Fish Populations Collapsing

July 29, 2020

But there is hope.

Conflict between hydropower and wildlife. As more dams are removed, populations can rebound.
This is why the credible plans for decarbonizing do not include more new hydro.

AFP via Courthouse News:

PARIS (AFP) — Populations of migratory river fish collapsed by 76% on average in the last 50 years, according to a report by conservation groups Tuesday, warning the “catastrophic” declines could impact people and ecosystems around the world.

Overfishing and loss of habitat have had a devastating impact on migratory fish, according to the research by groups including the International Union for the Conservation of Nature, WWF, World Fish Migration Foundation and the Zoological Society of London.

Almost one in three of all freshwater species are threatened with extinction, the report said, with migratory fish “disproportionately threatened.”   

The study looked at 247 species of fish from around the world and found that their populations had declined on average 3% per year between 1970 and 2016. 

Europe saw the sharpest falls of the regions studied, with a drop of 93%, while populations had shrunk an average of 84% in Latin America and the Caribbean.

“Catastrophic losses in migratory fish populations show we cannot continue destroying our rivers,” said Arjan Berkhuysen, managing director of the World Fish Migration Foundation. 

“This will have immense consequences for people and nature across the globe. We can and need to act now before these keystone species are lost for good.”

Migratory fish such as salmon, trout and Amazonian catfish support the livelihoods of millions of people around the world, researchers said.

The study found a lower decline of 28% in North America, where there has been a movement to remove dams and protect habitats, and argued that this indicated the potential effectiveness of fishery management.

Large fish such as the beluga, a sturgeon, or the giant Mekong catfish, are particularly vulnerable, it said, adding that dams and other obstacles blocked migrations that are crucial to their life cycles. 

“Habitat degradation, alteration, and loss accounted for around a half of threats to migratory fish, while over-exploitation accounted for around one third,” the report said.   

The main threats to fish species in Europe were dams and other waterway blockages, counting 1.2 million obstacles across the continent, said the report. 

But it said that the tide was turning, with a European Union plan to restore 15,534 miles of free-flowing rivers by 2030.

The report stressed that it could not provide a full global picture because of a lack of data for Africa, Asia, Oceania and South America.

8 Responses to “Fish Populations Collapsing”

  1. doldrom Says:

    Some hope, nevertheless terrifying

  2. Brent Jensen-Schmidt Says:

    When it is a choice between bad and worse, take the lesser one. Cutting hydro for the benefit of specific fish is a trifle hippie-dippy.

  3. dumboldguy Says:

    Ho-hum—-no surprises here. Just another one of those things that we are way behind on. Don’t forget that once the migratory species reach the ocean, they are vulnerable to overharvesting and the negative impacts of the deteriorating ocean habitat.

  4. J4Zonian Says:

    According to Derrick Jensen and others there are 2 million dams just in the US, with 70,000 dams over six feet tall and 60,000 dams over thirteen feet tall. Most are not used for power though many could be, while the rest could be torn down to improve overall ecological health.
    https://orionmagazine.org/article/world-at-gunpoint/

    We can also build run-of-the-river hydro that has less effect on the river ecology. Though not as dispatchable as dammed hydro, it generally complements solar, soon to be by far the cheapest energy source. So overbuilding solar somewhat, adding some batteries, some pumped storage where it will do the least ecological harm, and using some of the many small dams can improve the energy supply and our rivers’ ecological health.

    • rhymeswithgoalie Says:

      Aye, run-of-the-river or some hybrid reservoir that retains access.

      There is also the problem that DOG pointed out, where once they get to the open ocean they’re overfished.

      Add another AGW problem: Many streams are drying up and/or suffering from temperatures too high for the indigenous fish to thrive.


  5. Reblogged this on The Most Revolutionary Act and commented:
    Overfishing and loss of habitat have had a devastating impact on migratory fish, according to the research by groups including the International Union for the Conservation of Nature, WWF, World Fish Migration Foundation and the Zoological Society of London.


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