Researchers in Nepal have discovered a new resident in the morang’s waterways – the Pterygoplichthys disjunctivus, a fish native to South America’s Amazon River.
The discovery was made four years ago in the Belbari River by a team led by Jash Hang Limbu, Dipak Rajbanshi, Asmit Subba, and Laxman Khanal. Suspecting it to be a new species, they closely monitored the fish. With the help of Chinese researchers Jin-Quan Yang, and Chenhong Li, they confirmed it was indeed a new species for Nepal.
Their findings were published in the journal ‘Bioinvasions Records’. The research involved collecting 43 samples from the Lohandra River. This fish was only found in two locations – the Lohandra and another river near Damak – out of 50 permanent river sites surveyed in eastern Nepal.
While initially appearing docile, researchers warn that this fish poses a threat to Nepal’s native fish population.
Jashang Limbu suggests two possible ways this fish arrived in Nepal: escape from an aquarium or introduction from neighboring India. Regardless of origin, researchers are concerned about the fish’s impact on the local ecosystem.
Their primary concern is the Pterygoplichthys disjunctivus’ varied diet. While it consumes algae and detritus, it also feeds on small fish and fish eggs. This behavior could disrupt the food chain and harm native fish populations.
Researchers have observed a rise in the Pterygoplichthys disjunctivus population in the Lohandra River since 2019. They fear it could spread to other rivers and aquaculture ponds, causing significant damage to Nepal’s commercial fishing industry.
The research team emphasizes the need for immediate action to control this invasive species. They recommend further research and policy-level intervention. They warn that inaction could threaten the livelihoods of fishermen, cause financial losses, and disrupt the delicate balance of Nepal’s aquatic ecosystem.
This discovery highlights the importance of biosecurity measures to prevent the introduction of non-native species that could harm the environment and local economies.
Nepal has approximately 260 fish species, including the newly discovered Pterygoplichthys disjunctivus. Of these, 18 are non-native, while 17 are unique to Nepal.
