ZOOPLANKTON COMMUNITY STRUCTURE OF SUNGAI LUKUT AND ITS ESTUARY,

1SITI FAIRUS MUSA, 2HARINDER RAI SINGH

1,2Faculty of Applied Science, University Technology MARA, 40450 Shah Alam, , E-mail: [email protected], [email protected]

Abstract— The zooplankton community structure was studied in Sungai LukutNegeri Sembilan between February to April 2015. Sampling station included the estuary as well as the river until freshwater (estuarine, brackish and freshwater). Sampling was conducted utilizing a tow net with a 30 cm diameter having a 150 µm-mesh. The zooplankton sampling was conducted during floods and ebbs for both spring and neap tides. Physico-chemical parameters including salinity (estuary=34.17±1.22, brackish=31.79±1.83, freshwater=28.13±5.37), dissolved oxygen(DO) (estuary=104.92±17.30, brackish=91.24±19.02, freshwater=78.23±24.53), temperature (Estuarine=30.01±0.82, brackish=30.27±0.55, freshwater=30.08±0.67), and pH (estuary=8.87±0.71, brackish=8.55±0.80, freshwater=8.42±0.62) were recorded in situ station during sampling utilizing YSI meter model 556 MPS. The density and range of zooplankton during Spring tide for floods and ebbs for nine stations were (mean=215.47±62.59ind.m3; range=117.22 to 306.59) and (mean=223.17±58.20 ind.m3; range=136.99 to 315.75) respectively. Whereas for density and range of zooplankton during Neap tide for floods and ebbs for nine stations were (mean=244.24±58.20 ind.m3; range=159.71 to 321.25) and (mean=297.98±107.52 ind.m3; range=175.46 to 470.35) respectively.The species diversity (H’), species richness (d) and species evenness (J) for neap flooding were H’=2.2; d=6.36 and J=0.68 respectively. For neap ebbing however, the species diversity was H’=2.16, species richness d=6.21 and species evenness was J=0.67 which showed that the evenness stay constant (J=0.6) during neap tide for both flooding and ebbing. Spring tide for flooding showed different reading which were species diversity (H’=2.19), species richness (d=6.44) and species evenness (J=0.68) while for ebbing the species diversity was (H’=2.31), species richness (d=6.49) and species evenness (J=0.71).

Keywords— Zooplankton, Community Structure, Density, Sungai Lukut.

I. INTRODUCTION namely, Sungai LukutBesar and Sungai Lukut Kecil. Effluents from prawn ponds, residential- Sungai Lukut and its estuaryis located in Negeri developments, and workshops wash into the river. Sembilan andis an importantrivers that is used for fishing, drinking as well as for crop irrigation. Some 2.2. Sampling Technique stretches along Sungai Lukut are still covered with Zooplankton and water parameters sample collection mangroves. Removal of mangrove for alternate use was undertaken from February 2015 to April 2015. such as for prawn ponds, disposal of municipal waste The sampling was conducted from the estuary, and agricultural effluents have over the years brackish water andfreshwater habitat. Three sampling impacted Sungai Lukut and its estuary and these trips were conducted during spring tide and the three waste and effluents eventually end up in the Straits of during neap tides. Besides the tidal phase, . zooplankton was also sampled during flooding and Zooplankton are of interest as they inhabit coastal ebbing of tides. Nine sampling stations were waters, rivers and estuaries. Zooplanktonare sound demarcated along Sungai Lukut (Table 1). indicators of heavy metal pollution(Stemberger and Chen, 1998 respond to various disturbances such as contamination (Yan et al., 1996) and acidification (Armorek and Kormann, 1993). This study reports on the zooplankton community of Sungai Lukut and its estuary. The objectives of this study includes determining the species composition and community structure and to quantify the abundance and distribution of zooplankton of Sungai Lukut and its estuary.

