IQBAL ET AL.
Bio Palembanica 2.
: 59-65 .
This journal is available online at: https://ejournal.
Additional Freshwater Fishes of Simeulue Island, with Special Reference to the Presence of Sharp-Nosed River Mullet Cestraeus oxyrhyncus (Actinopterygii: Mugilida.
MUHAMMAD IQBAL1*.
TOM AMEY2.
IRDA KUSUMA2.
SATRI SARA ALIM3 & AFRI AMIN4 Department of Biology.
Universitas Indo Global Mandiri.
Jalan Jend.
Sudirman No.
Palembang 30129.
Sumatera Selatan.
Indonesia *Corresponding Author.
E-mail: miqbal@uigm.
https://orcid.
org/0000-0002-6657-0183 Ecosystem Impact Foundation.
Jalan Tgk.
Banurullah.
Desa Nancala.
Teupah Barat.
Simeulue 23897.
Aceh Province.
Indonesia E-mail: tom@ecosystemimpact.
E-mail: irda_k@yahoo.
Dinas Lingkungan Hidup Kabupaten Simeulue.
Jalan Teuku Umar.
Desa Amiria Bahagia.
Simeulue Timur 23891.
Aceh Province.
Indonesia Bagian Kesatuan Pengelolaan Hutan Simeulue.
Desa Suka Maju.
Simeulue Timur 24782.
Aceh Province.
Indonesia Received 1 June 2025iCAccepted by D.
Sari: 10 June 2025iCPublished online 27 June 2025.
Abstract This study reports new records of freshwater fish species from Simeulue Island.
Aceh Province.
Indonesia.
biodiversity survey conducted in July 2021 revealed five additional fish species not previously documented on the island, including Acentrogobius sp.
Giuris margaritaceus.
Cestraeus oxyrhyncus.
Poecilia reticulata and Clarias The survey also confirmed the presence of introduced species, such as Nile Tilapia Oreochromis niloticus and Guppy Poecilia reticulata, highlighting the need for monitoring and managing non-native species in the region.
The discovery of C.
oxyrhyncus, currently classified as Data Deficient, accentuates the importance of further research to determine its threats, ecology, population size, and trends.
This study contributes to the understanding of freshwater fish diversity on Simeulue Island and emphasises the importance of conservation efforts to protect the biodiversity of small islands in Indonesia.
Keywords: Aceh, freshwater fish.
Indonesia.
Simeulue Island.
Sumatra.
Introduction Indonesia is home to an incredibly diverse array of freshwater fish species, thanks to its vast archipelago and varied aquatic ecosystems (Hutama et al.
Windusari et al.
The country's unique geography has created numerous isolated habitats, allowing species to evolve independently and resulting in high levels of endemism (IBSAP 2024.
Iqbal et al.
2017a, .
Western Indonesia, particularly Sumatra, is a significant contributor to Indonesia's freshwater biodiversity (Kottelat et al.
Whitten et al.
Sumatra is home to numerous rivers, lakes, and wetlands that support a wide range of freshwater fish species (Wibowo & Suyatno 1998.
Hanum et al.
Research has shown that small islands off the coast of Sumatra, particularly the Barusan or West Sumatran Archipelago (?), possess rich freshwater fish diversity (Hadiaty & Sauri 2017.
Roesma et al.
The region's unique geology and geography have created a multitude of habitats that allow species to evolve independently, resulting in high levels of endemism (Roesma et al.
Simeulue Island, located off the coast of Sumatra.
Indonesia, is a region of high biodiversity, including freshwater fishes (Muchlisin et al.
Despite its unique geography and ecological significance, the freshwater fish fauna of Simeulue Island remains understudied (Batubara et al.
survey of freshwater fishes on the island would provide valuable insights into the diversity and distribution Additional Freshwater Fishes of Simeulue Island of fish species, as well as the ecological characteristics of the island's freshwater ecosystems.
Here, we report additional new records of freshwater fishes from Simeulue Island.
Aceh Province.
Indonesia.
Methods In 2 to 21 July 2021, a wide biodiversity survey to asses ecological importance was conducted in Simeulue Island .
A37AN, 96A05AE), nortwestern of Sumatra.
Indonesia.
Administratively.
Simeulue Island is situated in Aceh .
Indonesia (Fig.
The island is located 150 kilometers off the coast of Sumatra, with a total area of approximately 1,754 square kilometers and has a population of around 93,762 people, according to the 2021 estimate (BPS 2024.
Amey et al.
Figure 1.
Map of Simeulue Island (Aceh Province.
Sumatr.
with locations mentioned in the table 1.
