FISH AND WATER QUALITY SURVEY IN PAYA INDAH WETLANDS SANCTUARY

Zulkafli Abd-Rashid and Zahari Awang
Freshwater Fisheries Research Center
Batu Berendam 75350, Malacca
e-mail: zulbar@pc.jaring.my

Abstract

A 5-months survey of fish species found in Paya Indah Wetlands Sanctuary (degraded ex-tin mining area) was carried out together with the water quality analysis. A total of 16 fish species were caught using gill nets, cast nets, scoop nets and electro shocker. The four most abundant fish species are Notopterus notopterus; Mystus vittatus; Trichopterus trichopterus; and Oreochromis mosambicus with 37.1%; 31.2%; 13.5% and 8.1% of the total number of fish caught (1917 nos.) respectively. A rare Clariidae family, Clarias teijsmani were also caught. Two other species, which are found in more alkaline waters, Esomus malayensis and Chanda siamensis were also caught in two of the lakes in Paya Indah Wetlands Sanctuary. The pH of the water in Paya Indah ranges from pH 3.6 to pH 6.7. The oxygenated water column is less than 3 m. in all the water bodies studied but one, in which the whole water column (7 m deep), was well oxygenated (7.3 mg/l). The average phosphate level ranges from 0.006 mg/l to 0.31 mg/l. in all the water bodies studied. The fish composition in relation to the water quality is discussed.

Keywords: Weylands, fish composition, water quality

Introduction

Peat swamps is one of the freshwater habitats present in Malaysia. It is spongy, water–laddened substrate as a result of decayed matter (plant materials), clear brownish-colored water and appears black when view under reflected light. Peat swamps are extreme habitats for any organism, with low oxygen levels, low calcium content and high acidity. In the past, many biologists felt that peat swamps had a rather low biodiversity and productivity (Johnson, 1968).Kottelat & Whitten (1993) has estimated that there are 900-1000 freshwater species present in South-East Asia. About 300 fresh-water species are expected from Peninsular Malaysia (Lim et al., 1993). Some 55 species of peat swamp fishes of which about 60% are stenotopic are known from Peninsular Malaysia. The North Selangor Peat Swamp Forest is the most well-studied area in which 48 peat swamp fishes were known (Ng et al., 1992, 1994). Species, which were rare such as Encheloclarias, Bihunichthys, Betta and Parosphromenus, were identified and recorded (Ng & Lim 1993; Ng & Kottelat, 1992, 1994; Kottelat & Lim 1993, 1994).

Far from being a depauperate ecosystem, peat swamps possess an interesting fish fauna, which is diverse and unique having narrow niches and restricted ranges. Tin dredging activities in Dengkil, Selangor has created a large water bodies.The numerous and relatively deep disused mining pools provide new homes for the indigenous fish species from the neighbouring streams and canals to colonize. These species are vulnerable and thus facing risks as peat swamp areas are being cleared. Knowing the importance of conservation of fish species and rehabilitation of degraded ex-mining peat swamp, Department of Fisheries together with Malaysian Wetlands Foundation, initiated a 5 months survey of fish species and the study of physicochemical properties of Paya Indah Wetlands Sanctuary. Only when we know what is present can proper plans and decision be made and reasonable conservation established.

Area Profile

Paya Indah Wetlands Sanctuary covers an area of 3200 ha. in Kuala Langat, Selangor. The area encompass a myriad of ecosystems such as degraded tin-mine land, logged peat swamp forests, large open lakes and it is the northern part of the Kuala Langat North Permanent Forest Reserve (a peat swamp forest).

The degraded ex-mining land consists of many large parts where embankment has been established. The area presented a mix of ecosystems for a diverse range of flora and fauna and is habitats for bird population both local and migratory.

The wildlife in this area is representative of lowland forest habitats. The dominating swamp forest is reflected in the bird and human profile: 131 species of birds and 26 species of mammals were recorded within the area (Nor Hisham Pers. Comn).

