PinkSIES · Pink Salmon Invasion of the North Atlantic: Evaluation of Stable isotopes as a method to detect potential impacts

Pink Salmon Invasion of the North Atlantic: Evaluation of Stable isotopes as a method to detect potential impacts

Pink salmon are native to the North Pacific. They are the smallest yet the most abundant Pacific salmon species, having a strong impact on their native marine ecosystem. They have one of the fastest oceanic growth rates with typically a two-year life cycle. In 2017, an unexpectedly large number of pink salmon records were reported from countries around the North Atlantic. The dramatic increase in the numbers of this non-native species has generated much concern, particularly regarding impacts on native Atlantic salmon populations. Native salmonids, Atlantic salmon and sea trout, support important fisheries and tourism throughout Northern Europe, which this invasive species may impact. To date, there are unanswered questions regarding the implications of this invasion, particularly regarding competition with native salmonids at sea and in freshwater. PinkSIES (Pink Salmon Invasion of the North Atlantic: Evaluation of Stable isotopes as a method to detect potential impacts) was supported by collaborators from many countries around the North Atlantic, to determine the impact of pink salmon on native salmonids at sea and in recently invaded rivers. The objectives focused on the marine phase of pink salmon in the North Atlantic included, i) an assessment of the distribution of feeding grounds, co-occurrence and potential competition between pink and Atlantic salmon at sea, and ii) to establish field metabolic rates of pink and Atlantic salmon, in order to iii) model the impact of climate warming on the future distribution of pink salmon. The project also investigated the freshwater phase, aiming to determine the duration of this phase, the extent of feeding of pink salmon fry in freshwater, and predation on pink salmon fry by native fish species. Biological samples (otoliths, scales, muscle tissue) were collected from >500 pink salmon specimens, caught offshore, inshore and in rivers in Norway, Iceland, Faroe Islands, Ireland, the UK, Greenland, Sweden, Denmark, and Germany. Analysis of stable isotopes of nitrogen and carbon of these samples was used to determine the location of their feeding grounds in the North Atlantic. The same isotopic technique was used to analyse tissues from pink salmon juveniles, to assess their ecological role as both predators and prey. This project has received funding from the European Union’s Horizon 2020 Research and Innovation Programme, under the Marie Skłodowska-Curie grant agreement No 101026030.

Data: CORDIS, © European Union