Study ‘Assessment of the state of ichthyofauna in the Bileca and Trebinje Reservoirs and Plan for Protection and Sustainable use’

 

Investor: MHC ‘Elektroprivreda’ RS, SC ‘Hidroelektrane na Trebisnjici’, Trebinje

Implementation Period: 2013

 

The key attribute of the Trebisnjica System is its integrated multi-purpose character, which enables achievement of a complex structure of goals. In addition to hydropower, which as a highly profitable system has become the backbone of the development of the system and a driving force for the realization of a number of other goals (economic and social development), there are also water, urban and environmental goals. These are mostly realized by controlling and improving flow regimes of the Trebisnjica and watercourses in its wider basin.

The preparation of this study contributed to the review of the situation and measures required to improve the sustainable development of fish stocks in the Bileca and Trebinje reservoirs, and also provided recommendations that will be adaptable to the upstream watercourses in the Trebisnjica basin. The main objectives of the study are to determine the quantitative and qualitative state of fish stocks in the Bileca and Trebinje lakes, to develop a plan of measures for protection and improvement of ichthyofauna with sustainable use, and to determine a possibility of natural and artificial growth of fish stocks by species.

 

In order to gain a better insight into the current state of ichthyofauna, we collected all available documentation and data on previous water quality tests in the project area, and carried out an extensive field research on the structure of fish communities in the Bileca and Trebinje lakes, as well as in some significant parts of the Trebisnjica, Bregava and Musnica rivers. Based on the field research, we gained a useful insight into the state of fish populations and total fish biomass per hectare and carried out a quantitative-qualitative analysis of the structure of populations of individual fish species. These are the basic data which informed our conclusions and recommendations for management of fish resources in these two lakes.

The study also showed that the Trebisnjica basin (rivers and reservoirs) mainly has introduced fish fauna, which is a result of decades of planned fish stocking but also unplanned fish release with species mainly originating from the Danube basin. The condition of the populations of protected species in the Trebisnjica basin was found as satisfactory. In order to improve the state of fish fauna, it is necessary to carry fish stocking following the model presented in the study. There is also a need to change the fishing regime and the ban regime in certain sectors within the basin. The entire Trebisnjica basin has an exceptional potential, not only for the production of electricity, but also for the development of fishing tourism. This catchment area is close to Dubrovnik and the Croatian coast and is well connected with Montenegro and other parts of the RS and B&H. With these markets, the Trebisnjica basin can offer carp fishing in lakes, as well as trout fishing both in parts of river ecosystem and lake ecosystems.