Passing a seawater challenge test is not indicative of hatchery‐reared Atlantic salmon <i>Salmo salar</i> smolts performing as well at sea as their naturally produced conspecifics

Jensen, Arne J.; Berg, Marius; Bremset, Gunnbjørn; Finstad, Bengt; Hvidsten, Nils Arne; Jensås, Jan Gunnar; Johnsen, Bjørn Ove; Lund, Egil

doi:10.1111/jfb.12984

Cited by 7 publications

(6 citation statements)

References 94 publications

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“…To compensate for reduced juvenile production, River Eira has, since 1967, been stocked annually with ∼50,000 2-y-old hatchery-produced Atlantic salmon smolts of local origin ( 35 ). A smaller number of smolts were released in the years 1959–1966, these numbers being 1,065, 8,520, 4,181, 10,778, 11,194, 6,003, 5,507, and 39,180 smolts, respectively.…”

Section: Methodsmentioning

confidence: 99%

Large-effect loci mediate rapid adaptation of salmon body size after river regulation

Jensen

Hagen

Czorlich

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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Understanding the potential of natural populations to adapt to altered environments is becoming increasingly relevant in evolutionary research. Currently, our understanding of adaptation to human alteration of the environment is hampered by lack of knowledge on the genetic basis of traits, lack of time series, and little or no information on changes in optimal trait values. Here, we used time series data spanning nearly a century to investigate how the body mass of Atlantic salmon ( Salmo salar ) adapts to river regulation. We found that the change in body mass followed the change in waterflow, both decreasing to ∼1/3 of their original values. Allele frequency changes at two loci in the regions of vgll3 and six6 predicted more than 80% of the observed body mass reduction. Modeling the adaptive dynamics revealed that the population mean lagged behind its optimum before catching up approximately six salmon generations after the initial waterflow reduction. Our results demonstrate rapid adaptation mediated by large-effect loci and provide insight into the temporal dynamics of evolutionary rescue following human disturbance.

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Section: Methodsmentioning

confidence: 99%

Large-effect loci mediate rapid adaptation of salmon body size after river regulation

Jensen

Hagen

Czorlich

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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“…The marine part of the life cycle is dangerous, and mortality is generally high for Atlantic salmon (Chaput, 2012; Jonsson & Jonsson, 2004). Stocking of hatchery‐reared fish to supplement natural populations is common, and it has been documented that such hatchery‐reared fish usually have lower ocean survival than wild fish (Jensen et al ., 2016; Jonsson et al ., 2003). This is observed despite that growth often is considerably enhanced in hatcheries leading to larger size at age, and individual size is assumed to positively affect survival (Sogard, 1997).…”

Section: Introductionmentioning

confidence: 99%

Frequency of vateritic otoliths and potential consequences for marine survival in hatchery‐reared Atlantic salmon

Austad

Vøllestad

Foldvik

2021

Journal of Fish Biology

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Otoliths are inner-ear structures of all teleost fish with functional importance for hearing and balance. The otoliths usually consist of aragonite, a polymorph of calcium carbonate, but may also take the form partly or entirely of vaterite, a different polymorph of calcium carbonate. Vateritic otoliths occur sporadically in wild fish, but with a higher frequency in hatchery-reared fish. Abnormal otoliths have direct consequences for the inner-ear functions of fish and may be a symptom of environmental stress. In this study, the authors assess the differences in the frequency of abnormal otoliths and degree of abnormality (% vaterite) for different groups of hatchery-reared Atlantic salmon (Salmo salar) smolt and adults. The groups differed in parental broodstock origin (number of generations in hatchery) and treatment temperature. Smolt from the same groups were also released to complete their ocean migration. The otoliths of the returning and recaptured adults were subsequently extracted to assess the difference in frequency and degree of abnormality between the adults and the smolt from corresponding groups.Return rate varied among groups (0.2%-2.6%). The frequency of vateritic otoliths was high (11.4%-64.4%) and differed among smolt groups. The lowest return rates corresponded with the highest frequency of abnormal otoliths for the groups, suggesting that abnormal otoliths may have negative consequences for marine survival. Furthermore, indications of an effect of fast growth on the formation of abnormal otoliths were found for only one of the experimental groups, and for none of the groups after correcting for Type 1 error. This contradicts previous reports, suggesting rapid growth as the main cause of abnormal otoliths. Adult return rates were generally low, but abnormal otoliths were common, with high coverage (% vaterite).

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“…Understanding the factors for which hatchery reared salmon exhibit altered performance compared to wild salmon including faster growth rates, lower age to maturity, higher overall survival, lowered lifetime reproductive success, and increased aggression including competitiveness, may be important for improved ocean enhancement. (7–9).…”

Section: Introductionmentioning

confidence: 99%

Microbial ecology of Atlantic salmon, Salmo salar, hatcheries: impacts of the built environment on fish mucosal microbiota

Minich

Jantawongsri

Johnston³

et al. 2019

Preprint

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ABSTRACTSuccessful rearing of fish in hatcheries is critical for conservation, recreational fishing, and commercial fishing through wild stock enhancements, and aquaculture production. Flow through (FT) hatcheries require more water than Recirculating-Aquaculture-Systems (RAS) which enable up to 99% of water to be recycled thus significantly reducing environmental impacts. Here, we evaluated the biological and physical microbiome interactions of the built environment of a hatchery from three Atl salmon hatcheries (RAS n=2, FT n=1). Six juvenile fish were sampled from tanks in each of the hatcheries for a total of 60 fish across 10 tanks. Water and tank side biofilm samples were collected from each of the tanks along with three salmon body sites (gill, skin, and digesta) to assess mucosal microbiota using 16S rRNA sequencing. The water and tank biofilm had more microbial richness than fish mucus while skin and digesta from RAS fish had 2× the richness of FT fish. Body sites each had unique microbial communities (P<0.001) and were influenced by the various hatchery systems (P<0.001) with RAS systems more similar. Water and especially tank biofilm richness was positively correlated with skin and digesta richness. Strikingly, the gill, skin and digesta communities were more similar to the origin tank biofilm vs. all other experimental tanks suggesting that the tank biofilm has a direct influence on fish-associated microbial communities. The results from this study provide evidence for a link between the tank microbiome and the fish microbiome with the skin microbiome as an important intermediate.IMPORTANCEAtlantic salmon, Salmo salar, is the most farmed marine fish worldwide with an annual production of 2,248 million metric tonnes in 2016. Salmon hatcheries are increasingly changing from flow through towards RAS design to accommodate more control over production along with improved environmental sustainability due to lower impacts on water consumption. To date, microbiome studies on hatcheries have focused either on the fish mucosal microbiota or the built environment microbiota, but have not combined the two to understand interactions. Our study evaluates how water and tank biofilm microbiota influences fish microbiota across three mucosal environments (gill, skin, and digesta). Results from this study highlight how the built environment is a unique source of microbes to colonize fish mucus and furthermore how this can influence the fish health. Further studies can use this knowledge to engineer built environments to modulate fish microbiota for a beneficial phenotype.

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Passing a seawater challenge test is not indicative of hatchery‐reared Atlantic salmon Salmo salar smolts performing as well at sea as their naturally produced conspecifics

Cited by 7 publications

References 94 publications

Large-effect loci mediate rapid adaptation of salmon body size after river regulation

Large-effect loci mediate rapid adaptation of salmon body size after river regulation

Frequency of vateritic otoliths and potential consequences for marine survival in hatchery‐reared Atlantic salmon

Microbial ecology of Atlantic salmon, Salmo salar, hatcheries: impacts of the built environment on fish mucosal microbiota

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