. affinis edwardmolli from the east coast of Peninsular Malaysia formed Hap_16. The COI analysis found new haplotypes and showed that DNA barcodes are an excellent way to measure the diversity of a population.

A systematic review of Climate Change related Coral Reef research trend in Malaysia

Climate change related coral reef research has been receiving great interest globally as the world continues to experience worsening catastrophic climate change events, which causes the degradation of the ecosystem. While Malaysia is known for its extensive coral reef coverage, little is known about its coral reef research trajectory, especially related to climate change. Hence, this study aims to address the state of Malaysian coral reef research trend using the Web of Science (WoS; 1987–2022) database with comparison made within four areas in the country (East Coast of Peninsular Malaysia, West Coast of Peninsular Malaysia, Sarawak and Sabah), and explicitly looking into the aspect of climate change using three search strings respectively; (1) Bleach*, (2) Acid*, (3) Climate Change*. The results found the number of such publications in the WoS database is low (total of 31 publications in 36 years), with substantial research location bias dominated at the East Coast of Peninsular Malaysia. Generally, the study subjects of the publications focus on mixed organisms (Coral Reef) and Cnidaria as well as non-biological category ‘Environment’. Overall, the ecological assessment of the study trend shows notable climate change research gap in Malaysian coral reef research (lack of important organism studies; Pisces, Echinodermata, Mollusca). Thus, there is a need for climate change inclusive research direction in Malaysian coral reef research for the understanding, adaptation, prediction, and management of our coral reef ecosystem in an era of accelerated climate change circumstances.

First Record and Distribution Extension of Two Emperor Fishes, Lethrinus semicinctus and Lethrinus olivaceus to the East Coast of Peninsular Malaysia

This study reports the occurrence of two species of Lethrinus (family Lethrinidae) on the east coast of Peninsular Malaysia. The specimens were caught by commercial bottom trawlers operating in the southern part of the South China Sea and landed at several fish landing ports. Lethrinus semicinctusValenciennes, 1830 and Lethrinus olivaceus Valenciennes, 1830, previously known from Borneo, with the latter also occurring in the Straits of Malacca on the west coast of Peninsular Malaysia, are now documented as new records of geographic range in the northeastern coast of Peninsular Malaysia. These records add to published Malaysian literature with photographic records, locality details, collection numbers and preserved specimens. Diagnostic characters for both species are given, as well as detailed morphometric and meristic data.

Phylogenetic and Haplotype Analyses Offer Insights Towards Conservation of Pteroptyx tener Olivier, 1907 (Coleoptera: Lampyridae) Populations from Malaysia

The synchronous-flashing firefly, Pteroptyx tener Olivier, 1907 is a congregating firefly with high economic value for the ecotourism industry. However, the populations of P. tener are increasingly being threatened due to habitat destruction. The assessment of genetic variation within and among populations of the species from Malaysia might play a major role in conservation and management programs. Objectives of this study were to investigate the relationships among P. tener from five populations in Malaysia (Peninsular Malaysia and Borneo (Sabah) using cytochrome oxidase subunit I (COI), and to obtain its haplotype information. A total of 50 sequences of P. tener were used in the Neighbour-Joining (NJ), Maximum Parsimony (MP), and Bayesian Inference (BI) phylogenetic analyses and successfully formed several distinct clades of West and East Malaysia (East Coast and West Coast of Peninsular Malaysia) with moderately to highly supported bootstrap values and posterior probabilities. Several haplotype analysis parameters are presented; low nucleotide diversity (PiT, 0.01893), haplotype number (Hn, 19), and high haplotype diversity (Hd, 0.89469). Our findings assumed that the geographical isolation due to the inability for flying long distances without help by the wind and flooding in tidal rivers. The data presented here are important genetic information on the P. tener populations and are important for the conservation programme in Malaysia by conducting the breeding program among populations that have similar genetic information.