The area is also a green lung of the Multimedia Super Corridor due to its strategic location 30 km south of Kuala Lumpur, 12 km west of Putra Jaya, 15 km north of Kuala Lumpur International Airport and the nearest town Dengkil, is 4 km away. (Fig. 1& 2).

Fig.1    Location of Paya Indah Wetlands Sanctuary and the surrounding areas.

Materials And Methods

Fish sampling

Fish samplings were carried out by 4 different methods; gill nets, cast-net, scoop net and electro shocker. Gillnetting was done by using a gang of 5 panels nets of various mesh-sizes (31.75mm, 38.10mm, 44.45mm, 50.80mm, and 63.50mm) with the total length 150m(30m per panel) and 3m deep. Nettings were carried out in 8 lakes. Nets were set at 6.00 pm and lifted at 8.00 am the next morning. The fish caught were segregated for identification and enumeration of various species. Data on the total length (cm) and weight (gm) were recorded.

Net casting were done along the canal by using a cast-net of mesh-size 31.75mm and 360cm long. Electro-fishing were also carried out from the boat near the fringe of the lakes. Catching with scoop net was done along the shallower areas of the lakes. These activities were carried out between 10.00-12.00 am and 3.00-5.00 pm. The fish caught were segregated for identification and enumerated and released back to the water.

Water sampling

Water samples were collected in the morning at two different depths (surface and bottom). Samples were kept in polyethylene bottles and kept in cooler box for further analysis at the base camp. Spectrophotometric analyses were conducted for the ionic contents such as iron (Fe), ammonia nitrogen (NH₃-N), nitrate (NO₃-N), phosphate (PO₄), and sulfate (SO₄) using the HACH DR2010 Spectrophotometer. (Based on the APHA Standard methods). Conductivity and pH were recorded by using the HACH CO150 Conductivity meter and the HACH EC10 pH meter respectively, while the total hardness and alkalinity were determined by titration. In-situ dissolved oxygen and temperature profiling were also conducted using the YSI 58 Oxygen Meter.

Abbreviation used:     

Results and Discussion

Physico-chemical Properties of lakes water

Physico-chemical Properties of 9 lakes in Paya Indah Wetlands Sanctuary are shown in (Table 1). There are differences in the water quality of the lakes. The conductivity showed a relatively narrow range except in two lakes with high concentration of 145 and 185 mS/cm. In term of nutrient availability, the nitrate concentrations in all the lakes studied, are low (< 0.2 mg.L^-1). The orthophosphate concentrations are very low except in lakes L13 and L7 where the values are relatively high compared to the other lakes.

Table 1            Summaries of water quality parameters for some of the lakes in Paya Indah Wetlands Sanctuary (mean values)

*Data from surface water

The oxygenated water column in the lakes is shallow between 2-3 m (Table 2), except in lake L13where the whole water is well oxygenated. The shallowness of the oxygenated water column is reflected in the low secchi disk values in all the lakes studied except one, thus photosynthesis occur in a limited water column. An exception occur in lake L13 where the water is crystal clear with secchi disk value reaches >6.0 m.

Peat swamp areas are usually identified by the low pH values of their water bodies. The water pH varies from pH 3.60 to pH 7.15. The lakes can be classified into 4 groups according to the water acidity; pH >7.00 (L7), pH 6.19-6.66 (L8, L14, L5, L11), pH 4.30-4.93 (L3, L6, L4) and pH 3.60 (L13). Acidification in peat swamp areas is mainly caused by pyrite oxidation, where pyrite reacts with oxygen and water to release acidity, iron and sulfate.

The water chemistry in the studied lakes could be governed by different buffering system: the circumneutral bicarbonate buffer and the acidic aluminum and iron buffer in which aluminum buffer prevail in a region of pH 3.6-4.2 (Klapper et. al, 1996).

