What is the state of health of fish and rivers in France after confinement? Along the water, hydrobiologist Bruno Barbey director of the Indre fishing federation.
Trout fishing kicks off today Saturday March 13th. It’s a moment that fishermen look forward to every year, especially since trout is a species “landmark” because it is at the top of a food pyramid, and it is a good indicator of the state of aquatic environments and the quality of the water.
When the wild trout, which we call the brown trout, is present in abundance in the waterways, that means that the river in which it evolves is doing well.Bruno Barbey, director of the fishing federation of L’Indre
Fish reproduce at different times of the year. Some at the beginning of spring, when fishing opens in the first category watercourses. This will soon be the case for chub, sculpin, small minnow but also pike.
These fish follow the flows of the rivers, but also the meteorology and the flood zones towards the spawning grounds where they will reproduce. At the time of containment last year, we were in phases of drought-related flows.
In fact, the drought of recent years has had a far greater impact than mere containment. There is therefore a change in the behavior of the fish. 50% of their reason for living and their development is linked to temperatures and climate change, no matter how small, dramatically changes the behavior of fish.
To put it simply, fish that lived downstream of rivers tend to move up towards the middle of rivers. Those who lived in the middle go upstream, towards the sources, and those who lived at the sources tend to regress sharply.
“The agricultural component is indeed very important in the rural departments”, explains Bruno Barbey. The impact is twofold! It is first of all linked to the consolidation of the past and to the cleaning up of rivers carried out in the 1970s and 1980s. In those years the waterways were badly destroyed, but those are now gone.
Today, we carefully observe the impact of harmful products such as pesticides, because they have an impact on fish but also on the entire food chain.
“Today there are much less aerial insects like bees or butterflies”, explains Bruno Barbey. It’s the same underwater! “There are far fewer insects under the stones, and this situation is directly linked to pollution from toxic products. which accumulate over time because they are not biodegraded “, concludes the hydrobiologist.