Social Capital and Well-Being of Small-Scale Fishers in the West Coast Island of Peninsular Malaysia

Poverty in small-scale fisheries is a global issue; most of the time, the solution to poverty is discussed through economic variables. Scholars highlight the contribution of social capital factors to the livelihoods of small-scale fishing communities and suggest that social aspects can be used as an alternative solution to reduce poverty. The concept of social capital has been extensively used to explain the relationship between social capital factors and wellbeing. The role of social capital in the well-being of small-scale fisher communities in Malaysia needs to be clarified. The current study investigates the contribution of various livelihood assets to the household income of small-scale fishers in Malaysia. Data for the survey were collected from 182 respondents from across multiple fishing villages on Langkawi Island, off the west coast of Peninsular Malaysia, using a structured questionnaire. The partial least square (PLS) technique was applied for statistical analysis. The study’s empirical findings depict that social capital, trust, job experience, and financial capital are important factors contributing to fishers' household income. The results show that the contribution of social capital and trust factors are significant to household income, indicating that social factors are essential in improving the well-being of small-scale fisher households in Malaysia. Policy for livelihood improvement of small-scale fisheries in Malaysia needs to prioritise investments in financial, human, natural and physical capital assets.

Distribution and Contamination of Trace Elements in Mangrove Sediments Collected from West Coast of Peninsular Malaysia

In tropical and subtropical latitudes, woody plants known as mangroves flourish in slimy, anaerobic soils on the boundary between land and sea. They can withstand extreme weather conditions like high temperatures, unreliable tides, strong winds, and salt. The objective of this study was to determine the concentration of nine trace elements (Hf, Ga, Ba, V, Cs, Sc, Sb, Ta, and Co) in the sediment of the mangrove forest along the west coast of Peninsular Malaysia. Instrumental neutron activation analysis (INAA) was employed to determine the distribution of the elements within the sediments. The concentration of trace elements in the sediment in descending order are Sb < Co < Ta < Sc < Hf < Cs < Ga < V < Ba. The degree of elemental contamination in the sediments was assessed using the enrichment factor (EF) and geoaccumulation index (Igeo). The EF and Igeo of trace element ranged from 0.41 to 20.76 and -3.56 to 1.41 respectively. The EF and Igeo values of a few trace elements in the sediments at Kampung Panchor (L6) suggested that the area had probably deteriorated.

Identification of Tambelo (Bactronophorus thoracites) in Wamesa Waters, Manokwari, West Papua, Indonesia

Abstract. Akabessy JL, Yahya, Fadjar M, Suprayitno E. 2022. Identification of Tambelo (Bactronophorus thoracites) in Wamesa Waters, Manokwari, West Papua, Indonesia. Biodiversitas 23: 6021-6030. Tambelo, otherwise known as shipworm, is a marine bivalve mollusk comprising 16 genera in the Teridinidae family, of which Teredo is the most frequently mentioned. Furthermore, the only species in the genus Bactronophorus is the wood borer, Bactronophorus thoracites (Teredinidae), which has a wide distribution in the Indo-West Pacific biogeographical region. Identifying shipworm species is difficult due to their high diversity and the limited information about their taxonomic characteristics, which often leads to identification errors by collectors. Papuan people consume tambelo as a substitute for side dishes because they are believed to be able to cure various diseases. Therefore, this study aims to establish by morphology and molecular analysis that tambelo belongs to the B. thoracites of the Teredinidae family. Tambelo was identified using the morphological method of observing the physical characterization of the palette, which is unique between genera. It was collected from a mangrove forest near Wamesa Beach, South Manokwari, Manokwari Regency, Indonesia. Meanwhile, this study adopted PCR, an identification method that uses DNA from a small number of samples and can provide a DNA sample sequence. Morphological analysis based on pallet characterization showed that the characteristics of the tambelo pallet were similar to those of the B. thoracites based on the identification book. In addition, the molecular phylogenetic analysis using two mitochondrial protein-coding genes, cytochrome c oxidase subunit I (COI), showed tambelo was 91% similar to B. thoracites from mangroves environment on the west coast of Peninsular Malaysia, Malaysia.

