Amaia Angulo, a biologist from Navarra, has investigated in her doctoral thesis thesis the impact of dams on the habitats that are necessary for the conservation of Atlantic salmon. The researcher from the University of Navarra has focused on the dams of the Bidasoa River -which crosses the provinces of Navarra and Gipuzkoa- and the direct consequences they have on this emblematic species of the region. 

For this research it has been necessary to analyze the consequences that the elimination of dams by the Government of Navarra in recent decades has had on this salmon population. "It is necessary to understand and measure the impacts caused by these constructions in order to prevent or compensate for them, through a management that allows rivers to flow freely."

The researcher has also described new methods to measure the fragmentation of river basins in order to discover which dams have the most negative impact on rivers and which species are most affected. Angulo has studied their impact on diadromous fish species -those that migrate between the river and the sea, such as the Atlantic salmon- and potamodromous -freshwater species- in the Iberian Peninsula.

Live rivers

For this biologist, the demolition of some dams in Navarre could help protect the Atlantic salmon. "If we want to have living rivers, it is essential to eliminate all dams that are not necessary and build new ones in places where they have less impact.

The lack of planning in the elimination of obstacles in rivers and the lack of assessment in restoration are some of the conclusions drawn by the researcher. "In Spain there are a large number of dams, large and small, that do not fulfill any function, or that do not produce a significant benefit while generating an enormous environmental impact."

The methods developed in this research serve as a basis for detecting which dams cause the most damage to certain species, especially those that are in danger of extinction, such as sturgeon, eel, lamprey, shad or Atlantic salmon, among others. For Angulo, the future of this research field involves the creation of a national inventory of obstacles in rivers, as well as the long-term analysis deadline of the demolition of dams and how they affect certain fish populations.