scholarly journals Salmon lice increase the age of returning Atlantic salmon

2014 ◽  
Vol 10 (1) ◽  
pp. 20130896 ◽  
Author(s):  
Knut Wiik Vollset ◽  
Bjørn Torgeir Barlaup ◽  
Helge Skoglund ◽  
Eirik Straume Normann ◽  
Ove Tommy Skilbrei
Keyword(s):  
Atlantic Salmon ◽  
Life History Traits ◽  
Age Distribution ◽  
Wild Populations ◽  
Age At Maturity ◽  
Farmed Fish ◽  
Parasite Abundance ◽  
Salmon Lice ◽  
Global Increase ◽  
Host Parasite

The global increase in the production of domestic farmed fish in open net pens has created concerns about the resilience of wild populations owing to shifts in host–parasite systems in coastal ecosystems. However, little is known about the effects of increased parasite abundance on life-history traits in wild fish populations. Here, we report the results of two separate studies in which 379 779 hatchery-reared Atlantic salmon smolts were treated (or not) against salmon lice, marked and released. Adults were later recaptured, and we specifically tested whether the age distribution of the returning spawners was affected by the treatment. The estimates of parasite-induced mortality were 31.9% and 0.6% in the River Vosso and River Dale stock experiments, respectively. Age of returning salmon was on average higher in treated versus untreated fish. The percentages of fish returning after one winter at sea were 37.5% and 29.9% for the treated and untreated groups, respectively. We conclude that salmon lice increase the age of returning salmon, either by affecting their age at maturity or by disproportionately increasing mortality in fish that mature early.

scholarly journals Salmon lice evasion, susceptibility, retention, and development differ amongst host salmonid species

2017 ◽  
Vol 75 (3) ◽  
pp. 1071-1079 ◽  
Author(s):  
Samantha Bui ◽  
Elina Halttunen ◽  
Agnes M Mohn ◽  
Tone Vågseth ◽  
Frode Oppedal
Keyword(s):  
Atlantic Salmon ◽  
Chinook Salmon ◽  
Salmo Trutta ◽  
Parasite Development ◽  
Lepeophtheirus Salmonis ◽  
Sea Trout ◽  
Salmon Lice ◽  
Salmonid Species ◽  
Host Parasite ◽  
Temporal Overlap

Abstract With different ecological characteristics amongst salmonid species, their response to parasitic infestation is likely to vary according to their spatial and temporal overlap with the parasite. This study investigated the host–parasite interactions amongst three species of salmonids and the ectoparasitic salmon louse, Lepeophtheirus salmonis. To determine any variation in infestation parameters amongst salmonids, single population groups of Atlantic salmon (Salmo salar), chinook salmon (Onchorhynchus tshawytscha), and previously-infested and naïve sea trout (Salmo trutta) were exposed to a controlled infestation challenge. We found that chinook salmon and both sea trout groups were more susceptible to acquiring lice than Atlantic salmon. Behavioural responses during infestation were more pronounced in Atlantic and chinook salmon. Parasite development was similar in lice attached to Atlantic salmon and sea trout, but hindered on chinook salmon. At 16 days post-infestation, chinook salmon had reduced lice loads to the same level as Atlantic salmon, whilst sea trout retained their lice. These results demonstrate differences in interactions with L. salmonis amongst these species, and highlight the vulnerability of sea trout to infestation.

scholarly journals Risk assessment of the environmental impact of Norwegian Atlantic salmon farming

2014 ◽  
Vol 72 (3) ◽  
pp. 997-1021 ◽  
Author(s):  
Geir Lasse Taranger ◽  
Ørjan Karlsen ◽  
Raymond John Bannister ◽  
Kevin Alan Glover ◽  
Vivian Husa ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Atlantic Salmon ◽  
Viral Disease ◽  
Organic Load ◽  
Genetic Introgression ◽  
Wild Populations ◽  
Fish Farms ◽  
Marine Research ◽  
Salmon Farming ◽  
Salmon Lice

