Skip to main content

Data from: Introgression from farmed escapees affects the full life cycle of wild Atlantic salmon

Cite this dataset

Bolstad, Geir H. et al. (2021). Data from: Introgression from farmed escapees affects the full life cycle of wild Atlantic salmon [Dataset]. Dryad.


After a half a century of salmon farming, we have yet to understand how the influx of genes from farmed escapees affects the full life history of Atlantic salmon (Salmo salar L.) in the wild. Using scale samples of over 6900 wild adult salmon from 105 rivers, we document that increased farmed genetic ancestry is associated with increased growth throughout life and a younger age at both seaward migration and sexual maturity. There was large among-population variation in the effects of introgression. Most saliently, the increased growth at sea following introgression declined with the population’s average growth potential. Variation at two major-effect loci previously shown to be associated with age at maturity was little affected by farmed genetic ancestry and could not explain the observed phenotypic effects of introgression. Our study provides knowledge crucial for redicting the ecological and evolutionary consequences of increased aquaculture production worldwide.

Usage notes

Column names:

  • organismID = unique identifier of organism
  • inhouseID = label of each individual used at NINA (not necessarily unique)
  • random_sample = value of 0 means that the individual is considered for the wild population with regards to phenotype expressed in freshwater, but not for phenotypes expressed at sea
  • riverName = name of the river
  • rivID = Unique code for Norwegian watercourse outlets issued by The Norwegian Water Resource and Energ y Directorate (NVE)
  • dataType = collection method
  • yearCapture = the year the fish was captured
  • dateCapture = the date the fish was captured (format:
  • sex = sex of the fish, where F denotes female, and M denotes male
  • VGLL3_TOP = genotype at the VGLL3_TOP marker (format: 0,1,2, where 1 is the heterozygous genotype, while 0 and 2 are homozygores)
  • SIX6_TOP = genotype at the SIX6_TOP marker (same format as for VGLL3_TOP)
  • seaAgeMaiden = sea age at first return to freshwater (years)
  • seaAgeCapture = sea age when captured (years)
  • smoltAge = age at outmigration (years)
  • length_mm = length from tip of snout to end of tail (mm)
  • mass_g = mass of fish at capture (g)
  • Lsmolt_mm = back calculated length at outmigration (mm)
  • L1sea_mm = back calculated length after first winter at sea (mm)
  • L2sea_mm = back calculated length after second winter at sea (mm)
  • L3sea_mm = back calculated length after third winter at sea (mm)
  • L4sea_mm = back calculated length after fourth winter at sea (mm)
  • Pind = the proportional ancestry for each individual to the domesticated reference populations
  • I = farmed genetic ancestry
  • Julian = the Julian date (ordinal date)

Note that most of the data published in “Bolstad, Geir H. et al. (2018), Data from: Gene flow from domesticated escapes alters the life history of wild Atlantic salmon, Dryad, Dataset,” is a subset of the data published here.


The Research Council of Norway, Award: 254852

The Research Council of Norway, Award: 275862

Norwegian Environment Agency

Norwegian Institute for Nature Research