CatFish Day warns of the impact of European catfish on Portuguese ecosystems

The European catfish (Silurus glanis), one of the most concerning invasive species in Europe, was the focus of attention at CatFish Day, held on September 18 at the Faculty of Sciences of the University of Lisbon. The meeting, promoted by the Fish Invasions Lab (MARE) as part of the LIFE Predator project, brought together researchers and fishermen to discuss management strategies for this large predator. 

Currently, catfish are rapidly expanding in Portugal, with recent records in reservoirs such as Montargil and Torrão. This species can reach large sizes and has a significant impact on fish communities, including emblematic species such as the European eel, shad, and barbel.

According to João Gago, “Most fishermen recognize the negative effects of catfish on native fish, but it is necessary to raise awareness and strengthen enforcement, especially with regard to the illegal practice of catching and releasing catfish.”

The reproductive biology of the species also facilitates its spread. Recent studies in the Lower Tagus have revealed populations consisting mainly of females, which mature early and have a longer breeding season than in their native range, factors that contribute to the rapid establishment of the species in Portuguese ecosystems.

There are no simple solutions to stop catfish. The most effective methods are the use of large mesh nets and longlines with live bait. But only with the participation of professional fishermen will it be possible to apply these techniques effectively, as Rui Rivaes, a researcher at MARE, points out: "We need to involve professional fishermen in control solutions. Only with their participation will it be possible to mitigate the impacts of this invasive species on our rivers."

CatFish Day ended with a roundtable discussion dedicated to the role of science and society in combating biological invasions. In addition to the need to continue research on the ecology and behavior of the species, experts emphasized that everyone can contribute to stopping the spread of catfish. How? By following and sharing information on the project's social media (LIFE Predator on Facebook and Fish Invasions Lab on Instagram), responding to the catfish perception survey that helps to understand public knowledge about the species, and raising awareness among family, friends, and school communities about the problem of invasive species.

Text by Vera Sequeira