19855-1

Salmo salar 

Scope: Europe
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Salmoniformes Salmonidae

Scientific Name: Salmo salar Linnaeus, 1758
Regional Assessments:
Common Name(s):
English Atlantic Salmon, Black Salmon
Taxonomic Notes: European and North American salmons have long been considered as a single species but they are distinguished by chromosome numbers and genetic characteristics. Their status should be re-evaluated.

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2ace (Regional assessment) ver 3.1
Year Published: 2014
Date Assessed: 2014-01-15
Assessor(s): Freyhof, J.
Reviewer(s): Harrison, I.J., Hogan, Z., MacLean, J. & Mauroner, A.
Contributor(s): Kottelat, M., Hammerson, G.A., Comeros-Raynal, M., MacLean, J. & Allen, D.J.
Facilitator/Compiler(s): Allen, D.J.
Justification:
European regional assessment: Vulnerable (VU)

Atlantic Salmon is a keystone migratory species with a North Atlantic distribution, with presence in freshwaters across much of western and northern Europe and a marine extent that ranges across the North Atlantic to at least the west coast of southern Greenland and north of the Faroe Islands. The species is an important component of subsistence, recreational and commercial fisheries throughout the European region, and provides a range of ecosystem services.

The species has undergone historical extirpation from rivers in Belgium, Czech Republic, Germany, Netherlands, Poland, Slovakia, and Switzerland, and individual subpopulations have been lost from the Iberian Peninsula, Denmark, Sweden, Norway, Ireland, France, England, Wales, Scotland, and European Russia. These local extirpations and population declines have been attributed to a number of factors including, deliberate introductions and aquaculture escapement, overfishing (at sea and in freshwaters), pollution, damming and excessive sea lice (Lepiophtheirus salmoni) loads. The species has been the subject of widespread conservation actions (e.g., NASCO Action Plan; NASCO 1999), primarily focused on fisheries management, and on habitat conservation and restoration. Numbers of farmed salmon escaping to the wild are large relative to the abundance of their wild conspecifics (Thorstad et al. 2008), with negative effects on wild populations including both ecological interactions and genetic impacts of inter-breeding; Thorstad et al. (2008) show that inter-breeding of farm with wild salmon can result in reduced lifetime success, lowered individual fitness and decreases in production over at least two generations.

Because of the high but uncertain level of stocking across the species range (although it is recognised that in some regions this is low in relation to natural smolt numbers; e.g., Ireland: a total of c.500,000 smolts released annually in relation to a conservative estimated natural smolt production of 25-50 million annually; anon. reviewer pers. comm. 2014) and escapes, the scale of impact of the threats to the wild population is difficult to determine exactly and this requires further research. There are most likely relatively few truly self-sustaining wild populations remaining in Europe (some river basins in Russia and Norway, parts of Ireland and the UK). The species is estimated to have an average generation length of six years.

In the past 20 years (approximately three generations) salmon farming has increased substantially (introducing sea lice Lepeophtheirus salmonis and promoting the spread of the monogenetic trematode Gyrodactylus salaris), and many dams and other river obstructions have been built. Over a similar timeframe, salmon catches at sea (both reported and unreported catches) have undergone a continuing decline since 1987, with reported catches declining from more than 8,000 tonnes (fresh weight) in 1987 to less than 2,000 tonnes in 2012 (ICES 2013b). Well documented threats have led to an inferred population decline in wild self-sustaining populations of more than 30% over the last three generation lengths, based on suspected declines in pre-fishery abundance (PFA) across the European region, and corroborated by PFA data for the United Kingdom (JNCC 2013) that show a 27% decline over the same time period. This PFA figure is, most probably, increasingly composed of hatchery fish, and as for the above European PFA estimate, an overall decline over the last three generations exceeding 30% is inferred. The species is assessed as Vulnerable (VU A2ace) as a result of overfishing in the sea, declining habitat quality, reduced extent of occurrence (EOO), and the impact of pollution, climate change, and introduced taxa.