Abstract Norwegian aquaculture has grown from its pioneering days in the 1970s to be a major industry. It is primarily based on culturing Atlantic salmon and rainbow trout and has the potential to influence the surrounding environment and wild populations. To evaluate these potential hazards, the Institute of Marine Research initiated a risk assessment of Norwegian salmon farming in 2011. This assessment has been repeated annually since. Here, we describe the background, methods and limitations of the risk assessment for the following hazards: genetic introgression of farmed salmon in wild populations, regulatory effects of salmon lice and viral diseases on wild salmonid populations, local and regional impact of nutrients and organic load. The main findings are as follows: (i) 21 of the 34 wild salmon populations investigated indicated moderate-to-high risk for genetic introgression from farmed escaped salmon. (ii) of 109 stations investigated along the Norwegian coast for salmon lice infection, 27 indicated moderate-to-high likelihood of mortality for salmon smolts while 67 stations indicated moderate-to-high mortality of wild sea trout. (iii) Viral disease outbreaks (pancreas disease, infectious pancreatic necrosis, heart and skeletal muscle inflammation, and cardiomyopathy syndrome) in Norwegian salmon farming suggest extensive release of viruses in many areas. However, screening of wild salmonids revealed low to very low prevalence of the causal viruses. (iv) From ∼500 yearly investigations of local organic loading under fish farms, only 2% of them displayed unacceptable conditions in 2013. The risk of eutrophication and organic load beyond the production area of the farm is considered low. Despite several limitations, especially limited monitoring data, this work represents one of the world’s first risk assessment of aquaculture. This has provided the Norwegian government with the basis upon which to take decisions for further development of the Norwegian aquaculture industry.

scholarly journals Genetic architecture of age at maturity can generate divergent and disruptive harvest-induced evolution

2017 ◽  
Vol 372 (1712) ◽  
pp. 20160035 ◽  
Author(s):  
Anna Kuparinen ◽  
Jeffrey A. Hutchings
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
Genetic Architecture ◽  
Life History Traits ◽  
Single Locus ◽  
Sexually Dimorphic ◽  
Age At Maturity ◽  
Sexually Dimorphic Expression ◽  
Strong Control ◽  
Dimorphic Expression

Life-history traits are generally assumed to be inherited quantitatively. Fishing that targets large, old individuals is expected to decrease age at maturity. In Atlantic salmon ( Salmo salar ), it has recently been discovered that sea age at maturity is under strong control by a single locus with sexually dimorphic expression of heterozygotes, which makes it less intuitive to predict how life histories respond to selective fishing. We explore evolutionary responses to fishing in Atlantic salmon, using eco-evolutionary simulations with two alternative scenarios for the genetic architecture of age at maturity: (i) control by multiple loci with additive effects and (ii) control by one locus with sexually dimorphic expression. We show that multi-locus control leads to unidirectional evolution towards earlier maturation, whereas single-locus control causes largely divergent and disruptive evolution of age at maturity without a clear phenotypic trend but a wide range of alternative evolutionary trajectories and greater trait variability within trajectories. Our results indicate that the range of evolutionary responses to selective fishing can be wider than previously thought and that a lack of phenotypic trend need not imply that evolution has not occurred. These findings underscore the role of genetic architecture of life-history traits in understanding how human-induced selection can shape target populations. This article is part of the themed issue ‘Human influences on evolution, and the ecological and societal consequences’.

scholarly journals Genetic and phenotypic changes in an Atlantic salmon population supplemented with non-local individuals: a longitudinal study over 21 years

2015 ◽  
Vol 282 (1802) ◽  
pp. 20142765 ◽  
Author(s):  
Sabrina Le Cam ◽  
Charles Perrier ◽  
Anne-Laure Besnard ◽  
Louis Bernatchez ◽  
Guillaume Evanno
Keyword(s):  
Genetic Diversity ◽  
Life History ◽  
Atlantic Salmon ◽  
Life History Traits ◽  
Genetic Admixture ◽  
Phenotypic Traits ◽  
Source Population ◽  
Wild Populations ◽  
Non Local ◽  
Source Populations

While introductions and supplementations using non-native and potentially domesticated individuals may have dramatic evolutionary effects on wild populations, few studies documented the evolution of genetic diversity and life-history traits in supplemented populations. Here, we investigated year-to-year changes from 1989 to 2009 in genetic admixture at 15 microsatellite loci and in phenotypic traits in an Atlantic salmon ( Salmo salar ) population stocked during the first decade of this period with two genetically and phenotypically distinct source populations. We detected a pattern of temporally increasing introgressive hybridization between the stocked population and both source populations. The proportion of fish returning to the river after a single winter at sea ( versus several ones) was higher in fish assigned to the main source population than in local individuals. Moreover, during the first decade of the study, both single-sea-winter and multi-sea-winter (MSW) fish assigned to the main source population were smaller than local fish. During the second decade of the study, MSW fish defined as hybrids were lighter and smaller than fish from parental populations, suggesting outbreeding depression. Overall, this study suggests that supplementation with non-local individuals may alter not only the genetic diversity of wild populations but also life-history traits of adaptive significance.

