Fish trap


In recent decades, the abundance of wild Atlantic salmon has declined, despite regulations set in place to protect them. Evidence suggests that the death rate for salmon is very high at the smolt stage, a phase in their life-cycle during which they migrate downstream towards the sea.

Jumping salmon

Responding to the problem

In response to this mortality of salmon smolts, the North Atlantic Salmon Conservation Organisation (NASCO) has sponsored SMOLTRACK to research the causes and potential mitigation measures to counteract it. This project was established to determine the mortality of salmon smolts during their migration, with a focus on selected rivers, estuaries and near-shore marine areas in Ireland, Denmark, England, Sweden, Northern Ireland and Spain.

Tracking fish movement

To examine their migration patterns, salmon smolts will be tracked using acoustic telemetry. Traps will be used to catch migrating salmon smolts, which will be tagged or implanted with small tracking devices and released. The signals emitted from these tags will be recorded by a number of special listening stations that will be located strategically throughout important migration routes within the River Errif system and Killary Harbour, one of Ireland’s premier Atlantic salmon fisheries.

Preparing acoustic receivers for deployment

Sharing our work

Because salmon migrate across wide geographical areas, the information collected will be shared with scientists from the other countries to help us all better understand survival rates for this important species in Northern Europe. In addition, this international project allows researchers from across Europe to come together to share their knowledge and will inform future salmon management and conservation work internationally.

Inland Fisheries Ireland is contributing to SMOLTRACK by monitoring salmon smolts from the Black Water, a tributary of the River Erriff, which flows through County Mayo into Killary Harbour.

SMOLTRACK, which has been joined by new partner organisations in Finland and Portugal, has established projects in the following locations:

  • Ireland — River Erriff
  • Northern Ireland — River Bush
  • England — River Tamar
  • Wales — River Taff
  • Spain — River Ulla & River Tea
  • Denmark — River Skjern & River Storå
  • Sweden — River Göta Älv & River Högvadsån

More information, please visit