Population abundance of Atlantic Salmon is at an historically unprecedented low level in some rivers in Europe (Hedger et al. 2013). Trend data have never been comprehensively reviewed in detail for all the European or global populations, however river basin status data have been compiled at the country scale (WWF 2001: see attached table); only Iceland was assessed as having virtually unimpacted natural populations (99% of river basins considered 'Healthy'), and only Ireland (38%), Norway (47%), Scotland (63%) and England and Wales (33%) having significant percentages of 'healthy' salmon rivers. 'Healthy' salmon populations might also occur in northern European parts of Russia and this region might be the largest stronghold of the species, however data are poorly available from that region. The study by Limburg and Waldman (2009) reported that European stocks have crashed again since the 1980s from the low levels after the massive crash in the late 19th and early 20th centuries. This is not a local problem, as populations of wild S. salar are also at historic lows in North America (Limburg and Waldman 2009).

None of these studies distinguish between fully wild and ranched populations, in which fry, parrs or even smolts are stocked, often in huge numbers to sustain the salmon runs. We believe that if there were a critical assessment of this phenomenon, it would reveal that the conservation situation of Atlantic Salmon is much worse, especially in the Baltic, UK, central and eastern Europe, than inferred from data available for this assessment. The bottom line of decline has not yet been reached as climate change is thought to have already had some impacts and is likely to have greater future effects upon Atlantic Salmon in terms of both sub-population size and health (condition) (Johnsson and Johnsson 2009, IUCN 2009). Climate change may be partly to blame already for their decreasing numbers and conservation/reintroduction problems, especially in the southern part of its range. It is more than obvious that a cold stenothermic species such as the Atlantic Salmon will be impacted by climate change, especially in southern Europe, where anyhow, only few self-recruiting populations are left. In the northern part of the range, it is possible that salmon might benefit from climate change (Hedger et al. 2013), but the amount of suitable habitat available in the north does not balance the amount of habitat lost in the south. However McGinnity et al. (2009) suggest that climate change will have as much of an impact, if not an even greater impact at northern latitudes (due to increased winter temperatures leading to increased energy utilisation, the greater phenological adaptations required, and the greater magnitude and rate of projected temperature changes) as in southern latitudes. In addition, there is evidence that the temperature of the sea's surface may affect smolt survival. It is also thought that climate change may affect salmon growth rates or make their food less available.

This assessment does not take into account the clear differences in the status of individual stocks (sub-populations from individual river basins) where some are in serious decline or extirpated whereas others are doing much better, as evidenced by the river stock assessment presented by WWF (2001). It is therefore clear that each stock should be assessed independently in order to better reflect this variation, and to inform river basin population management and restoration actions. The COSEWIC (2010) report on the sub-population-level assessment of salmon in Canada is an example of such an approach that could be applied to inform the conservation of the species in European waters.
For further information about this species, see Status_of_salmon_rivers_by_country_WWF_2001.pdf.
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Geographic Range [top]

Range Description:The Atlantic Salmon has a North Atlantic distribution (Kottelat 1997, Kottelat and Freyhof 2007).

In Europe the species is known from the Atlantic, North, White, Barents and Baltic sea basins, from the Minho/Miño (Portugal, Spain) to the Kara drainages (Kara Sea, western Siberia). Within this range the species is present in Portugal, Spain, France, Germany (reintroduced), Denmark, Iceland, Great Britain, Ireland, and in northernmost rivers of Scandinavia and northern European Russia. Landlocked populations are known from southern Finland, Lakes Vänern (Sweden), Ladoga, Onega, and from some small lakes in the Vyg and Kem drainages, White Sea basin (Russia) and from southern Norway.

The main foraging areas of salmon of European origin are along the west coast of southern Greenland and north of the Faroe Islands, however it is unclear from the literature reviewed if there is exchange between the European and American populations. Baltic populations do not leave this sea (WWF 2001).

