Malaysia’s ‘fish hunters’ target invasive species, one catch at a time | Environment News

Puchong, Malaysia – On a latest Sunday morning, a few dozen males with fishing nets skirted the rubbish-strewn banks of the Klang River simply exterior the Malaysian capital of Kuala Lumpur.

Surveying the river, the boys forged their nets into the polluted water. The nets billowed open and sunk shortly underneath the load of metallic chains.

From the place they stood on the riverbank, they began to drag of their nets, already full of dozens of squirming black-bodied catfish.

“You don’t see another fish. Solely these,” mentioned Mohamad Haziq A Rahman, the chief of Malaysia’s “international fish hunter squad”, as they emptied their catch of wriggling suckermouth catfish into piles, away from the river.

Not one of the fish caught that morning had been bought at close by markets or meals stalls. The only goal of the expedition was to cull suckermouth catfish, one amongst a rising variety of invasive species which have in latest a long time dominated freshwater habitats throughout Southeast Asia.

As soon as introduced in for industrial or hobbyist causes, invasive fish will not be solely threatening to edge native species out of the meals chain in Malaysia and elsewhere, however additionally they unfold ailments and trigger nice injury to native environments.

Invasive fish are an issue the world over, however consultants say the difficulty is keenly felt in mega-biodiverse Malaysia.

“Greater than 80 p.c of rivers within the Klang Valley have been invaded by international fish species, which may trigger the extinction of the rivers’ indigenous aquatic life,” mentioned Dr Kalithasan Kailasam, a river professional with the Malaysia-based World Setting Centre.

“It’s rising in virtually all different primary rivers in Malaysia,” mentioned Kailasam, explaining how species such because the suckermouth have the potential to shortly reproduce and survive in soiled water, leaving native fish on the shedding aspect.

Except for the suckermouth, Malaysia’s waterways are actually threatened by species such because the aggressive peacock bass, Javanese carp and redtail catfish, he mentioned.

Whereas the complete extent of the issue shouldn’t be but recognized, Malaysia’s fisheries division, after a four-year research till 2024, discovered invasive species in 39 areas throughout practically each state in peninsular Malaysia and on the island of Labuan, together with in dams, lakes and main rivers.

Alarmed by the risk, a small group of residents banded collectively to combat the aquatic invaders.

Led by Haziq, they’re working to reclaim Malaysia’s rivers one fin at a time.

Invasive fish invasion

The citizen fish hunters’ quest to combat invasive species began through the nation’s COVID-19 lockdowns, when Haziq, a former healthcare advisor, turned to fishing as a pastime in a river close to his home in central Selangor state. He discovered each fish he caught was of the suckermouth selection, also referred to as the “pleco” or “ikan bandaraya” – which interprets because the “janitor fish” in Malay and is favoured by hobbyists to maintain aquariums clear, because the suckermouth feeds on algae, leftover meals and lifeless fish.

Native to South America, forms of the suckermouth have additionally been launched into waterways in the USA, Bangladesh, and Sri Lanka, typically when house owners dump them into rivers, canals, dams or free them after they develop too massive for his or her aquarium tanks.

Due to their thick, scaly pores and skin, suckermouths are often prevented by even bigger predators in Malaysia, and might develop to about half a metre (1.6ft) in size.

As backside feeders, the catfish have been recognized to eat the eggs of different species and destroy their nesting websites. Catfish additionally burrow into riverbanks to nest, inflicting them to erode and collapse, which is a severe environmental situation in flood-prone Malaysia the place year-end monsoon winds carry heavy rain.

Malaysia’s central financial institution mentioned in 2024 that floods are the reason for 85 p.c of the nation’s pure disasters, with their frequency growing since 2020.­

Although removed from his favorite fish to catch, Haziq found that suckerfish roe may very well be used as bait for different larger fish, and he earned some cash promoting their eggs to different fishing fans. He additionally gained a following by placing his exploits on social media. Additional analysis then led him to be taught in regards to the threats posed by invasive species.

Harziq began to draw like-minded anglers, and, in 2022, they determined to type a bunch for searching suckermouth, assembly practically each week in a river to hold out a cull.

Their public profile and recognition are rising. The group’s membership has now grown to greater than 1,000, and it has a robust fan following on social media.

“Individuals stored asking the right way to be part of our group, as a result of we had been wanting on the ecosystem,” Haziq mentioned.

Focusing first on Malaysia’s Selangor state and rivers within the capital Kuala Lumpur, the fish hunter squad netted practically 31 tonnes of suckermouths alone in 2024. They’ve additionally visited rivers in different states in Malaysia as their marketing campaign expands.

Dispose, use for analysis, or prepare dinner and eat?

Throughout a hunt within the Klang River earlier this 12 months, Haziq and his comrades deployed to the river’s banks on a mission to see what number of suckermouth they might catch throughout a single outing.

However looking for invasive fish will be tough. With out boats, the hunters must wade into the fast-moving polluted waters from muddy banks, whereas navigating underwater particles similar to garbage on the riverbed.

