Humans have severely damaged more than half of the world’s rivers

The Oyapock river, between Brazil and French Guiana, is one of the few waterways that a new paper identifies as being relatively undamaged by humans.

Two recent assessments of the world’s freshwater ecosystems catalogue the scope and severity of human impact on these once-bountiful, biodiverse habitats that contain a quarter of the world’s known vertebrate species.

Humanity’s ever-expanding footprint has slashed biodiversity in more than half of Earth’s freshwater river basins, with only 14 percent remaining pristine, according to new research published last week in the journal Science. This week, 16 conservation organizations released a global assessment of the world’s freshwater fish species, finding nearly a third are at risk of extinction. This most recent assessment, titled The World’s Forgotten Fishes, also finds that the biggest fishes—species weighing more than 60 pounds—have undergone a particularly calamitous decline, with their numbers plummeting by 94 percent over the past half century.

The World’s Forgotten Fishes frames this lost biodiversity—the 80 species declared extinct, 16 disappearing in 2020 alone—as not just a tragic draining of our planet’s natural beauty and evolutionary grandeur, but levies a heavy human cost. Some 200 million people are fed by protein from freshwater fishes and 60 million people depend on hauling in that essential catch to support themselves and their families.

Perhaps unsurprisingly, the researchers behind the paper in Science observed that the river basins surrounded by heavy human presences were the most severely degraded, reports Karina Shah for New Scientist.

Carmen Revenga, a senior fisheries scientist at the Nature Conservancy, tells BBC News, “it’s now more urgent than ever that we find the collective political will and effective collaboration with private sector, governments, NGOs and communities, to implement nature-based solutions that protect freshwater species, while also ensuring human needs are met.”

https://www.smithsonianmag.com/smart-news/two-studies-chart-decline-freshwater-fish-180977106/

Certainly buggered all the rivers around here.

Given how easy it is for any freshwater fish species to go extinct, it continually amazes me that there are any freshwater fish species ar all.

Let’s take an example, the ice ages. Not so long ago. There were no freshwater fish species surviving under the ice sheets.
Land animals, ocean animals, could move out of the way of the ice sheets. Freshwater fish couldn’t.
Or when a toxic plant decides to take up residence beside a river.
Or when a toxic algal bloom takes over a river.
Or when there’s a drought.

Or even Lake Baikal. For freshwater fish there was no way in, and no way out except through salt water. So how come it’s full of freshwater fish.

As I say, how the heck could so many freshwater fish species have actually survived to the present day?

The water quality of Home Bush Bay in the 60’s to 80’s was pretty bad and I think my mother suggested that the Parramatta River was almost considered dead at some point during the 40’s to the 70’s.

The Lane Cove river changed over years in my childhood, the Murray river has ongoing issues , The Snowy river had its need for more flows after the Snowy Mountain Scheme originally came into being as we all learned later on.

The Murrumbidgee was very sediment affected from soil erosion that I noted in the 70’s and the Macquarie river and Macquarie Marshes have been affected by severe droughts and more recently the big bush fires across the regions too.

And the Castlereagh river is absolutely infested with carp , which compounded by low flows for most of the year these days that I observed.

monkey skipper said:

The water quality of Home Bush Bay in the 60’s to 80’s was pretty bad and I think my mother suggested that the Parramatta River was almost considered dead at some point during the 40’s to the 70’s.

The Lane Cove river changed over years in my childhood, the Murray river has ongoing issues , The Snowy river had its need for more flows after the Snowy Mountain Scheme originally came into being as we all learned later on.

The Murrumbidgee was very sediment affected from soil erosion that I noted in the 70’s and the Macquarie river and Macquarie Marshes have been affected by severe droughts and more recently the big bush fires across the regions too.

And the Castlereagh river is absolutely infested with carp , which compounded by low flows for most of the year these days that I observed.

And Australia is regarded as a country with better ecological managed freshwater rivers.

PermeateFree said:

monkey skipper said:

The water quality of Home Bush Bay in the 60’s to 80’s was pretty bad and I think my mother suggested that the Parramatta River was almost considered dead at some point during the 40’s to the 70’s.

The Lane Cove river changed over years in my childhood, the Murray river has ongoing issues , The Snowy river had its need for more flows after the Snowy Mountain Scheme originally came into being as we all learned later on.

The Murrumbidgee was very sediment affected from soil erosion that I noted in the 70’s and the Macquarie river and Macquarie Marshes have been affected by severe droughts and more recently the big bush fires across the regions too.

And the Castlereagh river is absolutely infested with carp , which compounded by low flows for most of the year these days that I observed.

And Australia is regarded as a country with better ecological managed freshwater rivers.

Future proofing nations for access to freshwater and balancing that with environmental needs is something worth achieving.