Conservation and management actions for migratory fish in the Vouga river basin

Abstract

Habitat loss and overfishing are the most significant threats to diadromous fish, most of them of high socioeconomic and conservationist importance, like, for instance, Alosa alosa, A. fallax, Petromyzon marinus and Anguilla anguilla. Pilot restoration actions aiming to recover diadromous populations were conducted for the past 20 years in the Mondego river basin, materialized by the construction of seven fish passes that restored 45 km of freshwater habitat for diadromous fishes, including the first eel ladder built in Portugal. About 1.5 million fishes are annually recorded using a fish pass built at Coimbra dam by the Portuguese Environmental Agency (APA), and an increase of 100-fould in lamprey larvae abundance was registered in the upstream stretches. The approach also included the management of related commercial fisheries and stakeholder engagement, aiming to ensure the compatibility between the conservation of diadromous fish and other water uses (e.g. water abstractions, recreational activities, production of hydroelectricity). This novel and integrated pilot approach is currently being replicated in the Vouga river basin under the framework of the project “LIFE AGUEDA - Conservation and Management Actions for Migratory Fish in the Vouga River Basin”. The main objective of this project is the removal of hydro-morphological pressures towards the reestablishment of conditions for a good ecological status, as required by the Water Framework Directive (WFD) and associated River Basin Management Plans. This will be achieved by i) restoration of river morphology through the installation of nature-like fish passages, removal of river obstacles and re-naturalization of the river bed, design and operation of a pilot translocation program directed to European eel juveniles, and riparian habitat restoration; ii) recreational and commercial fisheries management; and iii) stakeholders’ engagement and compatibility of ecosystem uses. Anglers’ engagement in fish monitoring through the design and operation of a pilot mobile phone application will contribute to collect data on fish distribution, while the design and operation of a pilot “mobile auction” in the study area, together with the implementation of a “label of origin” system, will promote market differentiation and fish valorization. The expected benefits in migratory fish populations will contribute to attain the ecological targets of the WFD together with other multi-use objectives, encompassing needs established under the Floods Directive, the Habitats Directive, the European Biodiversity Strategy and the Eel Management Plans resulting from the council Regulation (EC) 1100/2007.