Abstract
Lemuru (Bali sardine) fisheries in the Bali Straits, Indonesia play significant role in fishing industry in the area bordering this cone shape strait In this paper we report and analyze the behavior of Lemuru fish school based on acoustic survey as an attempt to shed light on its spatial aggregation and its geometrical principle dimension and swimming speed. The survey was carried out in September 1998 and August 2000 using split-beam acoustic system capable of determining the position of individual fish, hence, the fish school. There are 31 schools of Lemuru and more than 9, 000 individual fish that occupy different depth in the water column was analyzed. The results shows that the geometrical dimension of the schools have high variability and smaller mean school density compare to typical sardine school. In terms of dynamic behavior of the fish, the swimming speed of Lemuru is found to be dependent on the fish target strength, depth and time of the day.
