Community Ecology of Freshwater Fish in Relation to Environmental Variables in Murum Hydroelectric Power Dam, Belaga, Sarawak
This study was aimed to evaluate the effects of environmental variables specifically, dam impoundment, riparian zone and water quality on the fish assemblages, growth, and their spatial shift in diet at upstream and downstream of the reservoir, as well as to document fish succession in Murum rese...
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| Format: | Thesis |
| Language: | English |
| Published: |
Universiti Malaysia Sarawak, (UNIMAS)
2022
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| Subjects: | |
| Online Access: | http://ir.unimas.my/id/eprint/38694/2/Angie%20Sapis%20ft.pdf http://ir.unimas.my/id/eprint/38694/ |
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| Summary: | This study was aimed to evaluate the effects of environmental variables specifically, dam
impoundment, riparian zone and water quality on the fish assemblages, growth, and their
spatial shift in diet at upstream and downstream of the reservoir, as well as to document fish
succession in Murum reservoir. As the impoundment of Murum reservoir starts, the stream
ecosystem, type of habitats and water quality gradually change as the environment changes.
Samplings were conducted from May 2014 to December 2015 at four areas located in the
vicinity of Murum Dam: downstream of Murum River, Dam site, inundated areas of Pleiran
River and Danum River. Water quality and fish fauna were studied. Types of land uses,
riparian habitat characteristics and other environmental variables were also enumerated, and
were found to be spatially and temporally different. Fish fauna samplings were carried out
at 17 stations by using three-layered nets, monofilament gill net of various mesh sizes and
electroshocking technique. Land use changes and degradation of riparian zone in Murum
catchment were shown to have influences on water quality and eventually affecting fish
communities of the newly impounded reservoir. In the case of newly impounded Murum
reservoir, the two major catchments of the reservoir, Pleiran and Danum, have shown
significant disturbances due to logging, forest and oil palm plantations and subsistence
farming. Two-way Analysis of Variance (ANOVA) showed that there are significant
differences (p<0.05) in quality of upstream and downstream waters of Murum Dam at spatial
and temporal scales. A total of 8773 fish individuals representing 58 species belonging to
11 families were caught from stations below and above Murum Dam. Fish populations were
dominated by the family Cyprinidae (63.6%). The highest number of species was recorded
in downstream of Murum River with 34 species, followed by inundated area of Pleiran River
(31 species) and the dam site (25 species). The lowest number was recorded at the inundated
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area of Danum River (23 species). Overall, Oreochromis niloticus was the most numerically
abundant species (33.0%) and is widely distributed in the whole area. This is followed by
Barbodes binotatus which comprised 16.8% of the total individuals caught. About 20 fish
species were indicators for the whole Murum catchment at different impoundment or filling
phases. Composition and assemblages of fish were influenced by fluctuation of water level,
conductivity, Chl-a, and BOD5. This study also found that the growth of B. binotatus, O.
niloticus, Hampala bimaculata, Barbonymus collingwoodii, and Lobocheilos falcifer varied
at spatial and temporal gradients. The growth of the fish declined from positive allometric
growth to negative allometric growth, throughout the impoundment and as water level
fluctuates. Temperature, conductivity, pH, turbidity, dissolved oxygen, total suspended
solids, Chl-a, transparency and water level are physicochemical parameters that contributed
to the variation in fish growth in Murum waters. Stomach content analysis showed that H.
planiceps, H. bimaculata, H. macrolepidota and C. apogon consumed a wide range of foods
and Wi was highly loaded with small predators thus suggest that they are carnivores. Tor
douronensis and Barbonymus schwanenfeldii are classified as omnivores. The feeding habit
of O. niloticus and P. waandersi was best represented by aquatic plant, detritus and digested
items and are categorised as herbivores. The results imply that conversion of forested area
at riparian corridor to open area and fluctuation in water level has led to changes in
physicochemical characteristics, and subsequently might have resulted in habitat partitioning
by the fish species according to their environmental tolerance limit |
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