International Journal of Pure and Applied Mathematics Volume 118 No. 24 2018 ISSN: 1314-3395 (on-line version) url: http://www.acadpubl.eu/hub/ Special Issue http://www.acadpubl.eu/hub/ Assessment of physico-chemicals water quality, substrate compositions and phytoplankton in relation to the density of Corbicula fluminea in Pattani river, Southern Thailand a Zaween Najjah Mohamad Shamsul , Aweng Eh Rak∗b, Sukree Hajisamaec, Sharifah Aisyah Syed Omard and Liyana Ahmad Afipe a Faculty of Earth Science, Universiti Malaysia Kelantan, Jeli Campus Locked Bag No. 100, 17600 Jeli, Kelantan, Malaysia b Faculty of Earth Science, Universiti Malaysia Kelantan, Jeli Campus Locked Bag No. 100, 17600 Jeli, Kelantan, Malaysia c Department of Fisheries Science, Faculty of Science and Technology, Prince of Songkla University Pattani, Rusamilae, Mueang Pattani District, Pattani 94000, Thailand d Faculty of Earth Science, Universiti Malaysia Kelantan, Jeli Campus Locked Bag No. 100, 17600 Jeli, Kelantan, Malaysia e Centre for Language Studies and Generic Development, Universiti Malaysia Kelantan *Corresponding Author Email: [email protected] March 27, 2018 1 International Journal of Pure and Applied Mathematics Special Issue Abstract Corbicula fluminea or commonly known as Asian clam has been consumed by people in Asian countries as exotic food and the consumption is spread all over the world where Asia people lived. They cook Asian clam just like cook- ing other type of clams. People in Kelantan, Malaysia and Southern Thailand smoked the Asian clam and consumed it as snack. However, the ecology of C. fluminea has not been fully explored in Malaysia and also in Southern Thailand. The objective of this study is to determine the influence of habitat elements on the density of C. fluminea in Pat- tani River. C. fluminea, physico-chemicals water quality, substrate compositions and phytoplankton availability were sampled in Pattani River, Thailand. The water quality pa- rameters involved in this study are dissolved oxygen, pH, temperature and the nutrient analysis which are phosphate and nitrate. The mean concentration of pH is 6.53 0.06, ± temperature is 31degC, dissolved oxygen (DO) is 3.3 0.10, ± phosphate is 0.07 0.01 and nitrate is 0.31 0.07. On the ± ± other hand, Pattani River has a sandy loam substrate com- prises of 84% of sand and 16% of clay. In terms of phyto- plankton, there are 21 species identified from 15 different families. The density of C. fluminea recorded at Pattani River is 369 clams per m2. Based on the results, it could be suggested that, the density of C. fluminea is likely to be influenced by the harvesting activities by the villagers for consumption since the water quality, substrate compo- sitions and the availability of phytoplankton are favouring their growth. Findings of this research are able to add to the existing knowledge of the ecology of C. fluminea nationally and internationally. Key Words:Corbicula fluminea, habitat, water quality, sediment, phytoplankton, density, Pattani River. 1 Introduction C. fluminea is a small clam with an inflated shell, slightly round to triangular in shape. The most distinctive feature is the shell which consist of numerous heavy concentric ridges (2). C. fluminea is a freshwater clam commonly found in Southeast Asia including 2 International Journal of Pure and Applied Mathematics Special Issue Southern Thailand and Malaysia. C. fluminea is one of the most invasive species in aquatic ecosystems and is well known by its rapid and extensive spread. This is native in Asia and has invaded several ecosystems worldwide in the last 80 years (3). Although C. fluminea is originated from Asia, there is no ecolog- ical study about this species for the tropical climate as in Malaysia and Thailand. Most of the researches done for this species are in the four season climate zone. C. fluminea or also known as etak by the local is commonly being harvested as a traditional food and snack. The number of this species is declining especially in Kelan- tan and Southern Thailand but there is no scientific information on ecological aspect of this species in Southeast Asia that can be used in order to conserve this species population from declining. With the objective to determine the influence of habitat ele- ments on the density of C. fluminea in Pattani River in Southern Thailand, the finding from this study can also be used by the lo- cal authority as a basis to set up management plan to conserve C. fluminea habitat and to prevent this species from declining. 