Gonad Maturity Development of Shortfin Scad (Decapterus macrosoma, Bleeker 1851) Landed at the Fish Landing Base, Kedonganan Bali

Abstract

The shortfin scad (Decapterus macrosoma Bleeker, 1851) is the small pelagic fish which is caught in the Indonesian Water. The sustainability of shortfin scad should be maintained because it has high economic value in Indonesian marine fisheries sector. Sustainable efforts on managing shortfin scad’s resources closely relate to the biological reproductive aspect. The objective of this study was to determine the gonad maturity development of shortfin scad landed at the fish landing base (PPI) Kedonganan, Bali. Sampling was carried out from November 2020 to January 2021 six times using a random sampling method. The ovary preparation uses paraffin method and Haematoxylin-Eosin staining. The parameters measured includes sex ratio, gonad maturity stage (GMS) according to morphological and histological analysis, oocyte diameter, gonadosomatic index (GSI), and length at first maturity. The result shows that the sex ratio of shortfin scad was balance. Morphological analysis shows that the immature (GMS I-II) and mature (GMS III-IV) females were found in every month of the sampling period which indicates that shortfin scad had protracted breeding season. Histological analysis shows that shortfin scad was at GMS I-VI. The oocyte development organization in the ovary was asynchronous and the oocyte diameter varied from 28,45-439,03 μm indicating that shortfin scad was partial spawner. The highest GSI value occurred in January. GSI ranged from 0,049-4,946% and the value increased along with enhancement of GMS. The female shortfin scad reached first maturity at a fork length of 16,91-17,63 cm