Modelling of Sea Water Level During High Tide Using Statistical Method and Neural Network

Recently, the rise of sea level has caused an increase in rising tides that affected about three million locations around the world. The tide rising phenomenon has been occurring in Peninsular Malaysia since the 20th century. The purpose of this study is to determine the most critical station and forecast three stations located on the West Coast of Peninsular Malaysia. The Box Plot analysis method has been used in this study; the results shown that Bagan Datuk Station is the most critical station. This is due to the maximum tide’s value of Bagan Datuk Station experienced the highest increment of 0.45 m, compared to Port Klang station and Permatang Sedepa Station with only 0.2 m increment in 10 years. However, these three stations are also experiencing rising tides. Thus, the focus of managing coastal structures should be given to all these three stations as well. In addition, for forecasting, the Artificial Neural Network (ANN) forecasting model provides better forecasting results compared to the Autoregressive Integrated Moving Average (ARIMA) model for long-term forecast. In this study, the artificial Neural Network (ANN) forecasting model obtained value of RMSE 0.05642 at Bagan Datuk Station compared to the RMSE value of 0.0928 obtained from the ARIMA model at the same station. Besides, MAE value of ANN method, 0.04387 compared to the MAE value of ARIMA which is worth 0.06391 at Bagan Datuk Station. This study can conclude that the Artificial Neural Network (ANN) forecasting model is better in high tide forecasting.

The Relationship between Work Environment and Work Engagement on The West Coast of Peninsular Malaysia

The study aims to investigate the relationship between the work environment and work engagement at one multinational company on the west coast of Peninsular Malaysia. The work environment was measured by Work Environment Scale (Billing and Moos, 1982) and work engagement was assessed by Utrecht Work Engagement Scale (UWES) (Schaufeli and Bakker, 2003). A total of 103 employees from the customer relations department of the multinational company have been chosen as the respondents in this research. Structural equation modelling using SmartPLS has been adopted to analyze the collected data. The results reveal that the level of the work environment is at moderate while work engagement is at high. The findings from SmartPLS discover that there is a significant and positive relationship between the work environment and work engagement at the multinational company on the west coast of Peninsular Malaysia. A few recommendations were suggested such as the company can improve the low level of relationship dimension in the work environment by initiating team-based projects rather than individual-based projects. Suggestions were also provided for future research including combining the quantitative and qualitative approaches in conducting the research.

On-Farm Practices Associated with Multi-Drug-Resistant Escherichia coli and Vibrio parahaemolyticus Derived from Cultured Fish.

Aquaculture activities have been implicated as responsible for the emergence of antimicrobial resistance (AMR), leading to broad dissemination and transference of antibiotic resistance to pathogens that affect humans and animals. The current study investigates the on-farm practices and environmental risk factors that can potentially drive the development and emergence of multi-drug-resistant (MDR) Escherichia coli and Vibrio parahaemolyticus in the aquaculture system. A cross-sectional study was conducted on 19 red hybrid tilapia (Oreochromis spp.) and 13 Asian seabass (Lates calcarifer, Bloch 1970) farms on the west coast of peninsular Malaysia. Data were collected using a structured questionnaire pertaining to farm demography, on-farm management practices and environmental characteristics. Multi-drug-resistant E. coli (n = 249) and V. parahaemolyticus (n = 162) isolates were analyzed using multi-level binary logistic regression to identify important drivers for the occurrence and proliferation of the MDR bacteria. On-farm practices such as manuring the pond (OR = 4.5; 95% CI = 1.21–16.57) were significantly associated with the occurrence of MDR E. coli, while earthen ponds (OR = 8.2; 95% CI = 1.47–45.2) and human activity adjacent to the farm (OR = 4.6; 95% CI = 0.75–27.98) were associated with an increased likelihood of MDR V. parahaemolyticus. Considering the paucity of information on the drivers of AMR in the aquaculture production in this region, these findings indicate the targeted interventions implementable at aquaculture farms to efficiently abate the risk of MDR amongst bacteria that affect fish that are of public health importance.

Assessing household perception, autonomous adaptation and economic value of adaptation benefits: Evidence from West Coast of Peninsular Malaysia

