“I know immediately by the smell if there is something. You open your mouth and you smell the decomposing fish, ”describes Baptiste Caverina. And there it smells. The stomach analysis is conclusive. The young man removes the remains of a feigned shad and those of a small catfish from the belly of the nearly 2-meter mastodon. A new clue that suggests that the super predator practices cannibalism as its population increases as quickly as the resource decreases.
The evening is beautiful, the Garonne calm, the stretch of water smooth. The boat of Vincent Desqueyroux, a professional fisherman in Preignac, is heading towards Langon, passing the Airbus station. A new net is cast across the river.
A cat femur
Mysterious catfish that feeds all fantasies. During the previous campaign, a cat’s femur and a duck’s leg were found at the bottom of stomachs. Some say that the remains of a dog caught on the shore were found. “It is surely a myth”, tempers Vincent Desqueyroux.
“The rising water temperature provides the catfish with an ideal environment. Everything is fine for him.”
What is certain for the fisherman from Preignac is that the catfish is the number one suspect in the carnage of migratory fish that go up the river to reproduce. And in particular lamprey, the fishing of which provides a living for around thirty professionals in Gironde.
The objective of the study carried out by Capena, in partnership with the Approved Association of Professional Freshwater Fishermen of the Gironde, Smeag, the Water Agency, the Migado Association, EDF, the Region, the Department and the University of Toulouse III, is to better understand the catfish. To study its diet, know its hunting areas and its real impact on migratory fish.
“For a month, we count the volume of fish swallowed up, in particular the migratory ones, shad, lamprey, salmon, eel”, lists Baptiste Caverina. The student notes everything scrupulously. Including the GPS points of the laying and surveying of the net.
The experimental fishing on the Dordogne and the Garonne carried out under the aegis of the Capena also aims to regulate the catfish in order to observe a possible positive effect. “We are trying to regulate the catfish to see if locally there are more migratory fish, if they reproduce more and if there are more of them during the downstream migration”, hopes Vincent Desqueyroux.
The lamprey fishery on hold
Because the stakes are high. Very recently, the association Defense of aquatic environments obtained from the administrative court the cancellation of the prefectural decree which regulates lamprey fishing. Hoping for an appeal from the state, professional and amateur fishermen do not know if they will be able to set their nets again next season.
Pointed out for their activity, the fishermen point to the catfish. “There are no more fish since the catfish was introduced 34 years ago. The rising water temperature provides him with an ideal environment. For him, everything is fine”, breathes Vincent Desqueyroux.
With his colleagues, they criticize their detractors for not taking into account the impact of catfish on the environment. And even to defend it with the open support of anglers, followers of this sensational fish that is released alive after a photo-trophy.
The Capena study may help to implement a systematic catfish control policy. This is all that professional fishermen want, with a classification of the predator as a harmful species and the organization of a chain for its consumption.
914 catfish caught in 2021
Still in progress, the Capena study has delivered some lessons during the first campaign in 2021. Thus last spring, 914 catfish (27.5 tonnes) were collected in Langon, Couthures-sur-Garonne, Saint -Sixte, at the Golfech power plant and at Pessac-sur-Dordogne. A report that shows “the high concentration of catfish on the Garonne and Dordogne axes”. The analyzes also show that “overall the migratory fish constituted the main part of the diet of the catfish caught with prey still in their stomach”.