Malaysia: Hobbyists should not dump alien fish in rivers

ROSLI ZAKARIA New Straits Times 22 Feb 19;

KUALA TERENGGANU: The damage is done. The invasion of the Mekong red tail catfish in Malaysian rivers is irreversible. Only time will tell the fate of the indigenous fish species.

Researchers are worried that the repeated mass spawning of the red tail catfish, also known as the Asian red tail catfish, means a nearly 100 per cent fry survival rate. And in a few years, this species could occupy every available space in the rivers.

“Rivers in Malaysia are not long or wide like the Chao Phraya River or Mekong River, where the red tail catfish originates.

“This species will devour any live food, and can grow to monstrous sizes. I am worried about the future of our local species,” said Dr Amiruddin Ahmad, a senior lecturer (Ecology) at the School of Marine and Environmental Sciences, Universiti Malaysia Terengganu (UMT), in Gong Badak.

He said the best method to remove the fish was by using fishing techniques, especially baited traps. Once caught, the red tail catfish should be removed from the habitat.

“Long lines or angling is also possible. Gill netting is the least favoured as other fish species may die,” he said.

He said he believed that the giant fish had adapted to the new environment, which is not much different from its native habitat.

“With its large appetite and size, it’s easy for the fish to obtain food.

“This creates competition with local species that occupy and play a similar role in local waters, such as our ikan baung (Mystus spp).

“There isn’t much that can be done.

“We at UMT are keen to reduce, if not eliminate, this species from our water bodies.

“For now, we can only provide locals with information about the introduced species and the dangers that the species pose.

“They must be educated on the effect of these fishes on our native ones.

“This is a challenge, but public awareness is necessary to stop people from introducing alien species into our rivers. Consistent catching programme and monitoring are needed.

“The future of local species is affected, but the rate and how severe it will be is hard to tell unless a monitoring programme is implemented.

“But for now, we know that the red tail catfish is dominating the environment as more of the species are being landed by fishermen.

“Fewer local species caught also suggests that the threat is serious and real,” he said.

The Fisheries Department, he said, should eradicate alien predatory species and the quarantine administration should stop the influx of unwanted foreign species before they caused bigger problems in the rivers and to other local species.

“I wish aquarium owners and hobbyists were more responsible and not release alien predatory species when they no longer want to keep them.

“I also wish to see the authorities play an active role in eradicating these alien species.

“The government needs to take a more serious stand in caring for our environment, especially the aquatic ecosystem.”

Aqmal Naser, a PhD student at UMT and who has been involved in research for five years studying ichthyofauna on rice agroecosystem in Seberang Prai, Penang, said preliminary observation showed that the African catfish, which was harvested for local consumption, fed on local species.

“This observation was made in a padi field. This fish (African catfish) may bring disruption to the depauperated ecosystem,” said Aqmal, who is studying inland fishes in rivers and streams flowing into the reservoirs of Kenyir and Temenggor, where there has been a decrease in fish population.

“We are losing inland water bodies to land conversion, and our rivers and streams are being invaded by alien species. The future looks scary for local fishes as more alien species are being landed.”


Swiss expert fears for local fish species
ROSLI ZAKARIA New Straits Times 22 Feb 19;

KUALA TERENGGANU: Biotope specialist Ronny Kyller, 30, travelled 3,200km from Switzerland to spend eight days in Malaysia to check the marine ecosystem and ensure that the habitat of some of the rarest fish is not disturbed.

“Malaysia is not the Amazon, but it is home to some of the rarest fish species and a destination loved by ichthyologists.

“Like everywhere else, its sustainability is under pressure from progress and habitat loss.

“I was told that some rivers are infested by alien predatory fish and I am worried about the future of the local species in these rivers,” he said while sampling fish in a swamp in Kemaman near here.

He said releasing alien predatory fish into rivers in Malaysia would upset the ecosystem, adding that there was a risk of indigenous species being wiped out either by predatory fish or viruses.

Kyller is popular among ichthyologists in Switzerland and Europe for sampling rare species from Malaysia and other tropical nations.

“In the United States, the authorities drained water from ponds, lakes and rivers just to get rid of the Channa striata or snakehead (haruan) and predatory species. They fear that these alien species could wipe out the local fish species.

“They are serious about the invasion of predatory species, even if it provides entertainment for sports anglers. The authorities here (in Malaysia) can learn from the US fishery and wildlife authorities on containment and preventive measures.

“It will be sad if one day, Sungai Kemaman, Sungai Perak and Sungai Pahang become a new home for the Mekong redtail catfish, Amazon catfish, African catfish, piranhas, arapaima gigas and peacock bass.

“It will be a disaster for fishermen. I hope the local enforcement agencies will check the entry of foreign species to ensure they are not predatory. It is also important to tighten the quarantine process to make sure all fishes are free of harmful bacteria or viruses.”

Kyller said he would return again next year to check the health of biotopes in rivers.

“I don’t mind travelling and spending money to ensure that the fish and their habitat remain intact.

“If it is disturbed or under threat, I will relay such information to ichthyologists in Europe, who may start a rehabilitation campaign to save these species from extinction.”


Fisheries Dept needs researchers' help to combat predatory alien species
ROSLI ZAKARIA New Straits Times 27 Feb 19;

KUALA TERENGGANU: Researchers in ichthyology (fish science) are urged to assist the state Fisheries Department by providing information on the locality of alien predatory fishes in Terengganu’s river systems so that it can carry out mitigation measures.

“It is important that researchers receive the approval of the authorities before conducting sampling in rivers for security reasons and to enable proper follow-up action to be taken,” the state Fisheries Department said in a statement.

It said the department viewed the invasion of alien predatory fish seriously, as reported recently in the New Straits Times.

“The African catfish (Clarias gariepinus) is an alien species which is allowed to be raised just like tilapia and carp to meet local demand for fish.

“These fish are reared in ponds, cages and fish tanks under controlled conditions.

“Last year, 890 fishermen in Terengganu were involved in aquaculture projects and 31 of them,l or 3.48 per cent, were from Kemaman.

“Of the 31 participants, 16 reared African catfish, patin (a species of local catfish), tilapia and puyu (climbing perch) in Felda Cerul.

“We also have six ornamental fish participants in Cukai, and two participants rearing tilapia and barramundi in cages in Sungai Kemaman.

“The others are located in the interior of Kertih and Seri Bandi.”

It added that the department’s resource protection unit monitored and engaged with the aquaculture projects participants regularly, and also inspected the premises to ensure that biosecurity procedures were adhered to.

“In 2014, we conducted an inspection on inventories in Sungai Kemaman and found no alien species. In 2017, when the department held a fishing competition, which attracted 1,000 participants, none of the anglers caught any alien species.

“However, we will continue with our inventories to check for the presence of alien predatory fish species.

“But, at the same time, we need support from researchers to provide us with information on these fish species,” it added.