Biological aspects of roundscads (Decapterus spp.) inhabiting the waters of Southeast Maluku, Eastern Indonesia

Abstract

This research was conducted at Langgur City, Southeast Maluku Regency, Maluku Province, Eastern Indonesia from November 2020 to February 2021 to study biological aspects of roundscads (Decapterus spp.) which consist of species composition, sex ratio, gonad maturation level, size distribution, length-weight relationship and condition factor. Samples were collected at traditional fish market in Langgur City. Fish samples collected at the market were put into cool box and then brought to the laboratory for further examination. Fish samples were identified, separated based on species, dissected to determine their sex and gonad maturation stage and then measured. Totally, there were 290 specimen collected which consist of five species namely Decapterus kurroides, D. macarellus, D. macrosoma, D. muroadsi and D. russelli. Sex ratio between male and female for all species showed 1:1. Gonad maturation level showed that stage I and II have higher percentage than stage III and IV indicates immature fish more dominant compare to mature one. Among five species found, D. macarellus has larger size while the smaller belongs to D. muroadsi. Results of length-weight relationship analysis showed that roundscads inhabiting Southeast Maluku waters have isometric and negative allometric growth pattern with relative condition factor around 1.00.

Biological reproduction of mackerel scad, Decapterus macarellus (Cuvier, 1833) caught by purse-seine net in Majene Waters, West Sulawesi, Indonesia

“…This is a different matter, whereas in other studies, a balanced sex ratio of 1:1 was obtained, such as D. ruselli in Ambon Island (Ongkers et al 2016), mackerel scad in Ambon Bay (Genisa 1998), Pemangkat Fish Port, West Kalimantan (Faizah and Sadiyah 2020) and Decapterus spp. inhabiting the waters of Southeast Maluku, Eastern Indonesia (Ajub et al 2022). A female-biased sex ratio and the first size of sexual maturity in Megalaspis cordyla Linnaeus, 1758 member of the family Carangidae reported (Qamar and Panhwar 2018) whereas the male-dominated population of Scomberoides commersonnianus Lacepède, 1801 and Scomberoides tol Cuvier, 1832 in Pakistan was gathered (Qamar et al 2020).…”