In recent years, the Reserve has worked to contain wels catfish (Silurus glanis), the most dangerous alien species for native fish.

Wels catfish have been present in the Reserve and in Lake Iseo in general for several decades and are now stably colonized in the water system of the Lake, including the Oglio River downstream, significantly impacting the native fish in the water system in question.

The general objective of the proposed interventions is to restore the composition of the fish population in the Torbiere del Sebino Nature Reserve and the lower Lake Iseo in general.

The activities in the projects are aimed at both increasing the effectiveness of removing the species and increasing the base of people involved, particularly professional fishermen and the Sommozzatori Iseo non-profit group. The capture techniques used in 2021 and 2022 included: electrofishing, net casting (large mesh), and underwater fishing.

Electrofishing was used in both the Lamette and Lame and aimed at: removing as many wels catfish as possible to encourage recolonization by native species; developing a standardized site-specific protocol to catch wels catfish; collecting morphometric data (length and weight) on wels catfish; and defining abundance of other species with respect to different environments in the project area.

Net casting regarded lower Lake Iseo (from Sarnico-Paratico to Sulzano), concentrating on the breeding areas of the main lake fish species, i.e. common whitefish (December–January), northern pike (late winter), carp, alosa agone, and tench (spring into summer). The nets used for containment had a minimum mesh size of 80 mm and a maximum length of 600 m to minimize the potential effect on species not targeted in the project.

Underwater fishing was done in the Lamette and strip of lake bordering the Reserve. This consisted of dives aimed primarily at monitoring the presence of wels catfish during the breeding season and subsequent underwater fishing.



The SOMMOZZATORI ISEO non-profit group monitored the species and fished underwater on a regular weekly basis between 04/06/2021 and 30/10/2021. However, the sudden rise in temperatures at the beginning of summer led to algae blooms and consequent cloudiness of the water for much of the intervention period, reducing visibility and therefore the ability to capture specimens.

Several specimens were sighted, but only one catch was made. Experience has led to the conclusion that the water is too turbid in summer to guarantee satisfactory performance. Potential future activities will therefore have to anticipate the above-mentioned schedule.

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