scholarly journals Effects of aquaculture on wild fish populations: a synthesis of data

2005 ◽  
Vol 13 (4) ◽  
pp. 145-168 ◽  
Author(s):  
Laura K Weir ◽  
James WA Grant
Keyword(s):  
Atlantic Salmon ◽  
Artificial Selection ◽  
Scientific Literature ◽  
Current Data ◽  
Wild Fish ◽  
Fish Populations ◽  
Negative Consequences ◽  
Wild Populations ◽  
Farmed Fish ◽  
In The Wild

The potential adverse environmental effects of aquaculture have been the subject of considerable attention in both the media and the scientific literature. We undertook a synthesis of the published scientific literature, primarily concerning Atlantic salmon (Salmo salar), to assess the current data available regarding these potential effects. No data are available to test for the direct effects of aquaculture organisms on the demographics of wild fish populations. However, seven studies show that escaped salmon in the wild have lower fitness, as measured by survival and reproductive success, than native salmon. Thirteen other studies, encompassing 91 different traits, provide strong evidence of phenotypic differences between farmed and wild salmon, presumably because of artificial selection in the aquaculture environment. An additional 10 studies have documented significant genetic differences between farmed salmon and the wild fish with which they will interact, or potentially interact. Given the paucity of data regarding actual population consequences of escaped farmed fish on wild populations, and the documented differences between the two types of fish, it seems prudent to treat farmed fish as exotic species with potentially negative consequences for wild populations, particularly when the latter are of conservation concern.Key words: aquaculture, Atlantic salmon, artificial selection, fitness, introgression.

scholarly journals Activities for Prevention of Gyrodactylus Salaris Distribution in the Kola Peninsula Rivers

2020 ◽  
Author(s):  
Natalia Kalinina ◽  
Petr Kravets
Keyword(s):  
Atlantic Salmon ◽  
Kola Peninsula ◽  
Barents Sea ◽  
Natural Populations ◽  
Wild Populations ◽  
Farmed Fish ◽  
Scientific Organizations ◽  
Northwest Europe ◽  
Baltic Sea Basin ◽  
Working Out

Monitoring of distribution of monogenean ectoparasite Gyrodactylus salaris, dangerous for wild populations of the Atlantic salmon in northwest Europe, is carried out by Veterinary Services and the profile scientific organizations in different European countries. In Murmansk area, Gyrodactylus lavareti was first found in a trout farm in Tuloma River in 1996. From now on, representatives of genus Gyrodactylus are annually identified in farmed fish in Tuloma River, according to ichthyopatholocic observations of salmonid farms in Murmansk area. Species G. salaris was indicated in 2016 in farmed trout in Tuloma River and in wild salmon smolts in Pak River of the Nizhnetulomsky water basin. Throughout a number of years, the experts of Regional Veterinary Service and the scientific organizations of Murmansk area discuss necessity of working out of measures to prevent Gyrodactylus salaris introduction in the rivers of the Kola Peninsula with wild populations of the Atlantic salmon. Any transport of smolt and live fish from the freshwater objects of Baltic Sea basin to the water objects of the Barents Sea basin sea would become the most significant threat by parasite Gyrodactylus salaris distribution and might cause a damage of natural populations of the Atlantic salmon of Kola Peninsula.

scholarly journals Impact of a candidate vaccine on the dynamics of salmon lice (Lepeophtheirus salmonis) infestation and immune response in Atlantic salmon (Salmo salar L.)

2020 ◽  
Author(s):  
Jaya Kumari Swain ◽  
Yamila Carpio ◽  
Lill-Heidi Johansen ◽  
Janet Velazquez ◽  
Liz Hernandez ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Vaccine Candidate ◽  
Negative Impact ◽  
Transcript Level ◽  
Parasitic Copepod ◽  
Lepeophtheirus Salmonis ◽  
Farmed Fish ◽  
Control Approach ◽  
Salmon Lice

AbstractInfection with parasitic copepod salmon louse Lepeophtheirus salmonis, represents one of the most important limitations to sustainable Atlantic salmon (Salmo salar L.) farming today in the North Atlantic region. The parasite exerts negative impact on health, growth and welfare of farmed fish as well as impact on wild salmonid populations. It is therefore central to ensure continuous low level of salmon lice with the least possible handling of the salmon and drug use. To address this, vaccination is a cost-effective and environmentally friendly control approach. In this study, efficacy of a vaccine candidate, containing a peptide derived from ribosomal protein P0, was validated post infestation with L. salmonis, at the lab-scale. The sampling results showed good potential of the vaccine candidate when administered intraperitoneally in the host, in reducing the ectoparasite load, through reduction of adult female lice counts and fecundity and with greater presumptive effect in F1 lice generation. The sampling results correlated well with the differential modulation of pro-inflammatory, Th1, Th2 and T regulatory mediators at the transcript level at different lice stages. Overall, the results supports the effectiveness of the vaccine candidate in controlling salmon lice infestation load. However, further validation is necessary under field conditions.

