Songkhla Lake Research Articles

Habitat of the amphibious mudskipper Periophtalmodon schlosseri in Songkhla Lake, Thailand

Abstract. Pattaratumrong MS, Pompha T. 2024. Habitat of the amphibious mudskipper Periophtalmodon schlosseri in Songkhla Lake, Thailand. Biodiversitas 25: 1875-1881. This study aimed to investigate the preferred habitat of giant mudskippers, Periophtalmodon schlosseri Pallas 1770. It was conducted from August to October 2022 at six sampling stations in Koh Yoh, a small island in the Lower Songkhla Lake. Environmental parameters such as organic matter and organic carbon in sediment, temperature, salinity, dissolved oxygen, and substrate were observed. The results indicate that the density of giant mudskipper weak to moderate correlates with all studied environmental parameters (P<0.05). Within the study area, the highest population density of P. schlosseri was recorded in the mudflat habitat adjacent to mangroves, and the lowest density was recorded in the mudflat habitat with a seawall, absent with nearby mangroves. This study suggests that environmental conditions affect the abundance of giant mudskippers, but this does not reach the limiting threshold; the more influential factor for this species is the character of the habitat. The mangrove habitat should be conserved and protected from development and urbanization. These results provide insights into the preferred habitat and offer a better understanding of the ecology of these fishes in the estuarine lake.

Genetic diversity and connectivity of the Irrawaddy dolphin in Southern Thailand: Emphasizing the last fourteen of the Songkhla dolphin status from a microsatellite perspective

Abstract. Budi T, Ninwat S, Sakornwimon W, Thongcham K, Phakphien R, Kalaya C, Phavaphutanon J. 2024. Genetic diversity and connectivity of the Irrawaddy dolphin in Southern Thailand: Emphasizing the last fourteen of the Songkhla dolphin status from a microsatellite perspective. Biodiversitas 25: 1729-1735. Irrawaddy dolphin (Orcaella brevirostris Gray, 1866) can be found in diverse aquatic environments, ranging from coastal to brackish water, stretching from the West of Bengal in India to the central part of the Indonesian archipelago. Despite its widespread distribution and flexible habitat tolerance, Irrawaddy dolphins in Songkhla Lake, Southern Thailand, are hypothesized to be isolated and exhibit concerningly low population numbers, threatening their long-term survival. Limited knowledge exists regarding their population genetics status. This study analyzed 30 samples from Songkhla Lake (SKL) and the Lower Gulf of Thailand (LGT) to assess their genetic diversity, structure, and connectivity using 16 microsatellite loci. Extremely low genetic diversity was observed in SKL (Ho = 0.039±0.039; AR = 1.122±0.489) and LGT (Ho = 0.033±0.033; AR = 1.141±0.566) populations. Population differentiation (FST = 0.033, p>0.05) and clustering analyses based on both Principal Coordinate Analysis (PCoA) and Discriminant Analysis of Principal Component (DAPC) suggest limited genetic divergence and potential panmixia (single genetic pool) between both populations. These findings highlight critical conservation concerns due to low diversity despite the lack of isolation, emphasizing the need for immediate and targeted efforts to ensure the long-term viability of this iconic yet vulnerable population.

Does Salinity Gradient Affect Distributions of Byssally-attached Bivalves in Songkhla Lake, the Largest Estuary in Thailand?

Does Salinity Gradient Affect Distributions of Byssally-attached Bivalves in Songkhla Lake, the Largest Estuary in Thailand?