Virtually all of the fish they caught had been of the invasive type, however now and again, they do internet a neighborhood.

“Haruan (snakehead)!” shouted ex-navy diver Syuhaily Hasibullah, 46, as he confirmed off a small fish half the scale of his arm, taken from a internet containing a number of suckermouths.

“This one is uncommon! There was loads of them within the river,” he informed Al Jazeera.

Haziq mentioned if the hunters discovered many invasive species of their nets, they might organise one other outing to the identical location, bringing alongside extra folks to participate.

The day they got down to calculate what number of invasive fish they might catch in a single outing turned out to yield half a tonne of suckermouth in simply three hours – so many they needed to stuff them into sacks.

Beforehand, the hunters buried their hauls in deep holes away from the river. Now, they’ve discovered extra artistic methods to dispose of what’s, usually, an undesirable fish.

On the occasion earlier this 12 months, sacks of suckermouths had been handed over to a neighborhood entrepreneur seeking to experiment with turning the fish right into a type of charcoal referred to as biochar.

Some native universities have additionally began researching the attainable use of the suckermouth. One college analysis article explored the potential of suckermouth collagen for pharmaceutical use, whereas one other thought of its use as fertiliser and even as a kind of leather-based.

On some events, the hunters even eat the fish they catch, although that is determined by which river they’ve been taken from.

Whereas redtail or African catfish are thought of delicacies by some, the suckermouth, additionally recognized in India as “satan fish”, is a much less engaging snacking possibility – however not out of the query with regards to a fast riverside grill.

“If the fish is from the Klang River, we don’t eat it,” Mohd Zulkifli Mokhtar informed Al Jazeera, earlier than dozens of hunters broke their quick through the holy Muslim month of Ramadan.

“But when it’s from the Langat River, it’s nonetheless OK,” Zulkifli mentioned, as dozens of suckermouth caught within the much less polluted Langat River, situated in Bangi some 25km (16 miles) south of Kuala Lumpur, had been gutted, marinated in satay and grilled on skewers.

Research from Bangladesh and Indonesia have discovered forms of catfish with excessive ranges of heavy metals and contaminants. A 2024 article by Malaysia’s Universiti Teknologi Mara cited a research that confirmed the extent of contaminants within the suckermouth was “closely influenced by the extent of air pollution within the river”.

‘If we don’t act now, it could be worse’

Whereas Malaysia’s fisheries division mentioned there have been no data of native species turning into endangered due to invasive ones, native fish however face threats.

Native fish both confronted turning into prey or have needed to combat to outlive, with the division discovering in a survey that 90 p.c of the fish in six rivers within the Selangor and Kuala Lumpur area had been now international arrivals.

The division’s Director-Basic Adnan Hussain mentioned numerous measures had been put in place, together with the discharge of some 33.6 million native fish and prawns into rivers nationwide from 2021 to 2025 to “steadiness the affect” of invasive fish.

Late final 12 months, the state authorities of Selangor additionally got here up with a scheme to pay anglers one Malaysian ringgit ($0.23) for each kilogramme (2.2lb) of the suckermouth fish faraway from two rivers. The captured fish had been to be was animal feed and natural fertiliser, an official mentioned.

Restrictions on the import of sure international aquatic species – together with whole species and teams – into Malaysia had been additionally imposed final 12 months, and he added that programmes and collaboration with the fish hunters had additionally helped to take care of the issue.

In a single river in Selangor state, Adnan mentioned the quantity of invasive fish caught following one eradication programme had dropped from 600kg (1,300lb) in a Could 2024 occasion to only greater than 150kg (330lb) 4 or 5 months later.

Nevertheless, Universiti Malaysia Terengganu fish researcher Professor Amirrudin Ahmad mentioned it was “virtually not possible” to totally exterminate the nation’s invasive fish.

“So many species reside in (native water our bodies) and eliminating invasive species by the technique of poisoning the water shouldn’t be possible in any respect,” he mentioned, including there have been near 80 recorded fish species launched in Malaysia thus far.

He additional warned that rising temperatures attributable to local weather change might even enable species just like the predatory Mekong redtail catfish to proliferate in cooler upstream waters in Malaysia.

“They’re right here to remain,” Amirrudin mentioned.

“It’s merely,” he mentioned, “that the atmosphere is usually just like their native nation, or these species are extremely adaptable.”

That that is an ecological battle that may by no means actually be received is some extent that Haziq and his fellow fish hunters are totally conscious of. Almost each river they visited in latest instances had virtually nothing however invasive fish, he mentioned.

However their mission will stick with it, he added, together with the searching and public consciousness that has spurred 1000’s to comply with his social media movies on the topic.

“Sure, this fish received’t be fully gone from our rivers,” he informed Al Jazeera.

“But when we don’t act now, it could be worse,” he mentioned.

“It’s higher to take motion than to only go away it alone,” he added.

“No less than we will cut back the inhabitants, than enable it to fully take over our native fish.”