A preliminary study on the size structure and sex ratio of orange-spotted grouper (Epinephelus coioides Hamilton, 1822) harvested from Kwandang Bay, Sulawesi Sea, Indonesia

Moh. Muchlis Djibran,Meity M Mokoginta,Dewa Oka Suparwata,Dewi Shinta Achmad,Susan Mokoolang,Merita Ayu Indrianti,Fahrullah Fahrullah,Indri Afriani Yasin,Muh Saleh Nurdin,Yusriyah Atikah Gobel

doi:10.13170/ajas.6.2.19389

Moh. Muchlis Djibran, Meity M Mokoginta

Open Access

https://doi.org/10.13170/ajas.6.2.19389

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Abstract

Orange-spotted grouper is one of the coral reef fish has the economic value and exploited by local fisherman. Information about the size structure and sex ratio are urgent to formulate a policy for sustainability. This research aims to analyze the size structure and sex ratio of the orange-spotted grouper in Kwandang Bay. The research was conducted from December 2016 to November 2017. Sampling is carried out twice a month for one year. The total sample of orange-spotted grouper used for the analysis of the sex ratio was 149 individuals. Sample of orange-spotted grouper collected from fish landed and middlemen (grouper traders) at the Kwandang Fishing Port. Data analysis applying chi-square. The results show that males bigger than females. The sex ratio of orange-spotted grouper is 87.25 % female, 7.38 % male, and 5.37 % hermaphrodites. Orange-spotted grouper dominated by females and undergoes a gonad differentiation to male (protogynous hermaphrodite). It is concluded that The size of the male orange-spotted grouper is larger than that of the female grouper. The caught orange-spotted grouper is dominated by the female phase and undergoes a differentiation of the gonad from female to male (protogynous hermaphrodite)

Highlights

The caught orange-spotted grouper is dominated by the female phase and undergoes a differentiation of the gonad from female to male
The results showed the ratio of females was bigger than males and there was a change in sex at a certain size (Ranjeet et al, 2015; Ohta and Ebisawa, 2016; Osman et al, 2018)
The dominant male orange-spotted grouper is caught in the class of 55-64 cm in size while the female in the class measures 75-84 cm

Summary

Introduction

Orange-spotted grouper (Epinephelus coioides) is one of the widespread sources of commercial fisheries in the Western Indo Pacific Waters (Heemstra and Randall, 1993; Kuiter and Tonozuka, 2001) such as Gulf of Arabia (Tharwat et al, 2005), South China Sea (Wang et al, 2011), Iranian Waters (Fourooghifard et al, 2017), Oman Waters (McIlwain et al, 2016) and Chinese Waters (Wang et al, 2011; Guo et al, 2016) as well as Indonesian waters including Kwandang Bay, Sulawesi Sea (Achmad et al, 2018). For orange-spotted grouper research, it is still limited, including the spawning season (Achmad et al, 2019) and fecundity (Achmad et al., 2020). The two pieces of information do not describe a description related to the orange-spotted grouper in Kwandang Bay. Information about biological aspects such as the size structure and sex ratio of orangespotted grouper is a need in the provision of brood and seeds, both for aquaculture and conservation purposes (Begossi and Silvano, 2008; Williams et al, 2009; Condini et al, 2013). Information related to sex ratio serves to analyze sex changes in orange-spotted groupers. Studies on the sex ratio of orange-spotted grouper have been conducted by previous researchers such as Al Marzouqi et al, (2015) and Sitepu (2014). The results showed the ratio of females was bigger than males and there was a change in sex at a certain size (Ranjeet et al, 2015; Ohta and Ebisawa, 2016; Osman et al, 2018)

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