Liming restores Atlantic salmon (Salmo salar) populations in acidified Norwegian rivers

2011 ◽  
Vol 68 (2) ◽  
pp. 224-231 ◽  
Author(s):  
Trygve Hesthagen ◽  
Bjørn M. Larsen ◽  
Peder Fiske
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Age Group ◽  
Total Catch ◽  
Atlantic Salmon Salmo Salar ◽  
Rate Of Increase ◽  
Native Populations

Acidification has exterminated or seriously reduced Atlantic salmon ( Salmo salar ) populations in 40–45 Norwegian rivers. As this problem still exists, liming to restore salmon has been necessary, which now involves 21 of these rivers. Thirteen rivers were electrofished 1 year before liming and again 1–12 years later. There was a significant effect both of time after liming and status (e.g., formerly lost and reduced stocks) on the densities of both fry (age 0+) and parr (age ≥ 1+). However, the rate of increase in densities of young salmon in these two status categories was not significantly different in either age group. The development in parr densities suggests that more than 20 years of liming is required to restore salmon in rivers with lost native populations. Stocked rivers and rivers unaltered by hydropower developments generally had higher fry densities and faster increase in parr densities. Annual rod catches of adult salmon increased significantly after liming started, reaching about 45 t after 10 years of treatment. This is 11%–12% of the current total catch of Atlantic salmon in all Norwegian rivers. Liming thus makes an important contribution to the restoration of salmon in formerly acidified rivers.

Cardiac Responses to a Natural Odorant as Evidence of a Sensitive Period for Olfactory Imprinting in Young Atlantic Salmon, Salmo salar

1989 ◽  
Vol 46 (1) ◽  
pp. 122-130 ◽  
Author(s):  
Pierre-Philippe Morin ◽  
Julian J. Dodson ◽  
François Y. Doré
Keyword(s):  
Heart Rate ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Age Groups ◽  
Sensitive Period ◽  
Age Group ◽  
Olfactory Recognition ◽  
Atlantic Salmon Salmo Salar ◽  
Cardiac Responses ◽  
Olfactory Imprinting

Olfactory imprinting was assessed in young Atlantic salmon, Salmo salar, undergoing smoltification (parr–smolt transition) by measuring their cardiac responses to a natural odorant, L-cysteine. Condition factor and body coloration were used for characterizing the degree of smoltification. In Experiment 1, heart rate conditioning to L-cysteine was used to compare olfactory learning between fish from different age groups of smoltification. In Experiments 2 and 3, other fish from the same age groups of smoltification were exposed to L-cysteine and their long-term olfactory memory was assessed by measuring their unconditioned cardiac responses to L-cysteine after smoltification. In Experiment 2, the time from the end of odor exposure to testing for olfactory recognition was kept constant for ail age groups of smoltification whereas in Experiment 3, the age of fish tested for olfactory recognition was kept constant. Greater conditioning (heart rate reduction) to L-cysteine occurred in age-groups 3 (612–619 d since birth) and 6 (642–649 d) as compared with any other age group of smoltification. Fish tested for odor recognition exhibited a greater unconditioned response (cardiac deceleration) to L-cysteine if they belonged to age-group 3 than to any other age group of smoltification. Our results demonstrated the existence of a sensitive period for olfactory imprinting in Atlantic salmon that occurred between 21 and 28 d after the onset of smoltification induced in the laboratory.

Microstructure and texture of fresh and smoked Atlantic salmon, Salmo salar L., fillets from fish reared and slaughtered under different conditions

2001 ◽  
Vol 32 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Sjofn Sigurgisladottir ◽  
Margret S. Sigurdardottir ◽  
Helga Ingvarsdottir ◽  
Ole J. Torrissen ◽  
Hannes Hafsteinsson
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Atlantic Salmon Salmo Salar

Persistence of Orally Administered Salmonella enterica Serovars Agona and Montevideo in Atlantic Salmon (Salmo salar L.)

