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

Project Information

PinkSIES

Grant agreement ID: 101026030

DOI

10.3030/101026030

Project closed

EC signature date 18 March 2021

Start date 1 June 2021

End date 31 May 2023

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 224 933,76

EU contribution

€ 224 933,76

Coordinated by

QUEEN MARY UNIVERSITY OF LONDON
United Kingdom

Periodic Reporting for period 1 - PinkSIES (Pink Salmon Invasion of the North Atlantic: Evaluation of Stable isotopes as a method to detect potential impacts)

Reporting period: 2021-06-01 to 2023-05-31

Summary of the context and overall objectives of the project

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.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The aim of the PinkSIES project was to determine the impact of pink salmon on native salmonids, both in marine and freshwater environments.

Supported by project collaborators, Dr Skora collected a unique, and the largest, collection of pink salmon biological samples (muscle tissue, scales, and otoliths) from the North Atlantic and Arctic Oceans, comprising >500 fish caught from an area that spanned West Greenland to North Norway (Finmark) to South England (Dorset). This collection comprises biological material from fish caught offshore, inshore and in rivers spanning 2013 – 2022.

Results of stable isotope analysis indicate that pink salmon utilise large feeding grounds in the Northern Atlantic and feed at multiple trophic levels. During secondment in Cefas, using the results of SIA, the Fellow mapped the distribution of pink salmon in the North Atlantic: there is considerable overlap with Atlantic salmon.
The PinkSIES project has also described previously unknown details of the life history of the species, which make the establishment of self-sustaining populations more likely, and has expanded the known invaded range of the species considerably. It was found that pink salmon juveniles overwinter in Scottish rivers and pink salmon complete their freshwater life cycle in the UK. Moreover, field observations provided the first evidence for reproduction and successful recruitment of pink salmon in Iceland. These two findings greatly expand the range where pink salmon populations are potentially established in the North Atlantic, increasing the concern that this invasive species will impact native species.

Finally, the PinkSIES project has detailed likely interactions with native species both in freshwater and at sea. Laboratory analysis of the diet of pink salmon juveniles provided evidence of active feeding in both localities, and of potential predation on pink salmon juveniles by sea trout parr.

The project results have been presented in one published paper and one paper under review, with a further two papers being prepared. The project was presented at international scientific meetings in Kirkenes, Norway and Edinburgh, UK, and at a national meeting in Fordingbridge, UK. Dr Skora also used the research to inform his input to an IUCN workshop on marine Invasive Alien Species. The project and results were also disseminated in professional magazines addressed at a wide range of readers (fish stocks managers, scientists, anglers, and nature conservationists). The project featured on the main news on National Icelandic Television broadcast 19th May 2022

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The project detailed the previously undescribed marine feeding grounds of pink salmon in the North Atlantic, a recent invasive species, and the extent of overlap, and hence potential competition with native Atlantic salmon.

The project provided new evidence indicating that pink salmon have potentially established in Scotland and Iceland, greatly expanding the known range of breeding populations. The project also found that pink salmon juveniles overwinter in Scottish rivers, previously unknown details of the life history of the species, obviating a presumed restriction on expansion of the species into lower latitudes and rendering the establishment of self-sustaining populations more likely.

Pink salmon are likely to impact native salmonid fisheries both through competition at sea and in freshwater, with consequent economic and societal implications. The results of the project will be used by local and regional authorities responsible for environment protection and fisheries, international institutions dedicated to fisheries management and nature conservation (ICES, IUCN), fisheries managers and non-governmental organisations such as river and angling trusts.

Pink salmon adult, smolts and nets used to catch smolts