scholarly journals Cis-regulatory differences in isoform expression associate with life history strategy variation in Atlantic salmon

2019 ◽  
Author(s):  
Jukka-Pekka Verta ◽  
Paul Vincent Debes ◽  
Nikolai Piavchenko ◽  
Annukka Ruokolainen ◽  
Outi Ovaskainen ◽  
...  
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
Life Histories ◽  
Life History Traits ◽  
Life History Strategies ◽  
Life History Trait ◽  
Gene Transcript ◽  
Genome Wide Association Studies ◽  
Age At Maturity ◽  
Life History Variation

AbstractA major goal in biology is to understand how evolution shapes variation in individual life histories. Genome-wide association studies have been successful in uncovering genome regions linked with traits underlying life history variation in a range of species. However, lack of functional studies of the discovered genotype-phenotype associations severely restrains our understanding how alternative life history traits evolved and are mediated at the molecular level. Here, we report a cis-regulatory mechanism whereby expression of alternative isoforms of the transcription co-factor vestigial-like 3 (vgll3) associate with variation in a key life history trait, age at maturity, in Atlantic salmon (Salmo salar). Using a common-garden experiment, we first show that vgll3 genotype associates with puberty timing in one-year-old salmon males. By way of temporal sampling of vgll3 expression in ten tissues across the first year of salmon development, we identify a pubertal transition in vgll3 expression where maturation coincided with a 66% reduction in testicular vgll3 expression. The late maturation allele was not only associated with a tendency to delay puberty, but also with expression of a rare transcript isoform of vgll3 pre-puberty. By comparing absolute vgll3 mRNA copies in heterozygotes we show that the expression difference between the early and late maturity alleles is largely cis-regulatory. We propose a model whereby expression of a rare isoform from the late allele shifts the liability of its carriers towards delaying puberty. These results reveal how regulatory differences can be a central mechanism for the evolution of life history traits.Author summaryAlternative life history strategies are an important source of diversity within populations and promote the maintenance of adaptive capacity and population resilience. However, in many cases the molecular basis of different life history strategies remains elusive. Age at maturity is a key adaptive life history trait in Atlantic salmon and has a relatively simple genetic basis. Using salmon age at maturity as a model, we report a mechanism whereby different transcript isoforms of the key age at maturity gene, vestigial-like 3 (vgll3), associate with variation in the timing of male puberty. Our results show how gene regulatory differences in conjunction with variation in gene transcript structure can encode for complex alternative life histories.

scholarly journals Organophosphate Poisoning of Atlantic Salmon in Connection with Treatment against Salmon Lice

1989 ◽  
Vol 30 (4) ◽  
pp. 385-390
Author(s):  
Tor Einar Horsberg ◽  
Tonje Høy ◽  
Inger Nafstad
Keyword(s):  
Atlantic Salmon ◽  
Organophosphate Poisoning ◽  
Salmon Lice

Postsmolt Atlantic Salmon (Salmo salar) in the Labrador Sea

1991 ◽  
Vol 48 (1) ◽  
pp. 2-6 ◽  
Author(s):  
D. G. Reddin ◽  
P. B. Short
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Age Distribution ◽  
Labrador Sea ◽  
Scale Reading ◽  
Gill Nets ◽  
Atlantic Salmon Salmo Salar ◽  
Catch Rates ◽  
Abundance And Distribution ◽  
High Catch

In order to learn more about the existence, abundance, and distribution of postsmolt Atlantic salmon (Salmo salar) in the Labrador Sea, exploratory fishing was done with surface-set gill nets in early autumn of 1987 and 1988. In total, there were 468 salmon of various sea ages captured, of which 207 were postsmolts. The high catch rates compared with catch rates from Greenland suggest that the population of postsmolts in the Labrador Sea may be large. Postsmolts from rivers in Maine to Labrador were caught in the Labrador Sea, as indicated by Carlin tags and river age distribution from scale reading. The highest catch rates of postsmolts occurred in the Labrador Sea between 56° and 58°N latitude.

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