The Size and The Shape of Sagittal Otolith of Redtail Scad, Decapterus kurroides Blekeer 1855 from Kema Bay, North Minahasa Regency, North Sulawesi, Indonesia

Abstract

This study aimed to examine the difference in the otolith size and otolith shape of redtail scad Decapterus kurrodes between sex in North Sulawesi. The otoliths of D. kurroides were studied for sagitta otolith pair samples of 34 juveniles,   58 females and 75 males from Kema Bay. These pairs sagitta otolith images were interpreted using ImageJ tool to describe the otolith size (length, width, perimeter, and area), then we calculated the shape index (form factor, roundness, circularity, rectangularity, ellipticity and aspect ratio or length-width ratio). No significant difference was found in otolith length between left and right otoliths of juveniles of D. kurroides or called symmetrical but significant differences or asymmetrical were found in all sample, females and males. The regressions of total length against otolith sizes (otolith lengt, otolith width otolith perimeter and otolith area of D. kurroides follow a power function. The growth patterns showed dominant allometric growth in total length–otolith sizes relationships of D. kurroides from Kema Bay, Key Words: size, shape index, otolith, Decapterus kurroides, Kema Bay.