Endangered Fish Found in Berau, Invasive Fish Threaten Native Species in Kukar

Researchers found endemic fish with endangered status in Berau. In Kukar, native species are threatened by invasive fish.

DOKUMENTASI UGM

Atuk sembelung (Pangio alternans) is a fish endemic to Kalimantan which has endangered status (Endangered – EN) in the Kelay River, Berau Regency, East Kalimantan.

BALIKPAPAN, KOMPAS — Researchers found endemic Kalimantan fish with endangered status in Kelay River, Berau, East Kalimantan. On the one hand, it shows that the river water quality is good. However, in other places, researchers also found a number of invasive fish which also threatened native species in Muara Siran, Kutai Kartanegara.

"We found a type of fish with the local name atuk sembelung (Pangio alternans), a fish endemic to Kalimantan which has endangered status (Endangered - EN) in the Kelay River," said Donan Satria Yudha , lecturer at the Faculty of Biology, Gadjah Mada University (UGM), Yogyakarta, in a written statement, Tuesday (7/5/2024).

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The findings are the result of Donan's research, who is part of a team of researchers from UGM and the Nusantara Conservation Foundation (YKAN). They conducted research on the biodiversity of freshwater biota in Muara Siran, Kutai Kartanegara, and Sungai Kelay, Berau, throughout 2023.

The researchers took samples using the purposive sampling method, both passive fishing and active fishing for 10 days. Passive fishing is done through traps. Active fishing is carried out through direct sampling by researchers using various fishing gear.

KOMPAS/LUKAS ADI PRASETYA

The spring at the foot of the karst hills in Merabu Village, Kelay, Berau Regency, East Kalimantan, has become a favorite spot for residents, especially children and teenagers, to swim or relax on Tuesday (May 13, 2014).

According to previous research (Daniels, 2020), the atuk sembelung fish is usually found in the middle part of the Mahakam River Basin (DAS). The research indicates that the fish is found in a peat river that flows into the Mahakam River.

Apart from the endangered fish, researchers also found vulnerable status fish in the Kelay River, namely the atuk bensong fish (Barbodes bunau). This fish was previously known to be easy to find in the Seturan Malinau river basin (DAS), North Kalimantan. The discovery of this fish in Berau Regency is new information.

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Around Sungai Kelay, according to Donan, there is PT Wana Bakti Persada Utama (PT WBPU), a production forest company holding a concession of 44,402 hectares. Research shows that Sungai Kelay in the company's area has become a habitat for 39 fish species and 5 crustacean species.

"This finding indicates that the waters around PT WBPU are still in a natural condition, not experiencing severe disruptions, and provide a suitable habitat for aquatic biota," he said.

DOKUMENTASI UGM

Atuk sapan (Pangio alternans), a fish endemic to Kalimantan in the Kelay River, Berau Regency, East Kalimantan.

Donan stated that the research results had been socialized in Samarinda on May 7, 2024. The activity was attended by the East Kalimantan Provincial Department of Marine and Fisheries, the Kelay District Government (Berau Regency), the Muar Siran Village Government (Kutai Kartanegara), and various stakeholders in the two research locations.

According to local residents, continued Donan, there are a number of species that have not been encountered during research. Two of them are catfish (Pangasius sp) and eel (Anguilla sp). This means that data on fish species in the river is likely to increase. There is potential for finding new species in future research.

Invasive fish

Another researcher from UGM, Rury Eprilurahman, stated that research results around the river flow of Muara Siran Village showed different findings. They found 57 species of fish and 5 species of crustaceans.

Out of that number, 51 fish species and 4 crustacean species are native to Indonesia. The rest, according to Rury, are introductions or alien species, organisms from other regions.

The lecturer at the Faculty of Biology at UGM stated that invasive species such as tilapia, catfish, and mudfish are easily found in the Muara Siran Village area and its surroundings. As for foreign species, they include catfish, siamese carp, and hudang.

KOMPAS/P RADITYA MAHENDRA YASA

Illustration. Officials carry plastic bags containing tilapia seeds to be distributed in the flow of the Banjir Kanal Barat River, Simongan, Semarang City, Central Java, on Tuesday (9/8/2022).

The foreign and invasive species are thought to be the result of residents releasing them into the river. "These introduced species will threaten the ecosystem and the preservation of native species," said Rury.

Therefore, he suggests banning the release of foreign species in the Muara Siran area and its surroundings. This is because Muara Siran village is a village that has a good lake and peat swamp in East Kalimantan.

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The peatlands in this village are a water catchment area and peat swamp forest with the largest formation of kahoi trees (Shorea balangeran) in East Kalimantan. By maintaining native species, it will strengthen the existing ecosystem.

This introduced species will threaten the ecosystem and the sustainability of native species.

Deputy Chair of the Indonesian Sustainable Movement Foundation, Susilo Irwan Jasmono, said that so far residents around the research location have only used freshwater fish for consumption. According to him, there is other potential that can be optimized, such as ornamental fish and special interest tourism.

ARSIP KEMENTERIAN KOPERASI DAN UKM

Minister of Cooperatives and SMEs, Teten Masduki, pointed to one of the showcased fish at the Kalikan Expo 2022, the largest freshwater ornamental fish exhibition in Indonesia, which was held on October 14-16, 2022 at the Jakarta International Expo Kemayoran, Jakarta, on Friday (14/10/2022). Indonesia's ornamental fish exports drive the national economy.

He suggested that the government make a master plan for the management of freshwater biota in East Kalimantan. "The sooner its management is regulated, the more ensured its sustainability," said Susilo.

Senior Program Manager of Terrestrial YKAN, Niel Makinuddin, hopes that the research results can become policy recommendations to save endemic species, especially those that have been declared endangered.