The Effects of Oil Palm Plantation on Fish Composition in Selangor Peatlands, Malaysia

Abstract

The cultivation of oil palm on peat swamps in Malaysia has changed the water quality and aquatic ecosystems. We determined the fish species composition and water quality conditions at a disturbed peat swamp, i.e., oil palm plantation, in Kuala Langat peat swamp reserve forest, Selangor. Fishes were collected via gill net in five selected drains during dry and wet seasons between August 2014 and January 2015. In-situ (electrical conductivity (EC), dissolved oxygen (DO), pH, turbidity and temperature) and ex-situ (dissolved organic carbon (DOC)) physicochemical parameters of water quality were measured bimonthly. The length-weight relationship (LWR) of fish related to seasonal and spatial variation was also examined. A total of 336 individuals belonging to five families of fish were found with Trichopodus trichopterus and Anabas testudineus were the two abundant species. The DOC ranges at drainage with established palm trees area (i.e., 15-yo(A) 1^stG, 3-yo 2^ndG, and 9-yo 2^ndG) was much greater than at cleared-felled (CF 2^ndG) suggested that these plantation areas have carbon leaching due to high supply of labile leaf litter produced by palm trees. The observed EC and temperature were 5% higher in the dry season compared to the wet season. The A. testudineus showed highly adaption with high DOC levels particularly in 15-yo 1^stG, and 9-yo 2^ndG drains during the wet season. The LWR showed that A. testudineus was in a desirable growth rate and demonstrated they were doing better compared to T. trichopterus in the oil palm plantation system.