scholarly journals The effects of oxygen depletion due to upwelling groundwater on the posthatch fitness of Atlantic salmon (Salmo salar)

2016 ◽  
Vol 73 (12) ◽  
pp. 1830-1840 ◽  
Author(s):  
Jack Bloomer ◽  
David Sear ◽  
Peter Dutey-Magni ◽  
Paul Kemp
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Oxygen Depletion ◽  
Hyporheic Exchange ◽  
Fine Scale ◽  
Review Of The Literature ◽  
Low Oxygen ◽  
Atlantic Salmon Salmo Salar ◽  
Effect Of Oxygen ◽  
Scale Control

The conditions experienced by incubating Atlantic salmon (Salmo salar) eggs are strongly influenced by hyporheic exchange. In some rivers, periods of intense groundwater upwelling can reduce oxygen levels in the incubation zone to 0% saturation. The present study investigated the effect of oxygen sags on the posthatch fitness of Atlantic salmon. A laboratory experiment allowed fine-scale control of oxygen concentrations to replicate those induced by low oxygen groundwater in rivers. Extreme oxygen sags in the earlier stages of embryo development resulted in a developmental lag with alevin hatching later and at an underdeveloped state. At the latest stages of development, oxygen sags caused premature hatching of severely underdeveloped alevin. These findings combined with a review of the literature suggest posthatch survival of embryos exposed to groundwater-induced hypoxia will be lower because of predation and poor competitiveness.

scholarly journals Low Oxygen Stress During Early Development Influences Regulation of Hypoxia-Response Genes in Farmed Atlantic Salmon (Salmo salar)

2020 ◽  
Vol 10 (9) ◽  
pp. 3179-3188
Author(s):  
Tara Kelly ◽  
Hanne Johnsen ◽  
Erik Burgerhout ◽  
Helge Tveiten ◽  
Tina Thesslund ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Early Development ◽  
Salmo Salar ◽  
Hypoxia Inducible Factor ◽  
Low Oxygen ◽  
Hypoxia Response ◽  
Oxygen Levels ◽  
Atlantic Salmon Salmo Salar ◽  
Natural Streams ◽  
Farmed Atlantic Salmon

Abstract Survival and growth of developing salmonids are negatively affected by low oxygen levels within gravel nests in natural streams, and hypoxic stress is often experienced by farmed Atlantic salmon (Salmo salar) within hatcheries. Exposure to hypoxia during early development may have long-lasting effects by altering epigenetic marks and gene expression in oxygen regulatory pathways. Here, we examine the transcriptomic response to low dissolved oxygen (DO) in post-hatch salmon reared continuously in 30%, 60% or 100% DO from fertilization until start of feeding. RNA sequencing revealed multiple differentially expressed genes, including oxygen transporting hemoglobin embryonic α subunit (hbae) and EGLN3 family hypoxia-inducible factor 3 (egln3) which regulates the stability of hypoxia inducible factor 1α (HIF-1α). Both hbae and egln3 displayed expression levels inversely correlated to oxygen concentration, and DNA methylation patterns within the egln3 promoter were negatively associated with the transcript levels. These results suggest that epigenetic processes are influenced by low oxygen levels during early development in Atlantic salmon to upregulate hypoxia-response genes.

Role of Olfaction in the Behavioral and Neuronal Responses of Atlantic Salmon, Salmo salar, to Hydrographic Stratification

1985 ◽  
Vol 42 (10) ◽  
pp. 1658-1667 ◽  
Author(s):  
Kjell B. Døving ◽  
Håkan Westerberg ◽  
Peter B. Johnsen
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Water Samples ◽  
Olfactory Nerve ◽  
Control Fish ◽  
Fine Scale ◽  
Vertical Movements ◽  
Atlantic Salmon Salmo Salar ◽  
Hydrographic Features ◽  
Ultrasonic Tracking

The behavior of sham-operated and anosmic Atlantic salmon, Salmo salar, was studied in a fjord system with close reference to the fine-scale hydrographic features. Control fish made small-amplitude vertical movements, with sudden large-amplitude excursions. The anosmic fish made large continuous searches up and down in the water column, descended below the sill depth of the fjord, and followed the bottom contours. None of these three behaviors was seen in the control fish. The trauma caused by the surgical incision did not prevent the fish from active swimming, and a fish with unilateral sectioning of the olfactory nerve returned to the river of release. Activity of single olfactory bulb neurons was recorded during stimulation of salmon olfactory epithelium with water samples taken from different depths of the fjord. These water samples had been taken from regions that showed layering and to which migrating salmon demonstrated behavioral preferences in ultrasonic tracking experiments. Ninety percent of responding neurons showed differencial responses to the water samples, indicating the capacity of the olfactory system to discriminate among stratified water layers found in the ocean. We conclude that olfactory discrimination of fine-scale hydrographic features may provide a necessary reference system for successful orientation in nearshore regions by salmon.

A new method to estimate habitat potential for Atlantic salmon (Salmo salar): predicting the influence of dam removal on the Sélune River (France) as a case study

2018 ◽  
Vol 75 (6) ◽  
pp. 2172-2181
Author(s):  
Guillaume Forget ◽  
Jean-Luc Baglinière ◽  
Frédéric Marchand ◽  
Arnaud Richard ◽  
Marie Nevoux
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Cost Effective ◽  
Dam Removal ◽  
Juvenile Salmon ◽  
Suitable Habitat ◽  
Fine Scale ◽  
Atlantic Salmon Salmo Salar

Abstract Maintaining connectivity in aquatic ecosystems is important to ensure adequate ecological functioning. A large dam removal project in the Sélune River (Normandy, France) would reconnect 827 km2 of catchment area to the sea. Only the downstream section of the Selune is currently available to diadromous fish, which migrate between freshwater and the marine environment. In particular, managers focus on the future potential abundance of Atlantic salmon, Salmo salar, for conservation and fishery purposes. As in stream channel habitat drives carrying capacity of juvenile salmon, salmon abundance is usually inferred from intensive and linear habitat surveys. However, this approach is neither cost-effective for large-scale surveys nor feasible for riverbed sections with low accessibility for measurement with traditional methods, e.g. dam lakes. We used well-defined relationships between gradient, hydrology and channel habitat structure to construct a simple model to estimate potential suitable habitat for juvenile salmon. Using fine-scale habitat data from nearby rivers, we parameterized a linear mixed model to estimate the area of suitable habitat based on simple physical descriptors of river characteristics. We compared our predictions to fine-scale habitat surveys on the upper Sélune. Using only slope and width, our model was able to explain 80% of the variance in suitable habitat. Estimates indicated that dam removal on the Sélune River would generate a threefold increase in suitable habitat for juveniles. This could increase the mean number of adult salmon returning to the river by 1420.9 (s.e. = 1015.5). More generally, this model provides an alternative and cost-effective tool to help better manage salmon populations in rivers impacted by dams.

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.

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