Distribution of artisanal fishing gears with impacts on sedimentation and benthic macroinvertebrate assemblages in Songkhla Lake, the largest lagoon in Thailand

The present study investigated the distribution and diversity of stationary fishing gears in Songkhla Lake and assessed the effects of the most abundant gear in the lake, the standing trap, on sedimentation and the abundance of benthic macroinvertebrates. Our survey revealed that six types of fishing gear were used: standing traps, fyke nets, fish aggregating devices, seabass net cages, small traps and stationary lift nets. The type of fishing gear used depended on the depth of water. The density of installed standing traps reached a maximum of 357 traps/km2, which was the highest density of any fishing gear installed on the lake. They were mainly set in the middle part of the lake, where the water was less than 2 m deep. Sedimentation was examined inside and outside the areas influenced by standing traps. Sediment samples were collected with sediment traps in the northeast and southwest monsoon seasons. Sedimentation rates inside and outside the areas influenced by standing traps differed at some sites but the pattern was not consistent across seasons. Sedimentation rates were higher in the northeast monsoon season with the average rate 1132.32 ± 43.73 (mean ± SE) g m−2day−1 when precipitation and run-off were higher and 323.98 ± 10.68 g m−2day−1 in the southwest monsoon or dry season. Moreover, the proportion of finer clay particles was greater in the sediment from the areas influenced by traps. Benthic macroinvertebrate communities between the two areas were different. A bivalve, Potamocorbula sp., which dominated benthic macroinvertebrate assemblages, had a higher abundance in areas influenced by traps. The effects of stationary fishing gears on sedimentation and benthic macroinvertebrates highlighted in this study suggest that the long-term deployment of these gears may affect food chain dynamics in this lagoon system. Ultimately, a proper regulation of the use of these gears may be needed.

A Confirmation Factor Analysis of the Potential Level Scale for Halal Tourist Sites in Lower Songkhla Lake

This research aims to examine the coherence between the potential levels of halal tourist attractions in the lower Songkhla lagoon area for Muslim tourists with empirical data. The sample consisted of 400 Muslim tourists. This research used questionnaire to collect the data which had a confidence value of Cronbach's Coefficient Alpha with a confidence value of 0.960. The researchers analyzed the structural validity of the potential levels about halal tourist attractions around the lower Songkhla lagoon for Muslim tourists by analyzing the second corroborative component using a statistical computer program. The second corroborative component analysis revealed that the potential levels of Halal Tourist Sites in the Lower Songkhla lagoon consisted of 6 components of equal importance with component weights of 0.78, 0.84, 0.83, 0.93, 0.90, and 0.87. The results of checking the consistency of the empirical component model found that the chi-square statistic is 391.24 at 259 degrees of freedom, the probability is 0.00, the relative chi-square statistic is 1.51, the Goodness of Fit Index (GFI) is 0.93 and the Adjusted Goodness of Fit Index (AGFI) is 0.90, the Comparative Fit Index (CFI) is 0.99, the Root Mean Square Residual (RMR) is 0.02 and the Root Mean Square Error of Approximation: RMSEA) is 0.04, which indicates that the potential levels of halal tourist attractions in the lower Songkhla lagoon area for Muslim tourists consistent with the empirical data and it consists of 6 components: Accessibility, Environment, Tourism Management, Facilities, Value, and Response.

Revision of Alpheus euphrosyne De Man, 1897 andA. microrhynchus De Man, 1897, with description of three new species and taxonomic remarks on several other morphologically and ecologically similar snapping shrimps (Malacostraca: Decapoda: Alpheidae).