II. MATERIALS AND METHOD

2.1. Sampling Location Zooplankton sampling was conducted from the river mouth of Sungai Lukut into the freshwater habitats along the river (N2°34’44.4” E101° 47’ 18.24’’). Figure 1.Map of Sungai LukutNegeri Sembilan. Red dots Sungai Lukut can be divided into two branches indicate the sampling stations

Proceedings of ISER 10th International Conference, , Malaysia, 8th November 2015, ISBN: 978-93-85832-34-5 9 Zooplankton Community Structure of Sungai Lukut and Its Estuary Table 1. Zooplankton sampling station and their stations respectively. Salinity ranged from 9.21±5.37 coordinates (at freshwater stations) to 35.59±1.22 (at estuarine stations). pH was lower at the freshwater stations(6.61±0.62) but was higher at the estuarine stations (9.87±0.71). Zooplankton composition and community structure of Sungai Lukut Twelve orders comprising 19 genera (Table 3) were sampled from Sungai Lukut. The copepoda(Calanoida, Cyclopodia, Poecilostomatoida and Harpacticoda) accounted for 53.13% of total zooplankton population collected throughout the study. Among the copepod groups, Calanoids were the most abundant sampled at all the stations contributing to 63.1% of the total copepod population.Copelata and Chaetognatha are both consist of single genus and comprised about 7.42% The zooplankton was collected using a zooplankton and 2.13% respectively. net with a mesh size 150 µm. The volume filtered was calculated manually. The net was towed 1 meter Fish eggs, fish larvae, copepod nauplii,brachyuran, below the water surface for about 3 to 5 minutes. porcellanid and polychaeta larvae comprised of Three replicates per station were taken. Temperature, 35.68% of total abundance and were combined salinity, dissolved oxygen (DO) and pH was recorded together under others group (Figure 2).The relative in situusinga YSI meter model 556 MPS and the abundances of the genera varied between tide (spring coordinates at each station was recorded using & neap) and phase of tide (flood & ebb). Acartia, Garmin GPS sensor (Tables 1 & 2). The stations were Paracalanus, Oithona, Macrosetella, Oncaea and divided into three parts along Sungai Lukut[estuarine- Oikopleura were always sampled during the different (stations 1,2, and 3); brackish (stations 4 ,5,and 6) tides and the tidal phases. ;and freshwater (stations 7, 8, and 9)] (Figure 1). Zooplankton density was highest during the ebb of 2.3. Sample Collection and Processing neap tides (104300±9592 ind.m3). Zooplankton The sample was concentrated into a sample bucket density during the flood of neap tides was after towing and transferred to a storage bottle with 85300±9592. The zooplankton densities during flood 10% buffered formalin added. The samples were later and ebb of spring tides were 75657±6534 ind.m3 and enumerated and identified under a dissecting 71471±5895 ind.m3 respectively (Table 4). microscope in the laboratory. Shannon’s (H’) was highest during ebb of spring tides 2.4. Analysis (H’=2.31) and lowestduring ebb of neap tides The Shannon-Weiner Diversity index [H’= – ∑ (H’=2.16). Margalef’s (d) was highest during ebb of (PiInPi)], Margalef’s species richness [(d=(S- spring tides(d=6.49)and lowest during ebb of neap 1)/log(N)] and Pielou’s evenness [(J=H’/loge(S)] tides (d=6.21). Pielou’s (J) was highest during ebb of were the community indices utilized.A two-way spring tides (J=0.71) and lowest during ebb of neap ANOVA was performed to examine the influence of tides (0.67) (Table 4). tides and flows on the univariate measures. Table 5 indicated that tides (spring & neap) and III. RESULTS habitat (Estuarine, brackish & freshwater) showed significant difference on the density of zooplankton Water physico-chemical parameters (p<0.05), pH and DO and salinity was also Dissolved oxygen varied from 33.30±24.53% (at the significantly different between tides and habitats freshwater stations) to 148.30±17.30% (at the (p<0.05) while temperature was not significantly estuarine stations) (Table 2).Temperature varied from different (p>0.05). 28.63±0.82°C to 32.67±0.68°C, with aminimum and maximum at the estuarine stations and freshwater

Table 2. Water physico-chemical parameters of Sungai Lukut

Proceedings of ISER 10th International Conference, Kuala Lumpur, Malaysia, 8th November 2015, ISBN: 978-93-85832-34-5 10 Zooplankton Community Structure of Sungai Lukut and Its Estuary

SD, standard deviation; DO, dissolved oxygen

Table 5. Results of two-way ANOVA based on density of zooplankton,pH,salinity, temperature and dissolved oxygen. Both tides (spring and neap) and habitats (estuarine, brackish and freshwater) were fixed factors.

