“It’s becoming impossible to fish”: in Dax, shock treatment against the proliferation of aquatic plants in ponds

Until now, the local fishing association has been taking care of the pond mowing on a voluntary basis. But faced with the proliferation of aquatic plants, it now admits to being overwhelmed by the situation, which is forcing it to turn to professionals.

With its inverted trapezoid shape and metal tracks allowing for off-road movement, one might at first think of a tank. An amphibious tank.

But while the Truxor T50 (for 50 horsepower) has the look (and name) of a war weapon, this 1.5-ton Swedish tool carrier only attacks aquatic plants. At the front, its comb rake cuts algae and watermilfoil from the bottom of stagnant waters, and at the rear, its basket pulls up water primrose, that invasive plant with pretty yellow flowers, and collects various waste products. Simple, effective. And the hydraulic oil is biodegradable: no risk of water pollution in the event of a leak.

This Tuesday, September 2, at the Etang des Gravières, in the Torte district of Dax, Luc Labbé is testing his brand new Truxor T50, purchased for 200,000 euros (including tools and accessories) from Christophe Favre of the company Innovations et Paysage. Luc Labbé is undergoing career change. Having attended the Bazas agricultural high school, this former cash-in-transit driver specializes in mowing and cleaning stagnant water.

"I mowed the moats of the Château de Rambouillet," he boasts. This isn't his first experience with the Truxor T50: "I've already used one at the port of Sainte-Eulalie-en-Born." But this time, he's getting down to business: this summer he set up his own company, LSCE, in Saugnac-et-Cambran, and is hoping to secure more contracts (1).

That day, standing at the edge of the pond, his gaze desperate but combative, Sébastien Labarrière is counting heavily on the Truxor T50. The president of the AAPPMA fishing association in Dax (2) is overwhelmed by the situation. Even though the pond is owned by the town hall, it is the operators, in this case the fishermen, who are responsible for maintaining the area.

"The municipality of Dax helps us a little," he explains, "particularly with the recovery and storage of invasive plants." But when it comes to mowing, it's the AAPPMA that manages it. And even if, last spring, as every year, the fifteen volunteers from the association cleaned (aboard a boat and using a mowing machine purchased for 25,000 euros) the Brazilian watermilfoil, the water primrose and the filamentous algae have already taken over the area.

These exotic species, ornamental plants that have become invasive because they have no predators, have gradually replaced native plants, which are tending to disappear.

"In the spring, Luc came to see us to talk about his project. And he contacted us again to see if we were okay with him working here. We said yes, he's starting his own business, we have to encourage him. And then, we'll probably hire him, we can't clean the pond ourselves anymore, it's become too hard. This year, we're struggling."

The price is not yet very precise, but for an area of ​​several hectares like that of Gravières, expect to pay several thousand euros.

In fact, if you look closely at the banks, they're overrun with aquatic plants. "When there are too many, like there are now, it becomes impossible to fish," laments Sébastien Labarrière. "But it's not just the lack of space that's a problem," continues the nurse. "This summer, we had a few dozen fish die during periods of intense heat, because there wasn't enough water due to the proliferation of plants, which caused a lack of oxygen."

However, invasive plants are not always the enemy of fish. They serve as shelter, nesting and spawning grounds, and food sources. "We're seeing the proliferation of species that had almost disappeared here, like the pike," says Sébastien Labarrière.

So mowing is a delicate balance to be found, between preserving biodiversity and maintaining the banks for fishing. "In fact," explains Sébastien Labarrière, "we must preserve certain areas of the pond in their wild state, and we only mow the areas near which fishermen settle."

The association president's gaze relaxes as he watches Luc Labbé's machine at work. It returns to dry land after about twenty minutes, covered in algae, adorned with its loot. The pond itself has a sort of watering hole amidst the invasive weeds. The running-in operation, and the seduction, is successful.

(1) Contact details: 06 22 91 17 11 and [email protected]. (2) The Dax Approved Association for Fishing and Protection of Aquatic Environments has more than 900 members.