Alpheus euphrosyne De Man, 1897 and A. microrhynchus De Man, 1897, two taxonomically challenging snapping shrimps without extant original type material, are rediagnosed based on recently collected and older museum material and adhering closely to their original descriptions. Two male specimens from Java and Kalimantan are designated as neotypes for A. euphrosyne and A. microrhynchus, respectively. Alpheus tirmiziae Kazmi, 1974 is placed in the synonymy of A. euphrosyne. The distributional range of A. euphrosyne extends from the South China Sea through the Sunda Shelf to the northern Arabian Sea. Alpheus eurydactylus De Man, 1920 is removed from the synonymy of A. euphrosyne and redescribed based on De Man's type material from Java and new material from South-East Asia, Indonesia and northern Australia. Alpheus richardsoni Yaldwyn, 1971, previously often regarded as a subspecies of A. euphrosyne, is confirmed as a valid species morphologically and ecologically distinct from A. euphrosyne. In addition, A. richardsoni is geographically separated from A. euphrosyne, being confined to subtropical and temperate waters of Australia and New Zealand. Alpheus microrhynchus appears to be geographically restricted to South-East Asia, with confirmed records from Thailand, peninsular Malaysia and Borneo, where it occurs in transitional freshwater to brackish water habitats. Alpheus cyanoteles Yeo & Ng, 1996 is currently seen as the only true freshwater snapping shrimp. This unique species is morphologically almost identical with A. microrhynchus and is presently known only from a few localities in southern Thailand, peninsular Malaysia and western Borneo (Sarawak). Three species that were previously confused with A. euphrosyne, A. euphrosyne euphrosyne or A. euphrosyne richardsoni, are described as new to science: A. nomurai sp. nov. from Japan, Korea and Taiwan; A. takla sp. nov. from South-East Asia, Philippines, Indonesia, Papua New Guinea and Australia; and A. mangalis sp. nov. from Singapore, Malaysia, Philippines, Indonesia, northern Australia, Taiwan and possibly New Caledonia. Alpheus takla sp. nov. may represent the largest presently known snapping shrimp, with the total body length reaching 90 mm and the length of the major chela reaching 52 mm; this species, locally known as takla, is consumed in some parts of the Philippines. The taxonomic identity of the material from the western and northern Indian Ocean previously reported as A. euphrosyne euphrosyne remains uncertain. Alpheus malabaricus songkla Banner & Banner, 1966 is tentatively elevated to species rank, as Alpheussongkla stat. nov. This taxon remains problematic, mainly because the original type material from Songkhla Lake, Thailand, is composed exclusively of females; its status is discussed based on the reexamination of type specimens and material tentatively identified as A. cf. songkla, which appears to have some affinities with both A. songkla and A. eurydactylus. In addition, taxonomic, biogeographic and/or ecological remarks are provided for five further species, which in the past were compared with A. euphrosyne, A. richardsoni and A. microrhynchus or are morphologically similar to them. These species are: A. paludicola Kemp, 1915 from India; A. nipa Banner & Banner, 1985 from Indonesia; A. bunburius Banner & Banner, 1982 from western Australia; A. pontederiae de Rochebrune, 1883 from both sides of the Atlantic Ocean; and A. firmus Kim & Abele, 1988 from the tropical eastern Pacific. The heterogeneity of the Panamanian and Mexican material currently assigned to A. firmus is discussed in more detail.

TOURISM LOGISTICS MANAGEMENT INFLUENING LOGISTICS PERFORMANCE, SATISFACTION, AND LOYALTY OF TOURISMS IN SONGKHLA PROVINCE.

The objectives of this research are to (1) study the context and logistics management system for tourism (2) study the components of tourism logistics management and the efficiency of logistics management of tourist attractions in Songkhla province (3) study logistics management for tourism that affects logistics management efficiency, satisfaction, and loyalty of tourists in Songkhla province (4) study way to develop the efficiency of logistics management of tourist attractions in Songkhla province. The researcher used Mixed Methodology. The secondary data of qualitative research were analyzed with content analysis and the data of quantitative research were collected by questionnaire with 400 tourists in Songkhla province. The statistics used in data analysis were percentage, mean, standard deviation and multiple regression analysis. Quantitative research results revealed that factors of Tourism Logistics Management including Financial Flow, Physical Flow, Customer Service, and Information Flow. Factors of efficiency of logistics management including Reliability, Cost, and Time. Tourism Logistics Management in Physical Flow (β = 0.153), Information Flow (β = 0.155), Financial Flow (β = 0.195), Customer Service (β = 0.338) and efficiency of logistics management all 3 components are Cost (β = 0.229), Time (β = 0.387), Reliability (β = 0.205) are positively effect on Tourism Satisfaction significant. Tourism Satisfaction (β = 0.848) are positively effect on Loyalty of tourisms significant. Qualitative research results revealed from the secondary data, can summarize the results that have Top 5 popular tourist attractions in Songkhla province: (1) Samila Beach (2) Gimyong Market - Santisuk Market (3) Songkhla Old Town (4) Songkhla Lake, and (5) Tinsulanonda Bridge. All 5 tourist destinations have efficient logistics management for tourism. As for guidelines for developing tourism logistics management should be cooperation with relevant agencies in developing basic facilities.

