Ikan bandaraya gets dumped into drains and freshwater areas once they have grown too big. — Filepic
Once teeming with aquatic life, Sungai Langat, near Universiti Kebangsaan Malaysia (UKM), in Bangi, Selangor, is now filled with invasive alien fish that threaten the ecosystem.
The suckermouth catfish (Hypostamus plecostomus), also known as ikan bandaraya and originally from South America, has multiplied there and in other waterways within the state in recent years.
This fish, which mainly eats algae and keeps aquariums clean, may be useful to those with fish tanks but in the wild, it becomes territorial and breeds rapidly.
Anglers casting a net to remove invasive fishes from Sungai Langat near Universiti Kebangsaan Malaysia in Bangi during Fisheries Department operations. 一 CHAN TAK KONG/The Star
Often, when these fish grow too large to manage, fish tank owners release them into the waterways instead of killing them.
As such, efforts are being made to reduce the species’ dominance in rivers and restore the ecological balance.
On June 9, the state Fisheries Department with the help of non-governmental organisations (NGOs) and Selangor government removed 700kg of the invasive catfish from the once popular fishing spot along Sungai Langat.
Ahmad fishing along Sungai Klang in Kuala Lumpur. — RAJA FAISAL HISHAN/The Star
Angler and maintenance worker Ahmad Nawawi Husin, 31, said he had stopped fishing there and moved to other spots, such as Sungai Dengkil and another part of Sungai Langat near Kampung Sungai Buah.
He said the abundance of invasive catfish in the river posed a challenge for anglers trying to catch native species such as ikan baung, also known as mystus, which are highly sought after but scarce.
“I had to change my fishing method to one that allows me to target specific fish,” Ahmad said.
Before the proliferation of invasive species in the river, he could catch at least RM2,500 worth of fish in a month, but now, the most he could get was RM1,000 on a good day.
Ahmad said during his last visit to Sungai Langat, he fished from midnight to dawn but only caught ikan bandaraya.
Damaged riverbank along Sungai Kuyoh near the National Hockey Stadium in Bukit Jalil, Kuala Lumpur. — Courtesy photo
Mohammad Khairul Amri, 26, said before this, anglers like him could typically catch at least 3kg of ikan baung.
However, in recent years, he said there had been times when they could catch only one native fish per outing, and on particularly bad nights, none at all.
“During those times, the fish that we catch is only for personal consumption,” he added.
Anglers are able to get up to RM35 for 1kg of ikan baung, depending on size.
Mohammad Khairul noted that some urban locations such as Sungai Klang near MidValley, Sungai Midah in Bukit Jalil and Sungai Langat near UKM, had seen a rise in the invasive fish population.
The anglers suggested implementing state infrastructure and agriculture committee chairman Izham Hashim’s idea of putting a bounty on the heads of alien fishes. At the time, he had said that the price would be RM2 per fish.
In response, Selangor Fisheries Department director Noraisyah Abu Bakar said whether the bounty was 50sen, RM1 or RM2 per fish, she fully supported the initiative to reduce the number of alien fishes within Klang Valley rivers.
Rehabilitating rivers
Noraisyah said it was important for people to consult with the department before releasing fish into waterways.
“No one is allowed to release any alien fish into rivers as this could damage our rivers’ ecosystem,” she explained.
She was unhappy to learn that Selayang Municipal Council (MPS) had released nearly 400kg of Chao Praya catfish, an invasive species, into a river on June 29.
Prof Mohammad says ‘ikan bandaraya’ burrow into riverbanks or ponds.“The Fisheries Department is currently refining the state’s river fisheries regulations to allow for action to be taken.
“These rules will provide a detailed framework under the authority of the Fisheries Act 1985 (Act 317).”
Noraisyah said the draft proposed licensing of fishing activities (river fisheries), listing prohibited fishing equipment, prohibition of fish releases (both native and alien fishes) without permission, establishment of resource management areas and the prohibition of capturing protected fish species.
The rules, she added, were aimed at regulating fishing activities in public inland waters and ensuring the sustainability of inland fisheries resources, particularly native fish species.
“It will help with the monitoring of fishing activities through licensing, reporting of catches and providing government support (if available) to genuine anglers,” she said, adding that it included implementing conservation activities and controlling the release of fish into public inland waters.
Noraisyah says some bunds across Sungai Langat have been damaged by invasive fishes.She said the department monitored aquarium shops and enforced regulations there.
“We will take action against a shopowner for having any foreign fish without a permit.
“We can take action under the Fisheries Act 1985 which prohibits imports and we have made some arrests,” said Noraisyah.
Every year, the department conducts an inventory programme to collect data on specific rivers depending on its allocation.
“The data can assess the condition of the river, determining whether it is still healthy based on the presence of native fish or if it has been overtaken by invasive fish.
“This will help us decide what is necessary and if needed, we will remove the invasive fish or release native fishes into a river.
“Additionally, we will collaborate with NGOs (such as Ikan Bandaraya Hunters and River Monster Hunters) on programmes and run periodic campaigns on social media,” she added.
Noraisyah said riverbanks and bunds at Sungai Langat and Sungai Klang had also been damaged by invasive fish, which could grow up to 50cm.
Universiti Putra Malaysia Faculty of Science Biology Department lecturer Prof Dr Mohammad Noor Amal Azmai said the invasive fish had a habit of burrowing into the ground, riverbanks or ponds.
“These burrows, which can be several feet deep, act as nests and mating places for the fish. They can weaken riverbanks or ponds.
“Fish farmers also dislike their presence because they dig up the pond, causing pond banks to collapse and this results in losses for the farmers.”
According to Prof Mohammad, a single female ikan bandaraya could produce from 1,200 to 12,000 eggs at one time.
He said if the country wanted to preserve its aquatic heritage, then a collaboration between the government, NGOs and the public was needed to accomplish this goal.
He added that the government and farmers should also promote local fish for ornamental and recreational purposes as well as aquaculture and reduce dependency on alien fish.
StarMetro reached out to Drainage and Irrigation Department (DID) to find out about the extent of the damage done by ikan bandaraya to riverbanks, but it was unable to respond by press time.
A Fisheries Department researcher, when approached, said studies had not been conducted following discussions with DID.
When asked about riverbank erosion studies, Noraisyah said such a task was under the purview of DID.
