Aquatic Insect Drift At Rocky Substate Of A Small River In Ranchan Recreational Park, Serian

Population composition of aquatic insects in a small river in Ranchan Recreational Park was studied. Samplings were carried out for 6 times to study the pattern of aquatic insects in the river. The samplings were carried out for 24 hours. Surber sampler was used to collect the samples of aquatic insects in the small river. Water quality variables such as pH, dissolved oxygen, water velocity, water discharge, water depth and total suspended solid were significantly associated with the abundance of aquatic insects. A total of 553 individuals comprising 7 orders of aquatic insects were recorded throughout the sampling period. The drift was dominated by Ephemeroptera followed by Trichoptera, Plecoptera, Diptera, Coleoptera, Odonata and the least was Hemiptera. Sampling 4 has the highest taxa diversity with 7 orders of aquatic insects and highest number of aquatic insects. Sampling I has the highest taxa richness of aquatic insects as the abundance of individuals in every order is highest. Ephemeroptera, Plecoptera and Trichoptera (EPT) are used as the biological indicator. High number of this organism in the river shows a good quality of water in the small river of Ranchan Recreational Park. Low number of less-sensitive order Diptera could be an indication of no pollution occurred in the small river