The Lot French Biodiversity Office has been regularly monitoring the evolution of otter populations in our department since 2002. Immersion… in the water with one of their team in search of these cute mammals.
Don’t look for her little face, she is practically impossible to find. With its four webbed feet, its slender body, its beautiful whiskers and its small ears, the otter is a nocturnal animal that hides from the gaze of man. It is therefore difficult to count them, but thanks to its footprints and its footprints (the particular name given to otter droppings), the French Office for Biodiversity (OFB) surveys and verifies that otter populations are maintained in our department.
On this Friday morning, head for an arm of the Lot next to the Mercuès hydroelectric power station. Stéphane Vidal, knowledge referent at the OFB and Nicolas Pesenti Bohand, head of the southern unit, put on their waders, these waterproof wetsuit boots that go up to the thorax. Once in the water, it’s off for an hour of searching for “signs of presence” on the banks, the trunks and the emerged stones.
Droppings that smell of honey
After 10 minutes, the first clues appear, Nicolas Pesenti Bohand bends over a trunk to smell a small gray heap. “These are otter marks, I can assure you it doesn’t smell bad, it smells of honey or linseed oil! You can easily see what she ate: there are fish bones and scales, here a crayfish leg, he observes with a small stick, the otter is an opportunistic species, it adapts its diet to what it finds, it can also be amphibians or rodents. Several excrements will thus be found everywhere. “The otter marks its territory. There are certainly huts, burrows whose entrance is under water. It feels good here because it is an arm of the Lot where it is calm, sheltered from navigation.” emphasizes Stéphane Vidal.
The French Office for Biodiversity of Lot has been regularly monitoring the evolution of otter populations in our department since 2002. It notably conducted two major surveys between 2003 and 2011 which confirmed their return to our waterways. The mammal is now present throughout the Lot. In the last century, it had practically disappeared in France, long sought after and hunted for its fur, it has been a protected species since 1972. Since the 1980s, its numbers have continued to climb, it has practically recolonized all of France. The 13 agents of the OFB therefore carry out several missions to protect the otters and ensure their proper development.
Today, its main predator is… man. Because the first causes of mortality remain road collisions as well as traps. “Thanks to our work, we have changed the regulations, so the whole department is now declared an “otter presence zone”, which means that killing traps are prohibited within 200 meters of an aquatic environment. “We also conduct training for certified trappers. And finally, we also carry out numerous checks: cage traps must be checked every day before noon, for example.” explains Nicolas Pesenti Bohand, head of the southern unit.
The OFB also intervenes as technical support when it comes to road or bridge developments, they recommend works to facilitate the passage of otters. In 2019, for example, in Bagnac-sur-Célé, banks were built under a bridge where the Veyre flows. “There have been a few accidents on this national road. The otters do not like to go through the water under the bridge so they crossed the road. To facilitate their passage under the bridge, access ramps and benches have therefore been built.” says Stéphane Vidal. Once threatened with extinction, the otter is today largely protected in our rivers for its greatest happiness.
To find out where the otters come from in our department, whether they belong to the populations of the Massif Central or to those from the Atlantic zone, OFB agents take tissue samples from the ear when they find a dead otter. DNA results are kept in a national file for scientific interest. It makes it possible to reference the different populations in France.