Diversity of commercially important grouper (Family: Epinephelidae) in Simeulue and Banyak Islands, Aceh, Indonesia

Grouper is one of the economically important fish groups in the Simeulue and Banyak Islands. However, data on the diversity of the grouper in this region is limited. This study aimed to inventory the commercially important grouper in Simeulue and Banyak Islands. Sampling was carried out in April - September 2021 at 16 locations around Simeulue and Banyak Islands. Grouper fish were collected from fishermen's catch, fish collectors, or fish landing sites (TPI). Representatives of each species were collected and photographed. Species identification was made by fish identification books. In total, 20 species of commercial grouper consisting of six genera were recorded during the study. Epinephelus was the most dominant genus with ten species, followed by Cephalopholis with four species. In addition, seventeen species (85%) were included in the Least Concern (LC), two species (10%) were categorized as Vulnerable (VU), and one species (5%) was Data Deficient (DD). This study provides a database of commercially important grouper in Simeulue and Banyak Islands that can be used to manage the fish group.


Introduction
The grouper is a demersal fish that mostly lives in coral reef areas in tropical and subtropical waters (Heemstra and Randall, 1993). There are at least 163 grouper species globally (Craig et al., 2011). In comparison, the Fisheries Resource Center of Indonesia (2021) reported that no less than 77 species of grouper are found in Indonesian waters. The groupers are protogynous hermaphrodites wherein the sex changes from female to male in one life cycle (Craig et al., 2011;Heemstra and Randall, 1993;Rhodes et al., 2013). FRCI (2021) The grouper is one of the economically important fish groups in Indonesia Yulianto et al., 2015). During the first quarter of 2020 (January-March), Indonesia's total grouper exports reached 4040 tons (19.97 million US$) consisting of frozen fish, live fish, seafood products, and others. Live grouper fish products are mainly exported to Hong Kong (91.73%) and China (5.59%), followed by Malaysia (38.18%), Singapore (23.84%), and Taiwan (18.03%). Meanwhile, frozen grouper products are mainly exported to China (24.22%), Taiwan (19.20%), the United States (12.78%), and France (12.77%) (Suhana, 2020).
Simeulue and Banyak Islands are situated in the southern part of Aceh Province, Indonesia. The islands are bordered directly by the Indian Ocean.
Depik Jurnal Ilmu-Ilmu Perairan, Pesisir dan Perikanan Volume 11, Number 1, Page 29-33 Razi et al. (2022) Like other coastal regions in Indonesia, these regions also depend on the fisheries sector (Batubara et al., 2018). In 2020, Badan Pusat Statistik data showed that the potential of the capture fisheries sector in the Simeulue and Banyak Islands area is the highest, and the grouper is one of their vital export fish commodities. The production of grouper reached 30 tons/year in Simeulue and 4 tons/year in Banyak Islands (Badan Pusat Statistik, 2020). (BPS, 2020).
Nevertheless, even though the grouper is an essential fisheries resource, minimal information or studies on the grouper are available in the region. Some grouper fish inventory studies had been conducted in Aceh (Astuti et al., 2016;Fadli et al., 2021;Fadli et al., 2020;Kamal et al., 2019), yet, they did not cover Simeulue and Banyak Islands.
Only a few fish inventory studies in Simeulue and Banyak Islands had been performed earlier. For example, Batubara et al. (2017) documented 77 marine fishes in Simeulue waters, including 14 grouper species. Muchlisin et al. (2017) described 11 fish species in two lakes located on Simeulue Island. In another study, Batubara et al. (2018) reported 52 peripheral fishes in the estuary area of Simeulue Island. However, these studies covered limited sampling times and restricted areas. The comprehensive record on grouper diversity in this region is not yet assessed. Therefore, this study aimed to record all the essential commercial groupers fished in Simeulue and Banyak Islands for fisheries management and species conservation in the future.

