PUTRAJAYA: Invasive fish species are now found in many urban and even rural rivers here, causing a headache to regulators and conservationists as they struggle to maintain the riverine system in balance.
Practically all urban rivers, such as those in Klang Valley, are found to harbour non-native species that either breed quickly or those that prey on native species.
In other cases, they compete for food, oxygen and space with local species, thus leading to the gradual extinction of local fish, say conservationists.
Most Malaysians would be familiar with the ban on the import and/or release of the dreaded flesh-eating piranha, but the threat to our waterways go way beyond just keeping the piranhas at bay.
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According to the Fisheries Department (DOF), an agency under the Agriculture and Food Security Ministry, these invaders include the African catfish, African black tilapia, Siamese (Mekong) catfish and of late, the algae suckermouth catfish (Hypostomus plecostomus), popularly known as ikan bandaraya or pleco due to its bottom-feeding habits.
Other species that are not allowed in Malaysia are the painted pavon (Cichla temensis), also known as speckled peacock bass, the redclaw freshwater crayfish (Cherax quadricarinatus) and tropical blue crayfish or udang kara air tawar in Malay.
Just this month, DOF updated its list of prohibited species by adding several genus such as ikan pacu (Mylopus), flower horn (Cichiasoma) and arapaima (also known as pirarucu, or paiche) to the list, which was just gazetted early this month.
The gazette is part of the Fisheries (Prohibition of Import, etc., of Fish) Regulations, 1990 and Amendments (2011), which decrees that “no person shall import into, sell, cultivate or keep live fish of the genus as specified in the Schedule to these Regulations except with a written permission of the Director General as defined by the Fisheries Act 1985. The Director General may attach any conditions he deems fit to the written permission. Contravention of this rule or of any condition imposed is declared an offence”.
“This move to revise the list is important to safeguard our (inland) waters from invasive fish species from dominating our major rivers,” said Fisheries Department director-general, Datuk Adnan Hussain.
In the larger rivers in states such as Perak, Selangor and Pahang, it can be seen that the Asian redtail catfish or baung ekor merah (Hemibagrus wyckioides) has wreaked havoc on native fish as they are highly predatory.
Keeping track of invasive alien fish species is not just under the purview of DOF, as there is a National Committee on Invasive Alien Species that keeps tabs on all organisms that may or may not pose a threat to humans, agriculture and the country’s economy as a whole.
The scientific information of these organisms of concern are stored in the Malaysia Biodiversity Information System (MyBIS), which acts as a one-stop repository for biodiversity information in Malaysia.
Other than tightening the law, DOF is now also more open to collaborating with civil society and NGOs to physically remove these invaders by fishing them out of rivers and lakes.
Just last Sunday, DOF and Aquawalk Sdn Bhd (owner of Aquaria KLCC), organised a community event along Sungai Kuyoh, at a spot next to the National Hockey Stadium in Bukit Jalil, Kuala Lumpur.
The event had a very important stakeholder, Komuniti Pemburu Ikan Bandaraya (Pleco Hunter Community), a group that has been going around removing the ikan bandaraya from waterways in the peninsula for the past few years.
The two-hour operation netted around 600 fish weighing about 400kg. Only a few native fish were found – which were quickly released back into the river – highlighting how badly “colonised” our rivers are, with the dominant species at Sungai Kuyoh being the ikan bandaraya and the black tilapia.
In a survey last year, DOF found that six rivers – Sungai Batu, Sungai Gombak, Sungai Jinjang, Sungai Keroh, Sungai Klang and Sungai Kuyoh are dominated by tilapia, along with pleco and African catfish.
“Conservation efforts that year involved releasing some 80,000 fish fries from native species such as lampan sungai, terbul and local baung to boost their stock in Kuala Lumpur’s rivers. DOF will also tighten regulations in other states to improve the management of inland fisheries in Malaysia,” said Adnan in an interview with The Star.
“The removal of alien species is part of efforts to support the global push for biodiversity conservation, and is in line with the 2024 World Biodiversity Day theme ‘Be part of the Plan’ to protect biodiversity, in particular native fish species.”
Meanwhile, Aquaria KLCC is promoting public awareness by having a permanent exhibit to showcase native fish species, along with posters to educate people about invasive species and their deleterious effect on the ecosystem.
“We are currently hosting Alien Invaders, an exhibition showcasing several invasive species. It ends in June,” said Aquawalk executive director Daryl Foong when met at the fish-catching event.
“It is part of our duty to educate the people about what’s native and what’s invasive, for the sake of biodiversity,” he added.
Sunday’s event was also supported by Universiti Utara Malaysia, Universiti Teknologi Mara and the hockey stadium management.
Komuniti Pemburu Ikan Bandaraya founder Mohamad Haziq A Rahman, 33, said his group started with 10 members and now has more than 300 from all over the peninsula.
His motivation stemmed from the fact that anglers like him were “fed up” when all the fish they could land from the rivers in Selangor, such as Sungai Langat near his home in Banting, consisted of black tilapia and pleco.
“If this situation goes on, the younger generation will not even know what is a native fish species, and may be lulled into thinking that the pleco is native. For our work, which is entirely voluntary, we appreciate all forms of support. In this regard, the endorsement from DOF is very valuable for us,” he said when met.
Recognising the limitations of government, Adnan is highly appreciative of the help given by civil society.
“We cannot go it alone in this, we need all the help we can get.
“The public can start by not releasing any of their non-native pet fish into our waterways, be it drains, lakes or rivers. If they are unsure about what to do, they can contact the Fisheries Department for assistance,” he said.
