Biological aspect of redtail scad (Decapterus kurroides) in the waters of Tulehu, central Maluku Regency, Maluku Province, Indonesia

Abstract

Research on the biological aspects of redtail scad (Decapterus kurroides) including sex ratio, size distribution, size at first catch, length-weight relationship and condition factors was conducted in Tulehu, Ambon Island, Maluku Province Indonesia in January – June 2025. Fish samples were collected randomly every month from the catches of handline fishermen in Tulehu waters. The collected fish samples were measured for total length, weighed and their sex was determined morphologically. During the research, 806 individuals were collected consisting of 422 males and 384 females. In total, the male to female sex ratio showed a 1:1 ratio although in certain months there were deviations from the 1:1 ratio. The total length ranges from 12.0 – 31.3 cm (? = 23.0.5 ± 3.33 cm) while the weight ranges from 18.6 - 272.2 g (? = 121.10 g ± 49.19 g) where the dominant of fish caught is in the mid-length range of 20.5 – 25.5 cm with the size at first captured, Lc = 22.9 cm. The length-weight relationship shows that there is no deviation from the cubic system (b = 3) which means the growth pattern is isometric or the increase in length of the fish is proportional with the increase in weight. The results of the condition factor analysis show that the relative condition factor value ranges from 1.0 – 1.1 which indicates that red tail scad (D. kurroides) and the waters of Tulehu are in good condition so that it allows the fish to grow and reproduce.