Scheduled every two years in Charente-Maritime, the “targeted inventory” of eels is of capital importance.
"This species is classified as critically endangered, the objective is to measure the colonization front of the eels and their free movement on the territory," recalls François Albert, project manager with the Migado association and member of the Unit. migratory Charente and Seudre specialized in the protection of endangered aquatic species.
Clearly, the more this fish, emblematic of the Charentes, moves upstream, the better its chances of preservation.
Because time is running out: eel populations have continued to collapse in recent decades.
Their fry - the glass eel or pibale - is excessively fished and sold at high prices in Asia and Eastern Europe.
Climate change, pesticides and the degradation of their environment weigh just as much.
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To more precisely measure the state of conservation of the European eel, the Charente and Seudre migratory cell organizes inventories, electric fishing - without danger for the fish - which allows them to be counted.
“The same places are targeted every two years, explains François Albert.
We are mainly interested in eels less than 15 centimeters.
Less than three years old, they are a recent and rapid signal of possible improvement.
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Measured and released
This afternoon, the members of the Migratory Unit supported by the Charente-Maritime Fishing Federation are combing a portion of 100 m2 on the Seudre, near the village of Corme-Écluse. Numb and caught with a dip net, the eels are measured and then released. “We have noticed an improvement on the Seudre since 2013 and 2015,” says François Albert. We managed to slow down the collapse but we are in the red, the situation remains extremely precarious. "
A few meters from the site of this operation is still a valve blocking the upwelling of migrating fish. These impassable dams are gradually being developed to restore ecological continuities. For the eel, this work is proving to be crucial: “The salt marshes on the coast, mostly produce males. To obtain females, the eels must travel far up streams in search of fresh water ”, specifies the person in charge of the Migado association.
Why ? Mystery. The European eel remains an enigma for science. To reproduce, this fish even leaves our waters and migrates for nearly twelve months 5000 kilometers further west, towards the Sargasso Sea. “This migratory species crosses several ecosystems and constitutes one of the keystones. Its disappearance could threaten these same ecosystems, ”explains Jules Coignard, project manager with the Charente-Maritime Fishing Federation.