It seems that at pH <4 hardly any life can be expected. Nevertheless, this extreme habitat, as shown in lake L13, has been colonized by specialists. Organisms, which are able to survive in this extreme condition, possess mechanism for the detoxification. Some algae are known to concentrate toxicants in terminal cells, which are later discarded (Luderitz, 1988 cited in Klapper et al., 1996). Compared to other freshwater bodies, the water bodies in peat swamp areas generally low in primary productivity. This is related to the shallowness of the euphotic zone in the water bodies. Hence, the algal biomass is expected to be low and based on this criterion alone, the water bodies can be classified as ‘oligotrophic’. In the case of lake L13, low primary production is unexpected, given the relatively high phosphorus values. Obviously factors other than nutrients limit the primary productivity. Besides the algal development, heterotrophic degradation is inhibited in acidic environment. Low respiration rates and low solubility of CO₂ in acidic waters seems to be the reasons for low primary productivity in the water bodies (Ohle, 1991; Schindler, 1994).

Table 2    D.O  and temperature profile for some of the lakes in Paya Indah Wetlands Sanctuary . Temperature values in parentheses

Fish Community

Table 3 shows that, there are 17 species of fish from 11 families were found and identified. The identifications were based on Smith, 1965; Mohsin & Ambak, 1983. There are 16 species found in the lake ecosystem and 12 species in the canal ecosystem. Apparently, higher fish diversity in the lake ecosystem due to the present of greater number of habitats as compared to the canal ecosystem. The lake ecosystems, provide wider range of habitats which in turn increase the living space of the littoral zones which resulted in abundance of prey and hence predator species (Aggus & Elliot, 1975; Ali, 1981).

Table 3      Comparative checklist of  fish species caught from the Paya Indah wetlands Sanctuary at different lakes as well as in the canal systems.

Higher fish species diversification were observed in lake L3, L11and L14 with 10, 11 and 11 species of fish respectively. These lakes have a range of pH >6. The lowest fish diversity were in lake L13 and lake L6 in which the pH values are pH 3.6 and pH 4.9 respectively

A total of 1917 nos. of fish were caught during the 5 months survey (Table 4). Notopterus notopterus forms the majority of the population (37.1%), followed by Mystus vittatus, Trichogaster trichopterus and Oreochromis mossambicus with percentages 31.2%, 13.5% and 8.1% respectively. These four species form about 90% of the fish community in the Paya Indah peat swamp ecosystem (Fig. 3). Majority of the species composition are carnivorous in nature feeding mainly on insects and inverterbrates. The higher order predators are few, such as Notopterus and Chana.

Conclusion

Peat swamp areas are complex ecosystem characterized by high biodiversity and sensitive to environmental perturbation. In Paya Indah Wetlands Sanctuary, the lakes (or ex-mining pools) are without substantial water flow, they are usually stratified in the reduction of dissolved oxygen below 2-3 m level. The living space for fish is generally limited to only the top layer. Therefore it is imperative that proper management of peat swamp lakes be implemented in order to ensure the continuity of their biodiversity as well as sustainability of the resources.

Although stocking and introduction programmes can be carried out to supplement poor fish stocks, species to be introduced should be carefully studied prior to the introduction since unsuitable species can results in declining biodiversity of the indigenous. At present, exotic species such as tilapias have been able to colonize and thrive in some of the lakes and canals. As far as possible, only the indigenous species present in the area should be stocked to enhance the population.

It is unrealistic to expect all areas in the Paya Indah Wetlands Sanctuary to be conserved, thus compromise has to be made. Conservation should center on trying to conserve unique habitats and areas that have a high biodiversity.

Acknowledgement

Funds for this survey were provided by the Department of Fisheries. Ancillary facilities were provided by Freshwater Fisheries Research Center and Malaysian Wetlands Foundation for the supply of sampling boat. We thank the Director General, Department of Fisheries, Dato’ Mohd. Mazlan Jusoh for his initiative and interest shown in this survey and conservation of fish species in inland water bodies in general. We also thank the staff of Freshwater Fisheries Research Center, especially to En. Ramley Abu Bakar and En. Nor Azman Zakaria for their help during the survey.

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