The species has undergone historical extirpation from Belgium, Czech Republic, Germany (now reintroduced), Netherlands, Poland, Slovakia, and Switzerland. Populations from the Duero, Tagus and Guadiana rivers in the Iberian Peninsula (based on historical records) are now extirpated, and populations have been lost or threatened with loss from numerous rivers in Denmark, Sweden, Norway, and the other Baltic Sea countries, Ireland, France, United Kingdom (England Wales, and Scotland), and Russia (the Lavna, Niva, Teriberka, Voronya, and Kalga rivers) (NASCO 2013a). The fish was thought to be extinct in Belarus since the mid-20th century as a result of dams built on the Western Dvina and Neman rivers, however recent research has found very small numbers of the fish migrate annually upstream in the Neris/Vilia rivers to the upper part of the Neman River basin in Belarus to spawn in the Vilia River tributaries (in the Dudka River about 800 m upstream from the confluence with Vilia) (Polutskaya 2005, 2009).

In both North America and in Europe the species has been widely stocked in river basins for fisheries, and farmed in coastal and estuarine aquaculture, from where feral populations have become locally established and hybridized with local populations, and the species has also been introduced in large numbers to the northeast Pacific (USA and Canada; anon. reviewer pers. comm. 2014). The species has also been introduced to New Zealand, Chile and southern Argentina, although salmon have not yet been able to establish self-reproducing stocks anywhere (H. Sparholt pers. comm. 2013).

In eastern North America the species is known from New England (Connecticut and Housatonic rivers, and possibly formerly to Delaware), north to Ungava Bay (northern Quebec) and to the Nastapoka River in eastern Hudson Bay (Morin 1991, G. Hammerson pers. comm. 2012). The only remaining populations that are believed to consist, at least in part, of native fishes in rivers in the United States of America occur in Maine (Dennys, Machias, East Machias, Narraguagus, Pleasant, Ducktrap, and Sheepscot rivers; Colligan and Nickerson 1996, G. Hammerson pers. comm. 2012); a few populations have been partially restored through hatchery production (Federal Register 1994). In Canada, the species' range extends northward from the St. Croix River (at the border with Maine, U.S.A.) to the outer Ungava Bay of Quebec, with one population in the eastern Hudson Bay (COSEWIC 2010).
Countries occurrence:
Native:
Belarus; Denmark; Estonia; Faroe Islands; Finland; France (France (mainland)); Greenland; Iceland; Ireland; Isle of Man; Latvia; Lithuania; Norway; Portugal (Portugal (mainland)); Russian Federation (Central European Russia, European Russia, North European Russia, Northwest European Russia); Spain (Spain (mainland)); Sweden; United Kingdom (Great Britain, Northern Ireland)
Regionally extinct:
Belgium; Czech Republic; Netherlands; Poland; Slovakia; Switzerland
Reintroduced:
Germany
FAO Marine Fishing Areas:
Native:
Arctic Sea; Atlantic – northeast; Atlantic – northwest; Mediterranean and Black Sea
Additional data:
Lower depth limit (metres):210
Range Map:19855-1

Population [top]

Population:The species is regionally abundant in European waters, however this is mainly due to massive stocking across its range in Europe and pre-fishery abundance (PFA) has declined from around 10 million individuals in the 1970s to c.3.6 million in recent years; this represents a 64% decline over the 29 year period (1975–2004), this represents a 64% decline over the 40-odd year period (c.1970–2010), equivalent to a 28.8% decline over the last 18 years (three generation lengths). This decline in PFA has been greater in southern European stocks than in northern European stocks (Windsor et al. 2012). This PFA is, most probably, increasingly composed of hatchery fish, and although the exact contribution of captive-bred fish is unknown, it is inferred that the decline of PFA population has declined by more than 30%.

This inferred level of decline is confirmed by data for United Kingdom waters. PFA estimates produced for the ICES Working Group (JNCC 2013) reports show a 44.5% decline in the 29 year period from the mid-1970s (average 1975-79 = 1,301,481 individuals) to the mid-2000s (average 2000-03/04 = 722,471), an average annual decline of 1.5%. Given that the period represents approximately five generations for the species, we can estimate a decline of 27% over the last three generation lengths. This PFA figure is, most probably, increasingly composed of hatchery fish, and as for the above PFA estimate, an overall decline over the last three generations exceeding 30% is inferred.