Climate change is causing sea-level rise, intense and frequent storm surge flooding, and significant shoreline erosion in Malaysian coastal areas. Consequently, coastal properties, infrastructure, and livelihoods are threatened. It has become apparent that adaptation at the household and community level is necessary to offset the adverse impacts of coastal hazards. The community needs to be made aware of the risks, acquire knowledge about adaptation options, and be empowered to take their own actions. Public perception and preference are therefore crucial for design and implementation of effective planning for climate change. Thus, this study assesses households' perception, adaptation measures and empirically estimates willingness to pay and preference for planned adaptation measures to guide policy instruments through public engagement. In Malaysia, ten highly vulnerable coastal areas in the Selangor coast were surveyed at the household level (n = 1016) through face-to-face interviews using a structured questionnaire. Regarding households’ perception and adaptation methods, most of the households in the highly exposed areas perceived less risk of inundation and sea-level rise threat and adopted less proactive adaptation and limited risk reduction behaviours during the extreme event. The study found that 66.9% of households were willing to pay for planned adaptation measures despite the limited income capabilities and in favour of moderate adaptation (23.9%). The binomial and ordinal regression results indicated that the probability of willingness to pay for planned adaptation measures significantly increases with age, prior exposure to coastal hazards, awareness, risk perception, community participation, being affected by property damage and loss of income due to extreme events. With increased monthly household income and access to telecommunication services, households will probably pay higher for better adaptation measures. A significant amount of perceived yearly adaptation benefits in the coastal districts revealed the economic value of extensive (22,969.50 MYR/5462.43 USD), moderate (21,853.20 MYR/5196.96 USD) and minimal adaptation measures (8022.90 MYR/1907.94 USD) that can be utilised to incentivise coastal adaptation plans. The findings suggest policies to incorporate social values to reduce vulnerability, enhance community resilience, and contribute to the knowledge gap of adaptation research in the coastal areas.

Faecal DNA metabarcoding reveals novel bacterial community patterns of critically endangered Southern River Terrapin, Batagur affinis.

Southern River Terrapin, Batagur affinis, is a freshwater turtle listed as critically endangered on the IUCN Red List since 2000. Many studies suggest that faecal DNA metabarcoding can shield light on the host-associated microbial communities that play important roles in host health. Thus, this study aimed to characterise and compare the faecal bacterial community between captive and wild B. affinis using metabarcoding approaches. A total of seven faeces samples were collected from captive (N = 5) and wild (N = 2) adult B. affinis aseptically, crossing the East and West coast of peninsular Malaysia. The DNA was extracted from the faeces samples, and the 16S rRNA gene (V3–V4 region) was amplified using polymerase chain reaction (PCR). The amplicon was further analysed using SILVA and DADA2 pipelines. In total, 297 bacterial communities taxonomic profile (phylum to genus) were determined. Three phyla were found in high abundance in all faeces samples, namely Firmicutes (38.69%), Bacteroidetes (24.52%), and Fusobacteria (6.95%). Proteobacteria were detected in all faeces samples (39.63%), except the wild sample, KBW3. Under genus level, Cetobacteriumwas found as the most abundant genus (67.79%), followed by Bacteroides (24.56%) and Parabacteroides (21.78%). The uncultured genus had the highest abundance (88.51%) even though not detected in the BK31 and KBW2 samples. The potential probiotic genera (75.00%) were discovered to be more dominant in B. affinis faeces samples. Results demonstrated that the captive B. affinis faeces samples have a greater bacterial variety and richness than wild B. affinis faeces samples. This study has established a starting point for future investigation of the gut microbiota of B. affinis.

Geometric morphometric discrimination between seven populations of Kawakawa Euthynnus affinis (Cantor, 1849) from Peninsular Malaysia

Small epipelagic and migratory, Euthynnus affinis (kawakawa) is one of the commercially significant tunas of Indo-Pacific tropical and subtropical waters. Unfortunately, the management and stock structure of certain migratory species in the area is not clear. The current study aimed to discriminate the E. affinis through shape and body size variations and to evaluate the variations among seven populations of E. affinis. A total of 114 individuals of E. affinis were collected from two main geographic areas; the Straits of Malacca and the South China Sea. Multivariate analyses, such as discriminant function analyses (DFA) and principal component analyses (PCA) of 11 homologous landmarks and seven morphometric variables were carried out to discriminate seven populations of E. affinis. The results revealed a significant variations among the body shape of the seven populations of E. affinis. Morphological homogenous occurred between populations obtained from the east coast of Peninsular Malaysia (Terengganu, Kelantan, and Johor). However, populations found on the west coast of Peninsular Malaysia (Selangor) were separated and formed another cluster. The variations in the body shape of E. affinis occurred in the body depth and the overall body shape. The percentage of overall correct classification for all seven populations of E. affinis is 88.6%. This present study is the first report using a geometric morphometric method performed on the E. affinis from Peninsular Malaysian waters.