Restoring River Mondego
Research oriented to management and conservation of diadromous fish in River Mondego began in 1998, and since then the knowledge about the ecological requirements of these species and the specific threats in this watershed increased substantially. It is estimated that more than 5 million euros have been invested in this river basin on direct actions regarding the rehabilitation of diadromous species, including long-term studies on the biology, ecology and distribution of migratory species, and in habitat restoration measures.
After an initial period dedicated to collect baseline information, recent efforts are now directed to restore important habitats for diadromous fish in this basin, with particular focus in the reestablishment of the longitudinal continuity. These actions are being supported by two projects, which constitute consecutive phases of a strategic rehabilitation plan of River Mondego for diadromous species:
- i) the construction of a vertical-slot fish pass in Coimbra Açude-Ponte dam, which enabled the extension of the available habitat in 51 km (340% increase), constructed by the Portuguese Environmental Agency;
- ii) the construction of five nature-like fish passes in small weirs, four of which are located upstream from the Coimbra Açude-Ponte dam, and the removal of another weir. All the restoration measures are accompanied by pre- and post-operational monitoring.
This integrated approach directed to the restoration of the longitudinal continuity in River Mondego is being successful and the main goal is to replicate this management strategy in other Portuguese watersheds also considered important for diadromous species.