The Atlantic Salmon Rivers Database (NASCO 2013a) records the stock status of the species in 1,399 European rivers;
  • Not Threatened With Loss (1,028 rivers in which the natural salmon stocks are not considered to be threatened with loss)
  • Threatened With Loss (161 rivers in which there is a threat to the natural stock of salmon which would lead to loss of the stock unless the factor(s) causing the threat is(are) removed)
  • Lost (79 rivers in which there is no natural or maintained stock of salmon but which are known to have contained salmon in the past)
  • Restored (45 rivers in which the natural stock of salmon is known to have been lost; but in which there is now a self-sustaining stock (restoration efforts or natural recolonization)
  • Maintained (42 rivers in which there is no natural stock of salmon; contained salmon in the past, but in which a salmon stock is now only maintained through human intervention)
  • Unknown (44 rivers in which there is no information available as to whether or not it contains a salmon stock)   
This equates (excluding 'Unknown' rivers) to 24.1% of river stocks considered to be impacted (threatened, lost, restored or maintained).

Populations from the Lima (WWF 2001), Duero, Tagus and Guadiana rivers in the Iberian Peninsula (based on historical records) are now extirpated, and populations have been lost or threatened with loss from numerous rivers in Denmark, Sweden, Norway, Ireland, France, United Kingdom (England Wales, and Scotland), and Russia (the Lavna, Niva, Teriberka, Voronya, and Kalga rivers) (NASCO 2013b). Baltic Sea populations underwent dramatic declines in the 20th Century, when the annual production of smolt in the Baltic declined by about 95% (WWF 2001), and less than 10% of salmon fry are the offspring of wild salmon hatcheries (IBSFC 2000).

In spite of these reductions in fishery pressures, many stocks of the species are not rebuilding. This is because, whilst there have been some recoveries based on habitat restoration and improvements (e.g., in England and Wales (NASCO 2007a), Denmark (NASCO 2007b) and Norway (e.g., Hesthagen et al. 2011), the natural mortality of juvenile salmon in the marine phase has increased. The causes for that remain largely unknown. The spawning stocks in the southern part of the distribution area are so low and habitat quality is so poor that the basin productivity of juveniles are reduced compared to the potential of the rivers. In the northern part there are generally enough spawners to fulfil the production potential of the rivers. The Baltic stocks are improving (HELCOM 2013a), but many other stocks are still under the production potential of the rivers. Also here, it is difficult to distinguish between rivers with fully or partly ranched stocks and those with fully natural stocks. Aquaculture production from North and South America and Europe has, on the other hand, massively increased over the same period from almost nil in the 1960s to over 2.07 million tonnes in 2012 (FAO 2013).

This species is represented by a large number of subpopulations and locations. Many wild salmon rivers have their own genetically distinct stock. ICES (2012) reported that many wild populations around the North Atlantic remain at very low levels despite many years of severe reductions in commercial salmon fisheries and other conservation actions.

Chaput (2012) reported a decline since mid- to late-1980s in marine survival, as measured by the return rates of smolts to adults from monitored rivers. A key element of concern has been the decline since the 1960s (Hendry and Cragg-Hine 2003) in the proportion of single winter fish to Multi-Sea-Winter (MSW) fish (fish that stay more than one year at sea) returning to spawn. MSW fish are larger in size and produce significantly greater numbers of eggs and egg deposition is reduced as a result of the decline in MSW fish.
For further information about this species, see Status_of_salmon_rivers_by_country_WWF_2001.pdf.
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Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
Continuing decline in subpopulations:Yes

Habitat and Ecology [top]

Habitat and Ecology:Habitat
Found in rivers where water temperature rises above 10°C for at least three months per year and does not exceed 20°C for more than a few weeks in summer. Juveniles and resident stream populations inhabit riffles of fast-flowing, moderately cold streams and rivers. In northern Europe, juveniles may live in cold lakes. Salmon spawn mostly in natal streams, in rivers and streams with swift flowing water and a succession of riffles and pools. Lacustrine populations migrate to tributaries. Usually spawns in depressions made by the female fish in the gravel. Pelagic at sea or in large lakes, mostly foraging in surface layers. In the ocean, the fish has been found to 210 m, but is usually present at depths of 2-5 m (anon. reviewer pers. comm. 2014).

