KUALA LUMPUR, Dec 17 — Massive armoured catfish and African catfish were caught by the Slingshot Fishing Malaysia Club (SFM) in Sungai Klang, right in front of a shopping mall here recently.
Each fish was as large as an adult male’s arm or thigh, with an average weight of six to ten kilogrammes. The potential devastation if these species were left to dominate our river basins is unimaginable. What’s more alarming is that both species have a lifespan of over a decade and reproduce rapidly in large numbers.
“For me, this is no longer a minor issue but a national concern. I’ve been an avid angler for the past 20 years, and over that time, we’ve noticed that native fish like the toman(giant snakehead) and haruan (striped snakehead) are becoming harder to find, whereas they were once abundant,” lamented Azahar Khalid, a member of SFM who took part in the operation.
He added that during a previous operation, the group managed to capture over 200 kg of armoured catfish alone, excluding other invasive species found in the same river.
Founded in 2020, SFM has 100 members and uses slingshot or catapult techniques with darts to catch invasive fish, particularly the armoured catfish (Hypostomus plecostomus), native to South America.
“We use this harpoon-like method because the slingshot allows the dart to reach far distances, and the specially made metal darts can penetrate the thick scales of the armoured catfish. After that, we reel in the dart along with the fish,” explained Azahar, adding that his experience as an angler helps him identify fish species just by their surface movements.
He further elaborated that invasive fish caught are either sold to traders, disposed of, or turned into compost fertiliser.
Describing the dominance of invasive fish species as a ticking time bomb threatening native river fish populations, Director-General of the Department of Fisheries (DoF) Datuk Adnan Hussain, said the issue is difficult to address because many people fail to understand the impact these species have on the country’s river ecosystems.
"Invasive fish refers to species not native to the area but introduced by humans for various purposes. For instance, tilapia and African catfish are brought in as protein sources, while koi and arapaima are kept as ornamental fish.
"The gambusia (mosquito fish) is used to control mosquito populations. Additionally, some invasive fish enter our waters unintentionally, such as through ship hulls or escape from aquaculture enclosures," he explained when contacted by Bernama.
According to him, invasive fish can be categorised into two types: those that do not cause harm, referred to as naturalised species, which have been economically beneficial to farmers, such as the Javanese carp and Siamese gourami.
"On the other hand, invasive species that disrupt ecosystems pose ecological risks that ultimately threaten ecological balance, as seen with the freshwater redclaw crayfish, which has proliferated in our ecosystems since its introduction over 15 years ago," he said.
Based on the Study of Alien Fish in Inland Waters of Peninsular Malaysia, the dominance of alien fish species primarily originates from commercial farming and ornamental fish like tilapia and armoured catfish.
Research by the DoF’s Glami Lemi Fisheries Research Institute also reveals that the armoured catfish, redclaw crayfish, and peacock bass are highly dominant in Peninsular Malaysia’s waterways.
Adnan noted that while official data on the impact of invasive species on local river fish landings is still being compiled, the DoF has received numerous complaints from fishermen about declining catches of high-value fish and damage to fishing equipment caused by invasive species.
"More concerning is the fact that invasive fish adapt easily to their environment, even in polluted rivers," he added.
Adnan said the DoF is taking various measures to ensure the sustainability of native species like the patin buah, kelah and freshwater prawns through breeding and reintroduction into their natural habitats.
A total of 13 native fish sanctuaries have been established to protect the habitats of these species. Under the 12MP, 23.9 million fish fry have been released into their original waters, supported by an allocation of RM1.5 million.
Additionally, Adnan shared that the department collaborates with universities to gain insights from researchers studying alien or invasive fish species.
— Bernama