2 Literature Review C.fluminea is present in habitats ranging from bedrock to deep silt, and can be found in ponds, lakes and streams of all sizes (4). There are two common species found in Malaysia and Thailand namely C. fluminea which normally found in freshwater and C. fluminalis in brackish water but the most commonly used is C. flu- minea. C.fluminea is the most abundant species collected and they were found in a larger number on intermediate substrate sizes un- like densities of other freshwater mussels that are not correlated with bottom type (5). As this species is native at semi-tropical or Southeast Asia, C. fluminea was rarely exposed to the extreme tem- perature (6). C. fluminea is very proficient at combining suspension and deposit feeding to meet their energy requirements (7). It has been observed that juveniles (¡1 year old) collect fine organic ma- terials from their substrate by pedal sweep and also by using their cilia to create an anterior suspension feeding current (8). This clam also is primarily a suspension- feeder that can filter phytoplankton and detritus from the water column at a very high rate (9, 10). 3 International Journal of Pure and Applied Mathematics Special Issue 3 Methodology/Materials 3.1 Study Area This study was conducted at Pattani River which was located in the southern part of Thailand. It originated in Betong district, Yala Province and empties into the Gulf of Thailand at the town of Pattani. Within Yala Province the river forms the Bang Lang Reservoir. The river is 214 kilometres long. 3.2 Water Quality There are three (3) elements measured during the study namely physico-chemicals river water quality, substrate compositions, present and absence of phytoplankton and density of the Asian clam. Five (5) physic-chemicals water quality were determined namely dis- solved oxygen (DO), temperature, pH, phosphate and nitrate. DO, pH and temperature were measured in-situ using portable meter. While, nitrate test was conducted according to the Standard Method EPA Method No. 352.1 (11). A series of nitrate solution were prepared (2 mg/L, 4 mg/L, 6 mg/L, 8 mg/L and 10 mg/L) and placed in the tube rack including the blank sample. Sulphuric acid (H2SO4), sodium chloride (NaCl) and brucine sulphate were pipet- ted into the samples. Then, the tube rack were placed in 100degC water bath for 25 minutes and after removed from heat, the tube were then placed in the cold water bath until reach thermal equi- librium. The absorbance of NO3- was determined using GENESYS 10S Series spectrophotometer at 410nm. Calibration curve was ob- tained by plotting the absorbance of the standard against mg NO3- / L to determine the concentration of the nitrate in each sample. The experimental method for total phosphate followed the Stan- dard Method APHA 4500-PEAscorbic Acid Method. A series of phosphate solutions were prepared (5 mg/L, 10 mg/L, 15 mg/L, 20 mg/L, 25 mg/L and 30 mg/L). Phenolphthalein and sulphuric acid (H2SO4) were then added into the series of samples. Then, a combined reagent of sulphuric acid, ammonium molybdate solu- tion, potassium antimonyl tartrate solution and ascorbic acid were added into the samples. GENESYS 10S Series spectrophotometer was used to read the absorbance of PO43- at 880nm. Calibra- 4 International Journal of Pure and Applied Mathematics Special Issue tion curve was obtained by plotting the absorbance of the standard against mg PO43-/ L to determine the concentration of the nitrate in each sample. 3.3 Sediments measurement The sediments were put in a plastic tray and a large clump of the sediment was break down into a smaller size. The sediments were air-dried for approximately 3 days at a place that does not ex- posed to the direct sunlight. Upon dried, the sediments were sieve through sieve size no. 10 (2 mm) and weight for approximately 20 g for each samples. The experimental analysis for the particle size distribution follows the Pipette Method (Kilmer & Alexan- der, 1949) to determine the percentage of the sand, silt and clay of each sample. Based on the percentage, the type of soil for each sample was determined by using United States Department of Agri- culture (USDA)particle size distribution and textural classification chart(Kilmer & Alexander, 1949) 3.4 Phytoplankton Approximately 300 litres of river water were filtered through the phytoplankton net (40m). The water samples were stored in a 50mL PTFE plastic bottles and then preserved by 5% formalin solution before brought to the laboratory for phytoplankton analysis. In the laboratory, 1mL of the water sample was observed under the mi- croscope with 4x or the 10x magnification by using Sedwick-Rafter Cell to identify phytoplankton samples. The identified samples were then scored for absence (-) and presence (√) in the different wa- ter sources for each category. The number of particular alga in the mount was also noted. Identification was through comparative morphology and description using relevant text books, manuals and articles ((12-15). Five (5) sampling points were selected for the col- lection of C. fluminea where five (5) replicates were performed at each point. Clam dredge was used to collect C.