Biology
Both anadromous and landlocked populations occur. Evidence suggests that spawning in 'couples' occurs the minority of times, with most spawnings involving multiple males (anadromous adults and parr; anon. reviewer. pers. comm. 2014). Spawning occurs during October-January (October in Norway and Russia, November in Germany, Denmark and southwestern Sweden; December in Ireland, France and Spain), although spawning time can also vary among populations in the same river (J. MacLean pers. comm. 2014). Translocated stocks are reported to retain their original spawning time. Females select spawning sites and create shallow spawning sites (redds; areas of disturbed gravel) which may contain one or more nests, each nest being the result of a separate spawning event. Males guard and defend females against other males. An individual female may dig up to fourteen nests (average of around six) depending on their size (anon. reviewer. pers. comm. 2014), and both sexes may mate with several partners. The female spawns into the nest depression and eggs are covered with gravel by the female. Most males die after reproduction, while 10-40% of females (kelts; post-spawning adult) may survive spawning and migrate back to sea in autumn or overwinter in rivers and migrate again in spring, although kelt survival can be as low as 1% (J. MacLean pers. comm. 2014).

Eggs are covered with 10-30 cm of gravel and hatch in 70-160 days. Successful development of eggs and alevins (fry with egg sack attached) requires a water permeability through gravel above one meter per hour (1 mh-1). Alevins are negatively phototactic and move deep into gravel. Fry are positively phototactic and inhabit very shallow riffles, usually downstream of spawning site. Fry usually emerge from gravel between March (Spain) and July (north Finland) when temperature rises above 8°C. Young over one year old (parr) are territorial, feeding on drifting and benthic invertebrates. Some males may spawn for the first time when they are still parr and are then able to fertilise more than 20% of eggs by sneaking into redds of anadromous couples. Mature parr are also able to successfully fertilize eggs in the absence of anadromous males. Mature male parr usually migrate to sea but have a lower probability of returning to breed as adults than males that did not mature as parr. Some parr may remain in freshwater. Ripe female parr are very rare. A few landlocked stream populations maturing as parr are known from Norway, in streams where waterfalls prevent access to anadromous salmons. Parr feed for 1-7 (usually 2-3) years in freshwater depending on temperature and feeding conditions. Usually, parr smoltify at 100-150 mm SL; smoltification is triggered by increasing day length in winter. Neither sex feeds in freshwater during the spawning and post-spawning migrations. Usually, 0.3-6.0% of females reproduce a second time. Kelts may spawn in the year following the first reproduction or may remain at sea for 18 months before returning once more to the river. In short rivers, up to 34% of the individuals reproduce a second time and there are records of individuals spawning for up to six seasons.

Smolt start to migrate downstream in April-June when temperature increases above 8-10°C from low winter levels. Migration peaks when rising water levels coincide with increased turbidity during spring floods or heavy rain. A small number may migrate to sea in autumn. Smolt are gregarious and migration is nocturnal with peaks at dusk and dawn. Learning the route during downstream migration seems to be the main factor determining successful homing. Smolt may spend some time in brackish estuaries or they may immediately move to the sea. At sea, the species is pelagic and feeds on small fish and large crustaceans such as amphipods and euphausids. After spending between one and four winters at sea, individuals migrate to their natal river. Patterns of upstream migration depend on the particular river and age of the fish. Individuals may enter rivers in any month of the year, with some fish entering more than a year before spawning. Individuals that have spent more than one winter at sea usually seem to enter rivers in spring while those that spent a single winter at sea dominate the autumn run. A number of individuals enter their non-natal river and either stay (and may breed successfully) or leave and enter another river (either natal or non-natal) (J. MacLean pers. comm. 2014). During upriver migration, the silvery colour of the marine phase is replaced by a dark breeding colour; the skull of males enlarges and they develop a kype on the lower jaw.

