Reported Escape incidence analysis. Genetic Intrusion Risk Assessment - ICES – GIRAF working paper

Abstract

This report provides an analysis of reported escape incidents involving farmed salmon in Icelandic fjords from 2018 to 2023, specifically addressing the risk of genetic introgression. It details significant events across key locations such as Hringsdalur, Laugardalur (2018), Haganes (2021), and Kvígindisdalur (2023). Methodologies for estimating escape numbers, including vaccination and slaughter rates, are discussed. The report also highlights the use of fatty acid analysis to determine fish origin and life history.

Furthermore, the expanding Atlantic salmon aquaculture in Iceland, as assessed by the Marine and Freshwater Research Institute (MFRI), emphasizes the need for monitoring genetic introgression risks from escaped farmed salmon into wild populations. Ova producers are mandated to maintain genetic databases that trace the origin of any escaped salmon, ensuring the ability to analyse genetic impacts from individual escape events.

Further sections cover maturation rates within farmed cages and instances of untraced escapees. Conclusions suggest that both light regulation in cages and smoltification methods profoundly impact salmon maturation, informing recommendations for future mitigation strategies.