Ecological Catastrophe in Doubs Pond: 95% of Fish Population Wiped Out in Just One Week

After the sudden disappearance of fish from a pond, fishermen in the region, as well as the authorities, try to understand the causes of this massacre. While analyzes are underway, several hypotheses are being considered, but the answer remains uncertain.

A pond emptied of fish in a week

In a few days, the Vieux-Charmont pond, in the Pays de Montbéliard, in the east of France, lost almost all of its aquatic fauna. It is estimated that 95% of the fish that inhabited it died, they were found on the surface of the water. Among the species affected are carp, catfish and fry.

Cyril Deuscher, president of the La Charmontais fishing association, regrets this situation, he confides to the local newspaper France 3 “ it's terrible, it's an unprecedented ecological disaster for our town”. The latter has managed this five-hectare pond since 2016, with his association, it is one of the largest in the region.

It was a fisherman who raised the alert, Friday September 20, 2024, in the evening, in fact he came across around a hundred dead fish. The president of the association, in shock, noted “in total, more than three tons of fish were removed from the water”. He regrets the misunderstood disappearance of these species, including carp 25 to 30 years old.

For the time being, water samples have revealed an oxygen level close to 0%, for comparison, a rate of less than 60% means that the oxygen level is low, between 60 to 79% means that the oxygen level is acceptable for most organisms in flowing water, a level of 80 to 125% means that the oxygen level is excellent for most organisms in flowing water, finally 125% or more means that the oxygen level is too high; it can be dangerous for fish according to the G3e website.

Three tonnes of fish incinerated and analysis results pending

While awaiting the analysis results expected in the coming days, the three tonnes of dead fish were incinerated. For the moment Cyril Deuscher does not plan to reintroduce new fish which could create a new ecological disaster, “I'm not putting fish back in this pond until we know what happened. This would send other fish to their deaths”.

The association also fears that this ecological disaster will have an impact on the future of fishing in the region. The analysis results will make it possible to understand the real causes of this disaster. But this will not prevent the fauna of this pond from taking years to recreate itself.

A mystery still unanswered…

The oxygen level in the water, at this level, would be responsible for the death of the fish according to fishermen and the authorities. But there is no real correlation with this sudden fall.

The mayor of Vieux Charmont, Henri-Francis Dufour, does not understand how the oxygen level fell to almost 0%. For his part, Cyril Deuscher recalls that in “normally, the oxygen level should oscillate between 4 and 5%, or even up to 10% to ensure the sustainability of wildlife”.

As a reminder, a similar phenomenon occurred 4 years ago. This disaster was linked to severe drought and the proliferation of duckweed, but that is far from being the case this year.

…but hypotheses considered

The authorities are studying several hypotheses to understand this ecological disaster. According to Cyril Deuscher, it could be caused by pollution from old pipes or a poorly connected collector under water, in fact he imagines “ maybe it comes from the spreading of slurry in neighboring fields, but it happens every year and it has never caused such a massacre”.

Another hypothesis put forward by the mayor remains particularly worrying, that of the

contamination of the groundwater which feeds the pond, “ if the water tables are polluted, it would be very serious, especially with the Savoureuse River which passes nearby”.

Finally, a less plausible hypothesis was imagined, that of a malicious act, but the latter remains ruled out for the time being.

To try to find answers to these questions, analysis results are awaited, water samples have been sent to a laboratory in Vesoul.

Sources : France 3, Study, East Republican, FranceBleu