Soča

The Soča River originates in Trenta at an altitude of 990 meters in Triglav National Park and, after 138 kilometers, flows into the Adriatic Sea in the Gulf of Trieste. RD Tolmin manages the section from the bridge in Čezsoča to the confluence with the Vogršček stream below the dam at Doblar Hydroelectric Plant. The entire upper course of the Soča, from its source to Tolmin, is included in the Natura 2000 protected area.

The Soča is primarily inhabited by trout species: marble trout, in some areas still its hybrids, and occasionally brown trout, as well as rainbow trout stocked to support sport fishing. The river also hosts the bullhead, and from the confluence with the Lepena downstream, grayling can also be found. Depending on the winter, the Soča can remain a glacial meltwater river (snow-fed) even into the summer.

After its calm flow through the Bovec basin, the Soča turns into a wild torrent below Srpenica, rushing between rocks and over rapids, catching its breath in deep pools before calming again near Kobarid. From there, it flows gently between white gravel banks towards Tolmin.

Below Kobarid, additional fish species join those already inhabiting the Soča, such as the chub, barbel, Italian barbel, gudgeon, spirlin, and occasional tench. Throughout this section, the Italian nase can also be found.