An eel.

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ARDEA / MARY EVANS / SIPA

  • The Seine has been populated with more varied fish since the start of the fight against pollution.

  • Migrating fish suffer from fishing and dams.

  • At the beginning of the 19th century, you could even see porpoises in Paris.

“In 2000, we won the fishing competitions with 30-40 kg of bream.

Today, it is with 2-3 kg of fish but sometimes 10 different species.

“Less quantity but more variety in the fish from the Seine, this is the observation made by Bernard Breton.

In forty years of practice, the president of the regional association for fishing and the protection of the aquatic environment of Ile-de-France has had time to see species multiply, in particular thanks to the quality of the water.

"At the end of the Second World War, the state of the rivers was catastrophic: we discharged our agricultural, industrial, chemical or domestic effluents", explains Florian Kirchner, in charge of the "species" program at the French committee of the International Union for nature conservation (IUCN).

An analysis shared by Philippe Keith, professor at the National Museum of Natural History: "The quality of water has generally improved over the past fifteen years because a lot of efforts have been made to stop chronic pollution or to purify the water. water ”.

It is mainly thanks to the treatment plants that the water quality has improved.

"Is it enough to find fish communities as they were at the beginning?"

Obviously, no!

He warns, however.

Dams, pollution, fishing ... the cumulative threats

In France, 39% of freshwater fish species (river, river, lake, etc.) are threatened or almost threatened with extinction * according to the IUCN red list of freshwater fish.

If the salmon - which had deserted the Seine - have been returning since the early 2000s (around 100 would cross Paris per year according to fishermen's estimates), this is not the case for other migratory fish.

Certain species native to the Seine, such as the eel, the sea lamprey or the large shad, are endangered and others have already disappeared such as the sturgeon.

Migrating fish, they live part of their cycle in freshwater and another in the sea. By moving, they encounter multiple risks for their survival: pollution, fishing, and obstacles, such as dams, which endanger them and exhaust.

Their habitats and reproduction areas are also threatened (by dikes, concrete banks, etc.): “Small, salmon love areas of freshwater 10-20 cm with a stony bottom.

If we put a dam, the water level rises, goes to 1 meter and things are wrong!

», Recalls Jean-Luc Baglinière, research director at the National Institute for Agricultural Research (INRAE).

"Environmental amnesia"

At the beginning of the 19th century, it was not impossible to see a porpoise or a seal crossing Paris, recalls Patrick Haffner, mammalogist (National Museum of Natural History / French Office for Biodiversity).

“We consider today that if these species are not in the Seine, it is because they are exclusively marine.

But no, it is that they have modified their behavior with the expansion of Man to avoid us.

Patrick Haffner insists: "We have a vision of the fauna of the Seine as we know it, but we forget to look at the past".

This is what we call "environmental amnesia" as explained by Florian Kirchner of the IUCN.

“We see a few fish and birds in the Seine, we say to ourselves that it's great, that it's the return of nature.

But we forget that half of the species are missing than there were a century earlier!

".

Our dossier on the Seine

Florian Kirchner describes “a rather gloomy general picture” for freshwater fish, but still wants to remain optimistic: “If we give ourselves the means, we see that certain species are occasionally better.

We have the solutions, it is up to us to stop destroying our natural environment ”.

Fishing regulations, development of dams to create fish passageways (devices allowing them to cross them), European action plans for the most endangered species, continued improvement of water quality ... There is still a long way to go… before, perhaps, seeing seals again while having a drink on the banks of the Seine.

* Red List of Threatened Species in France - Chapter Freshwater Fishes of Metropolitan France, IUCN French Committee, MNHN, SFI & AFB (2019).

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