DIVERSITY OF LEIOGNATHIDAE FISH COMMUNITY IN HIGH TEMPERATURE WATERS AROUND BONTANG INDUSTRIAL ESTATE IWAN SUYATNA, A. SYAFEI SIDIK, ISMAIL FAHMY ALMADI, SAMSUL RIZAL KOMSANAH SUKARTI Faculty of Fisheries and Marine Science, University of Mulawarman, Jl. Gunung Tabur, Kampus Gunung Kelua, Samarinda 75116, Esat Kalimantan, Indonesia Tel./Fax.: 0541-748648; HP 081347935111. E-mail: isuyatna@ymail.com INTRODUCTION Bontang City geographically stretches between 117 o Ϯϯ aŶd ϭϭϳ o ϯϴ E aŶd Ϭ o Ϭϭ aŶd Ϭ o ϭϮ N, aŶd lies between Mahakam Delta and Sangkulirang Bay, East Kalimantan. Defined as a centre for petrochemical industries receiving raw gas materials by piping from oil and gas exploitation in the Mahakam Delta, the coastal zone of Bontang City continuously transforms with new constructions such as industrial plants, reclamation, ports, and channel dredging (Suyatna and Sidik, 2013). Commonly, industrial estate uses sea water to cool their machines and others involved, and discharge it to the sea after it has become heated. Higher water temperature not only accelerates biological and chemical processes in the sea, ďut also reduĐiŶg the ǁaters aďility to retaiŶ dissolved oxygen. This can affect fish life such as growth, reproduction and distribution. However, the environmental factors change according to day/night, the tidal cycle and climatic change (Lam et al., 2005). Hot water flowing from the outlets of industries is already subject to the rising of sea water temperature in Bontang City and may harm fishes. A result of the study on diversity of Leiognathidae fish community in high temperature waters around Bontang industrial estate was performed. AIMS OF THE STUDY The study aimed at knowing fish diversity and density of Leiognathidae fish community in high temperature waters around Bontang industrial estate. MATERIALS AND METHODS The study was undertaken between January and February 2013 in Guntung village, Bontang Utara subdistrict. Fishes were collected in spring tide during both high water level (HWL) and low water level (LWL) and in neap tide around the cooling water outlet using a net with size of 10 m length and performed by a motorized boat sizing 8m x 2m x 1.5m (minitrawler) to tow the net. Towing time varied from 5 to 15 minutes. To find fish density, the sǁeft area or the effeĐtiǀe path sǁept (Can et al., 2006) was used : a = D.h.X, where h is the length of the head-rope, D is the cover of distance. X is the fraction of the head-rope length. The value of X varies from 0.4 to 0.66. It is suggested that X = 0.5.