Radio tracking in River Minho (Iberian Peninsula). Photo Patrícia Ferreira

PhD defence on bottlenecks for Atlantic Salmon smolt migration

Thursday 13 Aug 20


Kim Aarestrup
DTU Aqua
+45 35 88 31 42


On 19 August 2020 Hugo de Moura Flávio, DTU Aqua will defend his PhD thesis. The defence can be watched online

The populations of Atlantic salmon have been declining worldwide, and it is important to find ways to help this species recover. During his PhD project, Hugo de Moura Flávio, DTU Aqua has explored the migration of Atlantic salmon juveniles (termed smolts) as they leave the headwaters and make their way to the sea, where they will grow into adults.

Because the smolt migration is a particularly challenging period, it is important to find out how many smolts are dying before reaching the sea. Therefore, Hugo Flávio followed the Atlantic salmon smolt migration in different rivers across Europe. 

In the research, he discovered that over 50% of the migrating smolts die before reaching the sea, which constitutes an important limitation for the recovery of this species. Furthermore, multiple sources of mortality were identified, which he concludes can be addressed through focused management plans. 

Hugo Flávio advises that future studies must continue to explore the smolt migration in diverse rivers; identifying local survival bottlenecks and providing managers with the knowledge they require to develop effective management plans. 

“It is essential that we continue restoring the riverine habitat of Europe and, most importantly, the access to that habitat. Only so can we truly ensure that the Atlantic salmon continues to be an iconic species for generations to come,” he concludes.

About the defence

Hugo de Moura Flávio will defend his PhD thesis "Bottlenecks for Atlantic salmon smolt migration in freshwater and estuarine ecosystems", Wednesday 19 August 2020 at 13.00 CEST, online via Zoom. For the link to join the defence please contact Hugo Flávio, no later than 18 August at 14:00 CEST.  

  • Principal supervisor: Professor Kim Aarestrup, DTU Aqua
  • Co-supervisor: Senior Researcher, Niels Jepsen, DTU Aqua
  • Co-supervisor: Professor Anders Koed, DTU Aqua

Examiners committee
  • Senior Researcher, Dorte Bekkevold, DTU Aqua (Chairwoman for the committee)
  • Professor Eva Thorstad, NINA, Norway
  • Professor Martyn Lucas, University of Durham, United Kingdom

Chairperson at defence
  • Professor Einar Eg Nielsen, DTU Aqua

The thesis

The PhD thesis “Bottlenecks for Atlantic salmon smolt migration in freshwater and estuarine ecosystems" is available for reading at DTU Aqua. Please contact Rikke Hansen,