Scientific fishing for catfish with the sonar.

On the evening of Friday June 26, a new fishing technique for catfish was tested in the Avigliana Lakes Natural Park. This is a scientific activity aimed at identifying, using a sonar, the largest specimens of Silurus glanis that typically reside in the deeper areas of the lakes. The equipment, mounted on a specially designed boat, uses hydro-acoustic technology (emission and reception of ultrasound in the water) which can signal the presence of fish indicating their size and depth and allowing for species determination based on the form reproduced on a screen. Subsequently, the capture activity proceeds using an artificial lure that is lowered into the water near the identified specimen. The operations were carried out by a team of ichthyologists appointed by the Parks of the Cozie Alps with the support of park rangers.

The results

After months of capturing aquatic predators, mainly concentrated in the bank zone of Lake Grande di Avigliana, using electrofishing by the appointed ichthyologists and hook fishing with a team of specially trained amateur fishermen from the Park Authority, the experimentation with sonar allows for the initiation of a third phase of work focused on harvesting the largest individuals of Silurus glanis.
In particular, the session on June 26 held in the Lake Grande enabled the identification of over a thirty individuals of large size, among which one was approximately 2 meters long, maintaining an average depth between 6 and 8 meters. Presumably due to high temperatures making them lethargic, only 4 took the bait allowing for the extraction of about 28 kg of biomass. A small note on the side, the ichthyologists who used the sonar were pleasantly surprised by the abundance of fish fauna present in the lake, empirically confirming the results of the latest monitoring that suggested a fish community that is substantially healthy.

Beyond the limited result of the captures, the use of sonar has proven to be a valid additional resource to the techniques adopted so far in the Life Predator activities, thanks to the ability to implement a very targeted and selective fishing technique that will be further experimented in the continuation of the project.