Improving Upstream and Downstream Fish Passage at Retis Dam on Hârtibaciu River - Sibiu County (Transylvania)

Retis (dam Retis), hydro-technical development like many other transverse hydraulic structures cancel the longitudinal connectivity of Hârtibaciu water course, blocking the migration of different (migrating) species of fish in the river. Also, the lateral connectivity was heavily affected on this water course at a rate of 60%. Therefore, proposing engineering solutions to recover both (lateral and longitudinal) types of connectivity is vital to restore the local ecobiom. The purpose of this article is to establish longitudinal connectivity through an engineering solution that facilitates the fish migration upstream - downstream of Retis dam. This paper proposes an engineered fish passage solution for Retiș Dam on the Hârtibaciu River, using the criteria described in the Water Framework Directive 2000/60/EC document. Anthropogenic barriers located in the Hârtibaciu River disrupt and delay movement of local fish fauna including: Alburnoides bipunctatus (Bloch, 1782), Squalius cephalus (Linnaeus, 1758), Alburnus alburnus (Linnaeus, 1758), Rhodeus amarus (Bloch, 1782), Gobio gobio (Linnaeus, 1758), Romanogobio kessleri (Dybowski, 1862), Barbatula barbatula (Linnaeus, 1758), Barbus meridionalis Risso, 1827 Misgurnus fossilis (Linnaeus, 1758), Cobitis taenia Linnaeus, 1758, Cobitis romanica (Băcescu, 1943), and Cobitis aurata (De Filippi, 1863).

Stone loach in Stockholm, Sweden, and royal fish-ponds in the seventeenth and eighteenth centuries

The stone loach (Barbatula barbatula) occurs in three main areas in Sweden. In the north, it is found in Lapland in the River Torneälven. In the south, it is found in Skåne. There are also two populations near the cities of Stockholm and Nyköping. New data suggest that these two populations originate from fish that were kept in ponds. In the 1740s King Frederick I is said to have released stone loaches from German sources in Lake Mälaren, but this cannot explain its occurrence in Igelbäcken near Stockholm. There is also reason to believe that it was kept in ponds at the royal castle Ulriksdal in the mid-eighteenth century. The fish was possibly imported from the king's native Germany, to be eaten as a delicacy. However, historical records tell of pond-keeping of stone loach by the Royal court in the Stockholm area during the 1680s.