Salmo salar | Atlantic Salmon



Conservation status

Future Prospects
Overal Assessment of Conservation Status
Overal trend in Conservation Status

Source: NPWS 2013.

IUCN Conservation Status
Ireland (1)
Vulnerable  [A2abcde]
Europe (2)
Vulnerable [A2ace]
Global (3)*
Least Concern

Sources: (1) King, J.L. et al 2011; (2) Freyhof, J. 2014 ; (3) World Conservation Monitoring Centre 1996.

*It is acknowledged on the IUCN website that this this assessment is in need of updating.

Legal status

Protected by the following legal instruments:

  • Habitats Directive [92/42/EEC] Annex II, Annex V
  • Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) Appendix III (in freshwater only)
  • Fisheries Acts 1959 to 2006
  • The Convention for the Protection of the marine Environment of the North-East Atlantic (OSPAR)
  • Fisheries Acts 1959 to 2006
  • Fisheries Act (Northern Ireland) 1966
  • Foyle Fisheries Act (NI) 1952
  • Foyle and Carlingford Fisheries Act 2007.
Sources:King, J.L. et al 2011; Froese, R. and D. Pauly (eds.), 2014; Maitland, Peter S., 2004.

Native status


Species Biology


  • Paired fins present.
  • Upper and lower jaws present.
  • Tail fin lobes not markedly asymmetrical.
  • Two dorsal fins, one of which is adipose (i.e. fleshy, not rayed).
  • Head without barbels.
  • Scales are relatively small with 100-130 along the lateral line.
  • Red colouration often present.
  • Enlarged dagger shaped scale present above pelvic fins.
  • In adult, non-adipose dorsal fin has 10-12 rays.
  • In adult there are 10-13 scales between adipoose fin and lateral line.
  • Adult may reach 120cms in length but the range 40-100cms in more usual.
  • Colouration changes with life stage. Juveniles or 'parr' who have yet to begin first migration from freshwater to marine are relatively brightly coloured but may be confused with similar age trout. Salmon parr have a series of quite distinct, fingerprint shaped blotches extending along and above and below the lateral line that have a blue-purple colour. Between these blotches are much smaller red / orange spots more or less parallel to the lateral line.

        In trout parr the 'fingerprint' blotches are much less distinct and the red spots are more scattered about the lateral line, and         more numerous. The tail fin in salmon parr is more deeply forked. Salmon parr will only have 4, usually less, spots on gill         cover, trout parr have more.

        In salmon the line of the mouth does not extend back beyond the eye, in trout it does. Both have dark spotting dorsally but         in trout these darker spots are surrounded by a paler aureole but this aureole is lacking in Atlantic salmon, and in Atlantic         salmon these darker spots are mostly restricted to above the lateral line.

  • Atlantic salmon parr may reach lengths of 12-25cms, but this length is usually an inidication that parr are approaching  the 'smolt' stage and will undergo physiological and behavioural changes and prepare to migrate to sea.
  • Smoltification causes the 'brighter' colouration to  be replaced with a silver grey colouration. The Adult salmon colouration is a blue-green above becoming silver grey at the sides then paler below. Dark spotting generally above the lateral line, without very marked paler aureoles surrounding the dark spotting as is seen in trout.
  • When adults approach spawning the silvery colouration is most often lost with individuals gaining a yellow or brown ground colour. Males may display a reddish tone at this time and also the lower jaw in the male lengthens to form a 'hook'.

Sources:; Maitland, Peter S., 2004; Froese, R. and D. Pauly (eds.), 2014.


Predominantly anadromous,with offspring migrating to to sea after a freshwater phase and adults returning to freshwater to breed . At younger stages shallower, well oxygenated, good quality, fast-flowing running freshwater ideally with  a gravel or cobble bed is the ideal habitat. Later stage juveniles may require deeper freshwater habitats.

Source: Davies et al (2004).

Habitats include but are not necessarily limited to;

  • Eroding / upland rivers (FW1)
  • Depositing / lowland rivers (FW2)
  • Lakes and ponds (FL)- (but not turloughs (FL6) and artificial lakes and ponds (FL8). Dystrophic lakes (FL1) are unlikely habitats)
  • Marine water body (M)

Sources: Maitland, Peter S., 2004; Fossitt, J.A. 2001.


Spawning occurs between late Autumn and early Spring mostly in November and December. Female fish excavate a redd, or nest, in gravel or cobble. Most adults die after spawning.

Fertilised eggs may take between 70 and 160 days to hatch. Hatched eggs progress from alevins (newly hatched with egg sac still attached), through fry, then parr and smolt stages prior to migration to sea. Most time is spent as parr and in Britain the usual period spent in freshwater from hatching to migration to sea can take between 1-3 years,, which may be similar in Ireland. In other regions this time can be longer. Most of this time is spent in the parr stage. Prior to migration to sea the parr undergo various physiological changes, the most obvious being in colouration, prior to moving from freshwater to sea for the first time. In Ireland this is timed for Spring.

