Softmouth trout in the Upper Neretva River, Bosnia and Herzegovina

This study by BOKU University in Vienna and the Institute of Hydrobiology and Aquatic Ecosystem Management assessed the distribution of the endangered softmouth trout (Salmo obtusirostris) in the Upper Neretva River basin in Bosnia and Herzegovina. The Upper Neretva hosts one of the last intact populations of this little-known trout species. Through environmental DNA (eDNA) sampling and mapping of spawning grounds in spring 2024, scientists showed for the first time that softmouth trout actively inhabit and spawn in the Ljuta River, a major tributary of the upper catchment.

The findings confirm that the Upper Neretva still supports a reproductively viable population capable of sustaining itself naturally. However, the report warns that the newly built Ulog Hydropower Plant is already negatively impacting the species, while additional planned hydropower developments on the Neretva and its tributaries threaten to severely disrupt habitats and drive stock declines.

To safeguard the species, the authors highlight the urgent need for an integrated conservation strategy, strict habitat protection, the abandonment of all further hydropower development in the upper basin, including tributaries, the regulation of discharge fluctuations, and the prohibition of stocking fish to protect the trout's genetic integrity.

Read the FULL STUDY.