Assessment of small hydropower in Songkhla Lake Basin, Thailand using GIS-MCDM

Assessment of small hydropower in Songkhla Lake Basin, Thailand using GIS-MCDM

Diversity and Phylogenetics of Freshwater Mussels (Unionidae) from Southern Thailand with the Description of One New Genus and Five New Species-Group Taxa

Southern Thailand represents a region of unique freshwater biodiversity with many endemic taxa, including a number of freshwater mussel species (Bivalvia: Unionidae). In this study, we recognize 13 taxa in the tribes Contradentini, Rectidentini, Pseudodontini (subfamily Gonideinae), and Indochinellini (subfamily Parreysiinae) that inhabit different localities in the Songkhla Lake, Tapi River, and Tha Taphao River basins. Based on the results of morphological and phylogenetic analyses, we discovered among these mussels six taxa new to science, including one genus, three species, and two subspecies. New taxonomic names are introduced here as follows: Songkhlanaiagen. nov.; S. tamodienicagen. & sp. nov.; Sundadontina plugpomenicasp. nov.; Monodontina vondembuschiana tapienicassp. nov.; M. vondembuschiana thasaenicassp. nov. (Pseudodontini); and Trapezoideus thachiadensissp. nov. (Contradentini). These new taxa confirm the high conservation priority of the Southern Thai freshwater mussel fauna.

Concentrations and source identification of priority polycyclic aromatic hydrocarbons in sediment cores from south and northeast Thailand

In this study, the environmental fate of carcinogenic polycyclic aromatic hydrocarbons (PAHs) in tropical lake sediments and their potential sources have been discussed. 15 PAHs (i.e. ΣPAH) have been investigated in two lakes, namely Songkhla Lake (SKL) and Nong Han Kumphawapi Lake (NHL), which are located at the southern and north-eastern parts of Thailand, respectively. Since these two lakes are registered as important wetlands under the Ramsar convention (United Nations Educational, Scientific and Cultural Organization: UNESCO), the quantitative identification of potential contributors of PAHs is an inevitable analytical tool for launching an evidence-based policy. The ΣPAH concentrations observed in SKL and NHL sediments (n = 135) were in the range of 19.4–1,218 ng g−1 and 94.5–1,112 ng g−1, respectively. While the exponential decline of ΣPAH contents were detected in SKL sediments, NHL showed a trend of enhancing PAH contents with depth. The averaged benzo [a]pyrene (B [a]P) contents of surface sediments in both lakes were much below the value stipulated by the United States Environmental Protection Agency (US-EPA) guidelines for carcinogen risk assessment. Based on numerous multivariate statistical techniques coupled with source apportionment analysis, “biomass burning” and “anthropogenic activities” are two potential contributors of the PAHs detected in the study areas. To achieve the long-term conservation of nature with related ecosystem services and cultural values, it is therefore important to promote decision-making based on ecotoxicological studies of carcinogenic substances.

The Hot-Water Extract of Sargassum sp. as a Feed Ingredient for Spotted Scat (Scatophagus argus Linnaeus, 1766) Reared in Songkhla Lake: Effects on Growth, Feed Efficiency, Hematological Data and Body Composition