Some individuals return to freshwater in the year following initial migration to sea. These are termed 'grilse', and generally return in the summer months. Other may spend 2-3 years before returning, usually in the spring and are known as 'spring salmon'.

It is rare for adults, particularly males, to spawn more than once however it does happen that following spawning some adults will migrate to sea again and return within the following 18 months to spawn again.

Sources: Davies et al 2004; Froese, R. and D. Pauly (eds.). 2014;Maitland, Peter S., 2004.

Threats faced

Agricultural intensification
Disposal of household / recreational facility waste
Diffuse pollution to surface waters due to household sewage and waste watersH01.08
Diffuse pollution to surface waters due to agricultural and forestry activities
Artificial planting on open ground (non-native trees)
Forest replanting (non native trees)
Use of fertilizers (forestry)
Disposal of industrial waste
Intensive fish farming, intensification
Water abstractions from surface waters
Threats and pressures from outside the Member State
Invasive non-native species I01Low
Management of aquatic and bank vegetation for drainage purposes
Modification of hydrographic functioning, general

Pollution to surface waters by industrial plants

Peat extraction
Intensive sheep grazing

Source: NPWS 2013.

The 2011 Irish Red Data Book assessment also identified as a threat to the species.;

  • Artificial Barriers to migration

which may be covered by the Article 17 Threat category 'Modification of hydrographic functioning, general'.

Source:King, J.L. et al 2011.

Conservation actions

In the Article 17 Habitats Directive reporting for the period 2007-2012 Conservation Actions in place or being implemented during the period were;

  • Continued legal protection of the species and its habitats inside and outside of Natura 2000 sites.
  • Regulation and / or management of the exploitation of Natural Resources on the Sea
  • Management measures for specific single species or groups
  • Regulation and / or management of hunting or taking
  • Restoring and / or improving water quality
  • Adaptation of forest management.

Source: NPWS 2013.


World distribution(GBIF)

North Atlantic natively but introduced elsewhere. In natural range, in freshwater phases occurs in rivers connected to the east coast of North America, Greenland, Iceland, Scandinavia,Baltics, Britain, Ireland and south as far as Portugal.

Sources: Davies et al 2004; Froese, R. and D. Pauly (eds.), 2014.

Accuracy of world distribution shown in the Global Biodiversity Information Facility (GBIF) map below will be constrained by, amongst other factors, data held but not shared by countries and organizations not participating in the GBIF.

Irish distribution

Widespread in large and medium river systems in Ireland.

Source:King, J.L. et al 2011.

Temporal change

Records submitted to Data Centre in 2021

The following map is interactive. If you would prefer to view it full screen then click here.

How can you help

The National Biodiversity Data Centre is trying to improve our knowledge on the distribution of the Atlantic Salmon in Ireland. Should you observe the species, please submit sightings to add to the database. Detailed observations will assist us gaining a better insight into where the species is most abundant in Ireland and we might also be able to detect regional variations. Please submit any sightings and photographs at:

All records submitted on line can be viewed on Google Maps – once checked and validated these will be added to the database and made available for conservation and research.

Further information

For further information contact Dr. Liam Lysaght



Anonymous, 2005. All Ireland Species Action Plans: Irish Lady’s-tresses Spiranthes romanzoffiana, Pollan Coregonus autumnalis, Hare Lepus timidus hibernicus, Corncrake Crex crex. National Parks & Wildlife Service, Ireland and the Environment & Heritage Service, Northern Ireland.

Davies, CE, Shelley, J, Harding, PT, McLean, IFG, Gardiner, R, Peirson, G (2004), Freshwater fishes in Britain - the species and their distribution. Harley Books

Fossitt, J.A. 2001 A Guide to Habitats in Ireland. The Heritage Council.

Freyhof, J. 2014. Salmo salar. The IUCN Red List of Threatened Species. Version 2014.3. <>. Downloaded on 08 January 2015.

Froese, R. and D. Pauly. Editors. (2014). FishBase. World Wide Web electronic publication., version (11/2014).

King, J.L., Marnell, F., Kingston, N., Rosell, R., Boylan, P., Caffrey, J.M., FitzPatrick, Ú., Gargan, P.G., Kelly, F.L., O’Grady, M.F., Poole, R., Roche, W.K. & Cassidy, D. (2011) Ireland Red List No. 5: Amphibians, Reptiles & Freshwater Fish. National Parks and Wildlife Service, Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland.

NPWS (2013) The Status of EU Protected Habitats and Species in Ireland.  Species Assessments Volume 3. Version 1.0. Unpublished Report, National Parks & Wildlife Services. Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland.

World Conservation Monitoring Centre 1996. Salmo salar. The IUCN Red List of Threatened Species. Version 2014.2. <>. Downloaded on 24 September 2014