The species sometimes hybridises with S. trutta.

Generation length
The generation length of the species in Europe is estimated at six years (H. Sparholt pers. comm. 2013), based on generation length for salmon with a smolt age of between two to five years, representing the case in southern parts of its European distribution. In the north, the smolt age is four years. However age-at-maturity varies from three years (one if you include mature male parr) to 10 years (Hutchings and Jones 1998), with an average of between four and five years.
Systems:Freshwater; Marine
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):6
Movement patterns:Full Migrant
Congregatory:Congregatory (and dispersive)

Use and Trade [top]

Use and Trade: Salmon aquaculture includes farming, ranching and stocking activities. Production of farmed salmon in the North Atlantic in 2010 was approximately 600 times the harvest of wild fish (NASCO 2013c).

Salmon is an iconic species in both historical and contemporary culture, found in many aspects of art, literature, jewellery, and architecture etc. The species is a focus for social activities (e.g., fishery clubs), and the driver of general river restoration activities. Salmon runs draw visitors throughout Europe where the species is present in numbers. Salmon are central to the cultures of the Sami and Kven northern indigenous peoples in Norway (WWF 2001).

The species is an important food and recreational angling fish throughout its European range (Kulmala et al. 2013) with high commercial, social and cultural values, and it is an iconic species in both historical and contemporary culture. The species also provides important ecosystem services as a source of oceanic carbon and river organic enrichment, and as direct prey for large numbers of oceanic and river species including other fishes, many birds, mammals including some whales and seals (anon. reviewer pers. comm. 2014). Kulmala et al. (2013) estimate that the cultural value of the species may exceed the value of commercial landings in northern Europe. Further research to obtain information on the scale of these benefits across the European region is required.

Threats [top]

Major Threat(s): The species is strongly affected by water pollution and sedimentation, primarily caused by logging and agricultural activities (especially in spawning habitats), damming and overfishing. Because of degraded environmental conditions, most populations depend largely or exclusively on stocking, especially in western and central Europe. Due to intensive farming and fishery controls, the fishing pressure on wild stocks has decreased but other problems have increased. The natural mortality of juvenile salmon in the marine phase has increased, however the causes of this are not well understood (H. Sparholt pers. comm. 2012). Depletion of forage species by commercial fisheries and freshwater exposure of juveniles to an endocrine disrupter (leads to mortality in marine phase) are suggested possible causes in the case of North American populations (G. Hammerson pers. comm. 2012).

Farmed salmon are usually the result of hybridization of different stocks with selection favouring farm conditions. Large numbers of farmed salmon escape and - as they have no homing site - move to any river and hybridise with wild stocks. Usually egg and juvenile survival rates are much less than in wild salmon and thus farm escapees drain the reproductive success and pollute the genetic and adaptive identity of wild populations. Large scale releases have, for example, been cited as a potential threat to Baltic salmon genetic diversity (Palmé et al. 2012).

Sea lice Lepeophtheirus salmonis, an ectoparasitic copepod, occur in large numbers on captive salmon and seriously infect wild smolts, as they migrate past salmon farms in estuaries (Whelan 2010). The primary concern relating to sea lice originating from aquaculture is the impact on outmigrating post-smolt salmon, which are susceptible to lice infections. Further comparison of sea lice burdens of inward and outward migrating salmon, and of salmon from areas with and without salmonid aquaculture is required (ICES 2013a). It has been well shown that wild salmon adjacent to salmon aquaculture have high infestations of sea lice (Bostick et al. 2005), however the mode of transmission to wild salmon from aquaculture is not well understood. ICES (2013a) reports a continuing lack of research into sea lice burdens on salmon, either studies comparing sea lice prevalence on 'wild' salmon pre- and post-development of aquaculture within a region, or comparison between stocks with and without aquaculture (ICES 2013a). Butler (2002) concluded that in Scottish waters less than 1% of the sea lice originated from wild salmonids. Whelan (2010) undertook a comprehensive review of the impact of sea lice on salmon and found extensive evidence linking localised epizootics of juvenile lice with increased lice levels on migratory salmonids (Bjørn et al. 2001, Gargan et al. 2003, Krkošek et al. 2005). Heuch and Mo (2001) concluded that total lice egg production annually in farming areas in Norway had increased by more than 50 times compared to pre-farming conditions. WWF (2001) report that diseases and sea lice transferred from caged salmon to wild salmon are a severe hazard to juveniles in countries where salmon farming is predominant.