*Significant at (p<0.05)

Proceedings of ISER 10th International Conference, Kuala Lumpur, Malaysia, 8th November 2015, ISBN: 978-93-85832-34-5 11 Zooplankton Community Structure of Sungai Lukut and Its Estuary

III. DISCUSSION related to the existence of copepods. According to Rezai et al. (2010) in his study, chaetognatha feed on The dissolved oxygen concentrations were close to copepods and thus their abundance is high in the saturation values was probably attributed to both air areas which high copepods abundance. water exchange and the production of oxygen by Zooplankton abundance was lower during neap tide phytoplankton photosynthesis and varies with floods, but higher during ebbs. The high zooplankton location, season and water depth (USEPA, 2006). abundance may be attributed to lower tidal speed Such differences in spatial and temporal differences which zooplankton can swim against and also that in dissolved oxygen were apparent from the study during neap tide night is darker which reduces losses which showed significant variation with tides (spring of zooplankton to predation (Sponaugle and Cowen & neap) and habitats (estuarine, brackish & 1997). freshwater). Eventhough temperature was significantly different between tides and habitas, Goa CONCLUSION (2006) however stated that it is important in assessing water quality can influence parameter such as pH and Due to the importance of zooplankton in accessing dissolved oxygen which together can alter the the ecosystem, investigation on their community and physical and chemical properties of water. Besides composition are in need especially in Sungai Lukut. temperature, changes in salinity can affect The results of this study provide baseline data on the zooplankton abundance Wickstead (1958) as noted in community structure of zooplankton for upcoming resent study. research and monitoring program particularly in Copepods are the most abundant zooplankton in the Sungai Lukut, Negeri Sembilan. Malaysian coastal waters (Rezai, 2002 ;Idris et al., 1999; Idris et al., 1995). In the coastal and oceanic ACKNOWLEDGEMENTS waters, copepods play a vital role in transferring energy between primary producers towards the higher This work was supported by grant from the Faculty of trophic levels (Idris et al., 1999). According to Peralta Applied Sciences, UITM, Shah Alam. Special thanks et al. (2015) Calanoida are perhaps the most to all the project members for their collaboration ecologically significant organisms at the first throughout the project. consumer level and the most conspicuous among the primary carnivores. REFERENCES Generally, copepods are organisms which are able to act as an indicator for climatic trends (Hopcroft et al., [1] Armorek, D.R. and J. Korman. (1993). The use of 1998). Since copepods have a short life cycle, there zooplankton in a biomonitoring program to detect lake acidification and recovery. Water, Air, Soil Pollution, 69 (3- are indeed the best nominee in the study of ecosystem 4): 223-241. response to climatic variability (Beaugrand et al., [2] Beaugrand, G., Ibañez, F., Reid, P.C. (2000).Long-term and 2000). seasonal fluctuations of plankton in relation to The decapod contributed less than 1% of total hydroclimatic features in the English Channel, Celtic Sea and Bay Biscay. Marine Ecology Progress Series 232, pp. zooplankton but as meroplankton they are the most 179-195. important contributor since benthic communities are [3] Gao, Q. (2006). Correlation of Total Suspended Solids composed of vital decapod populations (Viegas et al., (TSS) and Suspended Sediment Concentration (SSC) Test 2007). The abundance of chaetognatha is closely Methods. In New Jersey Department of Environmental Protection Division of Science, Research, and Technology.

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