BIODIVERSITAS ISSN: 1412-033X Volume 23, Number 4, April 2022 E-ISSN: 2085-4722 Pages: 1875-1883 DOI: 10.13057/biodiv/d2304xx Fish behavior based on the effect of variations in oceanographic condition variations in FADs Area of Bone Bay Waters, Sulawesi, Indonesia ARHAM RUMPA 1, , NAJAMUDDIN 2 , SAFRUDDIN 2 , MUHAMMAD ABDUH IBNU HAJAR 2 1 Doctoral Program in Fisheries Science, Faculty of Marine Science and Fisheries, Universitas Hasanuddin. Jl. Perintis Kemerdekaan Km. 10, Makassar 90245, South Sulawesi, Indonesia. Tel./fax.: +62-411-586025,  email: arhamrumpa@gmail.com 2 Faculty of Marine Science and Fisheries, Universitas Hasanuddin. Jl. Perintis Kemerdekaan Km. 10, Makassar 90245, South Sulawesi, Indonesia Manuscript received: 3 February 2022. Revision accepted: 20 March 2022. Abstract. Rumpa A, Najamuddin, Safruddin, Hajar MAI. 2022. Fish behavior based on the effect of variations in oceanographic condition variations in FADs Area of Bone Bay Waters, Sulawesi, Indonesia. Biodiversitas 23: 1875-1883. Fish behavior is the response of fish to conditions existing in their environment. One of the causes is oceanographic factors, which can affect the schooling movement of fish. This study aimed to identify the schooling behavior of fish based on the influence of oceanographic variations in the Fish Aggregating Device (FADs) area. Study took place from March to September 2021 in Bone Bay Waters, Indonesia. The type of research was experimental fishing with an acoustic approach for 57 times. Parameters observed were current velocity, current direction, and water temperature to the distance of schooling fish from FADs vertically and horizontally in the afternoon, evening, night, and early morning. The behavioral data of fish species were namely Decapterus russelli. The results showed namely the variation in current velocity affected the horizontal distance; variation in the direction of currents affected the horizontal distribution distance, while the water temperature affected the vertical schooling of fish. In the operation of fishing gear, especially in the early morning, in terms of the concentration pattern of schooling fish under FADs. The ideal current velocity was in the range of 0.2-0.29 [m s -1 ], while the ideal current direction is direct current was at the angle of 0°-60°. The schooling of fish approached to the surface and was concentrated under FADs at >30°C. Understanding on the distribution of horizontal and vertical movements and the time of concentration of fish schooling at the central point of FADs due to oceanographic variations will facilitate the effectiveness of fishing gear operation. Keywords: Current, FADs, fish behavior, temperature, schooling INTRODUCTION There are a lot of Fish Aggregating Device (FADs) in Bone Bay waters which are spread from the mouth to the base of the bay. Indirectly, the presence of these FADs greatly affects the distribution pattern or distribution of pelagic fish that reside or migrate out of or into the waters. The habit of fishermen in the waters of Bone Bay in determining whether the FADs area has a lot of fish or not is observing the fish under the FADs visually during the day. If there is no schooling of fish, the fishermen will go to other FADs. This procedure is not necessarily true and it is possible that the schools of fish are located vertically and horizontally away from the FADs area due to variations in oceanographic factors such as currents (Véras et al. 2020) and water temperature (Orue et al. 2020). On the other hand, although there is much fish at certain times, the setting and hauling fishing gear are difficult to fully concentrate under the FADs area, causing fish catches to be less optimal. Effectiveness of the fishing gear operation by utilizing FADs aims to attract fish to associate with them to facilitate catching (Dagorn et al. 2013; Albert et al. 2014; Chaliluddin et al. 2018; Hamar and Bone 2021), but on the other hand, not all FADs have good productivity. Some FADs are abundant and some are poor in fish resources (Yusfiandayani 2013; Matrutty et al. 2019; Sarianto et al. 2019). This is strongly influenced by variations in oceanographic changes causing schools of fish to appear in the FADs area (Dempster and Taquet 2004; Capello et al. 2012). Several studies have tried to examine the effect of oceanographic parameters such as surface temperature, currents, salinity, and chlorophyll-a concentration based on remote sensing and geographic Information systems (Arrizabalaga et al. 2015; Ghufron et al. 2019; Seloi et al. 2019) and information based on local knowledge of fishermen (Moreno et al. 2007; Macusi et al. 2017; Jauharee et al. 2021), including the use of GPS buoys to FADs (Irineo et al. 2014; Lopez et al. 2014; Maufroy et al. 2016), providing initial information on potential pelagic fishing zones and habitat distribution of fish in the fishing ground. The results of this study also provide a general description of the influence of oceanographic parameters on fish distribution, but the scope of the research is still for a large area and has not been able to provide a more specific description of the behavior of fish in the FADs area itself as a media for purse seine catching aids. General description related to the distribution of fish species around FADs has been studied for several years, such as the certain location of depth, especially tuna (Forget et al. 2015; Matsumoto et al. 2016; Lopez et al.