The International Council for the Exploration of the Sea (ICES) raises serious concerns regarding the data and the lack of data used in the risk assessment of genetic mixing between farmed salmon and natural salmon populations in Iceland.
ICES points out that the current focus on sampling following escape incidents is unlikely to detect all escapees in rivers. The Council recommends establishing a systematic monitoring program in rivers, independent of escape incidents, in order to improve the data foundation for the risk assessment of genetic admixture.
ICES also recommends that all salmon samples be analyzed for potential farmed origin, regardless of their presumed origin, in order to confirm their true background in the context of risk assessment.
Furthermore, ICES suggests strengthening the monitoring program with systematic sampling in rivers, independent of escape events. Systematic monitoring should ensure that samples reflect conditions with regard to river habitats, seasonality, and the fact that the distribution of farmed salmon within watersheds can be uneven.
Since overestimation of population size leads to underestimation of genetic mixing, ICES advises that the assumptions and analytical methods used for estimating population size be reviewed to ensure the genetic admixture risk assessment model is sufficiently precautionary.
ICES warns against including sea-ranched salmon when estimating the size of wild salmon populations. The Council recommends that population size data reflect the developmental trends observed in wild Atlantic salmon returns to Iceland. The model’s sensitivity to such factors should be assessed to ensure the analytical framework reflects appropriate precaution.
ICES recommends that sensitivity analyses be conducted to determine how data gaps or variations in different parameters affect the outcome of the risk assessment under Icelandic conditions.
ICES also proposes holding an expert workshop specifically dedicated to defining and testing parameters for assessing the risk of genetic admixture, based on historical and contemporary data. This should include sensitivity testing of the robustness of the genetic risk assessment outcomes against various assumptions and parameter values derived from industry and governmental data. Such a process would strengthen the scientific basis for salmon farming management in Iceland, Canada, Ireland, Scotland, and Norway.
ICES recommends considering the definition of an acceptable level of genetic admixture from escaped farmed salmon.
However, ICES considers that until various sources of uncertainty are identified and incorporated into the genetic admixture risk assessment model, the estimate of the volume of salmon deemed safe to farm in sea pens does not align with the precautionary approach.
Available data on the frequency and scale of escape events are currently based on information from Norway. Therefore, caution should be exercised when applying those data to the genetic admixture risk assessment model for Iceland.