The introduction of the monogenetic trematode Gyrodactylus salaris from Baltic hatchery salmon to Baltic farmed and wild stocks has caused mass mortalities. Gyrodactylus is a freshwater ectoparasite on parrs; it is spread by salmon eggs or parrs (or trout) used for stocking. In some rivers, Norwegian fisheries authorities killed all fish (not only salmon but the whole population of all native non-anadromous species) with ichthyocides in an attempt to eradicate the parasite.

Overfishing at sea, and in particular with drift nets, is a major threat to the species, although fisheries controls have been implemented. The species is also impacted as bycatch in the mackerel fishery in the North Norwegian Sea.

Overfeeding in farms and the use of chemicals and/or antibiotics can result in localised pollution impacts in the marine environment, however evidence of impacts on wild salmon is required.

The direct and indirect impacts of climate change on the species and its habitats are not well understood and require further research. Jonsson and Jonsson (2009) suggest that a northward movement of the thermal niche of anadromous salmon will result in decreased production and population extinctions in the southern part of the species distribution, earlier migrations, later spawning, younger age at smolting and sexual maturity and increased disease susceptibility and mortality. Northern populations are predicted to benefit from increased parr recruitment and smolt production as a result of climate change, whilst higher levels of parr mortality might occur due to decreased summer water availability (Hedger et al. 2013).

Conservation Actions [top]

Conservation Actions: There are many conservation actions in place for the species, including scientific research and monitoring, habitat restoration and legal measures such as the Convention for the Conservation of Salmon in the North Atlantic Ocean (NASCO) which entered into force on 1 October 1983. Through the contracting parties (Canada, Denmark (in respect of the Faroe Islands and Greenland), the European Union, Norway, Russian Federation and the United States of America) the convention aims to promote the conservation, restoration, enhancement, and rational management of salmon stocks in the North Atlantic Ocean.

Conservation actions include habitat protection and restoration (e.g., removing weirs and other obstructions to migrations and improved water quality through liming to reduce pH of acidified rivers in Norway (Hesthagen et al. 2011). There should be a presumption against stocking practices undertaken to enhance salmon and sea trout fisheries (McIntyre and Kettlewhite 2014), whilst ex situ conservation, reintroduction and support of natural populations should be undertaken with care. Ongoing research and monitoring is essential to fully understand the impacts of ongoing and novel threats on the species.

The species has been assessed as Vulnerable (VU A4b) in the Baltic (HELCOM 2013b), and occurs on the national Red Lists of the following European countries: UK (Biodiversity Action Plan species), Ireland, Sweden, Denmark, Holland, Belgium, France, Spain, Portugal, Switzerland, Germany, Czech Republic, Finland, Poland, Russia, Estonia, and Lithuania (JNCC 2013).

The freshwater populations (except those in Finland) have been listed in Annexes II, IV and V of the EU Habitats Directive (HELCOM 2013b). The species appears in the Bern Convention (Appendix 3), and has been listed on the OSPAR List of Threatened and/or Declining Species and Habitats (OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic; JNCC 2013). The species is recorded as occurring in 515 Natura 2000 protected areas throughout much of Europe (EUNIS 2014).
The fish had been assessed at the global scale as Lower Risk/least concern for the IUCN Red List in 1996 (World Conservation Monitoring Centre 1996).

Citation: Freyhof, J. 2014. Salmo salar. The IUCN Red List of Threatened Species 2014: e.T19855A2532398. . Downloaded on 23 June 2018.
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