THESIS 2 - DIVERSITY AND FEEDING GUILDS OF FISH POPULATIONS IN PENGKALAN GAWI – PULAU DULA SECTION OF TASIK KENYIR TERENGGANU, MALAYSIA

Kamaruddin, I.S. (2011). Diversity and feeding guilds of fish populations in Pengkalan Gawi - Pulau Dula section of Tasik Kenyir Terengganu, Malaysia. Master of science thesis. Universiti Putra Malaysia. 94p.    

CHAPTER 1

INTRODUCTION

The need for hydroelectric power, irrigation, flood mitigation, drinking water and recreational opportunities has led to the construction of many reservoirs. According to Yusoff et al. (1995), most reservoirs were constructed for non-fisheries purposes but many of them contribute to food as well as recreational fisheries. In Malaysia, there are 63 large reservoirs with a total storage of 25 billion m³ ranging in size from 10 ha for Mahang Reservoir to 37,000 ha for the Kenyir Reservoir (Makhlough, 2008).

Dams and reservoirs in Malaysia which are constantly increasing in numbers play an important role not only in electric and water supply but also in providing a source of fish to the local community, sustainable aquaculture and maintenance of fish diversity. The aborigine depends on the freshwater fishes as their main source of protein and the local people depend on the lakes for their livelihood by fishing and servicing tourists. Thus, the initiation of reservoir fisheries could offer a significant contribution to fish production and socioeconomic development of local communities (De Silva and Davy, 2009).

Besides that, fishes that live in the reservoirs play important roles in maintaining and stabilizing the lake ecosystem. They act as primer and secondary consumers and were found in all trophic level in the food web including omnivorous, herbivorous and carnivorous fishes. The primer consumer fishes feed on plant, plankton and benthos as their diet and at the same time they are actually a prey for the secondary consumer. The availability and abundant of these fishes also could influence on the stability of aquatic food web where usually the primary consumer are found to be more abundance from the secondary consumer in aquatic ecosystem. 

Tasik Kenyir (Lake Kenyir) is one of the aquatic ecosystems that can be found in Malaysia, is actually a reservoir that was inundated due to the dam construction for hydroelectric power. Since its inundation, Tasik Kenyir has generated various socio-economic activities for the local people and recreational fishing activities for the tourists, and is known as a paradise for anglers. Tasik Kenyir is an important source of freshwater fish where major fish species landed are tinfoil barb (Lampam Sungai), Barbodes schwanenfeldii, Hampala barb (Sebarau), Hampala macrolepidota, river catfish (Baung), Hemibagrus nemurus, and giant snakehead (Toman), Channa micropeltes.

However, the freshwater fish catch in Tasik Kenyir have declined over the past few years. Jackson and Marmulla (2001) reported that an annual catch of 720 metric tonnes of fish in Tasik Kenyir. This figure was calculated based on Yusoff et al. (1995) findings which has reported a yield of 20 kg/ha/year. This figure however declined in 2007 where the estimated fish production as reported by the Department of Fisheries Malaysia was only 105.13 metric tonnes.

It is believed that over exploitation and habitat degradation have depleted the fish stocks in the reservoir. Excessive exploitations by the local community as food sources might affect the composition of fish population in the lake and resulted in overfishing. The numbers of fish within many major species have been reduced by the use of gill nets, cast net and fish traps by these people in Tasik Kenyir. The depletion in fish stock has also been linked by the destruction of fish habitat. Pressure in the water catchment area such as development of tourism activities, logging activities and land degradation from plantation agriculture resulted in siltation and pollution which effect fish habitat and biodiversity looses.

Hence, a concerted effort in Tasik Kenyir is required in order to maintain the fish sources at a sustainable level. Study on the biology of fishes is important in providing information on the management and conservation programmes. Study on fish species diversity and their feeding habits are needed to characterise present status of the Tasik Kenyir fishery. In addition, detailed and comprehensive studies on the fish population in Tasik Kenyir are still lacking. It is partly for this reason that we are inspired to conduct the current study on Pengkalan Gawi – Pulau Dula section in Tasik Kenyir so as to determine the current conditions of the lake.

The findings from this study are expected to provide some useful inputs for fishery management in the lake. Maybe in the future Tasik Kenyir could be a premier and yet a sustainable recreational fishing waters in Malaysia.

The objectives of this study are:

1.             To determine the number of species of fish in Pengkalan Gawi – Pulau Dula section of Tasik Kenyir and the diversity of these species within the fish population of the lake. 

2.            To determine the feeding habits of fish species in the fish population of Pengkalan Gawi- Pulau Dula section of Tasik Kenyir.