Intensive angling of non-native brook trout in high-mountain lakes: insights for eradication actions and awareness-building

Introduced fish represent a widespread threat to the biodiversity of naturally fishless mountain and alpine lakes, a problem that can be mitigated through mechanical eradication. Recreational anglers, as key stakeholders, could be engaged in eradications via fish removal using angling techniques to raise awareness of high-mountain lake conservation, although the practical and educational effectiveness of such involvement remains uncertain. Prior to initiating the eradication of brook trout Salvelinus fontinalis (Mitchil, 1814) from four high-mountain lakes, we therefore tested the use of intensive angling sessions with two objectives: (i) removing non-native individuals to support subsequent eradication phases, and (ii) engaging anglers and promoting ecological awareness. Angling sessions substantially reduced the biomass of previously angling-naïve populations and attracted numerous participants, but without producing a measurable shift toward more conservation-oriented attitudes. High catch rates nonetheless highlight the potential of angling as both an engaging participatory tool and a complementary method to structured eradication techniques. At the same time, our results indicate that angler engagement alone does not guarantee effective environmental education. We therefore recommend considering angling sessions as a convenient complement to eradication actions, while embedding such initiatives within structured, long-term educational programs to foster tangible educational outcomes.