Notes AL = Alafan Subdistrict.
LLT = Lake Lauik Tawar.
LL = Lake Laso.
SI = Sinabang.
During our visit to Simeulue Island, we explored various aquatic locations, including Lake Lawik Tawar and several freshwater rivers.
Although our survey wasn't specifically focused on fish, we had opportunities to observe local communities catching fish and see their catches.
At Lake Lawik Tawar, for instance, we saw locals using traditional nets and traps called "bubu" to catch fish.
In some inland river areas, we observed locals using fishing rods to catch fish.
We attempted to identify the fish species using relevant field guides for freshwater fish in western Indonesia (Kottelat et al.
Larson & Lim 2005.
Iqbal 2011.
Iqbal et al.
2018, 2.
Our study revealed that some of the species we encountered were previously unrecorded on the island.
We compiled a list of all the freshwater fish species found on the island and added new species based on our observations during the survey.
Results and Discussion Additional Freshwater Fishes The list of freshwater fish species recorded on Simeulue Island, and additional species recorded during the July 2021 survey are presented in Table 1.
This table provides a comprehensive overview of the fish IQBAL ET AL.
fauna found on the island, including species previously documented by Muchlisin et al.
and new records identified during the recent survey.
Table 1.
Annotated Cehcklist of the Freshwater Fishes in Simeulue Island.
Aceh Province.
Indonesia.
Notes: AL = Alafan Subdistrict.
LLT = Lake Lauik Tawar.
LL = Lake Laso.
SI = Sinabang.
Pers.
Obs = refer to our survey in July 2021, species in bold are new record from survey in Juli 2021.
Scientific Name Family Location Sources Megalops cyprinoides Gobiidae 1 .
Gobiopterus sp.
Gobiidae 1 .
Acentrogobius sp.
Bunaka gyrinoides Giuris margaritaceus Ambasis miops Cestraeus oxyrhyncus Oreochromis niloticus Poecilia reticulata Caranx ignobilis Anabas testudineus Osphronemus gouramy Channa striata Clarias batrachus Clarias sp.
Simeulue Gerres filamentosus
Megalopidae Gobiidae Gobiidae Eleotridae Eleotridae Ambassidae Mugilidae Cichlidae Poecilidae Carangidae Anabantidae Osphronemidae Channidae Clariidae Clariidae Gerreidae LLT
LLT
LLT
LLT.
LLT
LLT.
LLT
LLT
LLT.
LLT.
LLT
LLT
Muchlisin et al.
Muchlisin et al.
Pers.
Obs.
Muchlisin et al.
Pers.
Obs.
Muchlisin et al.
Pers.
Obs.
Muchlisin et al.
Pers.
Obs Pers.
Obs Muchlisin et al.
Muchlisin et al.
Muchlisin et al.
Muchlisin et al.
Muchlisin et al.
Pers.
Obs.
Muchlisin et al.
The table 1 comprises 16 species of fish from 13 families, with some families represented by multiple species, showcasing the diversity of fish species in the studied area.
The previous list of fish from Simeulue Island refers to the fish data from Muchlisin et al.
, which recorded 11 species of freshwater fish on the island.
After this study, five additional fish species were documented, namely goby species .
Acentrogobius sp.
Giuris margaritaceus.
Cestraeus oxyrhyncus.
Poecilia reticulata and Clarias sp.
Simeulue.
The notation Clarias sp.
simeulue suggests that the species' identity is uncertain and requires further research to confirm its taxonomic status.
Interestingly.
Clarias batrachus was previously reported to occur on Simeulue Island (Muchlisin et al.
However, recent studies have revealed that the distribution of C.
batrachus is more limited than previously thought, with populations in the Indian subcontinent reidentified as Clarias magur (Ng & Kottelat 2.
It is now believed that C.
batrachus is only found in Java, and populations from the Greater Sunda Islands and Indochina, including those from Simeulue Island, are likely to represent distinct species (Ng & Kottelat 2.
Our survey of freshwater fish found on Simeulue Island, revealed the presence of one introduced species.
Guppy Poecilia reticulata.
The P.
reticulata, native to the northeastern part of South America, has been widely introduced and established in various countries across Asia, including Indonesia.
Despite its popularity and widespread presence in Indonesia, research on P.
reticulata in the region remains limited (Hariyanto et al.
Small islands like Simeulue are particularly vulnerable to introduced species due to their unique and often fragile ecosystems.
This finding emphasises the importance of monitoring and managing introduced species in western Sumatra and other small islands in Indonesia to prevent further invasions and protect native species.
In addition, another introduced species.
