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

Puchong, Malaysia – On a latest Sunday morning, a couple of 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 lads forged their nets into the polluted water. The nets billowed open and sunk rapidly below the burden of metallic chains.

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

“You don’t see another fish. Solely these,” mentioned Mohamad Haziq A Rahman, the chief of Malaysia’s “overseas 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 real 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 business or hobbyist causes, invasive fish aren’t solely threatening to edge native species out of the meals chain in Malaysia and elsewhere, however additionally they unfold ailments and trigger nice harm to native environments.

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

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

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

Apart from the suckermouth, Malaysia’s waterways at the moment are threatened by species such because the aggressive peacock bass, Javanese carp and redtail catfish, he mentioned.

Whereas the complete extent of the issue is just not but identified, Malaysia’s fisheries division, after a four-year research till 2024, discovered invasive species in 39 areas throughout almost 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 struggle 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 struggle invasive species began in the course of 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 called 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 useless fish.

Native to South America, sorts 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 may develop to about half a metre (1.6ft) in size.

As backside feeders, the catfish have been identified 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 critical environmental situation in flood-prone Malaysia the place year-end monsoon winds convey heavy rain.

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

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

Haziq began to draw like-minded anglers, and, in 2022, they determined to kind a bunch for searching suckermouth, assembly almost 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 powerful fan following on social media.

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

Focusing first on Malaysia’s Selangor state and rivers within the capital Kuala Lumpur, the fish hunter squad had netted almost 31 tonnes of suckermouths by 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 yr, Haziq and his comrades deployed to the river’s banks on a mission to see what number of suckermouth they may catch throughout a single outing.

However trying to find invasive fish might be tough. With out boats, the hunters need to wade into the fast-moving polluted waters from muddy banks, whereas navigating underwater particles reminiscent of garbage on the riverbed.

Nearly all of the fish they caught had been of the invasive sort, however now and again, they do internet an area.

“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 once numerous them within the river,” he advised 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 individuals to participate.

The day they got down to calculate what number of invasive fish they may 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 inventive methods to dispose of what’s, usually, an undesirable fish.

On the occasion earlier this yr, sacks of suckermouths had been handed over to an area entrepreneur trying to experiment with turning the fish right into a type of charcoal often called biochar.

Some native universities have additionally began researching the doable 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 sort 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 identified in India as “satan fish”, is a much less engaging snacking choice – however not out of the query on the subject of a fast riverside grill.

“If the fish is from the Klang River, we don’t eat it,” Mohd Zulkifli Mokhtar advised Al Jazeera, earlier than dozens of hunters broke their quick in the course of 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, positioned 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 sorts 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 will 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 struggle to outlive, with the division discovering in a survey that 90 % of the fish in six rivers within the Selangor and Kuala Lumpur area had been now overseas arrivals.

The division’s Director-Common Adnan Hussain mentioned varied 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 “stability the affect” of invasive fish.

Late final yr, 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 became animal feed and natural fertiliser, an official mentioned.

Restrictions on the import of sure overseas aquatic species – together with total species and teams – into Malaysia had been additionally imposed final yr, and he added that programmes and collaboration with the fish hunters had additionally helped to cope with 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 Might 2024 occasion to simply greater than 150kg (330lb) 4 or 5 months later.

Nonetheless, Universiti Malaysia Terengganu fish researcher Professor Amirrudin Ahmad mentioned it was “virtually unattainable” 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 is just not 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 brought on by local weather change could even permit 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 setting 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 gained is some extent that Haziq and his fellow fish hunters are absolutely conscious of. Practically each river they visited in latest occasions had virtually nothing however invasive fish, he mentioned.

However their mission will keep it up, 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 gained’t be utterly gone from our rivers,” he advised Al Jazeera.

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

“It’s higher to take motion than to simply depart it alone,” he added.

“At the least we will scale back the inhabitants, than permit it to utterly take over our native fish.”