The growth performance of Scatophagus argus (25.53 ± 0.89 g) reared in Songkhla Lake, a brackish lagoon, was evaluated after feeding isonitrogenous and isocaloric diets containing hot-water extract from a seaweed, Sargassum sp., at 0, 0.25, 0.50, 0.75 or 1 g·kg−1. Triplicate groups of fish were reared in 15 net cages (50 × 50 × 60 cm) at a density of 20 fish per cage, and the diets were fed twice a day at a rate of 5% of fish body weight per day for 8 weeks. The final body weight, weight gain (WG), average daily gain, and feed intake (FI) showed significant positive and quadratic responses to the Sargassum extract level. The highest WG (57.97%) and FI (0.34) were recorded in the fish that received the hot-water extract at 0.25–0.5 g·kg−1 of diet. The protein efficiency ratio showed significant positive linear and quadratic responses to the Sargassum extract level, while the hepatosomatic index showed a significant positive linear response to the Sargassum extract level. The body protein and ash contents showed positive, linear and quadratic responses to the Sargassum extract level, and the highest crude protein (49%) was observed in the 0.5 g·kg−1 diet group. There were no significant effects of the Sargassum extract levels on feed conversion ratio, food conversion efficiency, lipid and moisture contents, survival rate, hematocrit, and white or red blood cell counts. However, hematological data between fish in the control group and the Sargassum extract groups tended to be different. Overall, the optimum level of seaweed-extract supplementation for spotted scat under natural conditions was determined to be approximately 0.5 g·kg−1 diet.

Bat Activity in Organic Rice Fields Is Higher Than in Conventional Fields in Landscapes of Intermediate Complexity

The extent to which organic farming can support biodiversity has been extensively studied. However, most of the research has been conducted on organic farms in temperate regions, with the focus mainly being on birds, insects, and plants and rarely on insectivorous bats, especially in Southeast Asia. We studied pairs of matched organic and conventional rice fields along a gradient of landscape complexity in the Songkhla Lake Basin and conducted acoustic surveys using bat detectors to analyze the influence of farming system and landscape characteristics on bat activity and prey availability. We also tested the “intermediate landscape complexity” hypothesis, which states that local conservation efforts are most effective in landscapes of intermediate complexity compared to extremely simple or extremely complex landscapes. We detected no difference in bat species richness, total bat activity, feeding activity, and insect prey abundance between organic fields and conventional fields. Even though organic farming did not increase bat activity on its own, it was most beneficial to bat activity in landscapes of intermediate complexity. Our findings suggest that landscape traits contribute more to bat activity than farm management and that insectivorous bats have species- and guild-specific responses to various landscape contexts. We also found that disturbance caused by tropical storms negatively impacts the activity of insectivorous bat.

Combined proteomic strategies for in-depth venomic analysis of the beaked sea snake (Hydrophis schistosus) from Songkhla Lake, Thailand

This study focuses on comprehensive characterization of the venom proteome of the beaked sea snake (Hydrophis schistosus) from Songkhla Lake, Thailand. H. schistosus can be considered as the deadliest sea snake commonly found in the Pacific and Indian oceans. Their envenomation causes muscular paralysis and rhabdomyolysis. To develop effective treatment for this snakebite, it is necessary to understand the detailed venom composition. In this study, multiple mass spectrometry-based approaches were employed. Bottom-up proteomics revealed that tryptic digestion in-solution provided a higher number of toxin proteins identified and a larger sequence coverage, compared to in-gel digestion. In addition, a venom gland transcriptome-derived database was constructed and used as a reference, which 43 known and novel toxin proteins were identified using this database and the UniProtKB. Three-finger toxin and phospholipase A2 were shown to be top two most abundant protein families. Minor compositions included other toxin families and a number of non-toxin proteins. Moreover, a hybrid de novo sequencing was performed to enhance identification of the small proteins/peptides. Using non-digested samples, there were 46 predicted toxin peptides. The finding from this study could lead to a better understanding in pathological effects of the snakebite and the future development of effective antivenoms. SignificanceThis study provides a better understanding of the venom proteome composition of the beaked sea snake (H. schistosus) found in the Gulf of Thailand, using a combination of different sample preparation techniques, Serpentes protein database searching, transcriptome-derived protein database searching, and a hybrid de novo peptide sequencing strategy. It revealed 13 toxin protein families and novel proteins in the beaked sea snake venom including new species of phospholipase A2s (PLA2s) and three-finger toxins (3FTxs). It could serve as a basis for the development of snakebite treatments and for the discovery of novel pharmaceutical drugs from the toxin peptides.

