Freshwater fishes decline seriously

Fishermen in Mekong River Delta says that for the last few years, their livelihood has faced many difficulties due to the decline of freshwater fishes. They hardly find giant barb - a typical fish in the region. Almost all freshwater fishes currently sold in the market are raised at farms.

Big floods nearly disappeared in Mekong River Delta for the last few years. No flood water overflows onto fields, so there are not favourable conditions for fish proliferation.

Associate Professor and Doctor Tran Dac Dinh from Aquaculture Department of Can tho University said that there was not a completed report on the decline of freshwater fishes in the Mekong River Delta but studies in particular areas, ecozones in particular time showed that in the last ten years, aquacultural diversification in general and freshwater fishes in particular declined about 30-60 per cent.

Improper fishing and ecological degradation were two main causes for the decline, he said, adding that the constructions of dams/hydropower plants, environmental pollutions and urbanisation led to the ecological degradation.

According to World Wildlife Fund, a report published late February 2021 by 16 global conservation organisations found that the world’s dazzlingly diverse freshwater fishes are critical for the health, food security and livelihoods of hundreds of millions of people, but they are under ever-increasing threat with one in three already threatened with extinction, according to

The report “World’s Forgotten Fishes” details the extraordinary variety of freshwater fish species, with the latest discoveries taking the total to 18,075 - accounting for over half of all the world’s fish species and a quarter of all vertebrate species on Earth.

In the Mekong river alone, there are 1,148 species and the river host 4 of the world’s 10 largest freshwater fish. This wealth of species is essential to the health of the world’s rivers, lakes and wetlands - and supports societies and economies across the globe.

Freshwater fisheries provide the main source of protein for 200 million people across Asia, Africa and South America, as well as jobs and livelihoods for 60 million people.

In Vietnam, fish is one of the most popular sources of animal protein 30 - 35% of protein consumption of Vietnamese people is derived from fish products. It is estimated that some Healthy freshwater fish stocks also sustain two huge global industries: recreational fishing generates over US$ 100 billion annually, while aquarium fishes are the world’s most popular pets and drive a global trade worth up to US$ 30 billion.

But freshwater fishes continue to be undervalued and overlooked - and thousands of species are now heading towards extinction.

Freshwater biodiversity is declining at twice the rate that in our oceans or forests. Indeed, 80 species of freshwater fish have already been declared ‘Extinct’ by the IUCN Red List of Threatened Species, including 16 in 2020 alone. In our region, the Mekong Giant Catfish are both listed as critically endangered. Meanwhile, populations of migratory freshwater fish have fallen by 76 per cent since 1970 and mega-fish by a catastrophic 94 per cent.

The report highlights the devastating combination of threats facing freshwater ecosystems – and the fishes that live in them – including habitat destruction, hydropower dams on free-flowing rivers, over-abstraction of water for irrigation, and domestic, agricultural and industrial pollution.

Besides, freshwater fishes are also at risk from overfishing and destructive fishing practices, the introduction of invasive non-native species and the impacts of climate change as well as unsustainable sand mining, which alter fish biosphere and stocks, and wildlife crime.  

“Nowhere is the world’s nature crisis more acute than in our rivers, lakes and wetlands, and the clearest indicator of the damage we are doing is the rapid decline in freshwater fish populations,” said Stuart Orr, the World Wildlife Fund global Freshwater Lead.

“Despite their importance to local communities and indigenous people across the globe, freshwater fish are invariably forgotten and not factored into development decisions about hydropower dams or water use or building on floodplains. Freshwater fish matter to the health of people and the freshwater ecosystems that all people and all life on land depend on,” he said.