Mapping Barriers and Preserving Endemic Fish in Eastern Herzegovina

Identifying and mapping the barriers on the rivers and streams of Eastern Herzegovina, and assessing their impact on the migration of endangered endemic fish species.


Located within the Republic of Srpska’s jurisdiction, the upper watershed of the Neretva and Trebišnjica rivers forms a vital component of Eastern Herzegovina’s natural heritage. This area is renowned for its unique karst topography, characterised by sinking streams and a remarkable diversity of endemic species. 

To harness the waters of these rivers for hydroelectric power, a complex of seven substantial dams, six artificial reservoirs, extensive tunnel systems, and a canal network has been constructed. This infrastructure plays a crucial role in the local economy. However, amidst this development, numerous antiquated barriers—originally erected for irrigation purposes—now serve no practical function yet continue to obstruct the passage of threatened endemic fish species. 

Despite significant alterations to their natural state, the rivers and streams of Eastern Herzegovina maintain a high level of endemism. Remarkably, certain freshwater species can adapt by migrating underground, enabling them to thrive in these challenging conditions.  

At a glance

Project typeBarrier identification and prioritisation
Project statusLive
CountryBosnia and Herzegovina
RiversUpper Neretva and Trenišnjica watershed, including rivers: Trebišnjica, Sušica, Opačica, Vrijeka, Mušnica, Zalomka, Zovidolka, Ključka Rijeka, Brova, and Bukov Potok
Focal speciesParaphoxinus ghetaldi, Paraphoxinus pstrossi, Paraphoxinus metohiensis

Project context and opportunity

The barriers on the upper watershed of Trebišnjica and Neretva hinder the migration of endemic fish species, notably the Gatacka gaovica, Popovo gaovica, and Trebinje gaovica. These barriers, largely obsolete structures from past irrigation systems, have drastically reduced the available habitat for these species to a mere 7% of their natural range. By mapping and identifying these barriers and assessing their impact, we can pave the way for their subsequent removal to restore connectivity between surface and underground waters, which is vital for the survival of these endemic fishes during their migratory cycles. 

Project aims

The project aims to mitigate the ecological impacts of human activities and foster the preservation of the unique biodiversity in the upper Neretva and Trebisnjica watersheds. By identifying and mapping existing barriers, the project will create opportunities for their future removal, reducing the pressures on the riparian ecosystem, increasing the available habitat for endemic fish species, and restoring connectivity between surface and underground waters vital for their survival. Another key goal is to engage local communities and authorities in conservation efforts, increasing awareness of the impact of barriers and the benefits of their removal. By promoting sustainable environmental practices and management strategies, the project aims to ensure the long-term health and resilience of the Trebišnjica River and its associated ecosystems. Overall, the project aims to contribute to the revitalisation and ecological recovery of the rivers and streams of Eastern Herzegovina, ensuring the survival of its endemic fish species.