Physicochemical Parameters and Fish Assemblages in the Downstream River of a Tropical Hydroelectric Dam Subjected to Diurnal Changes in Flow

Lee, Nyanti and Noor Iskandar, Noor Azhar and Soo, Chen Lin and Ling, Teck Yee and Sim, Siong Fong and Jongkar, Grinang and Tonny, Ganyai and Lee, Karen Suan Ping (2018) Physicochemical Parameters and Fish Assemblages in the Downstream River of a Tropical Hydroelectric Dam Subjected to Diurnal Changes in Flow. International Journal of Ecology, 2018. pp. 1-9. ISSN 16879708

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Abstract

Te downstream river of the tropical Batang Ai Dam is experiencing diurnal fow fuctuation due to power generation operation. Tree samplings were conducted to collect the water quality and fsh assemblage data and one sampling was conducted to study the hydrological characteristics of the downstream river. Te results show that the downstream river is extremely shallow and moves slowly when the power generation is halted and no water is discharged from the powerhouse. Signifcant correlations between river fow and pH, dissolved oxygen (DO), total suspended solids (TSS), and fve-day biochemical oxygen demand (BOD5) indicated that those parameters were infuenced by the water discharge regulation. Fish abundance was low in upstream segment but it gradually increased as distance from the dam increased and was signifcantly correlated with DO. Fish diversity in the downstream river was infuenced by the river depth and chlorophyll a concentration. Te most abundant fsh species, Cyclocheilichthys apogon, exhibited a negative allometric growth pattern, while Hampala macrolepidota and Hemibagrus planiceps exhibited an isometric growth pattern. Fulton’s condition factor (�) values for 89.4% of H. planiceps were ≤1, indicating poor to extremely poor conditions.

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