Nile Tilapia Oreochromis niloticus was found in Lake Lauik Tawar.
The presence of Oreochromis niloticus was reported from Lake Lauik Tawar and Lake Laso (Muchlisin et al.
This cichlid species has been found to be widely distributed throughout Indonesia, from Sabang in the northwest to Merauke in the southeast, highlighting the need for further research and management of non-native species in the region (Iqbal et al.
Additional Freshwater Fishes of Simeulue Island Figure 2.
Four additional freshwater fishes for Simeulue Island based on the survey in July 2021: 2a.
Acentrogobius sp.
Giuris margaritaceus.
Poecilia reticulata.
Clarias sp.
Simeulue.
The Presence of Sharp-nosed River Mullet Cestraeus oxyrhyncus The little known freshwater mullet.
Sharp-nosed River Mullet Cestraeus oxyrhyncus, was found during our survey in Simeulue Island (Fig.
3?).
This species is found in the Indo-West Pacific region, spanning from Indonesia to Philippines, and extending to the Papua New Guinea.
Fiji and New Caledonia (Harrison & Senou 1999.
Shen & Durand 2.
However, due to potential confusion with Lobed River Mullet Cestraeus plicatilis, the actual distribution might be more limited than reported (Hoese et al.
Further verification is needed to confirm its presence in Vanuatu, the Solomon Islands and Japan (Hoese Hoese et al.
Figure 3.
A Sharp-Nosed River Mullet Cestraeus oxyrhyncus found on July 2021 in Lauik Tawar Lake.
Simeulue Island.
Aceh Province.
Sumatra.
IQBAL ET AL.
The freshwater mullet from Simeulue Island is identified as C.
oxyrhynchus based on its sharp snout profile, distinguishing it from Lobed River Mullet Cestraeus plicatilis and Goldie River Mullet Cestraeus goldiei, which have blunt snouts (Harrison & Senou 1999.
Kottelat et al.
Notably, in Indonesia.
plicatilis is only found in Sulawesi, while C.
goldiei is distributed in Sulawesi.
Moluccas.
Lesser Sunda, and West Papua, but neither species occurs in Sumatra.
In contrast.
oxyrhynchus has been reported in Sumatra (Padang and Bengkul.
Sulawesi (Manado.
Sawangan.
Buton, and Klaba.
, and Molucca (Ambon.
Seram, and Baca.
in Indonesia (Weber & de Beaufort 1922.
Kottelat et al.
Hoose et al.
The C.
oxyrhyncus has a relatively wide distribution, but its ecology and distribution are poorly understood due to confusion with C.
It is considered rare with notable declines reported in the Philippines, where it's a valued food fish, warranting further research to address significant knowledge gaps and potential threats, leading to its classification as Data Deficient (Hoose et al.
There are only few recent records in Indonesia, all from mainland Sumatra, including from Lhok Guci .
rovince of Ace.
Pelangai waters (West Sumatra Provinc.
, and a recent record in November 2013 identified as C.
plicatis from Muko-Muko.
Bengkulu.
Sumatra (Radarsumbar 2023.
Fishbase 2025a, 2025.
The record of C.
oxyrhyncus is Simeulue Island represent of this species in smaller western Islands chain in Sumatra.
There is a significant lack of information on this species in Indonesia, including population data, life history, preferred habitat requirements, and potential threats.
As a result.
oxyrhyncus is listed as Data Deficient, highlighting the need for further research to determine its threats, ecology, population size, and trends, and to inform effective conservation.
Conclusion This study contributes to the understanding of freshwater fish diversity on Simeulue Island.
Aceh.
Indonesia, by documenting five additional fish species not previously recorded on the island, including the C.
The discovery of introduced species such as Oreochromis niloticus and Poecilia reticulata highlights the need for monitoring and managing non-native species to protect the island's unique ecosystem.
Further research is necessary to determine the threats, ecology, population size, and trends of species like C.
oxyrhynchus, which is currently classified as Data Deficient.
This study emphasizes the importance of conservation efforts to protect the biodiversity of Simeulue Island and other small islands in Indonesia.
Acknowledgments We extend our gratitude to Ecosystem Impact Foundation.
Dinas Lingkungan Hidup and Bagian Kesatuan Pengelolaan Hutan Kabupaten Simeulue for their support in facilitating our biodiversity survey on Simeulue Island.
Aceh Province.
Indonesia.
We also thank Universitas Indo Global Mandiri (UIGM) for providing access to references on freshwater fishes of Simeulue Island.
Additionally, we appreciate the constructive feedback from anonymous reviewers, which greatly enhanced the quality of this paper.
References