X
GO

Understanding the migration routes of Atlantic salmon during their first months at sea

Publisert 13.09.2021

Extensive international collaboration and analysing 30 year’s catches of salmon at sea provide new information on key foraging areas.

Location of Atlantic salmon catches per month, given as number of post-smolts. Source: Gilbey et al. 2021.
Location of Atlantic salmon catches per month, given as number of post-smolts. Source: Gilbey et al. 2021.

 

The distribution and migration routes of Atlantic salmon from different countries and regions have been explored in a new study.

Key foraging areas in the Norwegian Sea

The study confirms major aggregations of salmon on the continental shelf-edge off Ireland, Scotland and Norway, and an important marine foraging area in the Norwegian Sea. These were salmon that had left their home rivers in the spring, and that were captured at sea later in the summer and autumn.

Nearly 30 years of fish collection - and new genetic methods

The study was based on the collection of nearly 10 000 young salmon during 385 marine cruises, spanning three decades and ~4.75 million km2 of ocean.

The geographic origin of more than 3000 of these salmon were identified by using genetic methods.

Population differences in migrations

Salmon from different countries and regions differed in their marine migration routes and distribution. Salmon from the northern rivers were surprisingly under-represented in the samples from the high-seas. So for instance, we still lack information on the migration of Norwegian salmon during their first months at sea.

The different distribution of regional stocks points to fundamental differences in their migration behaviours, which may lead to inter-stock variation in responses to environmental change and marine survival.

Important results

The results inform analyses of potential impacts on salmon from climate change and by-catch from high seas fisheries.

John Gilbey from Marine Scotland was the lead author.

He said to the Marine Scotland blogs: “This study brings together 30 years of observations of post smolt salmon at sea, achieved through collaborations with colleagues from across the eastern north Atlantic area.

- In a changing environment, where salmon face diverse and increasing pressures, such insights on the marine phase of salmon are of vital importance for understanding the pressures these fish face, and inform conservation efforts.

Long-term international collaboration

The team of researchers was from the UK, Norway, Ireland, France, Spain, Faroes, Denmark, Finland, and Russia. Many of the post-smolts were collected and screened as part of the EU Seventh Framework Programme funded SALSEA-Merge. Data analyses, interpretation and writing of the manuscript was done as part of the SeaSalar-project.

Read the new publication here

Gilbey, J., Utne, K.R., Wennevik, V., Beck, A.C., Kausrud, K., Hindar, K., Garcia de Leaniz, C., Cherbonne, C., Coughlan, J., Cross, T.F., Dillane, E., Ensing, D., García-Vázquez, E., Hole, L.R., Holm, M., Holst, J.C., Jacobsen, J.A., Jensen, A.J., Karlsson, S., Ó Maoiléidigh, N., Mork, K.A., Nielsen, E.E., Nøttestad, L., Primmer, C.R., Prodöhl, P., Prusov, S., Stevens, J.R., Thomas, K., Whelan, K., McGinnity, P. & Verspoor, E., 2021. The early marine distribution of Atlantic salmon in the North-east Atlantic: a genetically informed stock-specific synthesis. Fish and Fisheries, doi:10.1111/faf.12587