2005 ◽  
Vol 68 (7) ◽  
pp. 1336-1339 ◽  
Author(s):  
L. L. NESSE ◽  
T. LØVOLD ◽  
B. BERGSJØ ◽  
K. NORDBY ◽  
C. WALLACE ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Salmonella Enterica ◽  
Most Probable Number ◽  
Fish Feed ◽  
Internal Organs ◽  
Probable Number ◽  
Atlantic Salmon Salmo Salar ◽  
Gastric Intubation

The objective of our experiments was to study the persistence and dissemination of orally administered Salmonella in smoltified Atlantic salmon. In experiment 1, salmon kept at 15°C were fed for 1 week with feed contaminated with 96 most-probable-number units of Salmonella Agona per 100 g of feed and then starved for 2 weeks. Samples were taken from the gastrointestinal tract and examined for Salmonella 1, 2, 8, 9, 15, and 16 days after the feeding ended. In experiment 2, Salmonella Agona and Montevideo were separately mixed with feed and administered by gastric intubation. Each fish received 1.0 × 108, 1.0 × 106, or 1.0 × 104 CFU. The different groups were kept in parallel at 5 and 15°C and observed for 4 weeks. Every week, three fish in each group were sacrificed, and samples were taken from the skin, the pooled internal organs, the muscle, and the gastrointestinal tract and examined for the presence of Salmonella. The results from the two experiments showed that the persistence of Salmonella in the fish was highly dependent on the dose administered. Salmonella was not recovered from any of the fish that were fed for 1 week with the lowest concentration of Salmonella. In the fish given the highest dose of Salmonella, bacteria persisted for at least 4 weeks in the gastrointestinal tract as well as, to some extent, the internal organs. The present study shows that under practical conditions in Norway, the risk of Salmonella in fish feed being passed on to the consumer of the fish is negligible.

scholarly journals The Analysis of Live-Attenuated Piscirickettsia salmonis Vaccine Reveals the Short-Term Upregulation of Innate and Adaptive Immune Genes in Atlantic Salmon (Salmo salar): An In Situ Open-Sea Cages Study

2021 ◽  
Vol 9 (4) ◽  
pp. 703
Author(s):  
Deborah Vargas ◽  
Eva Vallejos-Vidal ◽  
Sebastián Reyes-Cerpa ◽  
Aarón Oyarzún-Arrau ◽  
Claudio Acuña-Castillo ◽  
...  
Keyword(s):  
Immune Response ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Cellular Response ◽  
Short Term ◽  
Live Attenuated Vaccine ◽  
Gene Markers ◽  
Post Vaccination ◽  
Atlantic Salmon Salmo Salar ◽  
Piscirickettsia Salmonis

Piscirickettsia salmonis, the etiological agent of the Salmon Rickettsial Septicemia (SRS), is one the most serious health problems for the Chilean salmon industry. Typical antimicrobial strategies used against P. salmonis include antibiotics and vaccines, but these applications have largely failed. A few years ago, the first attenuated-live vaccine against SRS (ALPHA JECT LiVac® SRS vaccine) was released to the market. However, there is no data about the agents involved in the activation of the immune response induced under field conditions. Therefore, in this study we evaluated the expression profile of a set of gene markers related to innate and adaptive immunity in the context of a cellular response in Atlantic salmon (Salmo salar) reared under productive farm conditions and immunized with a live-attenuated vaccine against P. salmonis. We analyzed the expression at zero, 5-, 15- and 45-days post-vaccination (dpv). Our results reveal that the administration of the attenuated live SRS LiVac vaccine induces a short-term upregulation of the cellular-mediated immune response at 5 dpv modulated by the upregulation of ifnα, ifnγ, and the cd4 and cd8α T cell surface markers. In addition, we also registered the upregulation of il-10 and tgfβ. Altogether, the results suggest that a balanced activation of the immune response took place only at early times post-vaccination (5 dpv). The scope of this short-term upregulation of the cellular-mediated immune response against a natural outbreak in fish subjected to productive farm conditions deserves further research.

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