Otolith Shape Indices of Japanese Threadfin Bream (Nemipterus japonicus, Bloch 1791) from the Makassar Strait, Indonesia

Japanese threadfin bream (Nemipterus japonicus) is a demersal fish that plays a very important role in maintaining ecosystem stability related to webs and food chains. This fish often becomes prey for predatory fish. In efforts to reveal the relationship between predators and prey in food webs and food chains, there is still limited information due to the difficulty of identifying digested food. In connection with this, this study aims to identify the morphology shape index value otolith of Japanese threadfin bream. Sampling was carried out at the Labuang Maros Fish Landing Site with 150 samples and morphometric data were collected from 150 pairs of otoliths in April and May 2023. The calculation of the shape index uses six descriptors, which include form factor (FF), roundness (RO), circularity or compactness (C), rectangularity (Rt), ellipticity (E), and aspect ratio (AR). The results showed that there was no significant difference in the otolith morphometry of the right and left otoliths (P>0.05). Based on the shape index value obtained, it explains that the morphometric shape of the otolith of Japanese threadfin bream tends to be oval, elongated, and has an irregular surface.