Farmed salmon genes found in wild stock, UCC study finds

A study led by UCC has found evidence of farmed salmon genes in approximately one third of wild Atlantic salmon populations sampled in Ireland.

Undertaken by UCC in collaboration with Inland Fisheries Ireland (IFI) and Teagasc, the study provides the first major assessment of the extent of interbreeding between wild Atlantic salmon and fish farm escapees in Irish rivers. For the analysis, IFI collected samples of salmon in rivers from 133 locations across Ireland between 2023 and 2025, with samples collected between 2003 and 2008 from 61 rivers also used in the study.

The findings noted elevated levels of farmed genes in wild stocks sampled near marine salmon farms and near freshwater salmon farms. Wild salmon populations that were distant from major areas of salmon farming were also found to be affected.

Professor Philip McGinnity, of Sustainability Institute/UCC, said the study highlights the long term significance of safeguarding Ireland’s wild salmon population.

“Ireland’s Atlantic salmon populations represent a unique and irreplaceable 15,000-year legacy from the last ice age.

“Gene flow from escaped salmon has the potential to be a powerful evolutionary force.

“Any fundamental change to the genetic make-up of these populations could seriously hamper their capacity to evolve and adapt to future challenges, including those associated with global warming,” Prof McGinnity added.