maximum length. One of the largest freshwater fish.
1 of 16
species that disappeared in 2020.
Loss of biodiversity and ecological functions
(e.g. relaxation of top-down control of prey populations)
Dams are not the only reason why these fish go extinct, but they play an important role. Around the world, more than 40,000 large dams have been built since the 1950s, and 3,700 further dam projects are pending. Many of these projects are planned in areas that are considered biodiversity hotspots, including the Amazon, Congo and Mekong Rivers.
Freshwater ecosystems represent only 1 per cent of Earth’s area but host more than 51 per cent of the known fish species, which provide the equivalent of the total animal protein consumption of 158 million people. IUCN declared at least 80 freshwater fish extinct, and one out of every three freshwater fish species is threatened by extinction. In the last 50 years, the population of migratory fish has fallen by 75 per cent; in the same time period the population of larger fish species has fallen by 94 per cent.
A world without freshwater fishes is a very concerning (and depressing) one, particularly for developing countries where fishing represents the main source of income and fish are part of the daily basic diet.
It is estimated that these dams will alter 93 per cent of the river volume worldwide, which means they have an impact on almost all global habitats of freshwater fish.