Sustainable Conflict Management Strategies for Fishery Resources in Songkhla Lake, Southern Thailand

Sustainable Conflict Management Strategies for Fishery Resources in Songkhla Lake, Southern Thailand

Multi-Disciplinary Assessment of Napier Grass Plantation on Local Energetic, Environmental and Socioeconomic Industries: A Watershed-Scale Study in Southern Thailand

Napier grass is an energy crop that is promising for future power generation. Since Napier grass has never been planted extensively, it is important to understand the impacts of Napier grass plantations on local energetic, environmental, and socioeconomic features. In this study, the soil and water assessment tool (SWAT) model was employed to investigate the impacts of Napier grass plantation on runoff, sediment, and nitrate loads in Songkhla Lake Basin (SLB), southern Thailand. Historical data, collected between 2009 and 2018 from the U-tapao gaging station located in SLB were used to calibrate and validate the model in terms of precipitation, streamflow, and sediment. The simulated precipitation, streamflow, and sediment showed agreement with observed data, with the coefficients of determination being 0.791, 0.900, and 0.997, respectively. Subsequently, the SWAT model was applied to evaluate the impact of land use change from the baseline case to Napier grass plantation cases in abandoned areas with four different nitrogen fertilizer application levels. The results revealed that planting Napier grass decreased the average surface runoff and sediment in the watershed. A multidisciplinary assessment supporting future decision making was conducted using the results obtained from the SWAT model; these showed that Napier grass will provide enhanced benefits to hydrology and water quality when nitrogen fertilizers of 0 and 125 kgN ha−1 were applied. On the other hand, the benefits to the energy supply, farmer’s income, and CO2 reduction were highest when a nitrogen fertilization of 500 kgN ha−1 was applied. Nonetheless, planting Napier grass should be supported since it increases the energy supply and creates jobs while also reducing surface runoff, sediment yield, nitrate load, and CO2 emission.

Age and growth estimates from three hard parts of the spotted catfish, Arius maculatus (Actinopterygii: Siluriformes: Ariidae), in Songkhla Lake, Thailand’s largest natural lake

The spotted catfish, Arius maculatus (Thunberg, 1792), is a euryhaline fish that is economically important in the Indo-West Pacific. Population dynamics studies and stock assessments of this species have focused on marine stocks, but not those from fresh water. In this study, the age and growth of A. maculatus were, therefore, investigated for the inland stock in Songkhla Lake, Thailand. A total of 213 individuals ranging between 35 and 238 mm TL were used. The length–weight relation indicated positive allometry of this population. Three hard parts (otolith, dorsal- and pectoral-fin spines) were used for aging. The marginal increment ratio confirmed that an annulus was deposited once a year in all three hard parts. All of the samples were aged between 0+ and 6+ years. Verification of age estimates from three readers showed that the otolith was the most suitable part for age estimation. Three growth models (von Bertalanffy, Gompertz, and logistic) were applied in the study. The von Bertalanffy model best described the growth of this fish in Songkhla Lake. The obtained asymptotic length was 290.87 mm TL and the relative growth rate parameter was 0.166 year–1. Our results will be applied as inputs for fish stock assessment models. The obtained growth parameters also can serve as a reference for A. maculatus stocks elsewhere.

Sedimentary History of Trace Metals Over the Past Half-Century in Songkhla Lake, Western Coast of the Gulf of Thailand: Anthropogenic Impacts and Contamination Assessment

Coastal lagoons are among the most vulnerable and economically significant ecosystems on Earth. Songkhla Lake, connected with the Gulf of Thailand, is the second largest lake in Southeast Asia and supports the development of the fishery, transportation, and tourism industries in southern Thailand. With increasing anthropogenic disturbances, the lake is facing acute ecological problems and further research is needed. Here, we provide 55-year record of grain size, color reflectance, magnetic susceptibility, total organic carbon, total nitrogen, and trace element (As, Hg, Pb, Cr, Ni, Cu, and Zn) concentrations of sediment core SKL8-2 collected from Songkhla Lake. These records reveal a three-stage sedimentary and input history of trace metals under anthropogenic effects: 1) From 1964 to 1982, it was a natural terrigenous input period with a relative reduction environment when the channel connecting Songkhla Lake and the Gulf of Thailand was closed. 2) Trace metal concentrations, organic carbon content, b* value, and magnetic susceptibility changed abruptly in 1982. During 1982–2000, the sources of trace metals were more complex than during 1964–1982 and mainly came from urban wastewater, industrial effluent, and fishery discharge. 3) From 2000 to 2019, contamination signals of Pb, Hg, As, Zn, and Ni emerged in the first decade because of the rapid development and poor sewage treatment around nearby cities.

