Withdrawals and removal of catfish in the Avigliana Lakes: the 2025 report

     In the course of 2025, the project Life Predator activity in the Avigliana Lakes Natural Park has entered the heart of the captures after the study phase conducted in previous years by project partners coordinated by IRSA CNR with the staff of the Protected Areas of the Cottian Alps and the appointed professionals. With the end of the calendar year and taking advantage of the winter break from extraction operations, it is possible to draw up a first assessment on the actual reduction of the biomass of Silurus glanis from the two Avigliana Lakes. The actions have been carried out within the European Life Predator project, of which the Park Authority is a partner, for the containment of catfish, an invasive alien species, in the freshwater basins of southern Europe.

The techniques used

The extractions were carried out during 24 sessions of amateur and scientific fishing with the aim of differentiating the capture techniques as much as possible to evaluate the pros and cons and the different levels of effectiveness of the various methods. Regarding amateur fishing, in the spring of 2025, the park rangers of the Protected Areas of the Cottian Alps selected a group of fishermen who were provided with specific training. Subsequently, from June to November, 9 evening sessions and 3 dawn sessions were organized during which members of the group could fish on Lake Grande, thanks to the availability and collaboration of the fishing rights holder and the presence of the Park's monitoring staff. The fishing in derogation of nighttime hours was specially authorized by the Metropolitan City of Turin for the achievement of the project's objectives.

The professional activities, on the other hand, were carried out in the autumn by a team of ichthyologists appointed by the Park Authority primarily using the technique of electrofishing and, in some sessions, through longlines. The sessions totaled 13, of which 7 on the Lake Piccolo and 6 on the Lake Grande.

The results

Amateur fishermen captured 12 individuals of catfish (for a total of 17.85 kg) during the sessions organized by the Park Authority, while during their occasional fishing activities, they removed 15 individuals (for a total of 117.81 kg) verified by the Park Rangers.

In contrast, the scientific fishing sessions allowed for the removal of 68 specimens (for a total of 259.17 kg) from Lake Grande and 44 specimens (for a total of 255.29 kg) from Lake Piccolo.

The comments

«The results of the work carried out so far are encouraging – says Bruno Aimone, head of the Biodiversity Area of the Protected Areas of the Cottian Alps – because they practically confirm what we had already hypothesized with the monitoring of fish species conducted at the end of 2023. The low number of catfish removed from the waters of the two lakes, particularly from Lake Piccolo, compared to the data collected by other project partners, confirms a not excessive concentration of individuals present in Avigliana».

«From this point of view – adds Fabio Santo, park ranger and head of supervision – the activity carried out with amateur fishermen is particularly important, as they collectively removed 26% of the catfish biomass, as it allows for diversifying capture activities and ensuring the continuity of actions even when the Life Predator project ends. From spring 2026, scientific fishing activities will resume, and amateur fishing will continue in the summer. The experience and data collected in 2025 have enabled us to finalize capture techniques and understand the best times and areas of the lake to operate in order to bring the population of Silurus glanis to levels compatible with the conservation of varied and healthy fish biodiversity».