Because of dam building, freshwater fish are in catasrophic decline. It is more black nature news. David Attenborough recently said that we should try and present some good, optimistic news about nature and the environment. I agree because nature news is not all bad but there is so much that is bad it is hard to sidestep it. It is like walking down a pavement strewn with dog turds. This news is one such example. What are called ‘megafish’, large freshwater fish such as the beluga sturgeon and the Mekong giant catfish weighing more than 30 kilograms have halved in numbers since the 1970s.
Threatened with extinction? One third of the 10,000 assessed species of freshwater fish globally. This is according to 16 zoological organisations such as the Zoological Society of London, IUCN and WWF.
Last year, sixteen species became extinct including the Chinese paddlefish. This freshwater fish inhabited the Yangtze River and grew to seven meters in length. Initially overfishing caused a decline in population but they’ve been made extinct by the building of dams on the river as the fish can’t reach spawning grounds.
The 16 organisations are asking governments to implement a six point recovery plan:
- Allow rivers to flow more naturally;
- remove obselete dams;
- improve water quality;
- protect critical habitats;
- end overfishing and;
- control invasive species.
In Britain the sturgeon and burbot have disappeared (extinct?) while the population size of salmon has declined dramatically since the 1960s. Also the European eel is critically endangered.
Most UK rivers suffer from agricultural pollution, sewage spills or modifications to river flow by dams. One third of the world’s rivers are allowed to flow freely but many are threatened with hydropower plants (dams and other constructions).
Barriers such as dams, weirs and culverts have stopped migratory fish behavior. Salmon have declined by 76% since the 1970s. In Europe there are 100,000 obsolete man-made barriers in rivers out of a total of one million.
“Freshwater habitats are in catasrophic decline. Nature is in freefall and the UK is no exception: wildlife struggles to survive in our polluted waters.” — Dave Tickner of WWF.
Black nature news indeed.
Comment: It won’t change. Overly pessimistic? No, realistic. Covid-19 will make it even harder to tackle environmental and conservation problems as cash is short. Countries have accrued more national debt. The purse strings are being drawn. There is no cash and it will take trillions of US dollars to fix this catastrophic problem. And committment to change our ways is also in short supply as humans struggle to survive themselves in an ever more competitive and aggressive world created in the human image. And as there are more people the need for more electrical power increases so there will be more dams. Also electric cars (EVs) will take more electrical power to charge them. There is a negative to EVs. It’s horrible and depressing. I’ll try and think of something happy to write about next but I’ll struggle.