Material and method
This research was conducted from April to September 2021. Grouper sampling was carried out in 16 locations in Simeulue and Banyak Islands (SIMAKSI Number: SI.07/K.20/TU/KSA.2.1/5/2021) ( Figure 1 and Table 1). Grouper fish were collected from fishermen's catch, fish collectors, or fish landing sites (TPI). Representatives of each species were collected and photographed ( Figure 2). Species identification was made by fish identification books (Craig et al., 2011;Froese and Pauly, 2021;Heemstra and Randall, 1993).

Discussion
Overall, 20 grouper species belonging to six genera were recorded from Simeulue and Banyak Islands. The number of grouper species observed in this study is higher than reported in earlier research conducted in a different part of Indonesia. For example, Basith et al. (2021) reported 14 species of grouper on Madura island. In another study, Tapilatu et al. (2021) identified 16 species of commercially important grouper in the northern part of Papua. However, the observed number of grouper genera recorded in this study is similar to other studies worldwide, for instance, in the Philippines (six genera) (Alcantara and Yambot, 2016), India (six genera) (Basheer et al., 2017), and the Red Sea, Egypt (six genera) (Galal-Khallaf et al., 2019). Furthermore, the number of genera is higher than reported in peninsular Malaysia (3 genera) (Aziz et al., 2016).
Anyperodon and Hyporthodus were reported for the first time in the Aceh region. Both genera are not described in earlier grouper studies in Aceh (Astuti et al., 2016;Fadli et al., 2021;Fadli et al., 2020;. Anyperodon leucogrammicus is reef-associated fish and mainly lives at a depth range of 5 -80 m (Froese and Pauly, 2021). The fish is one of the significant fisheries resources in the Arafura Sea, Indonesia (Pane et al., 2021). However, it appears that this species is not an essential fish in the grouper fishery in Aceh as the species is not recorded in other Aceh's fish landing sites. On the other hand, Hyporthodus octofasciatus is a deep-water grouper (Wakefield et al., 2013). They usually live at 150 -300 m depth (Heemstra dan Randall, 1993). The Indian Ocean directly borders Simeulue and Banyak Islands with a deep ocean floor. Simeulue forearc basin has a maximum water depth of about 1300 m (Berglar et al., 2008), providing suitable habitat for the fish. This fish is suspected to be difficult to fish and has not been observed in other fish landing sites in Aceh.
This study also revealed that two of the 20 grouper species were found vulnerable by the IUCN, namely E. fuscoguttatus and P. areolatus. Due to their large size and high market demand, these two species have become a target for fishing in Simeulue and Banyak Islands. Grouper fish in the vulnerable category tend to be bigger than other groupers (Sadovy de Mitcheson et al., 2013). Epinephelus fuscoguttatus can reach a maximum of 120 cm and a maximum weight of around 308 kg, while P. areolatus can reach a maximum length of 80 cm with a reported maximum weight of 24.2 kg (Craig et al., 2011;Heemstra and Randall, 1993
Local and provincial governments should implement some fisheries management interventions to maintain the grouper fisheries to be sustainable in this region. As stated by Fadli et al. (2021) in their study, these interventions should involve prohibiting fishing activities, especially during spawning times, creating marine protected areas in grouper habitat, etc. In addition, the introduction of grouper aquaculture is also one of the strategies that can be implemented in this region. According to Rimmer and Glamuzina (2019), Indonesia is the third-ranked country in grouper aquaculture globally after China and Taiwan. The eastern coastal area of Simeulue Island was identified as appropriate for grouper netcage culture mariculture (Purnawan et al., 2015).

Conclusion
This study provides a database of commercially important of grouper in the Simeulue and Banyak Islands that can be used for fisheries management. Overall, 20 grouper species belonging to six genera were recorded from 16 sampling locations in Simeulue and Banyak Islands. The genera of Anyperodon and Hyporthodus were the first reported in the Aceh region. In addition, Epinephelus is the dominant genus found based on the number of species.