Microcystis Sp. Co-Producing Microcystin and Saxitoxin from Songkhla Lake Basin, Thailand.

The Songkhla Lake Basin (SLB) located in Southern Thailand, has been increasingly polluted by urban and industrial wastewater, while the lake water has been intensively used. Here, we aimed to investigate cyanobacteria and cyanotoxins in the SLB. Ten cyanobacteria isolates were identified as Microcystis genus based on16S rDNA analysis. All isolates harbored microcystin genes, while five of them carried saxitoxin genes. On day 15 of culturing, the specific growth rate and Chl-a content were 0.2–0.3 per day and 4 µg/mL. The total extracellular polymeric substances (EPS) content was 0.37–0.49 µg/mL. The concentration of soluble EPS (sEPS) was 2 times higher than that of bound EPS (bEPS). The protein proportion in both sEPS and bEPS was higher than the carbohydrate proportion. The average of intracellular microcystins (IMCs) was 0.47 pg/cell on day 15 of culturing, while extracellular microcystins (EMCs) were undetectable. The IMCs were dramatically produced at the exponential phase, followed by EMCs release at the late exponential phase. On day 30, the total microcystins (MCs) production reached 2.67 pg/cell. Based on liquid chromatograph-quadrupole time-of-flight mass spectrometry, three new MCs variants were proposed. This study is the first report of both decarbamoylsaxitoxin (dcSTX) and new MCs congeners synthesized by Microcystis.

Packaging Design for OTOP Products: a Case Study of CHALARE Community Enterprise, Singhanakhon, Songkhla

This study was aimed to (1) investigate, survey, and collect the data of OTOP products and identity of Chalare Community and (2) to design packaging for OTOP products of Chalare Community Enterprise, which represent the community’s identity. The data were collected using structured interview with 30 OTOP producers selected by purposive sampling. The data were managed and analyzed into two parts. (1) The physical data were collected from the survey and photographing to describe the identity of OTOP products in Chalare Community. (2) The data from the interview were collected and concluded to be a guidance for packaging design. The result of this study indicated that (1) the identity of Chalare Community represents the agricultural community located along Songkhla Lake around Chalare Temple Hills. Most of the people in the community are Buddhist and do some farming and Palmyra Palm planting to earn their living. In addition, (2) the packaging design of the products is separated into two groups: group A packages for sugar palm products, and group B packages for fresh sugar palms with honey-mixed lemon juice and fresh sugar palms with plum juice. In terms of branding, the packages in both groups are branded with the word “Not Na Lare” which was designed in a smiling-curve shape.

Predictive analytics modifications in wavelet: case study on Songkhla Lake basin runoff

Accurate short-term rainfall-runoff prediction is very important for flood mitigation and the safety of infrastructures in Southern Thailand. This study aims to utilize both analysis and prediction of the runoff forecast by combining the wavelet technique with regression and artificial neural network. The daily rainfall and runoff data were collected from 1,031 days during January 2017 to October 2019 in Songkhla Lake Basin, Thailand. The performance of calibration and validation of the models is evaluated with appropriate statistical methods; coefficient of determination (R 2 ), root mean square error (RMSE) and Nash-Sutcliffe efficiency coefficient (ENS). The results of daily runoff series modeling indicated that the wavelet artificial neural network model performed the best among those models. This model showed the Coefficient of Determination, Nash-Sutcliffe Efficiency and Root mean Square Error in the value of 0.9999, 0.9998 and 0.0037, respectively. These values explained that the model can describe 99.99% of the variation of the current runoff in Songkhla Lake Basin.