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Sturgeons are worst victims of global biodiversity crisis

We are emptying our rivers

The Living Planet Report 2022 by World Wildlife Fund has shown that animal populations have plummeted all across the world in less than fifty years. Freshwater species' homes in rivers are the worst hit of all groups. Migratory fish species that include sturgeon have declined by over three quarters! 

Graph: World Wildlife Fund (2022)

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We care for animals but overlook some

The recent report State of the World's Migratory Species makes use of IUCN's so-called Red List Index. Species near one (1) on the index are of least concern while those near zero (0) are nearing extinction. According to this index, sturgeons are the most threatened species group on Earth!  Despite this, humanity's gaze is still mostly fixed on large mammals like lions, elephants and whales whereas underwater extinctions of the less fashionable species go unnoticed. 

Graph: Convention on Migratory Species (2024)

Threats in the Danube

Blockage of passageways

The Danubian countries have reaped great benefits from river infrastructure, including flood safety, navigation and hydropower as source of renewable energy. On the other hand, current dams are constraining the last sturgeon populations to the Lower Danube. 

Picture: Friedrich (2010)

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Illegal poaching persists

Already constrained to a smaller portion of the Danube, sturgeons face extreme pressure from illegal poaching. Not only their caviar is sought after, but also their meat. Although sturgeon fishing has been outlawed by countries in the region, wild species are still traded in fish markets. Also, the war in Ukraine has limited conservation funding for monitoring and enforcement of these laws.

Picture: EUREPORTER

Climate change-induced droughts

The Danube is suffering more and more droughts, the last being in 2022, 2017 and 2015. When a river runs dry, concentration of pollutants increases and oxygen levels decrease, creating a toxic cocktail for fish. Droughts also have economic ramifications for boat navigation, tourism and communities on the banks of the river. 

Picture: ICPDR

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Gravel mining and erosion river beds

After migrating upriver, sturgeons shed their eggs on gravel backs where they stick small stones. The extraction of gravel for industry and river straightening that creates stronger currents lead to more banks of the river becoming unsuitable for reproduction.

Picture: NETBID

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